On Sat, Apr 14, 2018 at 11:43 AM, syzbot <syzbot+9275da3e0f734e102b61@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Hello, > > syzbot hit the following crash on upstream commit > 16e205cf42da1f497b10a4a24f563e6c0d574eec (Fri Apr 13 03:56:10 2018 +0000) > Merge tag 'drm-fixes-for-v4.17-rc1' of > git://people.freedesktop.org/~airlied/linux > syzbot dashboard link: > https://syzkaller.appspot.com/bug?extid=9275da3e0f734e102b61 > > Unfortunately, I don't have any reproducer for this crash yet. > Raw console output: > https://syzkaller.appspot.com/x/log.txt?id=4692036947017728 > Kernel config: > https://syzkaller.appspot.com/x/.config?id=-5947642240294114534 > compiler: gcc (GCC) 8.0.1 20180301 (experimental) > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+9275da3e0f734e102b61@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. #syz dup: INFO: rcu detected stall in d_walk > INFO: rcu_sched self-detected stall on CPU > 1-...!: (124995 ticks this GP) idle=b86/1/4611686018427387906 > softirq=32196/32196 fqs=3 > (t=125000 jiffies g=16751 c=16750 q=347) > rcu_sched kthread starved for 124987 jiffies! g16751 c16750 f0x0 > RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=1 > RCU grace-period kthread stack dump: > rcu_sched R running task 23544 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 > NMI backtrace for cpu 1 > CPU: 1 PID: 4559 Comm: syz-executor6 Not tainted 4.16.0+ #2 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > <IRQ> > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1b9/0x294 lib/dump_stack.c:113 > nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 > nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62 > arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 > trigger_single_cpu_backtrace include/linux/nmi.h:156 [inline] > rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1376 > print_cpu_stall kernel/rcu/tree.c:1525 [inline] > check_cpu_stall.isra.61.cold.80+0x36c/0x59a kernel/rcu/tree.c:1593 > __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:ffff88018e2e7a80 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 > RAX: ffff88018e2de680 RBX: ffff88018e2e7bf8 RCX: ffffffff81c2b1d9 > RDX: 0000000000000000 RSI: ffffffff81c26bf3 RDI: ffff88018e2e7bf8 > RBP: ffff88018e2e7a80 R08: ffff88018e2de680 R09: ffffed003b51c378 > R10: ffffed003b51c378 R11: ffff8801da8e1bc3 R12: ffff88018e2e7c30 > R13: dffffc0000000000 R14: 1ffff10031c5cf7e R15: ffffed0031c5cf81 > shrink_dentry_list+0x5a8/0x7c0 fs/dcache.c:1087 > shrink_dcache_parent+0xba/0x230 fs/dcache.c:1490 > 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:00007fff8b6b76b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000054 > RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 0000000000455087 > RDX: 0000000000000000 RSI: 00007fff8b6b9460 RDI: 00007fff8b6b9460 > RBP: 00007fff8b6b9460 R08: 0000000000000000 R09: 0000000000000001 > R10: 000000000000000a R11: 0000000000000206 R12: 0000000002768940 > R13: 0000000000000000 R14: 00000000000001ec R15: 000000000001984e > > > --- > 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/0000000000008c36c90569cbd09d%40google.com. > For more options, visit https://groups.google.com/d/optout.
