Hi all,
While fuzzing with trinity inside KVM tools guest running latest -next kernel
I've stumbled on the following:
[ 1336.998827] ======================================================
[ 1337.000394] [ INFO: possible circular locking dependency detected ]
[ 1337.001425] 3.14.0-rc7-next-20140321-sasha-00018-g0516fe6-dirty #265 Tainted: G W
[ 1337.001964] -------------------------------------------------------
[ 1337.001964] trinity-c24/33631 is trying to acquire lock:
[ 1337.001964] (&pgdat->kswapd_wait){..-.-.}, at: __wake_up (kernel/sched/wait.c:94)
[ 1337.001964]
[ 1337.001964] but task is already holding lock:
[ 1337.001964] (&(&n->list_lock)->rlock){-.-.-.}, at: list_locations (mm/slub.c:4159)
[ 1337.001964]
[ 1337.001964] which lock already depends on the new lock.
[ 1337.001964]
[ 1337.001964]
[ 1337.001964] the existing dependency chain (in reverse order) is:
[ 1337.001964]
-> #3 (&(&n->list_lock)->rlock){-.-.-.}:
[ 1337.001964] lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
[ 1337.001964] _raw_spin_lock (include/linux/spinlock_api_smp.h:143 kernel/locking/spinlock.c:151)
[ 1337.001964] get_partial_node.isra.35 (mm/slub.c:1623)
[ 1337.001964] __slab_alloc (mm/slub.c:1725 mm/slub.c:2193 mm/slub.c:2359)
[ 1337.001964] kmem_cache_alloc (mm/slub.c:2465 mm/slub.c:2476 mm/slub.c:2481)
[ 1337.001964] __debug_object_init (lib/debugobjects.c:97 lib/debugobjects.c:311)
[ 1337.001964] debug_object_init (lib/debugobjects.c:364)
[ 1337.001964] hrtimer_init (kernel/hrtimer.c:432 include/linux/jump_label.h:105 include/trace/events/timer.h:130 kernel/hrtimer.c:477 kernel/hrtimer.c:1199)
[ 1337.001964] __sched_fork (kernel/sched/core.c:1732)
[ 1337.001964] init_idle (kernel/sched/core.c:4483)
[ 1337.001964] fork_idle (kernel/fork.c:1566)
[ 1337.001964] idle_threads_init (kernel/smpboot.c:54 kernel/smpboot.c:72)
[ 1337.001964] smp_init (kernel/smp.c:493)
[ 1337.001964] kernel_init_freeable (init/main.c:757 init/main.c:910)
[ 1337.001964] kernel_init (init/main.c:842)
[ 1337.001964] ret_from_fork (arch/x86/kernel/entry_64.S:555)
[ 1337.001964]
-> #2 (&rq->lock){-.-.-.}:
[ 1337.001964] lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
[ 1337.001964] _raw_spin_lock (include/linux/spinlock_api_smp.h:143 kernel/locking/spinlock.c:151)
[ 1337.001964] wake_up_new_task (include/linux/sched.h:2884 kernel/sched/core.c:313 kernel/sched/core.c:2014)
[ 1337.001964] do_fork (kernel/fork.c:1627)
[ 1337.001964] kernel_thread (kernel/fork.c:1647)
[ 1337.001964] rest_init (init/main.c:383)
[ 1337.001964] start_kernel (init/main.c:653)
[ 1337.001964] x86_64_start_reservations (arch/x86/kernel/head64.c:194)
[ 1337.001964] x86_64_start_kernel (arch/x86/kernel/head64.c:183)
[ 1337.001964]
-> #1 (&p->pi_lock){-.-.-.}:
[ 1337.001964] lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
[ 1337.001964] _raw_spin_lock_irqsave (include/linux/spinlock_api_smp.h:117 kernel/locking/spinlock.c:159)
[ 1337.001964] try_to_wake_up (kernel/sched/core.c:1592)
[ 1337.001964] default_wake_function (kernel/sched/core.c:2846)
[ 1337.001964] autoremove_wake_function (kernel/sched/wait.c:294)
[ 1337.001964] __wake_up_common (kernel/sched/wait.c:72)
[ 1337.001964] __wake_up (include/linux/spinlock.h:358 kernel/sched/wait.c:95)
[ 1337.001964] wakeup_kswapd (mm/vmscan.c:3328)
[ 1337.001964] __alloc_pages_slowpath (mm/page_alloc.c:2429 mm/page_alloc.c:2530)
[ 1337.001964] __alloc_pages_nodemask (mm/page_alloc.c:2767)
[ 1337.001964] alloc_pages_current (mm/mempolicy.c:2055)
[ 1337.001964] __vmalloc_node_range (include/linux/gfp.h:339 mm/vmalloc.c:1594 mm/vmalloc.c:1650)
[ 1337.001964] __vmalloc_node (mm/vmalloc.c:1696)
[ 1337.001964] vmalloc (mm/vmalloc.c:1725)
[ 1337.001964] SyS_init_module (kernel/module.c:2508 kernel/module.c:3342 kernel/module.c:3330)
[ 1337.001964] tracesys (arch/x86/kernel/entry_64.S:749)
[ 1337.001964]
-> #0 (&pgdat->kswapd_wait){..-.-.}:
[ 1337.001964] __lock_acquire (kernel/locking/lockdep.c:1840 kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131 kernel/locking/lockdep.c:3182)
[ 1337.001964] lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
[ 1337.001964] _raw_spin_lock_irqsave (include/linux/spinlock_api_smp.h:117 kernel/locking/spinlock.c:159)
[ 1337.001964] __wake_up (kernel/sched/wait.c:94)
[ 1337.001964] wakeup_kswapd (mm/vmscan.c:3328)
[ 1337.001964] __alloc_pages_slowpath (mm/page_alloc.c:2429 mm/page_alloc.c:2530)
[ 1337.001964] __alloc_pages_nodemask (mm/page_alloc.c:2767)
[ 1337.001964] alloc_pages_current (mm/mempolicy.c:2055)
[ 1337.001964] __get_free_pages (mm/page_alloc.c:2804)
[ 1337.001964] alloc_loc_track (mm/slub.c:4030)
[ 1337.001964] process_slab (mm/slub.c:4096 mm/slub.c:4130)
[ 1337.001964] list_locations (mm/slub.c:4160)
[ 1337.001964] alloc_calls_show (mm/slub.c:4765)
[ 1337.001964] slab_attr_show (mm/slub.c:5011)
[ 1337.001964] sysfs_kf_seq_show (fs/sysfs/file.c:63)
[ 1337.001964] kernfs_seq_show (fs/kernfs/file.c:155)
[ 1337.001964] seq_read (fs/seq_file.c:223)
[ 1337.001964] kernfs_fop_read (fs/kernfs/file.c:230)
[ 1337.001964] vfs_read (fs/read_write.c:408)
[ 1337.001964] SyS_read (fs/read_write.c:519 fs/read_write.c:511)
[ 1337.001964] tracesys (arch/x86/kernel/entry_64.S:749)
[ 1337.001964]
[ 1337.001964] other info that might help us debug this:
[ 1337.001964]
[ 1337.001964] Chain exists of:
&pgdat->kswapd_wait --> &rq->lock --> &(&n->list_lock)->rlock
[ 1337.001964] Possible unsafe locking scenario:
[ 1337.001964]
[ 1337.001964] CPU0 CPU1
[ 1337.001964] ---- ----
[ 1337.001964] lock(&(&n->list_lock)->rlock);
[ 1337.001964] lock(&rq->lock);
[ 1337.001964] lock(&(&n->list_lock)->rlock);
[ 1337.001964] lock(&pgdat->kswapd_wait);
[ 1337.001964]
[ 1337.001964] *** DEADLOCK ***
[ 1337.001964]
[ 1337.001964] 5 locks held by trinity-c24/33631:
[ 1337.001964] #0: (&f->f_pos_lock){+.+.+.}, at: __fdget_pos (fs/file.c:736)
[ 1337.001964] #1: (&p->lock){+.+.+.}, at: seq_read (fs/seq_file.c:175)
[ 1337.001964] #2: (&of->mutex){+.+.+.}, at: kernfs_seq_start (fs/kernfs/file.c:99)
[ 1337.001964] #3: (s_active#87){++++.+}, at: kernfs_seq_start (fs/kernfs/file.c:99)
[ 1337.001964] #4: (&(&n->list_lock)->rlock){-.-.-.}, at: list_locations (mm/slub.c:4159)
[ 1337.001964]
[ 1337.001964] stack backtrace:
[ 1337.001964] CPU: 24 PID: 33631 Comm: trinity-c24 Tainted: G W 3.14.0-rc7-next-20140321-sasha-00018-g0516fe6-dirty #265
[ 1337.001964] ffffffff87972190 ffff88032f1d37e8 ffffffff844b0f37 0000000000000000
[ 1337.001964] ffffffff879d65d0 ffff88032f1d3838 ffffffff844a398b 0000000000000005
[ 1337.001964] ffff88032f1d38c8 ffff88032f1d3838 ffff8803462f8dd0 ffff8803462f8e08
[ 1337.001964] Call Trace:
[ 1337.001964] dump_stack (lib/dump_stack.c:52)
[ 1337.001964] print_circular_bug (kernel/locking/lockdep.c:1216)
[ 1337.001964] __lock_acquire (kernel/locking/lockdep.c:1840 kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131 kernel/locking/lockdep.c:3182)
[ 1337.001964] ? __bfs (kernel/locking/lockdep.c:1030)
[ 1337.001964] lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
[ 1337.001964] ? __wake_up (kernel/sched/wait.c:94)
[ 1337.001964] ? _raw_spin_lock_irqsave (include/linux/spinlock_api_smp.h:109 kernel/locking/spinlock.c:159)
[ 1337.001964] _raw_spin_lock_irqsave (include/linux/spinlock_api_smp.h:117 kernel/locking/spinlock.c:159)
[ 1337.001964] ? __wake_up (kernel/sched/wait.c:94)
[ 1337.001964] ? zone_watermark_ok_safe (mm/page_alloc.c:1741)
[ 1337.001964] __wake_up (kernel/sched/wait.c:94)
[ 1337.001964] wakeup_kswapd (mm/vmscan.c:3328)
[ 1337.001964] __alloc_pages_slowpath (mm/page_alloc.c:2429 mm/page_alloc.c:2530)
[ 1337.001964] ? get_page_from_freelist (mm/page_alloc.c:1940)
[ 1337.001964] ? sched_clock (arch/x86/include/asm/paravirt.h:192 arch/x86/kernel/tsc.c:305)
[ 1337.001964] ? sched_clock_local (kernel/sched/clock.c:214)
[ 1337.001964] __alloc_pages_nodemask (mm/page_alloc.c:2767)
[ 1337.001964] alloc_pages_current (mm/mempolicy.c:2055)
[ 1337.001964] ? __get_free_pages (mm/page_alloc.c:2804)
[ 1337.001964] ? get_parent_ip (kernel/sched/core.c:2472)
[ 1337.001964] __get_free_pages (mm/page_alloc.c:2804)
[ 1337.001964] alloc_loc_track (mm/slub.c:4030)
[ 1337.001964] process_slab (mm/slub.c:4096 mm/slub.c:4130)
[ 1337.001964] ? list_locations (mm/slub.c:4159)
[ 1337.001964] list_locations (mm/slub.c:4160)
[ 1337.001964] alloc_calls_show (mm/slub.c:4765)
[ 1337.001964] slab_attr_show (mm/slub.c:5011)
[ 1337.001964] sysfs_kf_seq_show (fs/sysfs/file.c:63)
[ 1337.001964] kernfs_seq_show (fs/kernfs/file.c:155)
[ 1337.001964] seq_read (fs/seq_file.c:223)
[ 1337.001964] kernfs_fop_read (fs/kernfs/file.c:230)
[ 1337.001964] vfs_read (fs/read_write.c:408)
[ 1337.001964] SyS_read (fs/read_write.c:519 fs/read_write.c:511)
[ 1337.001964] tracesys (arch/x86/kernel/entry_64.S:749)
Thanks,
Sasha
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