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* workqueue: make workqueue available early during bootTejun Heo2016-09-173-17/+76
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Workqueue is currently initialized in an early init call; however, there are cases where early boot code has to be split and reordered to come after workqueue initialization or the same code path which makes use of workqueues is used both before workqueue initailization and after. The latter cases have to gate workqueue usages with keventd_up() tests, which is nasty and easy to get wrong. Workqueue usages have become widespread and it'd be a lot more convenient if it can be used very early from boot. This patch splits workqueue initialization into two steps. workqueue_init_early() which sets up the basic data structures so that workqueues can be created and work items queued, and workqueue_init() which actually brings up workqueues online and starts executing queued work items. The former step can be done very early during boot once memory allocation, cpumasks and idr are initialized. The latter right after kthreads become available. This allows work item queueing and canceling from very early boot which is what most of these use cases want. * As systemd_wq being initialized doesn't indicate that workqueue is fully online anymore, update keventd_up() to test wq_online instead. The follow-up patches will get rid of all its usages and the function itself. * Flushing doesn't make sense before workqueue is fully initialized. The flush functions trigger WARN and return immediately before fully online. * Work items are never in-flight before fully online. Canceling can always succeed by skipping the flush step. * Some code paths can no longer assume to be called with irq enabled as irq is disabled during early boot. Use irqsave/restore operations instead. v2: Watchdog init, which requires timer to be running, moved from workqueue_init_early() to workqueue_init(). Signed-off-by: Tejun Heo <tj@kernel.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/CA+55aFx0vPuMuxn00rBSM192n-Du5uxy+4AvKa0SBSOVJeuCGg@mail.gmail.com
* workqueue: dump workqueue state on sanity check failures in destroy_workqueue()Tejun Heo2016-09-161-0/+2
| | | | | | | | | | | | destroy_workqueue() performs a number of sanity checks to ensure that the workqueue is empty before proceeding with destruction. However, it's not always easy to tell what's going on just from the warning message. Let's dump workqueue state after sanity check failures to help debugging. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/CACT4Y+Zs6vkjHo9qHb4TrEiz3S4+quvvVQ9VWvj2Mx6pETGb9Q@mail.gmail.com Cc: Dmitry Vyukov <dvyukov@google.com>
* Merge branch 'uaccess-fixes' of ↵Linus Torvalds2016-09-1426-170/+179
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull uaccess fixes from Al Viro: "Fixes for broken uaccess primitives - mostly lack of proper zeroing in copy_from_user()/get_user()/__get_user(), but for several architectures there's more (broken clear_user() on frv and strncpy_from_user() on hexagon)" * 'uaccess-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits) avr32: fix copy_from_user() microblaze: fix __get_user() microblaze: fix copy_from_user() m32r: fix __get_user() blackfin: fix copy_from_user() sparc32: fix copy_from_user() sh: fix copy_from_user() sh64: failing __get_user() should zero score: fix copy_from_user() and friends score: fix __get_user/get_user s390: get_user() should zero on failure ppc32: fix copy_from_user() parisc: fix copy_from_user() openrisc: fix copy_from_user() nios2: fix __get_user() nios2: copy_from_user() should zero the tail of destination mn10300: copy_from_user() should zero on access_ok() failure... mn10300: failing __get_user() and get_user() should zero mips: copy_from_user() must zero the destination on access_ok() failure ARC: uaccess: get_user to zero out dest in cause of fault ...
| * avr32: fix copy_from_user()Al Viro2016-09-133-4/+13
| | | | | | | | | | | | | | | | | | really ugly, but apparently avr32 compilers turns access_ok() into something so bad that they want it in assembler. Left that way, zeroing added in inline wrapper. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * microblaze: fix __get_user()Al Viro2016-09-131-1/+1
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * microblaze: fix copy_from_user()Al Viro2016-09-131-3/+6
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * m32r: fix __get_user()Al Viro2016-09-131-1/+1
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * blackfin: fix copy_from_user()Al Viro2016-09-131-4/+5
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * sparc32: fix copy_from_user()Al Viro2016-09-131-1/+3
| | | | | | | | | | | | Cc: stable@vger.kernel.org Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * sh: fix copy_from_user()Al Viro2016-09-131-1/+4
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * sh64: failing __get_user() should zeroAl Viro2016-09-131-0/+1
| | | | | | | | | | | | | | | | | | It could be done in exception-handling bits in __get_user_b() et.al., but the surgery involved would take more knowledge of sh64 details than I have or _want_ to have. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * score: fix copy_from_user() and friendsAl Viro2016-09-131-21/+20
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * score: fix __get_user/get_userAl Viro2016-09-131-1/+4
| | | | | | | | | | | | | | | | * should zero on any failure * __get_user() should use __copy_from_user(), not copy_from_user() Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * s390: get_user() should zero on failureAl Viro2016-09-131-4/+4
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * ppc32: fix copy_from_user()Al Viro2016-09-131-23/+2
| | | | | | | | | | | | | | | | should clear on access_ok() failures. Also remove the useless range truncation logics. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * parisc: fix copy_from_user()Al Viro2016-09-131-2/+4
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * openrisc: fix copy_from_user()Al Viro2016-09-131-24/+11
| | | | | | | | | | | | | | | | | | | | | | ... that should zero on faults. Also remove the <censored> helpful logics wrt range truncation copied from ppc32. Where it had ever been needed only in case of copy_from_user() *and* had not been merged into the mainline until a month after the need had disappeared. A decade before openrisc went into mainline, I might add... Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * nios2: fix __get_user()Al Viro2016-09-131-2/+2
| | | | | | | | | | | | | | | | a) should not leave crap on fault b) should _not_ require access_ok() in any cases. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * nios2: copy_from_user() should zero the tail of destinationAl Viro2016-09-131-3/+6
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * mn10300: copy_from_user() should zero on access_ok() failure...Al Viro2016-09-131-1/+3
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * mn10300: failing __get_user() and get_user() should zeroAl Viro2016-09-131-0/+1
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * mips: copy_from_user() must zero the destination on access_ok() failureAl Viro2016-09-131-0/+3
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * ARC: uaccess: get_user to zero out dest in cause of faultVineet Gupta2016-09-131-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Al reported potential issue with ARC get_user() as it wasn't clearing out destination pointer in case of fault due to bad address etc. Verified using following | { | u32 bogus1 = 0xdeadbeef; | u64 bogus2 = 0xdead; | int rc1, rc2; | | pr_info("Orig values %x %llx\n", bogus1, bogus2); | rc1 = get_user(bogus1, (u32 __user *)0x40000000); | rc2 = get_user(bogus2, (u64 __user *)0x50000000); | pr_info("access %d %d, new values %x %llx\n", | rc1, rc2, bogus1, bogus2); | } | [ARCLinux]# insmod /mnt/kernel-module/qtn.ko | Orig values deadbeef dead | access -14 -14, new values 0 0 Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-snps-arc@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * metag: copy_from_user() should zero the destination on access_ok() failureAl Viro2016-09-131-1/+2
| | | | | | | | | | | | Cc: stable@vger.kernel.org Acked-by: James Hogan <james.hogan@imgtec.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * ia64: copy_from_user() should zero the destination on access_ok() failureAl Viro2016-09-131-14/+11
| | | | | | | | | | Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * hexagon: fix strncpy_from_user() error returnAl Viro2016-09-131-1/+2
| | | | | | | | | | | | | | | | | | It's -EFAULT, not -1 (and contrary to the comment in there, __strnlen_user() can return 0 - on faults). Cc: stable@vger.kernel.org Acked-by: Richard Kuo <rkuo@codeaurora.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * frv: fix clear_user()Al Viro2016-09-131-3/+9
| | | | | | | | | | | | | | | | It should check access_ok(). Otherwise a bunch of places turn into trivially exploitable rootholes. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * cris: buggered copy_from_user/copy_to_user/clear_userAl Viro2016-09-131-39/+32
| | | | | | | | | | | | | | | | | | | | * copy_from_user() on access_ok() failure ought to zero the destination * none of those primitives should skip the access_ok() check in case of small constant size. Cc: stable@vger.kernel.org Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * asm-generic: make get_user() clear the destination on errorsAl Viro2016-09-131-3/+7
| | | | | | | | | | | | | | both for access_ok() failures and for faults halfway through Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * asm-generic: make copy_from_user() zero the destination properlyAl Viro2016-09-101-4/+6
| | | | | | | | | | | | | | | | | | | | | | ... in all cases, including the failing access_ok() Note that some architectures using asm-generic/uaccess.h have __copy_from_user() not zeroing the tail on failure halfway through. This variant works either way. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * alpha: fix copy_from_user()Al Viro2016-09-101-11/+8
| | | | | | | | | | | | | | it should clear the destination even when access_ok() fails. Cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge tag 'for-linus-4.8b-rc6-tag' of ↵Linus Torvalds2016-09-141-4/+3
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen regression fix from David Vrabel: "Fix SMP boot in arm guests" * tag 'for-linus-4.8b-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: arm/xen: fix SMP guests boot
| * | arm/xen: fix SMP guests bootVitaly Kuznetsov2016-09-141-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 88e957d6e47f ("xen: introduce xen_vcpu_id mapping") broke SMP ARM guests on Xen. When FIFO-based event channels are in use (this is the default), evtchn_fifo_alloc_control_block() is called on CPU_UP_PREPARE event and this happens before we set up xen_vcpu_id mapping in xen_starting_cpu. Temporary fix the issue by setting direct Linux CPU id <-> Xen vCPU id mapping for all possible CPUs at boot. We don't currently support kexec/kdump on Xen/ARM so these ids always match. In future, we have several ways to solve the issue, e.g.: - Eliminate all hypercalls from CPU_UP_PREPARE, do them from the starting CPU. This can probably be done for both x86 and ARM and, if done, will allow us to get Xen's idea of vCPU id from CPUID/MPIDR on the starting CPU directly, no messing with ACPI/device tree required. - Save vCPU id information from ACPI/device tree on ARM and use it to initialize xen_vcpu_id mapping. This is the same trick we currently do on x86. Reported-by: Julien Grall <julien.grall@arm.com> Tested-by: Wei Chen <Wei.Chen@arm.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Acked-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
* | | Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds2016-09-133-7/+16
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 fixes from Ingo Molnar: "Three fixes: - AMD microcode loading fix with randomization - an lguest tooling fix - and an APIC enumeration boundary condition fix" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/apic: Fix num_processors value in case of failure tools/lguest: Don't bork the terminal in case of wrong args x86/microcode/AMD: Fix load of builtin microcode with randomized memory
| * | | x86/apic: Fix num_processors value in case of failureDou Liyang2016-09-081-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the topology package map check of the APIC ID and the CPU is a failure, we don't generate the processor info for that APIC ID yet we increase disabled_cpus by one - which is buggy. Only increase num_processors once we are sure we don't fail. Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1473214893-16481-1-git-send-email-douly.fnst@cn.fujitsu.com [ Rewrote the changelog. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | tools/lguest: Don't bork the terminal in case of wrong argsDaniel Baluta2016-09-081-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Running lguest without arguments or with a wrong argument name borks the terminal, because the cleanup handler is set up too late in the initialization process. Signed-off-by: Daniel Baluta <daniel.baluta@intel.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | x86/microcode/AMD: Fix load of builtin microcode with randomized memoryBorislav Petkov2016-09-051-3/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We do not need to add the randomization offset when the microcode is built in. Reported-and-tested-by: Emanuel Czirai <icanrealizeum@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20160904093736.GA11939@pd.tnic Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2016-09-131-0/+22
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fix from Ingo Molnar: "A try_to_wake_up() memory ordering race fix causing a busy-loop in ttwu()" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/core: Fix a race between try_to_wake_up() and a woken up task
| * | | | sched/core: Fix a race between try_to_wake_up() and a woken up taskBalbir Singh2016-09-051-0/+22
| |/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The origin of the issue I've seen is related to a missing memory barrier between check for task->state and the check for task->on_rq. The task being woken up is already awake from a schedule() and is doing the following: do { schedule() set_current_state(TASK_(UN)INTERRUPTIBLE); } while (!cond); The waker, actually gets stuck doing the following in try_to_wake_up(): while (p->on_cpu) cpu_relax(); Analysis: The instance I've seen involves the following race: CPU1 CPU2 while () { if (cond) break; do { schedule(); set_current_state(TASK_UN..) } while (!cond); wakeup_routine() spin_lock_irqsave(wait_lock) raw_spin_lock_irqsave(wait_lock) wake_up_process() } try_to_wake_up() set_current_state(TASK_RUNNING); .. list_del(&waiter.list); CPU2 wakes up CPU1, but before it can get the wait_lock and set current state to TASK_RUNNING the following occurs: CPU3 wakeup_routine() raw_spin_lock_irqsave(wait_lock) if (!list_empty) wake_up_process() try_to_wake_up() raw_spin_lock_irqsave(p->pi_lock) .. if (p->on_rq && ttwu_wakeup()) .. while (p->on_cpu) cpu_relax() .. CPU3 tries to wake up the task on CPU1 again since it finds it on the wait_queue, CPU1 is spinning on wait_lock, but immediately after CPU2, CPU3 got it. CPU3 checks the state of p on CPU1, it is TASK_UNINTERRUPTIBLE and the task is spinning on the wait_lock. Interestingly since p->on_rq is checked under pi_lock, I've noticed that try_to_wake_up() finds p->on_rq to be 0. This was the most confusing bit of the analysis, but p->on_rq is changed under runqueue lock, rq_lock, the p->on_rq check is not reliable without this fix IMHO. The race is visible (based on the analysis) only when ttwu_queue() does a remote wakeup via ttwu_queue_remote. In which case the p->on_rq change is not done uder the pi_lock. The result is that after a while the entire system locks up on the raw_spin_irqlock_save(wait_lock) and the holder spins infintely Reproduction of the issue: The issue can be reproduced after a long run on my system with 80 threads and having to tweak available memory to very low and running memory stress-ng mmapfork test. It usually takes a long time to reproduce. I am trying to work on a test case that can reproduce the issue faster, but thats work in progress. I am still testing the changes on my still in a loop and the tests seem OK thus far. Big thanks to Benjamin and Nick for helping debug this as well. Ben helped catch the missing barrier, Nick caught every missing bit in my theory. Signed-off-by: Balbir Singh <bsingharora@gmail.com> [ Updated comment to clarify matching barriers. Many architectures do not have a full barrier in switch_to() so that cannot be relied upon. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Alexey Kardashevskiy <aik@ozlabs.ru> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <nicholas.piggin@gmail.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/e02cce7b-d9ca-1ad0-7a61-ea97c7582b37@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds2016-09-136-55/+180
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: "This contains: - a set of fixes found by directed-random perf fuzzing efforts by Vince Weaver, Alexander Shishkin and Peter Zijlstra - a cqm driver crash fix - an AMD uncore driver use after free fix" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/intel: Fix PEBSv3 record drain perf/x86/intel/bts: Kill a silly warning perf/x86/intel/bts: Fix BTS PMI detection perf/x86/intel/bts: Fix confused ordering of PMU callbacks perf/core: Fix aux_mmap_count vs aux_refcount order perf/core: Fix a race between mmap_close() and set_output() of AUX events perf/x86/amd/uncore: Prevent use after free perf/x86/intel/cqm: Check cqm/mbm enabled state in event init perf/core: Remove WARN from perf_event_read()
| * | | | perf/x86/intel: Fix PEBSv3 record drainPeter Zijlstra2016-09-101-8/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Alexander hit the WARN_ON_ONCE(!event) on his Skylake while running the perf fuzzer. This means the PEBSv3 record included a status bit for an inactive event, something that _should_ not happen. Move the code that filters the status bits against our known PEBS events up a spot to guarantee we only deal with events we know about. Further add "continue" statements to the WARN_ON_ONCE()s such that we'll not die nor generate silly events in case we ever do hit them again. Reported-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Tested-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vince@deater.net> Cc: stable@vger.kernel.org Fixes: a3d86542de88 ("perf/x86/intel/pebs: Add PEBSv3 decoding") Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | perf/x86/intel/bts: Kill a silly warningAlexander Shishkin2016-09-101-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | At the moment, intel_bts will WARN() out if there is more than one event writing to the same ring buffer, via SET_OUTPUT, and will only send data from one event to a buffer. There is no reason to have this warning in, so kill it. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: vince@deater.net Link: http://lkml.kernel.org/r/20160906132353.19887-6-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | perf/x86/intel/bts: Fix BTS PMI detectionAlexander Shishkin2016-09-101-4/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since BTS doesn't have a dedicated PMI status bit, the driver needs to take extra care to check for the condition that triggers it to avoid spurious NMI warnings. Regardless of the local BTS context state, the only way of knowing that the NMI is ours is to compare the write pointer against the interrupt threshold. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: vince@deater.net Link: http://lkml.kernel.org/r/20160906132353.19887-5-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | perf/x86/intel/bts: Fix confused ordering of PMU callbacksAlexander Shishkin2016-09-101-24/+80
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The intel_bts driver is using a CPU-local 'started' variable to order callbacks and PMIs and make sure that AUX transactions don't get messed up. However, the ordering rules in regard to this variable is a complete mess, which recently resulted in perf_fuzzer-triggered warnings and panics. The general ordering rule that is patch is enforcing is that this cpu-local variable be set only when the cpu-local AUX transaction is active; consequently, this variable is to be checked before the AUX related bits can be touched. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: vince@deater.net Link: http://lkml.kernel.org/r/20160906132353.19887-4-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | perf/core: Fix aux_mmap_count vs aux_refcount orderAlexander Shishkin2016-09-101-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The order of accesses to ring buffer's aux_mmap_count and aux_refcount has to be preserved across the users, namely perf_mmap_close() and perf_aux_output_begin(), otherwise the inversion can result in the latter holding the last reference to the aux buffer and subsequently free'ing it in atomic context, triggering a warning. > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 257 at kernel/events/ring_buffer.c:541 __rb_free_aux+0x11a/0x130 > CPU: 0 PID: 257 Comm: stopbug Not tainted 4.8.0-rc1+ #2596 > Call Trace: > [<ffffffff810f3e0b>] __warn+0xcb/0xf0 > [<ffffffff810f3f3d>] warn_slowpath_null+0x1d/0x20 > [<ffffffff8121182a>] __rb_free_aux+0x11a/0x130 > [<ffffffff812127a8>] rb_free_aux+0x18/0x20 > [<ffffffff81212913>] perf_aux_output_begin+0x163/0x1e0 > [<ffffffff8100c33a>] bts_event_start+0x3a/0xd0 > [<ffffffff8100c42d>] bts_event_add+0x5d/0x80 > [<ffffffff81203646>] event_sched_in.isra.104+0xf6/0x2f0 > [<ffffffff8120652e>] group_sched_in+0x6e/0x190 > [<ffffffff8120694e>] ctx_sched_in+0x2fe/0x5f0 > [<ffffffff81206ca0>] perf_event_sched_in+0x60/0x80 > [<ffffffff81206d1b>] ctx_resched+0x5b/0x90 > [<ffffffff81207281>] __perf_event_enable+0x1e1/0x240 > [<ffffffff81200639>] event_function+0xa9/0x180 > [<ffffffff81202000>] ? perf_cgroup_attach+0x70/0x70 > [<ffffffff8120203f>] remote_function+0x3f/0x50 > [<ffffffff811971f3>] flush_smp_call_function_queue+0x83/0x150 > [<ffffffff81197bd3>] generic_smp_call_function_single_interrupt+0x13/0x60 > [<ffffffff810a6477>] smp_call_function_single_interrupt+0x27/0x40 > [<ffffffff81a26ea9>] call_function_single_interrupt+0x89/0x90 > [<ffffffff81120056>] finish_task_switch+0xa6/0x210 > [<ffffffff81120017>] ? finish_task_switch+0x67/0x210 > [<ffffffff81a1e83d>] __schedule+0x3dd/0xb50 > [<ffffffff81a1efe5>] schedule+0x35/0x80 > [<ffffffff81128031>] sys_sched_yield+0x61/0x70 > [<ffffffff81a25be5>] entry_SYSCALL_64_fastpath+0x18/0xa8 > ---[ end trace 6235f556f5ea83a9 ]--- This patch puts the checks in perf_aux_output_begin() in the same order as that of perf_mmap_close(). Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: vince@deater.net Link: http://lkml.kernel.org/r/20160906132353.19887-3-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | perf/core: Fix a race between mmap_close() and set_output() of AUX eventsAlexander Shishkin2016-09-101-6/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the mmap_close() path we need to stop all the AUX events that are writing data to the AUX area that we are unmapping, before we can safely free the pages. To determine if an event needs to be stopped, we're comparing its ->rb against the one that's getting unmapped. However, a SET_OUTPUT ioctl may turn up inside an AUX transaction and swizzle event::rb to some other ring buffer, but the transaction will keep writing data to the old ring buffer until the event gets scheduled out. At this point, mmap_close() will skip over such an event and will proceed to free the AUX area, while it's still being used by this event, which will set off a warning in the mmap_close() path and cause a memory corruption. To avoid this, always stop an AUX event before its ->rb is updated; this will release the (potentially) last reference on the AUX area of the buffer. If the event gets restarted, its new ring buffer will be used. If another SET_OUTPUT comes and switches it back to the old ring buffer that's getting unmapped, it's also fine: this ring buffer's aux_mmap_count will be zero and AUX transactions won't start any more. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: vince@deater.net Link: http://lkml.kernel.org/r/20160906132353.19887-2-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | perf/x86/amd/uncore: Prevent use after freeSebastian Andrzej Siewior2016-09-101-4/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The resent conversion of the cpu hotplug support in the uncore driver introduced a regression due to the way the callbacks are invoked at initialization time. The old code called the prepare/starting/online function on each online cpu as a block. The new code registers the hotplug callbacks in the core for each state. The core invokes the callbacks at each registration on all online cpus. The code implicitely relied on the prepare/starting/online callbacks being called as combo on a particular cpu, which was not obvious and completely undocumented. The resulting subtle wreckage happens due to the way how the uncore code manages shared data structures for cpus which share an uncore resource in hardware. The sharing is determined in the cpu starting callback, but the prepare callback allocates per cpu data for the upcoming cpu because potential sharing is unknown at this point. If the starting callback finds a online cpu which shares the hardware resource it takes a refcount on the percpu data of that cpu and puts the own data structure into a 'free_at_online' pointer of that shared data structure. The online callback frees that. With the old model this worked because in a starting callback only one non unused structure (the one of the starting cpu) was available. The new code allocates the data structures for all cpus when the prepare callback is registered. Now the starting function iterates through all online cpus and looks for a data structure (skipping its own) which has a matching hardware id. The id member of the data structure is initialized to 0, but the hardware id can be 0 as well. The resulting wreckage is: CPU0 finds a matching id on CPU1, takes a refcount on CPU1 data and puts its own data structure into CPU1s data structure to be freed. CPU1 skips CPU0 because the data structure is its allegedly unsued own. It finds a matching id on CPU2, takes a refcount on CPU1 data and puts its own data structure into CPU2s data structure to be freed. .... Now the online callbacks are invoked. CPU0 has a pointer to CPU1s data and frees the original CPU0 data. So far so good. CPU1 has a pointer to CPU2s data and frees the original CPU1 data, which is still referenced by CPU0 ---> Booom So there are two issues to be solved here: 1) The id field must be initialized at allocation time to a value which cannot be a valid hardware id, i.e. -1 This prevents the above scenario, but now CPU1 and CPU2 both stick their own data structure into the free_at_online pointer of CPU0. So we leak CPU1s data structure. 2) Fix the memory leak described in #1 Instead of having a single pointer, use a hlist to enqueue the superflous data structures which are then freed by the first cpu invoking the online callback. Ideally we should know the sharing _before_ invoking the prepare callback, but that's way beyond the scope of this bug fix. [ tglx: Rewrote changelog ] Fixes: 96b2bd3866a0 ("perf/x86/amd/uncore: Convert to hotplug state machine") Reported-and-tested-by: Eric Sandeen <sandeen@sandeen.net> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Borislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20160909160822.lowgmkdwms2dheyv@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | perf/x86/intel/cqm: Check cqm/mbm enabled state in event initJiri Olsa2016-09-061-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Yanqiu Zhang reported kernel panic when using mbm event on system where CQM is detected but without mbm event support, like with perf: # perf stat -e 'intel_cqm/event=3/' -a BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 IP: [<ffffffff8100d64c>] update_sample+0xbc/0xe0 ... <IRQ> [<ffffffff8100d688>] __intel_mbm_event_init+0x18/0x20 [<ffffffff81113d6b>] flush_smp_call_function_queue+0x7b/0x160 [<ffffffff81114853>] generic_smp_call_function_single_interrupt+0x13/0x60 [<ffffffff81052017>] smp_call_function_interrupt+0x27/0x40 [<ffffffff816fb06c>] call_function_interrupt+0x8c/0xa0 ... The reason is that we currently allow to init mbm event even if mbm support is not detected. Adding checks for both cqm and mbm events and support into cqm's event_init. Fixes: 33c3cc7acfd9 ("perf/x86/mbm: Add Intel Memory B/W Monitoring enumeration and init") Reported-by: Yanqiu Zhang <yanqzhan@redhat.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1473089407-21857-1-git-send-email-jolsa@kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | perf/core: Remove WARN from perf_event_read()Peter Zijlstra2016-09-051-4/+12
| |/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This effectively reverts commit: 71e7bc2bab77 ("perf/core: Check return value of the perf_event_read() IPI") ... and puts in a comment explaining why we ignore the return value. Reported-by: Vegard Nossum <vegard.nossum@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Carrillo-Cisneros <davidcc@google.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 71e7bc2bab77 ("perf/core: Check return value of the perf_event_read() IPI") Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds2016-09-131-3/+4
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fix from Ingo Molnar: "Another lockless_dereference() Sparse fix" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/barriers: Don't use sizeof(void) in lockless_dereference()
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