syzbot


INFO: rcu detected stall in sys_unlink

Status: upstream: reported on 2024/03/12 14:47
Reported-by: syzbot+0ffff30dfdd49f51762e@syzkaller.appspotmail.com
First crash: 50d, last: 50d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_unlink (2) kernel 2 465d 550d 0/26 auto-obsoleted due to no activity on 2023/04/22 20:06
upstream INFO: rcu detected stall in sys_unlink (3) ext4 C error 20 18d 262d 0/26 upstream: reported C repro on 2023/08/13 23:42
linux-6.1 INFO: rcu detected stall in sys_unlink 2 29d 99d 0/3 upstream: reported on 2024/01/23 10:50
upstream INFO: rcu detected stall in sys_unlink kasan mm 1 641d 640d 0/26 auto-obsoleted due to no activity on 2022/10/29 07:23
android-5-15 BUG: soft lockup in sys_unlink 4 20h10m 15d 0/2 premoderation: reported on 2024/04/16 22:56

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 ticks this GP) idle=fd1/1/0x4000000000000000 softirq=45817/45817 fqs=0 
	(detected by 1, t=10503 jiffies, g=71381, q=42)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 9267 Comm: syz-executor.0 Not tainted 5.15.151-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
RIP: 0010:kasan_check_range+0x1/0x290 mm/kasan/generic.c:188
Code: 01 c6 48 89 c7 e8 0f 57 52 08 31 c0 c3 0f 0b b8 ea ff ff ff c3 0f 0b b8 ea ff ff ff c3 cc cc cc cc cc cc cc cc cc cc cc cc 55 <41> 57 41 56 53 b0 01 48 85 f6 0f 84 9a 01 00 00 48 89 fd 48 01 f5
RSP: 0018:ffffc90000007bd0 EFLAGS: 00000046
RAX: ffffffff88339e7b RBX: 0000000000000001 RCX: ffffffff88339e8d
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff8880823cb188
RBP: ffffc90000007cb0 R08: ffffffff886a44de R09: fffffbfff1f79e19
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880823cb000
R13: dffffc0000000000 R14: 1ffff92000000f80 R15: 17c10ba57c000000
FS:  000055555561e480(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555555627938 CR3: 0000000033e18000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
 test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:70 [inline]
 __netif_schedule+0x8d/0x310 net/core/dev.c:3073
 advance_sched+0x750/0x940 net/sched/sch_taprio.c:770
 __run_hrtimer kernel/time/hrtimer.c:1686 [inline]
 __hrtimer_run_queues+0x598/0xcf0 kernel/time/hrtimer.c:1750
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
 __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:lock_acquire+0x252/0x4f0 kernel/locking/lockdep.c:5627
Code: 2b 00 74 08 4c 89 f7 e8 7c 68 67 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90002fa7c00 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920005f4f8c RCX: ffffffff816340b2
RDX: dffffc0000000000 RSI: ffffffff8a8b27a0 RDI: ffffffff8ad88f40
RBP: ffffc90002fa7d58 R08: dffffc0000000000 R09: fffffbfff1f79e2d
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920005f4f88
R13: dffffc0000000000 R14: ffffc90002fa7c60 R15: 0000000000000246
 percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
 __sb_start_write include/linux/fs.h:1787 [inline]
 sb_start_write+0x4f/0x1c0 include/linux/fs.h:1857
 mnt_want_write+0x3b/0x80 fs/namespace.c:377
 do_unlinkat+0x1f9/0x950 fs/namei.c:4327
 __do_sys_unlink fs/namei.c:4396 [inline]
 __se_sys_unlink fs/namei.c:4394 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4394
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fa3a5273557
Code: 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffef8837fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa3a5273557
RDX: 00007ffef8838000 RSI: 00007ffef8838090 RDI: 00007ffef8838090
RBP: 00007ffef8838090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffef8839150
R13: 00007fa3a52bf3b9 R14: 00000000000ac4ca R15: 0000000000000005
 </TASK>
rcu: rcu_preempt kthread starved for 10503 jiffies! g71381 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:27000 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1884
 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
 kthread+0x3f6/0x4f0 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 14158 Comm: syz-executor.1 Not tainted 5.15.151-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3932 [inline]
 rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619
 update_process_times+0x196/0x200 kernel/time/timer.c:1788
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1686 [inline]
 __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1750
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
 __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xa93/0xd90 kernel/smp.c:969
Code: 04 03 84 c0 0f 85 84 00 00 00 45 8b 7d 00 44 89 fe 83 e6 01 31 ff e8 ac ce 0b 00 41 83 e7 01 75 07 e8 41 cb 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00
RSP: 0018:ffffc900040f7ac0 EFLAGS: 00000246
RAX: ffffffff81746a74 RBX: 1ffff11017348541 RCX: 0000000000040000
RDX: ffffc9000344a000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc900040f7bf0 R08: ffffffff81746a44 R09: ffffed1017367673
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff8880b9a42a08 R14: ffff8880b9b3b380 R15: 0000000000000001
 clock_was_set+0x7b6/0x880 kernel/time/hrtimer.c:974
 do_settimeofday64+0x673/0x7e0 kernel/time/timekeeping.c:1328
 __do_sys_clock_settime kernel/time/posix-timers.c:1124 [inline]
 __se_sys_clock_settime kernel/time/posix-timers.c:1112 [inline]
 __x64_sys_clock_settime+0x232/0x270 kernel/time/posix-timers.c:1112
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7fd8dc916da9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd8dae970c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 00007fd8dca44f80 RCX: 00007fd8dc916da9
RDX: 0000000000000000 RSI: 0000000020003c80 RDI: 0000000000000000
RBP: 00007fd8dc96347a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fd8dca44f80 R15: 00007fffe181d858
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/12 14:46 linux-5.15.y 574362648507 c35c26ec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlink
* Struck through repros no longer work on HEAD.