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INFO: rcu detected stall in sys_symlinkat (3)

Status: upstream: reported syz repro on 2025/05/03 06:00
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+9bdb9cb224274592f48b@syzkaller.appspotmail.com
First crash: 58d, last: 57d
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2025/05/23 upstream (ToT) 94305e83eccb C [report] INFO: rcu detected stall in corrupted
▶ ▼ Similar bugs (11)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in sys_symlinkat (3) ext4 3 702d 754d 0/29 auto-obsoleted due to no activity on 2023/10/26 22:46
linux-5.15 INFO: rcu detected stall in sys_symlinkat 1 765d 765d 0/3 auto-obsoleted due to no activity on 2023/09/03 15:54
linux-5.15 INFO: rcu detected stall in sys_symlinkat (3) 2 377d 403d 0/3 auto-obsoleted due to no activity on 2024/09/25 17:37
upstream INFO: rcu detected stall in sys_symlinkat (5) mm syz error 60 3d17h 208d 0/29 upstream: reported syz repro on 2024/12/04 02:45
linux-6.1 INFO: rcu detected stall in sys_symlinkat (2) 1 550d 550d 0/3 auto-obsoleted due to no activity on 2024/04/06 00:16
upstream INFO: rcu detected stall in sys_symlinkat kvm 5 1035d 1134d 0/29 auto-obsoleted due to no activity on 2022/11/28 07:06
linux-6.1 INFO: rcu detected stall in sys_symlinkat 1 795d 795d 0/3 auto-obsoleted due to no activity on 2023/08/23 09:07
upstream INFO: rcu detected stall in sys_symlinkat (2) ext4 lsm 2 847d 941d 0/29 auto-obsoleted due to no activity on 2023/06/03 10:14
upstream INFO: rcu detected stall in sys_symlinkat (4) ext4 1 579d 579d 0/29 auto-obsoleted due to no activity on 2024/02/27 04:07
linux-5.15 INFO: rcu detected stall in sys_symlinkat (2) 1 574d 574d 0/3 auto-obsoleted due to no activity on 2024/03/12 11:22
android-5-15 BUG: soft lockup in sys_symlinkat 13 350d 441d 0/2 auto-obsoleted due to no activity on 2024/10/13 01:26

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (3 ticks this GP) idle=d4e4/1/0x4000000000000000 softirq=9212/9212 fqs=0
	(detected by 0, t=10502 jiffies, g=9149, q=485 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4404 Comm: syz-executor Not tainted 6.1.136-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:22 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
RIP: 0010:_raw_spin_lock_irqsave+0x5d/0xf0 kernel/locking/spinlock.c:162
Code: 26 8c 48 c7 44 24 10 00 19 19 8a 49 89 e7 49 c1 ef 03 48 b8 f1 f1 f1 f1 00 f3 f3 f3 49 bc 00 00 00 00 00 fc ff df 4b 89 04 27 <48> c7 44 24 20 00 00 00 00 9c 8f 44 24 20 4c 8b 74 24 20 fa 41 f7
RSP: 0018:ffffc900001e0c00 EFLAGS: 00000802
RAX: f3f3f300f1f1f1f1 RBX: ffffffff96cb61d0 RCX: 000000000001a4a8
RDX: 0000000000010000 RSI: ffffffff8a6ded80 RDI: ffffffff96cb61d0
RBP: ffffc900001e0c88 R08: dffffc0000000000 R09: ffff8880738b1340
R10: ffffed100e71626b R11: 1ffff1100e716268 R12: dffffc0000000000
R13: ffffffff96cb61c8 R14: ffff8880b8f2a748 R15: 1ffff9200003c180
FS:  000055557271b500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f73ea44db22 CR3: 000000007a71c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 debug_object_deactivate+0x63/0x340 lib/debugobjects.c:753
 debug_hrtimer_deactivate kernel/time/hrtimer.c:416 [inline]
 debug_deactivate+0x29/0x240 kernel/time/hrtimer.c:472
 __run_hrtimer kernel/time/hrtimer.c:1659 [inline]
 __hrtimer_run_queues+0x2d0/0xc80 kernel/time/hrtimer.c:1755
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1817
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:-1 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:lock_release+0x15d/0x910 kernel/locking/lockdep.c:5678
Code: 83 3b 00 0f 85 4e 04 00 00 4c 89 74 24 08 48 c7 84 24 a0 00 00 00 00 00 00 00 9c 8f 84 24 a0 00 00 00 48 8b 84 24 a0 00 00 00 <48> 89 44 24 50 fa 48 c7 c7 e0 0a 6c 8a e8 a1 cd ab 08 65 ff 05 4a
RSP: 0018:ffffc900034b79a0 EFLAGS: 00000246
RAX: 0000000000000246 RBX: ffff88802e668adc RCX: 10388e94237a4f00
RDX: 0000000000000000 RSI: ffffffff8abf0d80 RDI: ffffffff8abf0d40
RBP: ffffc900034b7ab8 R08: dffffc0000000000 R09: fffffbfff1bfd03e
R10: fffffbfff1bfd03e R11: 1ffffffff1bfd03d R12: ffffc900034b7be0
R13: dffffc0000000000 R14: ffff88802e668000 R15: 1ffff92000696f40
 try_to_unlazy+0x302/0x5a0 fs/namei.c:783
 complete_walk+0x113/0x350 fs/namei.c:888
 path_parentat fs/namei.c:2528 [inline]
 __filename_parentat+0x221/0x610 fs/namei.c:2550
 filename_parentat fs/namei.c:2568 [inline]
 filename_create+0xcc/0x450 fs/namei.c:3857
 do_symlinkat+0xb9/0x3f0 fs/namei.c:4490
 __do_sys_symlinkat fs/namei.c:4517 [inline]
 __se_sys_symlinkat fs/namei.c:4514 [inline]
 __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4514
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f73ea38dee7
Code: 73 01 c3 48 c7 c1 a8 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 0a 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc27adfcf8 EFLAGS: 00000202 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f73ea38dee7
RDX: 00007f73ea41231e RSI: 00000000ffffff9c RDI: 00007ffc27adfd90
RBP: 00007ffc27adfd3c R08: 0000000000000013 R09: 00007ffc27adfa47
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 000055557272e590 R14: 0000000000016d23 R15: 00007ffc27adfd90
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g9149 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=3027
rcu: rcu_preempt kthread starved for 10502 jiffies! g9149 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27720 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4404 Comm: syz-executor Not tainted 6.1.136-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:debug_object_activate+0x65/0x490 lib/debugobjects.c:698
Code: 48 b9 eb 83 b5 80 46 86 c8 61 48 0f af c8 48 c1 e9 2f 83 e1 f8 4c 8d a4 c9 e0 97 bc 96 48 8d bc c9 e8 97 bc 96 48 89 7c 24 18 <e8> f6 40 0d 06 48 89 44 24 10 4c 89 e0 48 c1 e8 03 42 80 3c 30 00
RSP: 0018:ffffc900001e0c90 EFLAGS: 00000002
RAX: 000ffff8880738b1 RBX: ffff8880738b1340 RCX: 000000000001a4a8
RDX: 0000000000010000 RSI: ffffffff8a6ded80 RDI: ffffffff96cb61d0
RBP: 0000000000000000 R08: 0000000000000004 R09: 0000000000000003
R10: fffff5200003c180 R11: 1ffff9200003c180 R12: ffffffff96cb61c8
R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff8880b8f2a758
FS:  000055557271b500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f73ea44db22 CR3: 000000007a71c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 debug_hrtimer_activate kernel/time/hrtimer.c:411 [inline]
 debug_activate kernel/time/hrtimer.c:466 [inline]
 enqueue_hrtimer+0x30/0x3f0 kernel/time/hrtimer.c:1075
 __run_hrtimer kernel/time/hrtimer.c:1708 [inline]
 __hrtimer_run_queues+0x642/0xc80 kernel/time/hrtimer.c:1755
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1817
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
 __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:-1 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:lock_release+0x15d/0x910 kernel/locking/lockdep.c:5678
Code: 83 3b 00 0f 85 4e 04 00 00 4c 89 74 24 08 48 c7 84 24 a0 00 00 00 00 00 00 00 9c 8f 84 24 a0 00 00 00 48 8b 84 24 a0 00 00 00 <48> 89 44 24 50 fa 48 c7 c7 e0 0a 6c 8a e8 a1 cd ab 08 65 ff 05 4a
RSP: 0018:ffffc900034b79a0 EFLAGS: 00000246
RAX: 0000000000000246 RBX: ffff88802e668adc RCX: 10388e94237a4f00
RDX: 0000000000000000 RSI: ffffffff8abf0d80 RDI: ffffffff8abf0d40
RBP: ffffc900034b7ab8 R08: dffffc0000000000 R09: fffffbfff1bfd03e
R10: fffffbfff1bfd03e R11: 1ffffffff1bfd03d R12: ffffc900034b7be0
R13: dffffc0000000000 R14: ffff88802e668000 R15: 1ffff92000696f40
 try_to_unlazy+0x302/0x5a0 fs/namei.c:783
 complete_walk+0x113/0x350 fs/namei.c:888
 path_parentat fs/namei.c:2528 [inline]
 __filename_parentat+0x221/0x610 fs/namei.c:2550
 filename_parentat fs/namei.c:2568 [inline]
 filename_create+0xcc/0x450 fs/namei.c:3857
 do_symlinkat+0xb9/0x3f0 fs/namei.c:4490
 __do_sys_symlinkat fs/namei.c:4517 [inline]
 __se_sys_symlinkat fs/namei.c:4514 [inline]
 __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4514
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f73ea38dee7
Code: 73 01 c3 48 c7 c1 a8 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 0a 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc27adfcf8 EFLAGS: 00000202 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f73ea38dee7
RDX: 00007f73ea41231e RSI: 00000000ffffff9c RDI: 00007ffc27adfd90
RBP: 00007ffc27adfd3c R08: 0000000000000013 R09: 00007ffc27adfa47
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 000055557272e590 R14: 0000000000016d23 R15: 00007ffc27adfd90
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/03 16:57 linux-6.1.y b6736e03756f b0714e37 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_symlinkat
2025/05/03 05:59 linux-6.1.y b6736e03756f b0714e37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in sys_symlinkat
* Struck through repros no longer work on HEAD.