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: 845d, last: 12d
▶ ▼ Similar bugs (11)
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 1366d 1366d 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 2749d 2909d 0/29 closed as dup on 2019/01/02 16:58
linux-6.6 INFO: rcu detected stall in shmem_fault 1 9 214d 467d 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 777d 842d 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 1136d 1156d 23/29 fixed on 2023/10/12 12:48
linux-5.15 INFO: rcu detected stall in shmem_fault 1 1 1121d 1121d 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 1615d 1615d 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 133d 649d 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 2489d 2489d 0/29 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in shmem_fault (6) mm prio:low 1 syz, C 272 4h07m 738d 0/29 upstream: reported C repro on 2024/09/19 14:28
upstream BUG: workqueue lockup (5) prio:low kernel 1 syz, C done 17853 3h03m 2447d 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: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5437/1:b..l
	(detected by 0, t=10502 jiffies, g=15661, q=258)
task:syz.3.327       state:R  running task     stack:23216 pid: 5437 ppid:  4192 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:435
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5629
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0000:ffffc90003bb6b60 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0097b65d14207f00
RDX: 0000000000000000 RSI: ffffffff8a2b3e80 RDI: ffffffff8a7a48c0
RBP: ffffc90003bb6c80 R08: dffffc0000000000 R09: 1ffffffff203e218
R10: dffffc0000000000 R11: fffffbfff203e219 R12: ffffffff8c31ef60
R13: 1ffff92000776d78 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 mapping_get_entry mm/filemap.c:1823 [inline]
 pagecache_get_page+0x121/0xf20 mm/filemap.c:1894
 shmem_getpage_gfp+0x2fd/0x2c10 mm/shmem.c:1841
 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
 __get_user_pages_locked mm/gup.c:1382 [inline]
 get_dump_page+0x18c/0x670 mm/gup.c:1838
 dump_user_range+0x54/0x340 fs/coredump.c:1013
 elf_core_dump+0x2fe0/0x3530 fs/binfmt_elf.c:2285
 do_coredump+0x14e8/0x2a40 fs/coredump.c:894
 get_signal+0x531/0x12e0 kernel/signal.c:2899
 arch_do_signal_or_restart+0xe6/0x12a0 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:157 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:217
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:323
 exc_page_fault+0x88/0x100 arch/x86/mm/fault.c:1499
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7ff099cafbd7
RSP: 002b:00007ff098033120 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007ff099dfa159
RDX: 00007ff098033140 RSI: 00007ff098033270 RDI: 000000000000000b
RBP: 00007ff099e9103b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007ff09a082038 R14: 00007ff09a081fa0 R15: 00007fffe9e1c118
 </TASK>
rcu: rcu_preempt kthread starved for 10489 jiffies! g15661 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:27920 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: 0 Comm: swapper/0 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:default_idle+0xb/0x10 arch/x86/kernel/process.c:730
Code: b7 48 89 df e8 06 bf f3 f7 eb ad e8 1f ab f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 00 cc 66 90 0f 00 2d c7 44 5b 00 fb f4 <c3> 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48
RSP: 0000:ffffffff8c007dc8 EFLAGS: 000002c6
RAX: 9f645575a5cd9f00 RBX: ffffffff8c0bc480 RCX: 9f645575a5cd9f00
RDX: 0000000000000001 RSI: ffffffff8a2b2be0 RDI: ffffffff8a7a48c0
RBP: ffffffff8c007ef8 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: 1ffffffff1800fc4
R13: dffffc0000000000 R14: 1ffffffff1817890 R15: 0000000000000000
 default_idle_call+0x81/0xc0 kernel/sched/idle.c:112
 cpuidle_idle_call kernel/sched/idle.c:202 [inline]
 do_idle+0x251/0x650 kernel/sched/idle.c:326
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:424
 start_kernel+0x489/0x540 init/main.c:1114
 secondary_startup_64_no_verify+0xb1/0xbb
 </TASK>

Crashes (29):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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.