On 03/27/2014 11:33 AM, Sasha Levin wrote:
On 03/27/2014 11:11 AM, Sasha Levin wrote:
Hi all,
While fuzzing with trinity inside a KVM tools guest running latest -next
kernel I've stumbled on the following:
And another similar trace from a different vm:
[ 2696.454601] ======================================================
[ 2696.455460] [ INFO: possible circular locking dependency detected ]
[ 2696.456327] 3.14.0-rc8-next-20140326-sasha-00018-gffbc974-dirty #285 Not
tainted
[ 2696.457227] -------------------------------------------------------
[ 2696.457898] trinity-c31/26818 is trying to acquire lock:
[ 2696.458495] (&(&pool->lock)->rlock){-.-.-.}, at: __queue_work
(kernel/workqueue.c:1358)
[ 2696.459829]
[ 2696.459829] but task is already holding lock:
[ 2696.460315] (&ctx->lock){-.-...}, at: perf_event_exit_task
(kernel/events/core.c:7415 kernel/events/core.c:7492)
[ 2696.461706]
[ 2696.461706] which lock already depends on the new lock.
[ 2696.461706]
[ 2696.461706]
[ 2696.461706] the existing dependency chain (in reverse order) is:
[ 2696.461706]
-> #3 (&ctx->lock){-.-...}:
[ 2696.461706] lock_acquire (arch/x86/include/asm/current.h:14
kernel/locking/lockdep.c:3602)
[ 2696.461706] _raw_spin_lock (include/linux/spinlock_api_smp.h:143
kernel/locking/spinlock.c:151)
[ 2696.461706] __perf_event_task_sched_out (kernel/events/core.c:2340
kernel/events/core.c:2366)
[ 2696.461706] perf_event_task_sched_out (include/linux/perf_event.h:689)
[ 2696.461706] __schedule (kernel/sched/core.c:2064
kernel/sched/core.c:2102 kernel/sched/core.c:2226 kernel/sched/core.c:2713)
[ 2696.461706] preempt_schedule (arch/x86/include/asm/preempt.h:80
kernel/sched/core.c:2798)
[ 2696.461706] ___preempt_schedule (arch/x86/kernel/preempt.S:11)
[ 2696.461706] text_poke_bp (arch/x86/kernel/alternative.c:655)
[ 2696.461706] arch_jump_label_transform
(arch/x86/kernel/jump_label.c:111)
[ 2696.461706] __jump_label_update (kernel/jump_label.c:177)
[ 2696.461706] jump_label_update (kernel/jump_label.c:458)
[ 2696.461706] static_key_slow_inc (kernel/jump_label.c:68)
[ 2696.461706] tracepoint_update_probe_range (kernel/tracepoint.c:278
kernel/tracepoint.c:319)
[ 2696.461706] tracepoint_update_probes (kernel/tracepoint.c:354)
[ 2696.461706] tracepoint_probe_register (kernel/tracepoint.c:407)
[ 2696.461706] syscall_exit_register (kernel/trace/trace_syscalls.c:681
kernel/trace/trace_syscalls.c:750)
[ 2696.461706] perf_trace_init (kernel/trace/trace_event_perf.c:108
kernel/trace/trace_event_perf.c:182 kernel/trace/trace_event_perf.c:206)
[ 2696.461706] perf_tp_event_init (kernel/events/core.c:5937)
[ 2696.461706] perf_init_event (kernel/events/core.c:6598)
[ 2696.461706] perf_event_alloc (kernel/events/core.c:6754)
[ 2696.461706] SYSC_perf_event_open (kernel/events/core.c:7062)
[ 2696.461706] SyS_perf_event_open (kernel/events/core.c:6990)
[ 2696.461706] tracesys (arch/x86/kernel/entry_64.S:749)
[ 2696.461706]
-> #2 (&rq->lock){-.-.-.}:
[ 2696.461706] lock_acquire (arch/x86/include/asm/current.h:14
kernel/locking/lockdep.c:3602)
[ 2696.461706] _raw_spin_lock (include/linux/spinlock_api_smp.h:143
kernel/locking/spinlock.c:151)
[ 2696.461706] wake_up_new_task (include/linux/sched.h:2884
kernel/sched/core.c:313 kernel/sched/core.c:2014)
[ 2696.461706] do_fork (kernel/fork.c:1627)
[ 2696.461706] kernel_thread (kernel/fork.c:1647)
[ 2696.461706] rest_init (init/main.c:383)
[ 2696.461706] start_kernel (init/main.c:653)
[ 2696.461706] x86_64_start_reservations (arch/x86/kernel/head64.c:194)
[ 2696.461706] x86_64_start_kernel (arch/x86/kernel/head64.c:183)
[ 2696.461706]
-> #1 (&p->pi_lock){-.-.-.}:
[ 2696.461706] lock_acquire (arch/x86/include/asm/current.h:14
kernel/locking/lockdep.c:3602)
[ 2696.461706] _raw_spin_lock_irqsave
(include/linux/spinlock_api_smp.h:117 kernel/locking/spinlock.c:159)
[ 2696.461706] try_to_wake_up (kernel/sched/core.c:1592)
[ 2696.461706] wake_up_process (kernel/sched/core.c:1688 (discriminator
2))
[ 2696.461706] start_worker (kernel/workqueue.c:1800)
[ 2696.461706] create_and_start_worker (include/linux/spinlock.h:353
kernel/workqueue.c:1820)
[ 2696.461706] init_workqueues (kernel/workqueue.c:5061)
[ 2696.461706] do_one_initcall (init/main.c:696)
[ 2696.461706] kernel_init_freeable (init/main.c:797 init/main.c:904)
[ 2696.461706] kernel_init (init/main.c:842)
[ 2696.461706] ret_from_fork (arch/x86/kernel/entry_64.S:555)
[ 2696.461706]
-> #0 (&(&pool->lock)->rlock){-.-.-.}:
[ 2696.461706] __lock_acquire (kernel/locking/lockdep.c:1840
kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131
kernel/locking/lockdep.c:3182)
[ 2696.461706] lock_acquire (arch/x86/include/asm/current.h:14
kernel/locking/lockdep.c:3602)
[ 2696.461706] _raw_spin_lock (include/linux/spinlock_api_smp.h:143
kernel/locking/spinlock.c:151)
[ 2696.461706] __queue_work (kernel/workqueue.c:1358)
[ 2696.461706] queue_work_on (kernel/workqueue.c:1436)
[ 2696.461706] free_object (lib/debugobjects.c:206)
[ 2696.461706] __debug_check_no_obj_freed (lib/debugobjects.c:714)
[ 2696.461706] debug_check_no_obj_freed (lib/debugobjects.c:726)
[ 2696.461706] kmem_cache_free (mm/slub.c:2679 mm/slub.c:2707)
[ 2696.461706] __put_task_struct (kernel/fork.c:249 (discriminator 2))
[ 2696.461706] put_ctx (include/linux/sched.h:1807
kernel/events/core.c:896)
[ 2696.461706] perf_event_exit_task (kernel/events/core.c:905
kernel/events/core.c:7422 kernel/events/core.c:7492)
[ 2696.461706] do_exit (kernel/exit.c:801)
[ 2696.461706] do_group_exit (kernel/exit.c:919)
[ 2696.461706] SyS_exit_group (kernel/exit.c:930)
[ 2696.461706] tracesys (arch/x86/kernel/entry_64.S:749)
[ 2696.461706]
[ 2696.461706] other info that might help us debug this:
[ 2696.461706]
[ 2696.461706] Chain exists of:
&(&pool->lock)->rlock --> &rq->lock --> &ctx->lock
[ 2696.461706] Possible unsafe locking scenario:
[ 2696.461706]
[ 2696.461706] CPU0 CPU1
[ 2696.461706] ---- ----
[ 2696.461706] lock(&ctx->lock);
[ 2696.461706] lock(&rq->lock);
[ 2696.461706] lock(&ctx->lock);
[ 2696.461706] lock(&(&pool->lock)->rlock);
[ 2696.461706]
[ 2696.461706] *** DEADLOCK ***
[ 2696.461706]
[ 2696.461706] 1 lock held by trinity-c31/26818:
[ 2696.461706] #0: (&ctx->lock){-.-...}, at: perf_event_exit_task
(kernel/events/core.c:7415 kernel/events/core.c:7492)
[ 2696.461706]
[ 2696.461706] stack backtrace:
[ 2696.461706] CPU: 31 PID: 26818 Comm: trinity-c31 Not tainted
3.14.0-rc8-next-20140326-sasha-00018-gffbc974-dirty #285
[ 2696.461706] ffffffffbb9711d0 ffff88024f7a1a78 ffffffffb84b5057
0000000000000000
[ 2696.461706] ffffffffbb9b5c60 ffff88024f7a1ac8 ffffffffb84a7b57
0000000000000001
[ 2696.461706] ffff88024f7a1b58 ffff88024f7a1ac8 ffff88022f643cf0
ffff88022f643d28
[ 2696.461706] Call Trace:
[ 2696.461706] dump_stack (lib/dump_stack.c:52)
[ 2696.461706] print_circular_bug (kernel/locking/lockdep.c:1216)
[ 2696.461706] __lock_acquire (kernel/locking/lockdep.c:1840
kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131
kernel/locking/lockdep.c:3182)
[ 2696.461706] ? kvm_clock_read (arch/x86/include/asm/preempt.h:90
arch/x86/kernel/kvmclock.c:86)
[ 2696.461706] lock_acquire (arch/x86/include/asm/current.h:14
kernel/locking/lockdep.c:3602)
[ 2696.461706] ? __queue_work (kernel/workqueue.c:1358)
[ 2696.461706] ? __lock_is_held (kernel/locking/lockdep.c:3516)
[ 2696.461706] _raw_spin_lock (include/linux/spinlock_api_smp.h:143
kernel/locking/spinlock.c:151)
[ 2696.461706] ? __queue_work (kernel/workqueue.c:1358)
[ 2696.461706] __queue_work (kernel/workqueue.c:1358)
[ 2696.461706] queue_work_on (kernel/workqueue.c:1436)
[ 2696.461706] free_object (lib/debugobjects.c:206)
[ 2696.461706] __debug_check_no_obj_freed (lib/debugobjects.c:714)
[ 2696.461706] ? __this_cpu_preempt_check (lib/smp_processor_id.c:63)
[ 2696.461706] debug_check_no_obj_freed (lib/debugobjects.c:726)
[ 2696.461706] kmem_cache_free (mm/slub.c:2679 mm/slub.c:2707)
[ 2696.461706] ? __put_task_struct (kernel/fork.c:249 (discriminator 2))
[ 2696.461706] __put_task_struct (kernel/fork.c:249 (discriminator 2))
[ 2696.461706] put_ctx (include/linux/sched.h:1807 kernel/events/core.c:896)
[ 2696.461706] perf_event_exit_task (kernel/events/core.c:905
kernel/events/core.c:7422 kernel/events/core.c:7492)
[ 2696.461706] do_exit (kernel/exit.c:801)
[ 2696.461706] ? __this_cpu_preempt_check (lib/smp_processor_id.c:63)
[ 2696.461706] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2557
kernel/locking/lockdep.c:2599)
[ 2696.461706] ? trace_hardirqs_on (kernel/locking/lockdep.c:2607)
[ 2696.461706] do_group_exit (kernel/exit.c:919)
[ 2696.461706] SyS_exit_group (kernel/exit.c:930)
[ 2696.461706] tracesys (arch/x86/kernel/entry_64.S:749)
Figured I'd Cc' Thomas as well, as this trace seems to point at debugobjects.
Thanks,
Sasha
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