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* remove task and stack pointer printout from oops dumpLinus Torvalds2017-12-051-3/+0
| | | | | | | | | | | | | Geert Uytterhoeven reported a NFS oops, and pointed out that some of the numbers were hashed and useless. We could just turn them from '%p' into '%px', but those numbers are really just legacy, and useless even when not hashed. So just remove them entirely. Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2017-11-212-2/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk Pull printk updates from Petr Mladek: - print the warning about dropped messages on consoles on a separate line. It makes it more legible. - one typo fix and small code clean up. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: added new line symbol after warning about dropped messages printk: fix typo in printk_safe.c printk: simplify no_printk()
| * added new line symbol after warning about dropped messagesMaxim Akristiniy2017-10-301-1/+1
| | | | | | | | | | | | | | | | | | so this message will not mess with the next one Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Maxim Akristiniy <maksim.akristiniy@yotadevices.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk: fix typo in printk_safe.cBaoquan He2017-10-301-1/+1
| | | | | | | | | | | | | | | | | | Link: http://lkml.kernel.org/r/1508682655-27293-1-git-send-email-bhe@redhat.com Cc: rostedt@goodmis.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
* | Merge tag 'trace-v4.15' of ↵Linus Torvalds2017-11-171-7/+8
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from - allow module init functions to be traced - clean up some unused or not used by config events (saves space) - clean up of trace histogram code - add support for preempt and interrupt enabled/disable events - other various clean ups * tag 'trace-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (30 commits) tracing, thermal: Hide cpu cooling trace events when not in use tracing, thermal: Hide devfreq trace events when not in use ftrace: Kill FTRACE_OPS_FL_PER_CPU perf/ftrace: Small cleanup perf/ftrace: Fix function trace events perf/ftrace: Revert ("perf/ftrace: Fix double traces of perf on ftrace:function") tracing, dma-buf: Remove unused trace event dma_fence_annotate_wait_on tracing, memcg, vmscan: Hide trace events when not in use tracing/xen: Hide events that are not used when X86_PAE is not defined tracing: mark trace_test_buffer as __maybe_unused printk: Remove superfluous memory barriers from printk_safe ftrace: Clear hashes of stale ips of init memory tracing: Add support for preempt and irq enable/disable events tracing: Prepare to add preempt and irq trace events ftrace/kallsyms: Have /proc/kallsyms show saved mod init functions ftrace: Add freeing algorithm to free ftrace_mod_maps ftrace: Save module init functions kallsyms symbols for tracing ftrace: Allow module init functions to be traced ftrace: Add a ftrace_free_mem() function for modules to use tracing: Reimplement log2 ...
| * | printk: Remove superfluous memory barriers from printk_safeSteven Rostedt (VMware)2017-10-131-7/+8
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The variable printk_safe_irq_ready is set and never cleared at system boot up, when there's only one CPU active. It is set before other CPUs come on line. Also, it is extremely unlikely that an NMI would trigger this early in boot up (which I wonder why we even have this variable at all). Also mark the printk_safe_irq_ready as read mostly, as it is set at system boot up, and never touched again. Link: http://lkml.kernel.org/r/20171011124647.7781f98f@gandalf.local.home Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* / License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-023-0/+3
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2017-09-081-37/+32
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk Pull printk updates from Petr Mladek: - Do not allow use of freed init data and code even when boot consoles are forced to stay. Also check for the init memory more precisely. - Some code clean up by starting contributors. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: printk: Clean up do_syslog() error handling printk/console: Enhance the check for consoles using init memory printk/console: Always disable boot consoles that use init memory before it is freed printk: Modify operators of printed_len and text_len
| * printk: Clean up do_syslog() error handlingNikitas Angelinas2017-08-151-23/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The error variable in do_syslog() is preemptively set to the error code before the error condition is checked, and then set to 0 if the error condition is not encountered. This is not necessary, as it is likely simpler to return immediately upon encountering the error condition. A redundant set of the error variable to 0 is also removed. This patch has been build-tested on x86_64, but not tested for functionality. Link: http://lkml.kernel.org/r/20170730033636.GA935@vostro Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Nikitas Angelinas <nikitas.angelinas@gmail.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk/console: Enhance the check for consoles using init memoryPetr Mladek2017-07-271-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | printk_late_init() is responsible for disabling boot consoles that use init memory. It checks the address of struct console for this. But this is not enough. For example, there are several early consoles that have write() method in the init section and struct console in the normal section. They are not disabled and could cause fancy and hard to debug system states. It is even more complicated by the macros EARLYCON_DECLARE() and OF_EARLYCON_DECLARE() where various struct members are set at runtime by the provided setup() function. I have tried to reproduce this problem and forced the classic uart early console to stay using keep_bootcon parameter. In particular I used earlycon=uart,io,0x3f8 keep_bootcon console=ttyS0,115200. The system did not boot: [ 1.570496] PM: Image not found (code -22) [ 1.570496] PM: Image not found (code -22) [ 1.571886] PM: Hibernation image not present or could not be loaded. [ 1.571886] PM: Hibernation image not present or could not be loaded. [ 1.576407] Freeing unused kernel memory: 2528K [ 1.577244] kernel tried to execute NX-protected page - exploit attempt? (uid: 0) The double lines are caused by having both early uart console and ttyS0 console enabled at the same time. The early console stopped working when the init memory was freed. Fortunately, the invalid call was caught by the NX-protexted page check and did not cause any silent fancy problems. This patch adds a check for many other addresses stored in struct console. It omits setup() and match() that are used only when the console is registered. Therefore they have already been used at this point and there is no reason to use them again. Link: http://lkml.kernel.org/r/1500036673-7122-3-git-send-email-pmladek@suse.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Matt Redfearn <matt.redfearn@imgtec.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Cc: "Fabio M. Di Nitto" <fdinitto@redhat.com> Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk/console: Always disable boot consoles that use init memory before it ↵Matt Redfearn2017-07-271-11/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | is freed Commit 4c30c6f566c0 ("kernel/printk: do not turn off bootconsole in printk_late_init() if keep_bootcon") added a check on keep_bootcon to ensure that boot consoles were kept around until the real console is registered. This can lead to problems if the boot console data and code are in the init section, since it can be freed before the boot console is unregistered. Commit 81cc26f2bd11 ("printk: only unregister boot consoles when necessary") fixed this a better way. It allowed to keep boot consoles that did not use init data. Unfortunately it did not remove the check of keep_bootcon. This can lead to crashes and weird panics when the bootconsole is accessed after free, especially if page poisoning is in use and the code / data have been overwritten with a poison value. To prevent this, always free the boot console if it is within the init section. In addition, print a warning about that the console is removed prematurely. Finally there is a new comment how to avoid the warning. It replaced an explanation that duplicated a more comprehensive function description few lines above. Fixes: 4c30c6f566c0 ("kernel/printk: do not turn off bootconsole in printk_late_init() if keep_bootcon") Link: http://lkml.kernel.org/r/1500036673-7122-2-git-send-email-pmladek@suse.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Cc: "Fabio M. Di Nitto" <fdinitto@redhat.com> Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com> [pmladek@suse.com: print the warning, code and comments clean up] Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk: Modify operators of printed_len and text_lenPierre Kuo2017-07-271-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With commit <ddb9baa82226> ("printk: report lost messages in printk safe/nmi contexts") and commit <8b1742c9c207> ("printk: remove zap_locks() function"), it seems we can remove initialization, "=0", of text_len and directly assign result of log_output to printed_len. Link: http://lkml.kernel.org/r/1499755255-6258-1-git-send-email-vichy.kuo@gmail.com Cc: rostedt@goodmis.org Cc: linux-kernel@vger.kernel.org Cc: joe@perches.com Signed-off-by: Pierre Kuo <vichy.kuo@gmail.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
* | Revert "pstore: Honor dmesg_restrict sysctl on dmesg dumps"Kees Cook2017-08-181-2/+1
|/ | | | | | | | | | | | | | | | | | | | | This reverts commit 68c4a4f8abc60c9440ede9cd123d48b78325f7a3, with various conflict clean-ups. The capability check required too much privilege compared to simple DAC controls. A system builder was forced to have crash handler processes run with CAP_SYSLOG which would give it the ability to read (and wipe) the _current_ dmesg, which is much more access than being given access only to the historical log stored in pstorefs. With the prior commit to make the root directory 0750, the files are protected by default but a system builder can now opt to give access to a specific group (via chgrp on the pstorefs root directory) without being forced to also give away CAP_SYSLOG. Suggested-by: Nick Kralevich <nnk@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Petr Mladek <pmladek@suse.cz> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
* Merge branch 'for-linus' of ↵Linus Torvalds2017-07-053-14/+47
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk Pull printk updates from Petr Mladek: - Store printk() messages into the main log buffer directly even in NMI when the lock is available. It is the best effort to print even large chunk of text. It is handy, for example, when all ftrace messages are printed during the system panic in NMI. - Add missing annotations to calm down compiler warnings * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: printk: add __printf attributes to internal functions printk: Use the main logbuf in NMI when logbuf_lock is available
| * Merge branch 'for-4.13' into for-linusPetr Mladek2017-07-033-14/+47
| |\
| | * printk: add __printf attributes to internal functionsNicolas Iooss2017-06-131-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When compiling with -Wsuggest-attribute=format, gcc complains that some functions in kernel/printk/printk_safe.c transmit their argument to printf-like functions without having a printf attribute. Silence these warnings by adding relevant __printf attributes. Link: http://lkml.kernel.org/r/20170524054950.6722-1-nicolas.iooss_linux@m4x.org Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| | * printk: Use the main logbuf in NMI when logbuf_lock is availablePetr Mladek2017-05-193-9/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The commit 42a0bb3f71383b457a7d ("printk/nmi: generic solution for safe printk in NMI") caused that printk stores messages into a temporary buffer in NMI context. The buffer is per-CPU and therefore the size is rather limited. It works quite well for NMI backtraces. But there are longer logs that might get printed in NMI context, for example, lockdep warnings, ftrace_dump_on_oops. The temporary buffer is used to avoid deadlocks caused by logbuf_lock. Also it is needed to avoid races with the other temporary buffer that is used when PRINTK_SAFE_CONTEXT is entered. But the main buffer can be used in NMI if the lock is available and we did not interrupt PRINTK_SAFE_CONTEXT. The lock is checked using raw_spin_is_locked(). It might cause false negatives when the lock is taken on another CPU and this CPU is in the safe context from other reasons. Note that the safe context is used also to get console semaphore or when calling console drivers. For this reason, we do the check in printk_nmi_enter(). It makes the handling consistent for the entire NMI handler and avoids reshuffling of the messages. The patch also defines special printk context that allows to use printk_deferred() in NMI. Note that we could not flush the messages to the consoles because console drivers might use many other internal locks. The newly created vprintk_deferred() disables the preemption only around the irq work handling. It is needed there to keep the consistency between the two per-CPU variables. But there is no reason to disable preemption around vprintk_emit(). Finally, the patch puts back explicit serialization of the NMI backtraces from different CPUs. It was removed by the commit a9edc88093287183ac934b ("x86/nmi: Perform a safe NMI stack trace on all CPUs"). It was not needed because the flushing of the temporary per-CPU buffers was serialized. Link: http://lkml.kernel.org/r/1493912763-24873-1-git-send-email-pmladek@suse.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <rack+kernel@arm.linux.org.uk> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: x86@kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
* | | Merge branch 'WIP.sched/core' into sched/coreIngo Molnar2017-06-201-36/+10
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: kernel/sched/Makefile Pick up the waitqueue related renames - it didn't get much feedback, so it appears to be uncontroversial. Famous last words? ;-) Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | Merge branch 'for-linus' of ↵Linus Torvalds2017-06-081-36/+10
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk Pull printk fix from Petr Mladek: "This reverts a fix added into 4.12-rc1. It caused the kernel log to be printed on another console when two consoles of the same type were defined, e.g. console=ttyS0 console=ttyS1. This configuration was never supported by kernel itself, but it started to make sense with systemd. In other words, the commit broke userspace" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: Revert "printk: fix double printing with earlycon"
| | * | Revert "printk: fix double printing with earlycon"Petr Mladek2017-06-081-36/+10
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit cf39bf58afdaabc0b86f141630fb3fd18190294e. The commit regression to users that define both console=ttyS1 and console=ttyS0 on the command line, see https://lkml.kernel.org/r/20170509082915.GA13236@bistromath.localdomain The kernel log messages always appeared only on one serial port. It is even documented in Documentation/admin-guide/serial-console.rst: "Note that you can only define one console per device type (serial, video)." The above mentioned commit changed the order in which the command line parameters are searched. As a result, the kernel log messages go to the last mentioned ttyS* instead of the first one. We long thought that using two console=ttyS* on the command line did not make sense. But then we realized that console= parameters were handled also by systemd, see http://0pointer.de/blog/projects/serial-console.html "By default systemd will instantiate one serial-getty@.service on the main kernel console, if it is not a virtual terminal." where "[4] If multiple kernel consoles are used simultaneously, the main console is the one listed first in /sys/class/tty/console/active, which is the last one listed on the kernel command line." This puts the original report into another light. The system is running in qemu. The first serial port is used to store the messages into a file. The second one is used to login to the system via a socket. It depends on systemd and the historic kernel behavior. By other words, systemd causes that it makes sense to define both console=ttyS1 console=ttyS0 on the command line. The kernel fix caused regression related to userspace (systemd) and need to be reverted. In addition, it went out that the fix helped only partially. The messages still were duplicated when the boot console was removed early by late_initcall(printk_late_init). Then the entire log was replayed when the same console was registered as a normal one. Link: 20170606160339.GC7604@pathway.suse.cz Cc: Aleksey Makarov <aleksey.makarov@linaro.org> Cc: Sabrina Dubroca <sd@queasysnail.net> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Jiri Slaby <jslaby@suse.com> Cc: Robin Murphy <robin.murphy@arm.com>, Cc: Steven Rostedt <rostedt@goodmis.org> Cc: "Nair, Jayachandran" <Jayachandran.Nair@cavium.com> Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reported-by: Sabrina Dubroca <sd@queasysnail.net> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
* | / printk: Adjust system_state checksThomas Gleixner2017-05-231-1/+1
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To enable smp_processor_id() and might_sleep() debug checks earlier, it's required to add system states between SYSTEM_BOOTING and SYSTEM_RUNNING. Adjust the system_state check in boot_delay_msec() to handle the extra states. Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20170516184736.027534895@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | Merge tag 'tty-4.12-rc1' of ↵Linus Torvalds2017-05-093-10/+42
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial updates from Greg KH: "Here is the "big" TTY/Serial patch updates for 4.12-rc1 Not a lot of new things here, the normal number of serial driver updates and additions, tiny bugs fixed, and some core files split up to make future changes a bit easier for Nicolas's "tiny-tty" work. All of these have been in linux-next for a while" * tag 'tty-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (62 commits) serial: small Makefile reordering tty: split job control support into a file of its own tty: move baudrate handling code to a file of its own console: move console_init() out of tty_io.c serial: 8250_early: Add earlycon support for Palmchip UART tty: pl011: use "qdf2400_e44" as the earlycon name for QDF2400 E44 vt: make mouse selection of non-ASCII consistent vt: set mouse selection word-chars to gpm's default imx-serial: Reduce RX DMA startup latency when opening for reading serial: omap: suspend device on probe errors serial: omap: fix runtime-pm handling on unbind tty: serial: omap: add UPF_BOOT_AUTOCONF flag for DT init serial: samsung: Remove useless spinlock serial: samsung: Add missing checks for dma_map_single failure serial: samsung: Use right device for DMA-mapping calls serial: imx: setup DCEDTE early and ensure DCD and RI irqs to be off tty: fix comment typo s/repsonsible/responsible/ tty: amba-pl011: Fix spurious TX interrupts serial: xuartps: Enable clocks in the pm disable case also serial: core: Re-use struct uart_port {name} field ...
| * | console: move console_init() out of tty_io.cNicolas Pitre2017-04-181-0/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | All the console driver handling code lives in printk.c. Move console_init() there as well so console support can still be used when the TTY code is configured out. No logical changes from this patch. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | braille-console: Fix value returned by _braille_console_setupSamuel Thibault2017-03-312-10/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit bbeddf52adc1 ("printk: move braille console support into separate braille.[ch] files") introduced _braille_console_setup() to outline the braille initialization code. There was however some confusion over the value it was supposed to return. commit 2cfe6c4ac7ee ("printk: Fix return of braille_register_console()") tried to fix it but failed to. This fixes and documents the returned value according to the use in printk.c: non-zero return means a parsing error, and thus this console configuration should be ignored. Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Aleksey Makarov <aleksey.makarov@linaro.org> Cc: Joe Perches <joe@perches.com> Cc: Ming Lei <ming.lei@canonical.com> Cc: Steven Rostedt <rostedt@goodmis.org> Acked-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | crash: move crashkernel parsing and vmcore related code under CONFIG_CRASH_COREHari Bathini2017-05-091-3/+3
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Patch series "kexec/fadump: remove dependency with CONFIG_KEXEC and reuse crashkernel parameter for fadump", v4. Traditionally, kdump is used to save vmcore in case of a crash. Some architectures like powerpc can save vmcore using architecture specific support instead of kexec/kdump mechanism. Such architecture specific support also needs to reserve memory, to be used by dump capture kernel. crashkernel parameter can be a reused, for memory reservation, by such architecture specific infrastructure. This patchset removes dependency with CONFIG_KEXEC for crashkernel parameter and vmcoreinfo related code as it can be reused without kexec support. Also, crashkernel parameter is reused instead of fadump_reserve_mem to reserve memory for fadump. The first patch moves crashkernel parameter parsing and vmcoreinfo related code under CONFIG_CRASH_CORE instead of CONFIG_KEXEC_CORE. The second patch reuses the definitions of append_elf_note() & final_note() functions under CONFIG_CRASH_CORE in IA64 arch code. The third patch removes dependency on CONFIG_KEXEC for firmware-assisted dump (fadump) in powerpc. The next patch reuses crashkernel parameter for reserving memory for fadump, instead of the fadump_reserve_mem parameter. This has the advantage of using all syntaxes crashkernel parameter supports, for fadump as well. The last patch updates fadump kernel documentation about use of crashkernel parameter. This patch (of 5): Traditionally, kdump is used to save vmcore in case of a crash. Some architectures like powerpc can save vmcore using architecture specific support instead of kexec/kdump mechanism. Such architecture specific support also needs to reserve memory, to be used by dump capture kernel. crashkernel parameter can be a reused, for memory reservation, by such architecture specific infrastructure. But currently, code related to vmcoreinfo and parsing of crashkernel parameter is built under CONFIG_KEXEC_CORE. This patch introduces CONFIG_CRASH_CORE and moves the above mentioned code under this config, allowing code reuse without dependency on CONFIG_KEXEC. There is no functional change with this patch. Link: http://lkml.kernel.org/r/149035338104.6881.4550894432615189948.stgit@hbathini.in.ibm.com Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com> Acked-by: Dave Young <dyoung@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'for-linus' of ↵Linus Torvalds2017-05-041-25/+56
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk Pull printk updates from Petr Mladek: - There is a situation when early console is not deregistered because the preferred one matches a wrong entry. It caused messages to appear twice. This is the 2nd attempt to fix it. The first one was wrong, see the commit c6c7d83b9c9e ('Revert "console: don't prefer first registered if DT specifies stdout-path"'). The fix is coupled with some small code clean up. Well, the console registration code would deserve a big one. We need to think about it. - Do not lose information about the preemtive context when the console semaphore is re-taken. - Do not block CPU hotplug when someone else is already pushing messages to the console. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: printk: fix double printing with earlycon printk: rename selected_console -> preferred_console printk: fix name/type/scope of preferred_console var printk: Correctly handle preemption in console_unlock() printk: use console_trylock() in console_cpu_notify()
| * printk: fix double printing with earlyconAleksey Makarov2017-04-121-10/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a console was specified by ACPI SPCR table _and_ command line parameters like "console=ttyAMA0" _and_ "earlycon" were specified, then log messages appear twice. The root cause is that the code traverses the list of specified consoles (the `console_cmdline` array) and stops at the first match. But it may happen that the same console is referred by the elements of this array twice: pl011,mmio,0x87e024000000,115200 -- from SPCR ttyAMA0 -- from command line but in this case `preferred_console` points to the second entry and the flag CON_CONSDEV is not set, so bootconsole is not deregistered. To fix that, introduce an invariant "The last non-braille console is always the preferred one" on the entries of the console_cmdline array. Then traverse it in reverse order to be sure that if the console is preferred then it will be the first matching entry. Introduce variable console_cmdline_cnt that keeps the number of elements of the console_cmdline array (Petr Mladek). It helps to get rid of the loop that searches for the end of this array. Link: http://lkml.kernel.org/r/20170405202006.18234-1-aleksey.makarov@linaro.org Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Jiri Slaby <jslaby@suse.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: "Nair, Jayachandran" <Jayachandran.Nair@cavium.com> Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org> Reported-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk: rename selected_console -> preferred_consoleAleksey Makarov2017-04-121-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The variable selected_console is set in __add_preferred_console() to point to the last console parameter that was added to the console_cmdline array. Rename it to preferred_console so that the name reflects the usage. Petr Mladek: "[..] the selected_console/preferred_console value is used to keep the console first in the console_drivers list. IMHO, the main effect is that each line will first appear on this console, see call_console_drivers(). But the message will still appear also on all other enabled consoles. From this point, the name "preferred" sounds better to me. More consoles are selected (enabled) and only one is preferred (first)." Link: http://lkml.kernel.org/r/20170315102854.1763-3-aleksey.makarov@linaro.org Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: "Nair, Jayachandran" <Jayachandran.Nair@cavium.com> Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org> Suggested-by: Peter Hurley <peter@hurleysoftware.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk: fix name/type/scope of preferred_console varAleksey Makarov2017-04-121-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The variable preferred_console is used only inside register_console() and its semantics is boolean. It is negative when no console has been made preferred. Make it static bool and rename to has_preferred. Renaming was suggested by Peter Hurley Link: http://lkml.kernel.org/r/20170315102854.1763-2-aleksey.makarov@linaro.org Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Jiri Slaby <jslaby@suse.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: "Nair, Jayachandran" <Jayachandran.Nair@cavium.com> Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Aleksey Makarov <aleksey.makarov@linaro.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk: Correctly handle preemption in console_unlock()Petr Mladek2017-04-041-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some console drivers code calls console_conditional_schedule() that looks at @console_may_schedule. The value must be cleared when the drivers are called from console_unlock() with interrupts disabled. But rescheduling is fine when the same code is called, for example, from tty operations where the console semaphore is taken via console_lock(). This is why @console_may_schedule is cleared before calling console drivers. The original value is stored to decide if we could sleep between lines. Now, @console_may_schedule is not cleared when we call console_trylock() and jump back to the "again" goto label. This has become a problem, since the commit 6b97a20d3a7909daa066 ("printk: set may_schedule for some of console_trylock() callers"). @console_may_schedule might get enabled now. There is also the opposite problem. console_lock() can be called only from preemptive context. It can always enable scheduling in the console code. But console_trylock() is not able to detect it when CONFIG_PREEMPT_COUNT is disabled. Therefore we should use the original @console_may_schedule value after re-acquiring the console semaphore in console_unlock(). This patch solves both problems by moving the "again" goto label. Alternative solution was to clear and restore the value around call_console_drivers(). Then console_conditional_schedule() could be used also inside console_unlock(). But there was a potential race with console_flush_on_panic() as reported by Sergey Senozhatsky. That function should be called only where there is only one CPU and with interrupts disabled. But better be on the safe side because stopping CPUs might fail. Fixes: 6b97a20d3a7909 ("printk: set may_schedule for some of console_trylock() callers") Link: http://lkml.kernel.org/r/1490372045-22288-1-git-send-email-pmladek@suse.com Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: linux-fbdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk: use console_trylock() in console_cpu_notify()Sergey Senozhatsky2017-03-241-5/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is no need to always call blocking console_lock() in console_cpu_notify(), it's quite possible that console_sem can be locked by other CPU on the system, either already printing or soon to begin printing the messages. console_lock() in this case can simply block CPU hotplug for unknown period of time (console_unlock() is time unbound). Not that hotplug is very fast, but still, with other CPUs being online and doing printk() console_cpu_notify() can stuck. Use console_trylock() instead and opt-out if console_sem is already acquired from another CPU, since that CPU will do the printing for us. Link: http://lkml.kernel.org/r/20170121104729.8585-1-sergey.senozhatsky@gmail.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
* | sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | <linux/sched/task_stack.h> We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task_stack.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | <linux/sched/debug.h> We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/debug.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
|/ | | | | | | | | | | | | | | | | | | | <linux/sched/clock.h> We are going to split <linux/sched/clock.h> out of <linux/sched.h>, which will have to be picked up from other headers and .c files. Create a trivial placeholder <linux/sched/clock.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2017-02-234-237/+310
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk Pull printk updates from Petr Mladek: - Add Petr Mladek, Sergey Senozhatsky as printk maintainers, and Steven Rostedt as the printk reviewer. This idea came up after the discussion about printk issues at Kernel Summit. It was formulated and discussed at lkml[1]. - Extend a lock-less NMI per-cpu buffers idea to handle recursive printk() calls by Sergey Senozhatsky[2]. It is the first step in sanitizing printk as discussed at Kernel Summit. The change allows to see messages that would normally get ignored or would cause a deadlock. Also it allows to enable lockdep in printk(). This already paid off. The testing in linux-next helped to discover two old problems that were hidden before[3][4]. - Remove unused parameter by Sergey Senozhatsky. Clean up after a past change. [1] http://lkml.kernel.org/r/1481798878-31898-1-git-send-email-pmladek@suse.com [2] http://lkml.kernel.org/r/20161227141611.940-1-sergey.senozhatsky@gmail.com [3] http://lkml.kernel.org/r/20170215044332.30449-1-sergey.senozhatsky@gmail.com [4] http://lkml.kernel.org/r/20170217015932.11898-1-sergey.senozhatsky@gmail.com * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: printk: drop call_console_drivers() unused param printk: convert the rest to printk-safe printk: remove zap_locks() function printk: use printk_safe buffers in printk printk: report lost messages in printk safe/nmi contexts printk: always use deferred printk when flush printk_safe lines printk: introduce per-cpu safe_print seq buffer printk: rename nmi.c and exported api printk: use vprintk_func in vprintk() MAINTAINERS: Add printk maintainers
| * printk: drop call_console_drivers() unused paramSergey Senozhatsky2017-02-081-8/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | We do suppress_message_printing() check before we call call_console_drivers() now, so `level' param is not needed anymore. Link: http://lkml.kernel.org/r/20161224140902.1962-2-sergey.senozhatsky@gmail.com Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk: convert the rest to printk-safeSergey Senozhatsky2017-02-081-38/+65
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch converts the rest of logbuf users (which are out of printk recursion case, but can deadlock in printk). To make printk-safe usage easier the patch introduces 4 helper macros: - logbuf_lock_irq()/logbuf_unlock_irq() lock/unlock the logbuf lock and disable/enable local IRQ - logbuf_lock_irqsave(flags)/logbuf_unlock_irqrestore(flags) lock/unlock the logbuf lock and saves/restores local IRQ state Link: http://lkml.kernel.org/r/20161227141611.940-9-sergey.senozhatsky@gmail.com Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Calvin Owens <calvinowens@fb.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk: remove zap_locks() functionSergey Senozhatsky2017-02-081-61/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We use printk-safe now which makes printk-recursion detection code in vprintk_emit() unreachable. The tricky thing here is that, apart from detecting and reporting printk recursions, that code also used to zap_locks() in case of panic() from the same CPU. However, zap_locks() does not look to be needed anymore: 1) Since commit 08d78658f393 ("panic: release stale console lock to always get the logbuf printed out") panic flushing of `logbuf' to console ignores the state of `console_sem' by doing panic() console_trylock(); console_unlock(); 2) Since commit cf9b1106c81c ("printk/nmi: flush NMI messages on the system panic") panic attempts to zap the `logbuf_lock' spin_lock to successfully flush nmi messages to `logbuf'. Basically, it seems that we either already do what zap_locks() used to do but in other places or we ignore the state of the lock. The only reaming difference is that we don't re-init the console semaphore in printk_safe_flush_on_panic(), but this is not necessary because we don't call console drivers from printk_safe_flush_on_panic() due to the fact that we are using a deferred printk() version (as was suggested by Petr Mladek). Link: http://lkml.kernel.org/r/20161227141611.940-8-sergey.senozhatsky@gmail.com Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Calvin Owens <calvinowens@fb.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk: use printk_safe buffers in printkSergey Senozhatsky2017-02-081-15/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use printk_safe per-CPU buffers in printk recursion-prone blocks: -- around logbuf_lock protected sections in vprintk_emit() and console_unlock() -- around down_trylock_console_sem() and up_console_sem() Note that this solution addresses deadlocks caused by printk() recursive calls only. That is vprintk_emit() and console_unlock(). The rest will be converted in a followup patch. Another thing to note is that we now keep lockdep enabled in printk, because we are protected against the printk recursion caused by lockdep in vprintk_emit() by the printk-safe mechanism - we first switch to per-CPU buffers and only then access the deadlock-prone locks. Examples: 1) printk() from logbuf_lock spin_lock section Assume the following code: printk() raw_spin_lock(&logbuf_lock); WARN_ON(1); raw_spin_unlock(&logbuf_lock); which now produces: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 366 at kernel/printk/printk.c:1811 vprintk_emit CPU: 0 PID: 366 Comm: bash Call Trace: warn_slowpath_null+0x1d/0x1f vprintk_emit+0x1cd/0x438 vprintk_default+0x1d/0x1f printk+0x48/0x50 [..] 2) printk() from semaphore sem->lock spin_lock section Assume the following code printk() console_trylock() down_trylock() raw_spin_lock_irqsave(&sem->lock, flags); WARN_ON(1); raw_spin_unlock_irqrestore(&sem->lock, flags); which now produces: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 363 at kernel/locking/semaphore.c:141 down_trylock CPU: 1 PID: 363 Comm: bash Call Trace: warn_slowpath_null+0x1d/0x1f down_trylock+0x3d/0x62 ? vprintk_emit+0x3f9/0x414 console_trylock+0x31/0xeb vprintk_emit+0x3f9/0x414 vprintk_default+0x1d/0x1f printk+0x48/0x50 [..] 3) printk() from console_unlock() Assume the following code: printk() console_unlock() raw_spin_lock(&logbuf_lock); WARN_ON(1); raw_spin_unlock(&logbuf_lock); which now produces: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 329 at kernel/printk/printk.c:2384 console_unlock CPU: 1 PID: 329 Comm: bash Call Trace: warn_slowpath_null+0x18/0x1a console_unlock+0x12d/0x559 ? trace_hardirqs_on_caller+0x16d/0x189 ? trace_hardirqs_on+0xd/0xf vprintk_emit+0x363/0x374 vprintk_default+0x18/0x1a printk+0x43/0x4b [..] 4) printk() from try_to_wake_up() Assume the following code: printk() console_unlock() up() try_to_wake_up() raw_spin_lock_irqsave(&p->pi_lock, flags); WARN_ON(1); raw_spin_unlock_irqrestore(&p->pi_lock, flags); which now produces: ------------[ cut here ]------------ WARNING: CPU: 3 PID: 363 at kernel/sched/core.c:2028 try_to_wake_up CPU: 3 PID: 363 Comm: bash Call Trace: warn_slowpath_null+0x1d/0x1f try_to_wake_up+0x7f/0x4f7 wake_up_process+0x15/0x17 __up.isra.0+0x56/0x63 up+0x32/0x42 __up_console_sem+0x37/0x55 console_unlock+0x21e/0x4c2 vprintk_emit+0x41c/0x462 vprintk_default+0x1d/0x1f printk+0x48/0x50 [..] 5) printk() from call_console_drivers() Assume the following code: printk() console_unlock() call_console_drivers() ... WARN_ON(1); which now produces: ------------[ cut here ]------------ WARNING: CPU: 2 PID: 305 at kernel/printk/printk.c:1604 call_console_drivers CPU: 2 PID: 305 Comm: bash Call Trace: warn_slowpath_null+0x18/0x1a call_console_drivers.isra.6.constprop.16+0x3a/0xb0 console_unlock+0x471/0x48e vprintk_emit+0x1f4/0x206 vprintk_default+0x18/0x1a vprintk_func+0x6e/0x70 printk+0x3e/0x46 [..] 6) unsupported placeholder in printk() format now prints an actual warning from vscnprintf(), instead of 'BUG: recent printk recursion!'. ------------[ cut here ]------------ WARNING: CPU: 5 PID: 337 at lib/vsprintf.c:1900 format_decode Please remove unsupported % in format string CPU: 5 PID: 337 Comm: bash Call Trace: dump_stack+0x4f/0x65 __warn+0xc2/0xdd warn_slowpath_fmt+0x4b/0x53 format_decode+0x22c/0x308 vsnprintf+0x89/0x3b7 vscnprintf+0xd/0x26 vprintk_emit+0xb4/0x238 vprintk_default+0x1d/0x1f vprintk_func+0x6c/0x73 printk+0x43/0x4b [..] Link: http://lkml.kernel.org/r/20161227141611.940-7-sergey.senozhatsky@gmail.com Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Calvin Owens <calvinowens@fb.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * printk: report lost messages in printk safe/nmi contextsSergey Senozhatsky2017-02-083-37/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Account lost messages in pritk-safe and printk-safe-nmi contexts and report those numbers during printk_safe_flush(). The patch also moves lost message counter to struct `printk_safe_seq_buf' instead of having dedicated static counters - this simplifies the code. Link: http://lkml.kernel.org/r/20161227141611.940-6-sergey.senozhatsky@gmail.com Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Calvin Owens <calvinowens@fb.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk: always use deferred printk when flush printk_safe linesSergey Senozhatsky2017-02-081-8/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Always use printk_deferred() in printk_safe_flush_line(). Flushing can be done from NMI or printk_safe contexts (when we are in panic), so we can't call console drivers, yet still want to store the messages in the logbuf buffer. Therefore we use a deferred printk version. Link: http://lkml.kernel.org/r/20170206164253.GA463@tigerII.localdomain Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Calvin Owens <calvinowens@fb.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Suggested-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * printk: introduce per-cpu safe_print seq bufferSergey Senozhatsky2017-02-084-52/+157
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch extends the idea of NMI per-cpu buffers to regions that may cause recursive printk() calls and possible deadlocks. Namely, printk() can't handle printk calls from schedule code or printk() calls from lock debugging code (spin_dump() for instance); because those may be called with `sem->lock' already taken or any other `critical' locks (p->pi_lock, etc.). An example of deadlock can be vprintk_emit() console_unlock() up() << raw_spin_lock_irqsave(&sem->lock, flags); wake_up_process() try_to_wake_up() ttwu_queue() ttwu_activate() activate_task() enqueue_task() enqueue_task_fair() cfs_rq_of() task_of() WARN_ON_ONCE(!entity_is_task(se)) vprintk_emit() console_trylock() down_trylock() raw_spin_lock_irqsave(&sem->lock, flags) ^^^^ deadlock and some other cases. Just like in NMI implementation, the solution uses a per-cpu `printk_func' pointer to 'redirect' printk() calls to a 'safe' callback, that store messages in a per-cpu buffer and flushes them back to logbuf buffer later. Usage example: printk() printk_safe_enter_irqsave(flags) // // any printk() call from here will endup in vprintk_safe(), // that stores messages in a special per-CPU buffer. // printk_safe_exit_irqrestore(flags) The 'redirection' mechanism, though, has been reworked, as suggested by Petr Mladek. Instead of using a per-cpu @print_func callback we now keep a per-cpu printk-context variable and call either default or nmi vprintk function depending on its value. printk_nmi_entrer/exit and printk_safe_enter/exit, thus, just set/celar corresponding bits in printk-context functions. The patch only adds printk_safe support, we don't use it yet. Link: http://lkml.kernel.org/r/20161227141611.940-4-sergey.senozhatsky@gmail.com Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Calvin Owens <calvinowens@fb.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * printk: rename nmi.c and exported apiSergey Senozhatsky2017-02-082-33/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A preparation patch for printk_safe work. No functional change. - rename nmi.c to print_safe.c - add `printk_safe' prefix to some (which used both by printk-safe and printk-nmi) of the exported functions. Link: http://lkml.kernel.org/r/20161227141611.940-3-sergey.senozhatsky@gmail.com Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Calvin Owens <calvinowens@fb.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
| * printk: use vprintk_func in vprintk()Sergey Senozhatsky2017-02-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | vprintk(), just like printk(), better be using per-cpu printk_func instead of direct vprintk_emit() call. Just in case if vprintk() will ever be called from NMI, or from any other context that can deadlock in printk(). Link: http://lkml.kernel.org/r/20161227141611.940-2-sergey.senozhatsky@gmail.com Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Calvin Owens <calvinowens@fb.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Petr Mladek <pmladek@suse.com>
* | printk: use rcuidle console tracepointSergey Senozhatsky2017-02-191-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use rcuidle console tracepoint because, apparently, it may be issued from an idle CPU: hw-breakpoint: Failed to enable monitor mode on CPU 0. hw-breakpoint: CPU 0 failed to disable vector catch =============================== [ ERR: suspicious RCU usage. ] 4.10.0-rc8-next-20170215+ #119 Not tainted ------------------------------- ./include/trace/events/printk.h:32 suspicious rcu_dereference_check() usage! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 2, debug_locks = 0 RCU used illegally from extended quiescent state! 2 locks held by swapper/0/0: #0: (cpu_pm_notifier_lock){......}, at: [<c0237e2c>] cpu_pm_exit+0x10/0x54 #1: (console_lock){+.+.+.}, at: [<c01ab350>] vprintk_emit+0x264/0x474 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.10.0-rc8-next-20170215+ #119 Hardware name: Generic OMAP4 (Flattened Device Tree) console_unlock vprintk_emit vprintk_default printk reset_ctrl_regs dbg_cpu_pm_notify notifier_call_chain cpu_pm_exit omap_enter_idle_coupled cpuidle_enter_state cpuidle_enter_state_coupled do_idle cpu_startup_entry start_kernel This RCU warning, however, is suppressed by lockdep_off() in printk(). lockdep_off() increments the ->lockdep_recursion counter and thus disables RCU_LOCKDEP_WARN() and debug_lockdep_rcu_enabled(), which want lockdep to be enabled "current->lockdep_recursion == 0". Link: http://lkml.kernel.org/r/20170217015932.11898-1-sergey.senozhatsky@gmail.com Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reported-by: Tony Lindgren <tony@atomide.com> Tested-by: Tony Lindgren <tony@atomide.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Lindgren <tony@atomide.com> Cc: Russell King <rmk@armlinux.org.uk> Cc: <stable@vger.kernel.org> [3.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds2016-12-241-1/+1
| | | | | | | | | | | | | This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2016-12-161-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: - more ->d_init() stuff (work.dcache) - pathname resolution cleanups (work.namei) - a few missing iov_iter primitives - copy_from_iter_full() and friends. Either copy the full requested amount, advance the iterator and return true, or fail, return false and do _not_ advance the iterator. Quite a few open-coded callers converted (and became more readable and harder to fuck up that way) (work.iov_iter) - several assorted patches, the big one being logfs removal * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: logfs: remove from tree vfs: fix put_compat_statfs64() does not handle errors namei: fold should_follow_link() with the step into not-followed link namei: pass both WALK_GET and WALK_MORE to should_follow_link() namei: invert WALK_PUT logics namei: shift interpretation of LOOKUP_FOLLOW inside should_follow_link() namei: saner calling conventions for mountpoint_last() namei.c: get rid of user_path_parent() switch getfrag callbacks to ..._full() primitives make skb_add_data,{_nocache}() and skb_copy_to_page_nocache() advance only on success [iov_iter] new primitives - copy_from_iter_full() and friends don't open-code file_inode() ceph: switch to use of ->d_init() ceph: unify dentry_operations instances lustre: switch to use of ->d_init()
| * [iov_iter] new primitives - copy_from_iter_full() and friendsAl Viro2016-12-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | copy_from_iter_full(), copy_from_iter_full_nocache() and csum_and_copy_from_iter_full() - counterparts of copy_from_iter() et.al., advancing iterator only in case of successful full copy and returning whether it had been successful or not. Convert some obvious users. *NOTE* - do not blindly assume that something is a good candidate for those unless you are sure that not advancing iov_iter in failure case is the right thing in this case. Anything that does short read/short write kind of stuff (or is in a loop, etc.) is unlikely to be a good one. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | printk: Remove no longer used second struct contGeert Uytterhoeven2016-12-151-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If CONFIG_PRINTK=n: kernel/printk/printk.c:1893: warning: ‘cont’ defined but not used Note that there are actually two different struct cont definitions and objects: the first one is used if CONFIG_PRINTK=y, the second one became unused by removing console_cont_flush(). Fixes: 5c2992ee7fd8 ("printk: remove console flushing special cases for partial buffered lines") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Petr Mladek <pmladek@suse.com> [ I do the occasional "allnoconfig" builds, but apparently not often enough - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | printk: remove console flushing special cases for partial buffered linesLinus Torvalds2016-12-151-103/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It actively hurts proper merging, and makes for a lot of special cases. There was a good(ish) reason for doing it originally, but it's getting too painful to maintain. And most of the original reasons for it are long gone. So instead of having special code to flush partial lines to the console (as opposed to the record buffers), do _all_ the console writing from the record buffer, and be done with it. If an oops happens (or some other synchronous event), we will flush the partial lines due to the oops printing activity, so this does not affect that. It does mean that if you have a completely hung machine, a partial preceding line may not have been printed out. That was some of the original reason for this complexity, in fact, back when we used to test for the historical i386 "halt" instruction problem by doing pr_info("Checking 'hlt' instruction... "); if (!boot_cpu_data.hlt_works_ok) { pr_cont("disabled\n"); return; } halt(); halt(); halt(); halt(); pr_cont("OK\n"); and that model no longer works (it the 'hlt' instruction kills the machine, the partial line won't have been flushed, so you won't even see it). Of course, that was also back in the days when people actually had textual console output rather than a graphical splash-screen at bootup. How times change.. Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Joe Perches <joe@perches.com> Cc: Steven Rostedt <rostedt@goodmis.org> Tested-by: Petr Mladek <pmladek@suse.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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