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INFO: rcu detected stall in sys_unlinkat

Status: auto-obsoleted due to no activity on 2024/09/24 13:32
Reported-by: syzbot+c102d4c2ba21c0c580df@syzkaller.appspotmail.com
First crash: 736d, last: 736d
▶ ▼ Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_unlinkat net ext4 1 4 1165d 1366d 0/29 auto-obsoleted due to no activity on 2023/07/13 16:11
upstream INFO: rcu detected stall in sys_unlinkat (3) tomoyo mm 1 31 356d 381d 0/29 auto-obsoleted due to no activity on 2025/10/09 16:45
upstream INFO: rcu detected stall in sys_unlinkat (2) tomoyo 1 1 1030d 1030d 0/29 auto-obsoleted due to no activity on 2023/11/25 04:08
linux-6.1 INFO: rcu detected stall in sys_unlinkat 1 syz error 1 56d 56d 0/3 upstream: reported syz repro on 2026/04/27 03:08
linux-6.6 INFO: rcu detected stall in sys_unlinkat 1 2 165d 247d 0/2 auto-obsoleted due to no activity on 2026/04/18 09:38
upstream INFO: rcu detected stall in sys_unlinkat (4) tomoyo fs 1 2 171d 186d 0/29 auto-obsoleted due to no activity on 2026/04/02 11:46

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=785/1/0x4000000000000000 softirq=30103/30103 fqs=0 
	(detected by 1, t=10502 jiffies, g=38645, q=253)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6382 Comm: syz-executor.0 Not tainted 5.15.161-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:kasan_check_range+0x1ac/0x290 mm/kasan/generic.c:189
Code: 4c 89 d5 48 8d 5d 07 48 85 ed 48 0f 49 dd 48 83 e3 f8 48 29 dd 74 12 41 80 39 00 0f 85 a2 00 00 00 49 ff c1 48 ff cd 75 ee 5b <41> 5e 41 5f 5d c3 45 84 f6 75 61 41 f7 c6 00 ff 00 00 75 5d 41 f7
RSP: 0018:ffffc90000007a40 EFLAGS: 00000056
RAX: 0000000000000001 RBX: 0000000000000015 RCX: ffffffff8162becf
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8fbf90c0
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff1f7f219
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000006
R13: ffff8880203c8ae8 R14: fffffbfff1f7f219 R15: ffff8880203c8c00
FS:  000055555739c480(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555573a5938 CR3: 0000000059f39000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 hlock_class kernel/locking/lockdep.c:197 [inline]
 __lock_acquire+0xfaf/0x1ff0 kernel/locking/lockdep.c:5008
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:363 [inline]
 advance_sched+0x47/0x940 net/sched/sch_taprio.c:716
 __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 0c 7e 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:ffffc90002fe73c0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920005fce84 RCX: 1ffff920005fce24
RDX: dffffc0000000000 RSI: ffffffff8a8b3ca0 RDI: ffffffff8ad8f740
RBP: ffffc90002fe7508 R08: dffffc0000000000 R09: fffffbfff1f7f219
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920005fce80
R13: dffffc0000000000 R14: ffffc90002fe7420 R15: 0000000000000246
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 ext4_get_group_info+0x10e/0x3a0 fs/ext4/balloc.c:332
 ext4_mb_clear_bb fs/ext4/mballoc.c:6028 [inline]
 ext4_free_blocks+0xd02/0x2ea0 fs/ext4/mballoc.c:6289
 ext4_remove_blocks fs/ext4/extents.c:2519 [inline]
 ext4_ext_rm_leaf fs/ext4/extents.c:2685 [inline]
 ext4_ext_remove_space+0x24da/0x4db0 fs/ext4/extents.c:2933
 ext4_ext_truncate+0x191/0x250 fs/ext4/extents.c:4448
 ext4_truncate+0x9fd/0x1130 fs/ext4/inode.c:4238
 ext4_evict_inode+0xba1/0x1100 fs/ext4/inode.c:289
 evict+0x2a4/0x620 fs/inode.c:587
 d_delete_notify include/linux/fsnotify.h:261 [inline]
 vfs_rmdir+0x33c/0x460 fs/namei.c:4162
 do_rmdir+0x368/0x670 fs/namei.c:4210
 __do_sys_unlinkat fs/namei.c:4390 [inline]
 __se_sys_unlinkat fs/namei.c:4384 [inline]
 __x64_sys_unlinkat+0xdc/0xf0 fs/namei.c:4384
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f5cccab6687
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 07 01 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:00007ffee1f64c58 EFLAGS: 00000207 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 00007f5cccab6687
RDX: 0000000000000200 RSI: 00007ffee1f65dc0 RDI: 00000000ffffff9c
RBP: 00007f5cccb13636 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000207 R12: 00007ffee1f65dc0
R13: 00007f5cccb13636 R14: 000000000004d31c R15: 0000000000000002
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g38645 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=15934
rcu: rcu_preempt kthread starved for 10502 jiffies! g38645 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
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:I stack:26168 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:1914
 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:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6382 Comm: syz-executor.0 Not tainted 5.15.161-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:hlock_class kernel/locking/lockdep.c:192 [inline]
RIP: 0010:__lock_acquire+0xf88/0x1ff0 kernel/locking/lockdep.c:5008
Code: 8b 74 24 18 0f 85 19 03 00 00 48 83 7c 24 48 00 0f 84 64 02 00 00 48 8b 44 24 08 48 8d 58 f8 48 89 d8 48 c1 e8 03 0f b6 04 38 <84> c0 0f 85 0b 0e 00 00 8b 1b 81 e3 ff 1f 00 00 89 d8 c1 e8 06 48
RSP: 0018:ffffc90000007a60 EFLAGS: 00000806
RAX: 0000000000000000 RBX: ffff8880203c8bd8 RCX: 000000001055937d
RDX: 00000000c3affd79 RSI: 00000000ca838a38 RDI: dffffc0000000000
RBP: 9be2421a50ef4013 R08: dffffc0000000000 R09: fffffbfff1f7f219
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000006
R13: ffff8880203c8ae8 R14: ffff8880203c8000 R15: ffff8880203c8c00
FS:  000055555739c480(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555573a5938 CR3: 0000000059f39000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 advance_sched+0x6ce/0x940 net/sched/sch_taprio.c:769
 __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 0c 7e 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:ffffc90002fe73c0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920005fce84 RCX: 1ffff920005fce24
RDX: dffffc0000000000 RSI: ffffffff8a8b3ca0 RDI: ffffffff8ad8f740
RBP: ffffc90002fe7508 R08: dffffc0000000000 R09: fffffbfff1f7f219
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920005fce80
R13: dffffc0000000000 R14: ffffc90002fe7420 R15: 0000000000000246
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 ext4_get_group_info+0x10e/0x3a0 fs/ext4/balloc.c:332
 ext4_mb_clear_bb fs/ext4/mballoc.c:6028 [inline]
 ext4_free_blocks+0xd02/0x2ea0 fs/ext4/mballoc.c:6289
 ext4_remove_blocks fs/ext4/extents.c:2519 [inline]
 ext4_ext_rm_leaf fs/ext4/extents.c:2685 [inline]
 ext4_ext_remove_space+0x24da/0x4db0 fs/ext4/extents.c:2933
 ext4_ext_truncate+0x191/0x250 fs/ext4/extents.c:4448
 ext4_truncate+0x9fd/0x1130 fs/ext4/inode.c:4238
 ext4_evict_inode+0xba1/0x1100 fs/ext4/inode.c:289
 evict+0x2a4/0x620 fs/inode.c:587
 d_delete_notify include/linux/fsnotify.h:261 [inline]
 vfs_rmdir+0x33c/0x460 fs/namei.c:4162
 do_rmdir+0x368/0x670 fs/namei.c:4210
 __do_sys_unlinkat fs/namei.c:4390 [inline]
 __se_sys_unlinkat fs/namei.c:4384 [inline]
 __x64_sys_unlinkat+0xdc/0xf0 fs/namei.c:4384
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f5cccab6687
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 07 01 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:00007ffee1f64c58 EFLAGS: 00000207 ORIG_RAX: 0000000000000107
RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 00007f5cccab6687
RDX: 0000000000000200 RSI: 00007ffee1f65dc0 RDI: 00000000ffffff9c
RBP: 00007f5cccb13636 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000207 R12: 00007ffee1f65dc0
R13: 00007f5cccb13636 R14: 000000000004d31c R15: 0000000000000002
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/16 13:31 linux-5.15.y 4878aadf2d15 f429ab00 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in sys_unlinkat
* Struck through repros no longer work on HEAD.