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* semtimedop(): move compat to nativeAl Viro2017-07-161-23/+0
| | | | | | ... and finally kill the sodding compat_convert_timespec() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'work.mount' of ↵Linus Torvalds2017-07-151-3/+13
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull ->s_options removal from Al Viro: "Preparations for fsmount/fsopen stuff (coming next cycle). Everything gets moved to explicit ->show_options(), killing ->s_options off + some cosmetic bits around fs/namespace.c and friends. Basically, the stuff needed to work with fsmount series with minimum of conflicts with other work. It's not strictly required for this merge window, but it would reduce the PITA during the coming cycle, so it would be nice to have those bits and pieces out of the way" * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: isofs: Fix isofs_show_options() VFS: Kill off s_options and helpers orangefs: Implement show_options 9p: Implement show_options isofs: Implement show_options afs: Implement show_options affs: Implement show_options befs: Implement show_options spufs: Implement show_options bpf: Implement show_options ramfs: Implement show_options pstore: Implement show_options omfs: Implement show_options hugetlbfs: Implement show_options VFS: Don't use save/replace_mount_options if not using generic_show_options VFS: Provide empty name qstr VFS: Make get_filesystem() return the affected filesystem VFS: Clean up whitespace in fs/namespace.c and fs/super.c Provide a function to create a NUL-terminated string from unterminated data
| * bpf: Implement show_optionsDavid Howells2017-07-061-3/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | Implement the show_options superblock op for bpf as part of a bid to get rid of s_options and generic_show_options() to make it easier to implement a context-based mount where the mount options can be passed individually over a file descriptor. Signed-off-by: David Howells <dhowells@redhat.com> cc: Alexei Starovoitov <ast@kernel.org> cc: Daniel Borkmann <daniel@iogearbox.net> cc: netdev@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge tag 'pm-fixes-4.13-rc1' of ↵Linus Torvalds2017-07-151-0/+5
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management fixes from Rafael Wysocki: "These fix a recently exposed issue in the PCI device wakeup code and one older problem related to PCI device wakeup that has been reported recently, modify one more piece of computations in intel_pstate to get rid of a rounding error, fix a possible race in the schedutil cpufreq governor, fix the device PM QoS sysfs interface to correctly handle invalid user input, fix return values of two probe routines in devfreq drivers and constify an attribute_group structure in devfreq. Specifics: - Avoid clearing the PCI PME Enable bit for devices as a result of config space restoration which confuses AML executed afterward and causes wakeup events to be lost on some systems (Rafael Wysocki). - Fix the native PCIe PME interrupts handling in the cases when the PME IRQ is set up as a system wakeup one so that runtime PM remote wakeup works as expected after system resume on systems where that happens (Rafael Wysocki). - Fix the device PM QoS sysfs interface to handle invalid user input correctly instead of using an unititialized variable value as the latency tolerance for the device at hand (Dan Carpenter). - Get rid of one more rounding error from intel_pstate computations (Srinivas Pandruvada). - Fix the schedutil cpufreq governor to prevent it from possibly accessing unititialized data structures from governor callbacks in some cases on systems when multiple CPUs share a single cpufreq policy object (Vikram Mulukutla). - Fix the return values of probe routines in two devfreq drivers (Gustavo Silva). - Constify an attribute_group structure in devfreq (Arvind Yadav)" * tag 'pm-fixes-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: PCI / PM: Fix native PME handling during system suspend/resume PCI / PM: Restore PME Enable after config space restoration cpufreq: schedutil: Fix sugov_start() versus sugov_update_shared() race PM / QoS: return -EINVAL for bogus strings cpufreq: intel_pstate: Fix ratio setting for min_perf_pct PM / devfreq: constify attribute_group structures. PM / devfreq: tegra: fix error return code in tegra_devfreq_probe() PM / devfreq: rk3399_dmc: fix error return code in rk3399_dmcfreq_probe()
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| *-. \ Merge branches 'pm-cpufreq-sched' and 'intel_pstate'Rafael J. Wysocki2017-07-141-0/+5
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * pm-cpufreq-sched: cpufreq: schedutil: Fix sugov_start() versus sugov_update_shared() race * intel_pstate: cpufreq: intel_pstate: Fix ratio setting for min_perf_pct
| | * | | cpufreq: schedutil: Fix sugov_start() versus sugov_update_shared() raceVikram Mulukutla2017-07-121-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With a shared policy in place, when one of the CPUs in the policy is hotplugged out and then brought back online, sugov_stop() and sugov_start() are called in order. sugov_stop() removes utilization hooks for each CPU in the policy and does nothing else in the for_each_cpu() loop. sugov_start() on the other hand iterates through the CPUs in the policy and re-initializes the per-cpu structure _and_ adds the utilization hook. This implies that the scheduler is allowed to invoke a CPU's utilization update hook when the rest of the per-cpu structures have yet to be re-inited. Apart from some strange values in tracepoints this doesn't cause a problem, but if we do end up accessing a pointer from the per-cpu sugov_cpu structure somewhere in the sugov_update_shared() path, we will likely see crashes since the memset for another CPU in the policy is free to race with sugov_update_shared from the CPU that is ready to go. So let's fix this now to first init all per-cpu structures, and then add the per-cpu utilization update hooks all at once. Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* | | | | kmod: throttle kmod thread limitLuis R. Rodriguez2017-07-151-9/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we reach the limit of modprobe_limit threads running the next request_module() call will fail. The original reason for adding a kill was to do away with possible issues with in old circumstances which would create a recursive series of request_module() calls. We can do better than just be super aggressive and reject calls once we've reached the limit by simply making pending callers wait until the threshold has been reduced, and then throttling them in, one by one. This throttling enables requests over the kmod concurrent limit to be processed once a pending request completes. Only the first item queued up to wait is woken up. The assumption here is once a task is woken it will have no other option to also kick the queue to check if there are more pending tasks -- regardless of whether or not it was successful. By throttling and processing only max kmod concurrent tasks we ensure we avoid unexpected fatal request_module() calls, and we keep memory consumption on module loading to a minimum. With x86_64 qemu, with 4 cores, 4 GiB of RAM it takes the following run time to run both tests: time ./kmod.sh -t 0008 real 0m16.366s user 0m0.883s sys 0m8.916s time ./kmod.sh -t 0009 real 0m50.803s user 0m0.791s sys 0m9.852s Link: http://lkml.kernel.org/r/20170628223155.26472-4-mcgrof@kernel.org Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: Jessica Yu <jeyu@redhat.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Michal Marek <mmarek@suse.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | | kernel/watchdog.c: use better pr_fmt prefixKefeng Wang2017-07-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After commit 73ce0511c436 ("kernel/watchdog.c: move hardlockup detector to separate file"), 'NMI watchdog' is inappropriate in kernel/watchdog.c, using 'watchdog' only. Link: http://lkml.kernel.org/r/1499928642-48983-1-git-send-email-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Babu Moger <babu.moger@oracle.com> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | | Merge tag 'trace-v4.13-2' of ↵Linus Torvalds2017-07-134-20/+143
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull more tracing updates from Steven Rostedt: "A few more minor updates: - Show the tgid mappings for user space trace tools to use - Fix and optimize the comm and tgid cache recording - Sanitize derived kprobe names - Ftrace selftest updates - trace file header fix - Update of Documentation/trace/ftrace.txt - Compiler warning fixes - Fix possible uninitialized variable" * tag 'trace-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace: Fix uninitialized variable in match_records() ftrace: Remove an unneeded NULL check ftrace: Hide cached module code for !CONFIG_MODULES tracing: Do note expose stack_trace_filter without DYNAMIC_FTRACE tracing: Update Documentation/trace/ftrace.txt tracing: Fixup trace file header alignment selftests/ftrace: Add a testcase for kprobe event naming selftests/ftrace: Add a test to probe module functions selftests/ftrace: Update multiple kprobes test for powerpc trace/kprobes: Sanitize derived event names tracing: Attempt to record other information even if some fail tracing: Treat recording tgid for idle task as a success tracing: Treat recording comm for idle task as a success tracing: Add saved_tgids file to show cached pid to tgid mappings
| * | | | | ftrace: Fix uninitialized variable in match_records()Dan Carpenter2017-07-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | My static checker complains that if "func" is NULL then "clear_filter" is uninitialized. This seems like it could be true, although it's possible something subtle is happening that I haven't seen. kernel/trace/ftrace.c:3844 match_records() error: uninitialized symbol 'clear_filter'. Link: http://lkml.kernel.org/r/20170712073556.h6tkpjcdzjaozozs@mwanda Cc: stable@vger.kernel.org Fixes: f0a3b154bd7 ("ftrace: Clarify code for mod command") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * | | | | ftrace: Remove an unneeded NULL checkDan Carpenter2017-07-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | "func" can't be NULL and it doesn't make sense to check because we've already derefenced it. Link: http://lkml.kernel.org/r/20170712073340.4enzeojeoupuds5a@mwanda Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * | | | | ftrace: Hide cached module code for !CONFIG_MODULESArnd Bergmann2017-07-121-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When modules are disabled, we get a harmless build warning: kernel/trace/ftrace.c:4051:13: error: 'process_cached_mods' defined but not used [-Werror=unused-function] This adds the same #ifdef around the new code that exists around its caller. Link: http://lkml.kernel.org/r/20170710084413.1820568-1-arnd@arndb.de Fixes: d7fbf8df7ca0 ("ftrace: Implement cached modules tracing on module load") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * | | | | tracing: Do note expose stack_trace_filter without DYNAMIC_FTRACESteven Rostedt (VMware)2017-07-121-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The "stack_trace_filter" file only makes sense if DYNAMIC_FTRACE is configured in. If it is not, then the user can not filter any functions. Not only that, the open function causes warnings when DYNAMIC_FTRACE is not set. Link: http://lkml.kernel.org/r/20170710110521.600806-1-arnd@arndb.de Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * | | | | tracing: Fixup trace file header alignmentSteven Rostedt (VMware)2017-07-111-8/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The addition of TGID to the tracing header added a check to see if TGID shoudl be displayed or not, and updated the header accordingly. Unfortunately, it broke the default header. Also add constant strings to use for spacing. This does remove the visibility of the header a bit, but cuts it down from the extended lines much greater than 80 characters. Before this change: # tracer: function # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU#|||| TIMESTAMP FUNCTION # | | | |||| | | swapper/0-1 [000] .... 0.277830: migration_init <-do_one_initcall swapper/0-1 [002] d... 13.861967: Unknown type 1201 swapper/0-1 [002] d..1 13.861970: Unknown type 1202 After this change: # tracer: function # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | swapper/0-1 [000] .... 0.278245: migration_init <-do_one_initcall swapper/0-1 [003] d... 13.861189: Unknown type 1201 swapper/0-1 [003] d..1 13.861192: Unknown type 1202 Cc: Joel Fernandes <joelaf@google.com> Fixes: 441dae8f2f29 ("tracing: Add support for display of tgid in trace output") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * | | | | trace/kprobes: Sanitize derived event namesNaveen N. Rao2017-07-091-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we derive event names, convert some expected symbols (such as ':' used to specify module:name and '.' present in some symbols) into underscores so that the event name is not rejected. Before this patch: # echo 'p kobject_example:foo_store' > kprobe_events trace_kprobe: Failed to allocate trace_probe.(-22) -sh: write error: Invalid argument After this patch: # echo 'p kobject_example:foo_store' > kprobe_events # cat kprobe_events p:kprobes/p_kobject_example_foo_store_0 kobject_example:foo_store Link: http://lkml.kernel.org/r/66c189e09e71361aba91dd4a5bd146a1b62a7a51.1499453040.git.naveen.n.rao@linux.vnet.ibm.com Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * | | | | tracing: Attempt to record other information even if some failJoel Fernandes2017-07-071-8/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In recent patches where we record comm and tgid at the same time, we skip continuing to record if any fail. Fix that by trying to record as many things as we can even if some couldn't be recorded. If any information isn't recorded, then we don't set trace_taskinfo_save as before. Link: http://lkml.kernel.org/r/20170706230023.17942-3-joelaf@google.com Cc: kernel-team@android.com Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Joel Fernandes <joelaf@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * | | | | tracing: Treat recording tgid for idle task as a successJoel Fernandes2017-07-071-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we stop recording tgid for non-idle tasks when switching from/to idle task since we treat that as a record failure. Fix that by treat recording of tgid for idle task as a success. Link: http://lkml.kernel.org/r/20170706230023.17942-2-joelaf@google.com Cc: kernel-team@android.com Cc: Ingo Molnar <mingo@redhat.com> Reported-by: Michael Sartain <mikesart@gmail.com> Signed-off-by: Joel Fernandes <joelaf@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * | | | | tracing: Treat recording comm for idle task as a successJoel Fernandes2017-07-071-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we stop recording comm for non-idle tasks when switching from/to idle task since we treat that as a record failure. Fix that by treat recording of comm for idle task as a success. Link: http://lkml.kernel.org/r/20170706230023.17942-1-joelaf@google.com Cc: kernel-team@android.com Cc: Ingo Molnar <mingo@redhat.com> Reported-by: Michael Sartain <mikesart@gmail.com> Signed-off-by: Joel Fernandes <joelaf@google.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| * | | | | tracing: Add saved_tgids file to show cached pid to tgid mappingsMichael Sartain2017-07-061-0/+73
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Export the cached pid / tgid mappings in debugfs tracing saved_tgids file. This allows user apps to translate the pids from a trace to their respective thread group. Example saved_tgids file with pid / tgid values separated by ' ': # cat saved_tgids 1048 1048 1047 1047 7 7 1049 1047 1054 1047 1053 1047 Link: http://lkml.kernel.org/r/20170630004023.064965233@goodmis.org Link: http://lkml.kernel.org/r/20170706040713.unwkumbta5menygi@mikesart-cos Reviewed-by: Joel Fernandes <joelaf@google.com> Signed-off-by: Michael Sartain <mikesart@fastmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* | | | | | Merge branch 'akpm' (patches from Andrew)Linus Torvalds2017-07-1313-198/+654
|\ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge yet more updates from Andrew Morton: - various misc things - kexec updates - sysctl core updates - scripts/gdb udpates - checkpoint-restart updates - ipc updates - kernel/watchdog updates - Kees's "rough equivalent to the glibc _FORTIFY_SOURCE=1 feature" - "stackprotector: ascii armor the stack canary" - more MM bits - checkpatch updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (96 commits) writeback: rework wb_[dec|inc]_stat family of functions ARM: samsung: usb-ohci: move inline before return type video: fbdev: omap: move inline before return type video: fbdev: intelfb: move inline before return type USB: serial: safe_serial: move __inline__ before return type drivers: tty: serial: move inline before return type drivers: s390: move static and inline before return type x86/efi: move asmlinkage before return type sh: move inline before return type MIPS: SMP: move asmlinkage before return type m68k: coldfire: move inline before return type ia64: sn: pci: move inline before type ia64: move inline before return type FRV: tlbflush: move asmlinkage before return type CRIS: gpio: move inline before return type ARM: HP Jornada 7XX: move inline before return type ARM: KVM: move asmlinkage before type checkpatch: improve the STORAGE_CLASS test mm, migration: do not trigger OOM killer when migrating memory drm/i915: use __GFP_RETRY_MAYFAIL ...
| * | | | | | fork,random: use get_random_canary() to set tsk->stack_canaryRik van Riel2017-07-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use the ascii-armor canary to prevent unterminated C string overflows from being able to successfully overwrite the canary, even if they somehow obtain the canary value. Inspired by execshield ascii-armor and Daniel Micay's linux-hardened tree. Link: http://lkml.kernel.org/r/20170524155751.424-3-riel@redhat.com Signed-off-by: Rik van Riel <riel@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Daniel Micay <danielmicay@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Ingo Molnar <mingo@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | kexec_file: adjust declaration of kexec_purgatoryKees Cook2017-07-132-7/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Defining kexec_purgatory as a zero-length char array upsets compile time size checking. Since this is built on a per-arch basis, define it as an unsized char array (like is done for other similar things, e.g. linker sections). This silences the warning generated by the future CONFIG_FORTIFY_SOURCE, which did not like the memcmp() of a "0 byte" array. This drops the __weak and uses an extern instead, since both users define kexec_purgatory. Link: http://lkml.kernel.org/r/1497903987-21002-4-git-send-email-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Daniel Micay <danielmicay@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | kernel/watchdog: provide watchdog_nmi_reconfigure() for arch watchdogsNicholas Piggin2017-07-131-4/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After reconfiguring watchdog sysctls etc., architecture specific watchdogs may not get all their parameters updated. watchdog_nmi_reconfigure() can be implemented to pull the new values in and set the arch NMI watchdog. [npiggin@gmail.com: add code comments] Link: http://lkml.kernel.org/r/20170617125933.774d3858@roar.ozlabs.ibm.com [arnd@arndb.de: hide unused function] Link: http://lkml.kernel.org/r/20170620204854.966601-1-arnd@arndb.de Link: http://lkml.kernel.org/r/20170616065715.18390-5-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Don Zickus <dzickus@redhat.com> Tested-by: Babu Moger <babu.moger@oracle.com> [sparc] Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> 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>
| * | | | | | kernel/watchdog: split up config optionsNicholas Piggin2017-07-134-131/+177
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Split SOFTLOCKUP_DETECTOR from LOCKUP_DETECTOR, and split HARDLOCKUP_DETECTOR_PERF from HARDLOCKUP_DETECTOR. LOCKUP_DETECTOR implies the general boot, sysctl, and programming interfaces for the lockup detectors. An architecture that wants to use a hard lockup detector must define HAVE_HARDLOCKUP_DETECTOR_PERF or HAVE_HARDLOCKUP_DETECTOR_ARCH. Alternatively an arch can define HAVE_NMI_WATCHDOG, which provides the minimum arch_touch_nmi_watchdog, and it otherwise does its own thing and does not implement the LOCKUP_DETECTOR interfaces. sparc is unusual in that it has started to implement some of the interfaces, but not fully yet. It should probably be converted to a full HAVE_HARDLOCKUP_DETECTOR_ARCH. [npiggin@gmail.com: fix] Link: http://lkml.kernel.org/r/20170617223522.66c0ad88@roar.ozlabs.ibm.com Link: http://lkml.kernel.org/r/20170616065715.18390-4-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Don Zickus <dzickus@redhat.com> Reviewed-by: Babu Moger <babu.moger@oracle.com> Tested-by: Babu Moger <babu.moger@oracle.com> [sparc] Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> 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>
| * | | | | | kernel/watchdog: introduce arch_touch_nmi_watchdog()Nicholas Piggin2017-07-131-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For architectures that define HAVE_NMI_WATCHDOG, instead of having them provide the complete touch_nmi_watchdog() function, just have them provide arch_touch_nmi_watchdog(). This gives the generic code more flexibility in implementing this function, and arch implementations don't miss out on touching the softlockup watchdog or other generic details. Link: http://lkml.kernel.org/r/20170616065715.18390-3-npiggin@gmail.com Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Reviewed-by: Don Zickus <dzickus@redhat.com> Reviewed-by: Babu Moger <babu.moger@oracle.com> Tested-by: Babu Moger <babu.moger@oracle.com> [sparc] Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> 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>
| * | | | | | fault-inject: support systematic fault injectionDmitry Vyukov2017-07-131-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add /proc/self/task/<current-tid>/fail-nth file that allows failing 0-th, 1-st, 2-nd and so on calls systematically. Excerpt from the added documentation: "Write to this file of integer N makes N-th call in the current task fail (N is 0-based). Read from this file returns a single char 'Y' or 'N' that says if the fault setup with a previous write to this file was injected or not, and disables the fault if it wasn't yet injected. Note that this file enables all types of faults (slab, futex, etc). This setting takes precedence over all other generic settings like probability, interval, times, etc. But per-capability settings (e.g. fail_futex/ignore-private) take precedence over it. This feature is intended for systematic testing of faults in a single system call. See an example below" Why add a new setting: 1. Existing settings are global rather than per-task. So parallel testing is not possible. 2. attr->interval is close but it depends on attr->count which is non reset to 0, so interval does not work as expected. 3. Trying to model this with existing settings requires manipulations of all of probability, interval, times, space, task-filter and unexposed count and per-task make-it-fail files. 4. Existing settings are per-failure-type, and the set of failure types is potentially expanding. 5. make-it-fail can't be changed by unprivileged user and aggressive stress testing better be done from an unprivileged user. Similarly, this would require opening the debugfs files to the unprivileged user, as he would need to reopen at least times file (not possible to pre-open before dropping privs). The proposed interface solves all of the above (see the example). We want to integrate this into syzkaller fuzzer. A prototype has found 10 bugs in kernel in first day of usage: https://groups.google.com/forum/#!searchin/syzkaller/%22FAULT_INJECTION%22%7Csort:relevance I've made the current interface work with all types of our sandboxes. For setuid the secret sauce was prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) to make /proc entries non-root owned. So I am fine with the current version of the code. [akpm@linux-foundation.org: fix build] Link: http://lkml.kernel.org/r/20170328130128.101773-1-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | kcmp: add KCMP_EPOLL_TFD mode to compare epoll target filesCyrill Gorcunov2017-07-131-0/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With current epoll architecture target files are addressed with file_struct and file descriptor number, where the last is not unique. Moreover files can be transferred from another process via unix socket, added into queue and closed then so we won't find this descriptor in the task fdinfo list. Thus to checkpoint and restore such processes CRIU needs to find out where exactly the target file is present to add it into epoll queue. For this sake one can use kcmp call where some particular target file from the queue is compared with arbitrary file passed as an argument. Because epoll target files can have same file descriptor number but different file_struct a caller should explicitly specify the offset within. To test if some particular file is matching entry inside epoll one have to - fill kcmp_epoll_slot structure with epoll file descriptor, target file number and target file offset (in case if only one target is present then it should be 0) - call kcmp as kcmp(pid1, pid2, KCMP_EPOLL_TFD, fd, &kcmp_epoll_slot) - the kernel fetch file pointer matching file descriptor @fd of pid1 - lookups for file struct in epoll queue of pid2 and returns traditional 0,1,2 result for sorting purpose Link: http://lkml.kernel.org/r/20170424154423.511592110@gmail.com Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Andrey Vagin <avagin@openvz.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | kernel/sysctl_binary.c: check name array length in deprecated_sysctl_warning()Mateusz Jurczyk2017-07-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Prevent use of uninitialized memory (originating from the stack frame of do_sysctl()) by verifying that the name array is filled with sufficient input data before comparing its specific entries with integer constants. Through timing measurement or analyzing the kernel debug logs, a user-mode program could potentially infer the results of comparisons against the uninitialized memory, and acquire some (very limited) information about the state of the kernel stack. The change also eliminates possible future warnings by tools such as KMSAN and other code checkers / instrumentations. Link: http://lkml.kernel.org/r/20170524122139.21333-1-mjurczyk@google.com Signed-off-by: Mateusz Jurczyk <mjurczyk@google.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Matthew Whitehead <tedheadster@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | sysctl: add unsigned int range supportLuis R. Rodriguez2017-07-131-0/+66
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To keep parity with regular int interfaces provide the an unsigned int proc_douintvec_minmax() which allows you to specify a range of allowed valid numbers. Adding proc_douintvec_minmax_sysadmin() is easy but we can wait for an actual user for that. Link: http://lkml.kernel.org/r/20170519033554.18592-6-mcgrof@kernel.org Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Acked-by: Kees Cook <keescook@chromium.org> Cc: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Cc: Kees Cook <keescook@chromium.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | sysctl: simplify unsigned int supportLuis R. Rodriguez2017-07-131-7/+146
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32 fields") added proc_douintvec() to start help adding support for unsigned int, this however was only half the work needed. Two fixes have come in since then for the following issues: o Printing the values shows a negative value, this happens since do_proc_dointvec() and this uses proc_put_long() This was fixed by commit 5380e5644afbba9 ("sysctl: don't print negative flag for proc_douintvec"). o We can easily wrap around the int values: UINT_MAX is 4294967295, if we echo in 4294967295 + 1 we end up with 0, using 4294967295 + 2 we end up with 1. o We echo negative values in and they are accepted This was fixed by commit 425fffd886ba ("sysctl: report EINVAL if value is larger than UINT_MAX for proc_douintvec"). It still also failed to be added to sysctl_check_table()... instead of adding it with the current implementation just provide a proper and simplified unsigned int support without any array unsigned int support with no negative support at all. Historically sysctl proc helpers have supported arrays, due to the complexity this adds though we've taken a step back to evaluate array users to determine if its worth upkeeping for unsigned int. An evaluation using Coccinelle has been done to perform a grammatical search to ask ourselves: o How many sysctl proc_dointvec() (int) users exist which likely should be moved over to proc_douintvec() (unsigned int) ? Answer: about 8 - Of these how many are array users ? Answer: Probably only 1 o How many sysctl array users exist ? Answer: about 12 This last question gives us an idea just how popular arrays: they are not. Array support should probably just be kept for strings. The identified uint ports are: drivers/infiniband/core/ucma.c - max_backlog drivers/infiniband/core/iwcm.c - default_backlog net/core/sysctl_net_core.c - rps_sock_flow_sysctl() net/netfilter/nf_conntrack_timestamp.c - nf_conntrack_timestamp -- bool net/netfilter/nf_conntrack_acct.c nf_conntrack_acct -- bool net/netfilter/nf_conntrack_ecache.c - nf_conntrack_events -- bool net/netfilter/nf_conntrack_helper.c - nf_conntrack_helper -- bool net/phonet/sysctl.c proc_local_port_range() The only possible array users is proc_local_port_range() but it does not seem worth it to add array support just for this given the range support works just as well. Unsigned int support should be desirable more for when you *need* more than INT_MAX or using int min/max support then does not suffice for your ranges. If you forget and by mistake happen to register an unsigned int proc entry with an array, the driver will fail and you will get something as follows: sysctl table check failed: debug/test_sysctl//uint_0002 array now allowed CPU: 2 PID: 1342 Comm: modprobe Tainted: G W E <etc> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS <etc> Call Trace: dump_stack+0x63/0x81 __register_sysctl_table+0x350/0x650 ? kmem_cache_alloc_trace+0x107/0x240 __register_sysctl_paths+0x1b3/0x1e0 ? 0xffffffffc005f000 register_sysctl_table+0x1f/0x30 test_sysctl_init+0x10/0x1000 [test_sysctl] do_one_initcall+0x52/0x1a0 ? kmem_cache_alloc_trace+0x107/0x240 do_init_module+0x5f/0x200 load_module+0x1867/0x1bd0 ? __symbol_put+0x60/0x60 SYSC_finit_module+0xdf/0x110 SyS_finit_module+0xe/0x10 entry_SYSCALL_64_fastpath+0x1e/0xad RIP: 0033:0x7f042b22d119 <etc> Fixes: e7d316a02f68 ("sysctl: handle error writing UINT_MAX to u32 fields") Link: http://lkml.kernel.org/r/20170519033554.18592-5-mcgrof@kernel.org Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Suggested-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> Cc: Liping Zhang <zlpnobody@gmail.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Heinrich Schuchardt <xypron.glpk@gmx.de> Cc: Kees Cook <keescook@chromium.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | sysctl: fold sysctl_writes_strict checks into helperLuis R. Rodriguez2017-07-131-24/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The mode sysctl_writes_strict positional checks keep being copy and pasted as we add new proc handlers. Just add a helper to avoid code duplication. Link: http://lkml.kernel.org/r/20170519033554.18592-4-mcgrof@kernel.org Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Suggested-by: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | sysctl: kdoc'ify sysctl_writes_strictLuis R. Rodriguez2017-07-131-4/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Document the different sysctl_writes_strict modes in code. Link: http://lkml.kernel.org/r/20170519033554.18592-3-mcgrof@kernel.org Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | kdump: protect vmcoreinfo data under the crash memoryXunlei Pang2017-07-134-1/+71
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently vmcoreinfo data is updated at boot time subsys_initcall(), it has the risk of being modified by some wrong code during system is running. As a result, vmcore dumped may contain the wrong vmcoreinfo. Later on, when using "crash", "makedumpfile", etc utility to parse this vmcore, we probably will get "Segmentation fault" or other unexpected errors. E.g. 1) wrong code overwrites vmcoreinfo_data; 2) further crashes the system; 3) trigger kdump, then we obviously will fail to recognize the crash context correctly due to the corrupted vmcoreinfo. Now except for vmcoreinfo, all the crash data is well protected(including the cpu note which is fully updated in the crash path, thus its correctness is guaranteed). Given that vmcoreinfo data is a large chunk prepared for kdump, we better protect it as well. To solve this, we relocate and copy vmcoreinfo_data to the crash memory when kdump is loading via kexec syscalls. Because the whole crash memory will be protected by existing arch_kexec_protect_crashkres() mechanism, we naturally protect vmcoreinfo_data from write(even read) access under kernel direct mapping after kdump is loaded. Since kdump is usually loaded at the very early stage after boot, we can trust the correctness of the vmcoreinfo data copied. On the other hand, we still need to operate the vmcoreinfo safe copy when crash happens to generate vmcoreinfo_note again, we rely on vmap() to map out a new kernel virtual address and update to use this new one instead in the following crash_save_vmcoreinfo(). BTW, we do not touch vmcoreinfo_note, because it will be fully updated using the protected vmcoreinfo_data after crash which is surely correct just like the cpu crash note. Link: http://lkml.kernel.org/r/1493281021-20737-3-git-send-email-xlpang@redhat.com Signed-off-by: Xunlei Pang <xlpang@redhat.com> Tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Young <dyoung@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Juergen Gross <jgross@suse.com> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | powerpc/fadump: use the correct VMCOREINFO_NOTE_SIZE for phdrXunlei Pang2017-07-131-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | vmcoreinfo_max_size stands for the vmcoreinfo_data, the correct one we should use is vmcoreinfo_note whose total size is VMCOREINFO_NOTE_SIZE. Like explained in commit 77019967f06b ("kdump: fix exported size of vmcoreinfo note"), it should not affect the actual function, but we better fix it, also this change should be safe and backward compatible. After this, we can get rid of variable vmcoreinfo_max_size, let's use the corresponding macros directly, fewer variables means more safety for vmcoreinfo operation. [xlpang@redhat.com: fix build warning] Link: http://lkml.kernel.org/r/1494830606-27736-1-git-send-email-xlpang@redhat.com Link: http://lkml.kernel.org/r/1493281021-20737-2-git-send-email-xlpang@redhat.com Signed-off-by: Xunlei Pang <xlpang@redhat.com> Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Reviewed-by: Dave Young <dyoung@redhat.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Juergen Gross <jgross@suse.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | kexec: move vmcoreinfo out of the kernel's .bss sectionXunlei Pang2017-07-132-5/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As Eric said, "what we need to do is move the variable vmcoreinfo_note out of the kernel's .bss section. And modify the code to regenerate and keep this information in something like the control page. Definitely something like this needs a page all to itself, and ideally far away from any other kernel data structures. I clearly was not watching closely the data someone decided to keep this silly thing in the kernel's .bss section." This patch allocates extra pages for these vmcoreinfo_XXX variables, one advantage is that it enhances some safety of vmcoreinfo, because vmcoreinfo now is kept far away from other kernel data structures. Link: http://lkml.kernel.org/r/1493281021-20737-1-git-send-email-xlpang@redhat.com Signed-off-by: Xunlei Pang <xlpang@redhat.com> Tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Reviewed-by: Juergen Gross <jgross@suse.com> Suggested-by: Eric Biederman <ebiederm@xmission.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Young <dyoung@redhat.com> Cc: Hari Bathini <hbathini@linux.vnet.ibm.com> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | kernel/fork.c: virtually mapped stacks: do not disable interruptsChristoph Lameter2017-07-131-11/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The reason to disable interrupts seems to be to avoid switching to a different processor while handling per cpu data using individual loads and stores. If we use per cpu RMV primitives we will not have to disable interrupts. Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1705171055130.5898@east.gentwo.org Signed-off-by: Christoph Lameter <cl@linux.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | | | | Merge tag 'modules-for-v4.13' of ↵Linus Torvalds2017-07-132-53/+72
|\ \ \ \ \ \ \ | |/ / / / / / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux Pull modules updates from Jessica Yu: "Summary of modules changes for the 4.13 merge window: - Minor code cleanups - Avoid accessing mod struct prior to checking module struct version, from Kees - Fix racy atomic inc/dec logic of kmod_concurrent_max in kmod, from Luis" * tag 'modules-for-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux: module: make the modinfo name const kmod: reduce atomic operations on kmod_concurrent and simplify module: use list_for_each_entry_rcu() on find_module_all() kernel/module.c: suppress warning about unused nowarn variable module: Add module name to modinfo module: Pass struct load_info into symbol checks
| * | | | | | module: make the modinfo name constLuis R. Rodriguez2017-06-291-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This can be accomplished by making blacklisted() also accept const. Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Acked-by: Kees Cook <keescook@chromium.org> [jeyu: fix typo] Signed-off-by: Jessica Yu <jeyu@kernel.org>
| * | | | | | kmod: reduce atomic operations on kmod_concurrent and simplifyLuis R. Rodriguez2017-06-271-22/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When checking if we want to allow a kmod thread to kick off we increment, then read to see if we should enable a thread. If we were over the allowed limit limit we decrement. Splitting the increment far apart from decrement means there could be a time where two increments happen potentially giving a false failure on a thread which should have been allowed. CPU1 CPU2 atomic_inc() atomic_inc() atomic_read() atomic_read() atomic_dec() atomic_dec() In this case a read on CPU1 gets the atomic_inc()'s and we could negate it from getting a kmod thread. We could try to prevent this with a lock or preemption but that is overkill. We can fix by reducing the number of atomic operations. We do this by inverting the logic of of the enabler, instead of incrementing kmod_concurrent as we get new kmod users, define the variable kmod_concurrent_max as the max number of currently allowed kmod users and as we get new kmod users just decrement it if its still positive. This combines the dec and read in one atomic operation. In this case we no longer get the same false failure: CPU1 CPU2 atomic_dec_if_positive() atomic_dec_if_positive() atomic_inc() atomic_inc() The number of threads is computed at init, and since the current computation of kmod_concurrent includes the thread count we can avoid setting kmod_concurrent_max later in boot through an init call by simply sticking to 50 as the kmod_concurrent_max. The assumption here is a system with modules must at least have ~16 MiB of RAM. Suggested-by: Petr Mladek <pmladek@suse.com> Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jessica Yu <jeyu@kernel.org>
| * | | | | | module: use list_for_each_entry_rcu() on find_module_all()Luis R. Rodriguez2017-06-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The module list has been using RCU in a lot of other calls for a while now, we just overlooked changing this one over to use RCU. Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Jessica Yu <jeyu@kernel.org>
| * | | | | | kernel/module.c: suppress warning about unused nowarn variableCorentin Labbe2017-06-261-10/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fix the following warning: kernel/module.c: In function 'add_usage_links': kernel/module.c:1653:6: warning: variable 'nowarn' set but not used [-Wunused-but-set-variable] [jeyu: folded in first patch since it only swapped the function order so that del_usage_links can be called from add_usage_links] Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com> Signed-off-by: Jessica Yu <jeyu@kernel.org>
| * | | | | | module: Add module name to modinfoKees Cook2017-05-231-7/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Accessing the mod structure (e.g. for mod->name) prior to having completed check_modstruct_version() can result in writing garbage to the error logs if the layout of the mod structure loaded from disk doesn't match the running kernel's mod structure layout. This kind of mismatch will become much more likely if a kernel is built with different randomization seed for the struct layout randomization plugin. Instead, add and use a new modinfo string for logging the module name. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jessica Yu <jeyu@redhat.com>
| * | | | | | module: Pass struct load_info into symbol checksKees Cook2017-05-231-12/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since we're already using values from struct load_info, just pass this pointer in directly and use what's needed as we need it. This allows us to access future fields in struct load_info too. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jessica Yu <jeyu@redhat.com>
* | | | | | | fix a braino in compat_sys_getrlimit()Al Viro2017-07-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reported-and-tested-by: Meelis Roos <mroos@linux.ee> Fixes: commit d9e968cb9f84 "getrlimit()/setrlimit(): move compat to native" Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | | | | Merge branch 'akpm' (patches from Andrew)Linus Torvalds2017-07-118-38/+28
|\ \ \ \ \ \ \ | |_|_|/ / / / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge more updates from Andrew Morton: - most of the rest of MM - KASAN updates - lib/ updates - checkpatch updates - some binfmt_elf changes - various misc bits * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (115 commits) kernel/exit.c: avoid undefined behaviour when calling wait4() kernel/signal.c: avoid undefined behaviour in kill_something_info binfmt_elf: safely increment argv pointers s390: reduce ELF_ET_DYN_BASE powerpc: move ELF_ET_DYN_BASE to 4GB / 4MB arm64: move ELF_ET_DYN_BASE to 4GB / 4MB arm: move ELF_ET_DYN_BASE to 4MB binfmt_elf: use ELF_ET_DYN_BASE only for PIE fs, epoll: short circuit fetching events if thread has been killed checkpatch: improve multi-line alignment test checkpatch: improve macro reuse test checkpatch: change format of --color argument to --color[=WHEN] checkpatch: silence perl 5.26.0 unescaped left brace warnings checkpatch: improve tests for multiple line function definitions checkpatch: remove false warning for commit reference checkpatch: fix stepping through statements with $stat and ctx_statement_block checkpatch: [HLP]LIST_HEAD is also declaration checkpatch: warn when a MAINTAINERS entry isn't [A-Z]:\t checkpatch: improve the unnecessary OOM message test lib/bsearch.c: micro-optimize pivot position calculation ...
| * | | | | | kernel/exit.c: avoid undefined behaviour when calling wait4()zhongjiang2017-07-111-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wait4(-2147483648, 0x20, 0, 0xdd0000) triggers: UBSAN: Undefined behaviour in kernel/exit.c:1651:9 The related calltrace is as follows: negation of -2147483648 cannot be represented in type 'int': CPU: 9 PID: 16482 Comm: zj Tainted: G B ---- ------- 3.10.0-327.53.58.71.x86_64+ #66 Hardware name: Huawei Technologies Co., Ltd. Tecal RH2285 /BC11BTSA , BIOS CTSAV036 04/27/2011 Call Trace: dump_stack+0x19/0x1b ubsan_epilogue+0xd/0x50 __ubsan_handle_negate_overflow+0x109/0x14e SyS_wait4+0x1cb/0x1e0 system_call_fastpath+0x16/0x1b Exclude the overflow to avoid the UBSAN warning. Link: http://lkml.kernel.org/r/1497264618-20212-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhongjiang <zhongjiang@huawei.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | kernel/signal.c: avoid undefined behaviour in kill_something_infozhongjiang2017-07-111-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When running kill(72057458746458112, 0) in userspace I hit the following issue. UBSAN: Undefined behaviour in kernel/signal.c:1462:11 negation of -2147483648 cannot be represented in type 'int': CPU: 226 PID: 9849 Comm: test Tainted: G B ---- ------- 3.10.0-327.53.58.70.x86_64_ubsan+ #116 Hardware name: Huawei Technologies Co., Ltd. RH8100 V3/BC61PBIA, BIOS BLHSV028 11/11/2014 Call Trace: dump_stack+0x19/0x1b ubsan_epilogue+0xd/0x50 __ubsan_handle_negate_overflow+0x109/0x14e SYSC_kill+0x43e/0x4d0 SyS_kill+0xe/0x10 system_call_fastpath+0x16/0x1b Add code to avoid the UBSAN detection. [akpm@linux-foundation.org: tweak comment] Link: http://lkml.kernel.org/r/1496670008-59084-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhongjiang <zhongjiang@huawei.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Xishi Qiu <qiuxishi@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | lib/extable.c: use bsearch() library function in search_extable()Thomas Meyer2017-07-112-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [thomas@m3y3r.de: v3: fix arch specific implementations] Link: http://lkml.kernel.org/r/1497890858.12931.7.camel@m3y3r.de Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | kernel/kallsyms.c: replace all_var with IS_ENABLED(CONFIG_KALLSYMS_ALL)Masahiro Yamada2017-07-111-8/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'all_var' looks like a variable, but is actually a macro. Use IS_ENABLED(CONFIG_KALLSYMS_ALL) for clarification. Link: http://lkml.kernel.org/r/1497577591-3434-1-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | | | kernel/groups.c: use sort library functionRasmus Villemoes2017-07-111-24/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | setgroups is not exactly a hot path, so we might as well use the library function instead of open-coding the sorting. Saves ~150 bytes. Link: http://lkml.kernel.org/r/1497301378-22739-1-git-send-email-linux@rasmusvillemoes.dk Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>