INFO: rcu detected stall in shmem_fault (2)

Status: upstream: reported on 2024/06/03 20:13
Reported-by: syzbot+cf92cb07cc1063893ed7@syzkaller.appspotmail.com
First crash: 872d, last: 4d13h
▶ ▼ Similar bugs (12)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in shmem_fault (4) kernel 1 1 1393d 1393d 0/29 auto-obsoleted due to no activity on 2023/04/08 07:17
upstream INFO: rcu detected stall in shmem_fault mm 1 13 2776d 2936d 0/29 closed as dup on 2019/01/02 16:58
linux-6.6 INFO: rcu detected stall in shmem_fault 1 9 241d 494d 0/2 auto-obsoleted due to no activity on 2026/06/04 20:40
linux-6.1 INFO: rcu detected stall in shmem_fault 1 7 804d 868d 0/3 auto-obsoleted due to no activity on 2024/11/18 20:23
upstream INFO: rcu detected stall in shmem_fault (5) cgroups mm 1 3 1163d 1183d 23/29 fixed on 2023/10/12 12:48
linux-5.15 INFO: rcu detected stall in shmem_fault 1 1 1147d 1147d 0/3 auto-obsoleted due to no activity on 2023/12/11 11:17
upstream INFO: rcu detected stall in shmem_fault (3) mm fs 1 4 1642d 1642d 0/29 auto-closed as invalid on 2022/06/25 08:10
linux-6.1 INFO: rcu detected stall in shmem_fault (2) 1 22 160d 675d 0/3 auto-obsoleted due to no activity on 2026/08/25 07:39
upstream INFO: rcu detected stall in shmem_fault (2) cgroups mm 1 1 2515d 2515d 0/29 closed as invalid on 2019/12/04 14:04
linux-6.6 INFO: rcu detected stall in shmem_fault (2) 1 1 18d 18d 0/2 upstream: reported on 2026/10/05 16:19
upstream INFO: rcu detected stall in shmem_fault (6) mm prio:low 1 syz, C 285 13h56m 764d 0/29 upstream: reported C repro on 2024/09/19 14:28
upstream BUG: workqueue lockup (5) prio:low arm 1 syz, C done 18022 2h44m 2474d 0/29 upstream: reported C repro on 2020/01/14 22:04

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (11 ticks this GP) idle=6ff/1/0x4000000000000000 softirq=11691/11691 fqs=32 
	(detected by 0, t=10502 jiffies, g=13549, q=357)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5798 Comm: syz.1.457 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:3749 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3768 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3823 [inline]
RIP: 0010:__lock_acquire+0x144e/0x7d40 kernel/locking/lockdep.c:5120
Code: 00 00 00 00 fc ff df 48 89 5c 24 18 48 8b 1b 48 85 db 74 5c 48 83 c3 f8 74 56 4c 8d 73 18 4c 89 f0 48 c1 e8 03 42 80 3c 00 00 <74> 12 4c 89 f7 e8 68 60 61 00 49 b8 00 00 00 00 00 fc ff df 49 8b
RSP: 0018:ffffc90000dd08c0 EFLAGS: 00000046
RAX: 1ffffffff2204acf RBX: ffffffff91025660 RCX: ffffffff815d0753
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff910150c0
RBP: ffffc90000dd0b08 R08: dffffc0000000000 R09: 1ffffffff2202a18
R10: dffffc0000000000 R11: fffffbfff2202a19 R12: cf82e703b144b952
R13: ffff8880287f9dc0 R14: ffffffff91025678 R15: ffff8880287fa920
FS:  00007fbbf607e6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c28b9be CR3: 000000007d427000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 lock_acquire+0x19f/0x400 kernel/locking/lockdep.c:5737
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x63/0x380 lib/debugobjects.c:757
 debug_hrtimer_deactivate kernel/time/hrtimer.c:415 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1653 [inline]
 __hrtimer_run_queues+0x2c0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:rmqueue_pcplist mm/page_alloc.c:3711 [inline]
RIP: 0010:rmqueue mm/page_alloc.c:3742 [inline]
RIP: 0010:get_page_from_freelist+0x1f20/0x2670 mm/page_alloc.c:4189
Code: 8f 84 24 c0 01 00 00 f7 84 24 c0 01 00 00 00 02 00 00 c6 44 08 04 f8 0f 85 89 02 00 00 41 f7 c5 00 02 00 00 74 01 fb 4d 85 f6 <44> 8b 6c 24 2c 0f 84 d5 00 00 00 4c 89 f0 48 c1 e8 03 80 3c 08 00
RSP: 0018:ffffc900033cef20 EFLAGS: 00000286
RAX: 1ffff92000679e18 RBX: ffffffff8be44828 RCX: dffffc0000000000
RDX: dffffc0000000000 RSI: ffffffff8a2b2b60 RDI: ffffffff8a7a4b40
RBP: ffffc900033cf170 R08: ffffffff910150f7 R09: 1ffffffff2202a1e
R10: dffffc0000000000 R11: fffffbfff2202a1f R12: ffff88813fffd310
R13: 0000000000000202 R14: ffffea0001c50ec0 R15: 0000000001100cca
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
 alloc_pages_vma+0x2bc/0x790 mm/mempolicy.c:2146
 shmem_alloc_page mm/shmem.c:1586 [inline]
 shmem_alloc_and_acct_page+0x47f/0xbe0 mm/shmem.c:1611
 shmem_getpage_gfp+0x14be/0x2c10 mm/shmem.c:1906
 shmem_fault+0x1ac/0x550 mm/shmem.c:2118
 __do_fault+0x141/0x330 mm/memory.c:3928
 do_read_fault mm/memory.c:4264 [inline]
 do_fault mm/memory.c:4392 [inline]
 handle_pte_fault mm/memory.c:4650 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x2982/0x4440 mm/memory.c:4883
 faultin_page mm/gup.c:976 [inline]
 __get_user_pages+0x952/0x11e0 mm/gup.c:1197
 populate_vma_page_range+0x213/0x290 mm/gup.c:1529
 __mm_populate+0x275/0x3b0 mm/gup.c:1638
 mm_populate include/linux/mm.h:2646 [inline]
 vm_mmap_pgoff+0x212/0x2d0 mm/util.c:556
 ksys_mmap_pgoff+0x140/0x790 mm/mmap.c:1635
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fbbf7e26559
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbbf607e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fbbf80adfa0 RCX: 00007fbbf7e26559
RDX: b635773f06ebbee2 RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007fbbf7ebdad8 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbbf80ae038 R14: 00007fbbf80adfa0 R15: 00007ffdf9864068
 </TASK>
rcu: rcu_preempt kthread starved for 10438 jiffies! g13549 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:26864 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11f0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9a/0x370 kernel/rcu/tree.c:2145
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 4186 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x845/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b0/0xb60 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x397/0x8b0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xbb7/0xd80 kernel/smp.c:969
Code: 01 31 ff e8 ab 76 0b 00 83 e3 01 75 07 e8 41 73 0b 00 eb 42 f3 90 48 b8 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 75 10 <41> f7 06 01 00 00 00 74 1e e8 1b 73 0b 00 eb da 44 89 f1 80 e1 07
RSP: 0018:ffffc90002e8fa00 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88807a083b80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90002e8fb28 R08: ffffffff91015227 R09: 1ffffffff2202a44
R10: dffffc0000000000 R11: fffffbfff2202a45 R12: ffff8880b8e3b3c0
R13: 1ffff110171e80b9 R14: ffff8880b8f405c8 R15: 0000000000000001
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1134
 invalidate_bdev+0x8a/0xb0 block/bdev.c:86
 btrfs_close_bdev fs/btrfs/volumes.c:1186 [inline]
 btrfs_close_one_device fs/btrfs/volumes.c:1210 [inline]
 close_fs_devices+0x44f/0x950 fs/btrfs/volumes.c:1253
 btrfs_close_devices+0xca/0x510 fs/btrfs/volumes.c:1268
 close_ctree+0x774/0x8d0 fs/btrfs/disk-io.c:4515
 generic_shutdown_super+0x130/0x300 fs/super.c:475
 kill_anon_super+0x36/0x70 fs/super.c:1100
 btrfs_kill_super+0x3d/0x50 fs/btrfs/super.c:2390
 deactivate_locked_super+0x93/0xf0 fs/super.c:335
 cleanup_mnt+0x426/0x4d0 fs/namespace.c:1148
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:184
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:217
 __syscall_exit_to_user_mode_work kernel/entry/common.c:299 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:310
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f1907b23797
Code: a2 c7 05 5c 7f 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffcfe18fe78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f1907bb8f1b RCX: 00007f1907b23797
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffcfe18ff30
RBP: 00007ffcfe18ff30 R08: 00007ffcfe190f30 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcfe190fc0
R13: 00007f1907bb8f1b R14: 0000000000020c5d R15: 00007ffcfe191000
 </TASK>
vkms_vblank_simulate: vblank timer overrun

Crashes (31):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/19 20:08 linux-5.15.y 792fbe1537d8 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2026/10/15 05:43 linux-5.15.y a051a4bf909f 8fb0ae89 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2026/09/15 09:26 linux-5.15.y 0248c33e835e 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2026/09/01 08:26 linux-5.15.y 28c35638ec51 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2026/07/29 09:23 linux-5.15.y 674f684f7c61 19622d9d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2026/07/15 13:06 linux-5.15.y c86c4726e7f0 a4ed0f4f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2026/06/03 04:58 linux-5.15.y dc027a595035 3c0d2131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2026/05/18 06:42 linux-5.15.y 93741761e5e3 de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2026/02/24 06:41 linux-5.15.y 3330a8d33e08 41d2fa6a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/12/10 17:37 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/11/28 11:55 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/11/26 22:49 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/10/03 21:06 linux-5.15.y 29e53a5b1c4f 49379ee0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/08/18 08:43 linux-5.15.y c79648372d02 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/08/08 03:41 linux-5.15.y c79648372d02 6a893178 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/07/07 05:08 linux-5.15.y 3dea0e7f549e 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/06/26 08:03 linux-5.15.y 1c700860e8bc 26d77996 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/06/24 16:43 linux-5.15.y 1c700860e8bc e2f27c35 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/06/24 16:38 linux-5.15.y 1c700860e8bc e2f27c35 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/06/22 16:16 linux-5.15.y 1c700860e8bc d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/05/25 09:01 linux-5.15.y 98f47d0e9b8c ed351ea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/05/19 05:37 linux-5.15.y a68c15152131 f41472b0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/02/14 06:45 linux-5.15.y c16c81c81336 d9a046cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2025/02/05 16:19 linux-5.15.y c16c81c81336 4dc70884 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2024/12/02 17:59 linux-5.15.y 0a51d2d4527b b499ea68 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2024/10/27 20:55 linux-5.15.y 74cdd62cb470 65e8686b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2024/09/30 06:12 linux-5.15.y 3a5928702e71 ba29ff75 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2024/08/23 10:59 linux-5.15.y fa93fa65db6e ce8a9099 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2024/07/12 21:11 linux-5.15.y f45bea23c39c eaeb5c15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2024/06/03 20:12 linux-5.15.y c61bd26ae81a 0aba2352 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: rcu detected stall in shmem_fault
2024/09/19 06:48 linux-5.15.y 3a5928702e71 c673ca06 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 INFO: rcu detected stall in shmem_fault
* Struck through repros no longer work on HEAD.