INFO: rcu detected stall in sys_unlink

Status: upstream: reported on 2025/07/20 18:19
Reported-by: syzbot+dfe0a4ce11e613b0f2f7@syzkaller.appspotmail.com
First crash: 406d, last: 12d
▶ ▼ Similar bugs (11)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in sys_unlink (4) 1 1 516d 516d 0/3 auto-obsoleted due to no activity on 2025/07/10 21:02
linux-5.15 INFO: rcu detected stall in sys_unlink (3) 1 1 665d 665d 0/3 auto-obsoleted due to no activity on 2025/02/11 14:08
upstream INFO: rcu detected stall in sys_unlink (2) kernel 1 2 1316d 1400d 0/29 auto-obsoleted due to no activity on 2023/04/22 20:06
upstream INFO: rcu detected stall in sys_unlink (3) mm 1 syz, C error 418 1d01h 1112d 0/29 upstream: reported C repro on 2023/08/13 23:42
linux-6.1 INFO: rcu detected stall in sys_unlink (2) 1 32 12d 521d 0/3 upstream: reported on 2025/03/27 11:38
linux-5.15 INFO: rcu detected stall in sys_unlink (5) 1 15 5d15h 339d 0/3 upstream: reported on 2025/09/25 16:42
linux-6.1 INFO: rcu detected stall in sys_unlink 1 4 731d 950d 0/3 auto-obsoleted due to no activity on 2024/12/07 03:28
linux-5.15 INFO: rcu detected stall in sys_unlink (2) 1 3 784d 795d 0/3 auto-obsoleted due to no activity on 2024/10/15 13:02
upstream INFO: rcu detected stall in sys_unlink mm kasan 1 1 1491d 1491d 0/29 auto-obsoleted due to no activity on 2022/10/29 07:23
linux-5.15 INFO: rcu detected stall in sys_unlink 1 1 901d 901d 0/3 auto-obsoleted due to no activity on 2024/06/20 14:47
android-5-15 BUG: soft lockup in sys_unlink 1 7 843d 865d 0/2 auto-obsoleted due to no activity on 2024/08/07 01:29

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P59/1:b..l P5782/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=56441, q=22 ncpus=2)
task:syz-executor    state:R  running task     stack:21640 pid:5782  ppid:5776   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:stackdepot_memcmp lib/stackdepot.c:336 [inline]
RIP: 0010:find_stack lib/stackdepot.c:352 [inline]
RIP: 0010:__stack_depot_save+0x16a/0x660 lib/stackdepot.c:390
Code: 26 fa 12 44 21 e5 4d 8b 7c ed 00 4d 85 ff 74 31 89 c1 eb 08 4d 8b 3f 4d 85 ff 74 25 45 39 67 08 75 f2 41 39 47 0c 75 ec 31 d2 <48> 8b 34 d3 49 3b 74 d7 18 75 df 48 ff c2 39 d1 75 ee e9 0b 04 00
RSP: 0018:ffffc9000439f528 EFLAGS: 00000202
RAX: 000000000000000b RBX: ffffc9000439f5c0 RCX: 000000000000000b
RDX: 0000000000000007 RSI: ffffffff81f6a347 RDI: 0000000000000001
RBP: 00000000000074b8 R08: 0000000000002800 R09: 00000000f1a32f5b
R10: 00000000292307dd R11: fffffbfff1d18ee6 R12: 00000000437074b8
R13: ffff88823b400000 R14: 0000000000000001 R15: ffff88807d2b39a0
 save_stack+0x133/0x230 mm/page_owner.c:129
 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1182 [inline]
 free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366
 free_unref_page_list+0xbe/0x860 mm/page_alloc.c:2505
 release_pages+0x208a/0x2300 mm/swap.c:1022
 __folio_batch_release+0x71/0xe0 mm/swap.c:1042
 folio_batch_release include/linux/pagevec.h:83 [inline]
 shmem_undo_range+0x5ff/0x1a80 mm/shmem.c:1026
 shmem_truncate_range mm/shmem.c:1135 [inline]
 shmem_evict_inode+0x285/0xa70 mm/shmem.c:1264
 evict+0x4b7/0x8a0 fs/inode.c:705
 do_unlinkat+0x38c/0x590 fs/namei.c:4453
 __do_sys_unlink fs/namei.c:4494 [inline]
 __se_sys_unlink fs/namei.c:4492 [inline]
 __x64_sys_unlink+0x49/0x50 fs/namei.c:4492
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f514cd9d1c7
RSP: 002b:00007ffffb47c508 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f514cd9d1c7
RDX: 00007ffffb47c530 RSI: 00007ffffb47c5c0 RDI: 00007ffffb47c5c0
RBP: 00007ffffb47c5c0 R08: 00007ffffb47d5c0 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffffb47d650
R13: 00007f514ce34474 R14: 00000000000c5959 R15: 00007ffffb47d690
 </TASK>
task:kworker/u4:4    state:R  running task     stack:21784 pid:59    ppid:2      flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc900015a79c0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: cbc9fcd387a29b00
RDX: 0000000000000000 RSI: ffffffff8acadd60 RDI: ffffffff8b1d32e0
RBP: ffffc900015a7ae0 R08: dffffc0000000000 R09: 1ffffffff223daa0
R10: dffffc0000000000 R11: fffffbfff223daa1 R12: 1ffff920002b4f44
R13: ffffffff8d131da0 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 batadv_nc_process_nc_paths+0xdb/0x380 net/batman-adv/network-coding.c:687
 batadv_nc_worker+0x423/0x600 net/batman-adv/network-coding.c:728
 process_one_work kernel/workqueue.c:2657 [inline]
 process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734
 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: rcu_preempt kthread starved for 10575 jiffies! g56441 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:27848 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6701
 schedule+0xbd/0x170 kernel/sched/core.c:6775
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </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: 0 Comm: swapper/0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: 59 1a 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d b3 35 39 00 fb f4 <c3> 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2c 89 cb 80 f9
RSP: 0018:ffffffff8ce07d80 EFLAGS: 000002c6
RAX: 3413a8e58185dc00 RBX: ffffffff81630c41 RCX: 3413a8e58185dc00
RDX: 0000000000000001 RSI: ffffffff8acacbe0 RDI: ffffffff8b1d32e0
RBP: ffffffff8ce07eb8 R08: ffff8880b8e36bab R09: 1ffff110171c6d75
R10: dffffc0000000000 R11: ffffed10171c6d76 R12: 1ffffffff19c0fbc
R13: dffffc0000000000 R14: 1ffffffff19d2688 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000029030 CR3: 0000000051cc4000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:753
 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
 cpuidle_idle_call kernel/sched/idle.c:178 [inline]
 do_idle+0x221/0x5c0 kernel/sched/idle.c:302
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401
 rest_init+0x2e2/0x300 init/main.c:705
 arch_call_rest_init+0xe/0x10 init/main.c:801
 start_kernel+0x461/0x4e0 init/main.c:1046
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555
 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536
 secondary_startup_64_no_verify+0x179/0x17b
 </TASK>

Crashes (47):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/18 15:45 linux-6.6.y d27334b2888c 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/08/11 23:22 linux-6.6.y d27334b2888c 71790083 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/07/30 05:39 linux-6.6.y ae068b676196 6ef5c1e2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/07/25 15:17 linux-6.6.y c5596480c50e 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/06/29 00:09 linux-6.6.y d1cfde2d5d15 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/06/28 04:48 linux-6.6.y d1cfde2d5d15 fb92f11c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/06/21 02:50 linux-6.6.y d1cfde2d5d15 43bfcdb0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/06/17 04:23 linux-6.6.y 924b4a879cbb 62cc6db3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/06/06 21:54 linux-6.6.y 924b4a879cbb cc095639 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/06/04 09:48 linux-6.6.y 924b4a879cbb 197909be .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/05/28 21:30 linux-6.6.y 0a40c6fbd105 681715f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/05/28 17:31 linux-6.6.y 0a40c6fbd105 681715f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/05/23 10:45 linux-6.6.y eac8889a3a1c c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/05/22 17:42 linux-6.6.y eac8889a3a1c 5f091fcc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/05/17 23:53 linux-6.6.y eac8889a3a1c de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/05/17 13:48 linux-6.6.y 4d922539ad7d de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/05/13 13:19 linux-6.6.y 3b9f64db0496 fec2a7ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/05/10 20:42 linux-6.6.y 3b9f64db0496 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/05/05 02:12 linux-6.6.y 258cf62a6dfd a898ba9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/04/11 08:08 linux-6.6.y 80de0a958133 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/04/04 14:59 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/03/28 11:29 linux-6.6.y c09fbcd31ae6 356bdfc9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/03/26 05:44 linux-6.6.y c09fbcd31ae6 c6143aac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/03/02 18:54 linux-6.6.y 7a137e9bfa0e b9dd6534 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/02/25 07:20 linux-6.6.y 7a137e9bfa0e 787dfb7c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/02/23 16:56 linux-6.6.y 7a137e9bfa0e 6beca497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/02/21 10:40 linux-6.6.y 7a137e9bfa0e 6e7b5511 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/02/15 12:44 linux-6.6.y 1b4ef5214f17 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/02/11 18:48 linux-6.6.y 1b4ef5214f17 75707236 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/02/11 05:36 linux-6.6.y c56aaf1a85ae 441e25b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/02/09 01:21 linux-6.6.y c56aaf1a85ae 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/02/03 04:43 linux-6.6.y 2cf6f68313dc d78927dd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/01/31 05:19 linux-6.6.y 2cf6f68313dc c75a2f6e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2026/01/15 11:06 linux-6.6.y c596736dadab d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/12/20 01:17 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/12/12 05:51 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/12/11 10:44 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/12/10 10:44 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/11/08 07:48 linux-6.6.y 0a805b6ea8cd 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/11/07 04:11 linux-6.6.y 0a805b6ea8cd 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/11/07 03:37 linux-6.6.y 0a805b6ea8cd 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/10/26 19:07 linux-6.6.y 4a243110dc88 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/10/24 06:07 linux-6.6.y 4a243110dc88 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/09/30 05:14 linux-6.6.y 147338df3487 86341da6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/07/31 13:11 linux-6.6.y dbcb8d8e4163 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/07/23 13:51 linux-6.6.y d96eb99e2f0e e1dd4f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
2025/07/20 18:18 linux-6.6.y d96eb99e2f0e 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in sys_unlink
* Struck through repros no longer work on HEAD.