On Mon, Apr 16, 2018 at 10:59 AM, syzbot <syzbot+5c73ae1814a4a5f3f31b@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Hello, > > syzbot hit the following crash on upstream commit > 48023102b7078a6674516b1fe0d639669336049d (Fri Apr 13 23:55:41 2018 +0000) > Merge branch 'overlayfs-linus' of > git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs > syzbot dashboard link: > https://syzkaller.appspot.com/bug?extid=5c73ae1814a4a5f3f31b > > So far this crash happened 4 times on upstream. > Unfortunately, I don't have any reproducer for this crash yet. > Raw console output: > https://syzkaller.appspot.com/x/log.txt?id=6222684371288064 > Kernel config: > https://syzkaller.appspot.com/x/.config?id=-8852471259444315113 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) Looks like: #syz dup: INFO: rcu detected stall in d_walk > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+5c73ae1814a4a5f3f31b@xxxxxxxxxxxxxxxxxxxxxxxxx > It will help syzbot understand when the bug is fixed. See footer for > details. > If you forward the report, please keep this part and the footer. > > INFO: rcu_sched detected stalls on CPUs/tasks: > (detected by 0, t=125007 jiffies, g=10417, c=10416, q=290) > All QSes seen, last rcu_sched kthread activity 125014 > (4294860146-4294735132), jiffies_till_next_fqs=3, root ->qsmask 0x0 > syz-executor6 R running task 21784 4569 4561 0x00000008 > Call Trace: > <IRQ> > sched_show_task.cold.87+0x27a/0x301 kernel/sched/core.c:5325 > print_other_cpu_stall.cold.79+0x92f/0x9d2 kernel/rcu/tree.c:1481 > check_cpu_stall.isra.61+0x706/0xf50 kernel/rcu/tree.c:1599 > __rcu_pending kernel/rcu/tree.c:3356 [inline] > rcu_pending kernel/rcu/tree.c:3401 [inline] > rcu_check_callbacks+0x21b/0xad0 kernel/rcu/tree.c:2763 > update_process_times+0x2d/0x70 kernel/time/timer.c:1636 > tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:173 > tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1283 > __run_hrtimer kernel/time/hrtimer.c:1386 [inline] > __hrtimer_run_queues+0x3e3/0x10a0 kernel/time/hrtimer.c:1448 > hrtimer_interrupt+0x286/0x650 kernel/time/hrtimer.c:1506 > local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline] > smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050 > apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:862 > </IRQ> > RIP: 0010:__sanitizer_cov_trace_pc+0x14/0x50 kernel/kcov.c:94 > RSP: 0018:ffff88018d8bf8d8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 > RAX: ffff88018d8b4580 RBX: 1ffff10031b17f20 RCX: ffffffff81c1f494 > RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000005 > RBP: ffff88018d8bf8d8 R08: ffff88018d8b4580 R09: ffffed003b527e70 > R10: ffffed003b527e70 R11: ffff8801da93f383 R12: ffff88018d8bfbf0 > R13: ffff8801da93f300 R14: ffff88018d8bfbf8 R15: ffff88018d8bf9a0 > select_collect+0x267/0x5f0 fs/dcache.c:1451 > d_walk+0x3c3/0xc80 fs/dcache.c:1276 > shrink_dcache_parent+0x179/0x230 fs/dcache.c:1486 > vfs_rmdir+0x202/0x470 fs/namei.c:3850 > do_rmdir+0x523/0x610 fs/namei.c:3911 > SYSC_rmdir fs/namei.c:3929 [inline] > SyS_rmdir+0x1a/0x20 fs/namei.c:3927 > do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 > entry_SYSCALL_64_after_hwframe+0x42/0xb7 > RIP: 0033:0x455087 > RSP: 002b:00007ffe0e80b288 EFLAGS: 00000206 ORIG_RAX: 0000000000000054 > RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 0000000000455087 > RDX: 0000000000000000 RSI: 00007ffe0e80d030 RDI: 00007ffe0e80d030 > RBP: 00007ffe0e80d030 R08: 0000000000000000 R09: 0000000000000001 > R10: 0000000000000006 R11: 0000000000000206 R12: 0000000000fa5940 > R13: 0000000000000000 R14: 0000000000000117 R15: 0000000000010850 > rcu_sched kthread starved for 125603 jiffies! g10417 c10416 f0x2 > RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1 > RCU grace-period kthread stack dump: > rcu_sched R running task 23896 9 2 0x80000000 > Call Trace: > context_switch kernel/sched/core.c:2848 [inline] > __schedule+0x801/0x1e30 kernel/sched/core.c:3490 > schedule+0xef/0x430 kernel/sched/core.c:3549 > schedule_timeout+0x138/0x240 kernel/time/timer.c:1801 > rcu_gp_kthread+0x6b5/0x1940 kernel/rcu/tree.c:2231 > kthread+0x345/0x410 kernel/kthread.c:238 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 > > > --- > This bug is generated by a dumb bot. It may contain errors. > See https://goo.gl/tpsmEJ for details. > Direct all questions to syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this bug report. > If you forgot to add the Reported-by tag, once the fix for this bug is > merged > into any tree, please reply to this email with: > #syz fix: exact-commit-title > To mark this as a duplicate of another syzbot report, please reply with: > #syz dup: exact-subject-of-another-report > If it's a one-off invalid bug report, please reply with: > #syz invalid > Note: if the crash happens again, it will cause creation of a new bug > report. > Note: all commands must start from beginning of the line in the email body. > > -- > You received this message because you are subscribed to the Google Groups > "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit > https://groups.google.com/d/msgid/syzkaller-bugs/000000000000e894e30569f36ee8%40google.com. > For more options, visit https://groups.google.com/d/optout.
