INFO: rcu detected stall in generic_file_write_iter (3)

Status: upstream: reported on 2026/07/11 18:33
Reported-by: syzbot+376d38b3fd0cd006839b@syzkaller.appspotmail.com
First crash: 53d, last: 20h23m
▶ ▼ Similar bugs (14)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in generic_file_write_iter (3) mm 1 1 2465d 2465d 0/29 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in generic_file_write_iter (2) exfat 1 2 2680d 2719d 0/29 auto-closed as invalid on 2019/10/25 09:01
upstream BUG: soft lockup in generic_file_write_iter (2) mm 1 8 1151d 1139d 0/29 auto-obsoleted due to no activity on 2023/10/18 13:34
linux-6.1 INFO: rcu detected stall in generic_file_write_iter (2) 1 17 195d 623d 0/3 auto-obsoleted due to no activity on 2026/05/31 05:00
linux-5.15 INFO: rcu detected stall in generic_file_write_iter (2) 1 42 2d04h 908d 0/3 upstream: reported on 2024/03/08 18:29
linux-5.15 INFO: rcu detected stall in generic_file_write_iter 1 1 1094d 1094d 0/3 auto-obsoleted due to no activity on 2023/12/13 17:16
upstream INFO: rcu detected stall in generic_file_write_iter (4) cgroups 1 1 2398d 2394d 0/29 auto-closed as invalid on 2020/05/09 11:43
upstream BUG: soft lockup in generic_file_write_iter net fs mm 1 2 1336d 1371d 0/29 auto-obsoleted due to no activity on 2023/04/05 19:12
upstream INFO: rcu detected stall in generic_file_write_iter mm 1 58 2743d 2885d 0/29 closed as dup on 2018/10/27 15:28
upstream INFO: rcu detected stall in generic_file_write_iter (5) fs 1 2 2232d 2239d 0/29 auto-closed as invalid on 2020/10/22 01:02
upstream INFO: rcu detected stall in generic_file_write_iter (7) block 1 1 417d 417d 0/29 auto-obsoleted due to no activity on 2025/10/11 00:51
upstream INFO: rcu detected stall in generic_file_write_iter (6) mm cgroups 1 2 1717d 1774d 0/29 closed as invalid on 2022/02/08 09:50
linux-6.1 INFO: rcu detected stall in generic_file_write_iter 1 18 751d 864d 0/3 auto-obsoleted due to no activity on 2024/11/12 08:46
android-5-15 BUG: soft lockup in generic_file_write_iter 1 1 844d 844d 0/2 auto-obsoleted due to no activity on 2024/08/10 08:10

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (115 ticks this GP) idle=871c/1/0x4000000000000000 softirq=80195/80195 fqs=58
	(detected by 1, t=10502 jiffies, g=121737, q=1241 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 24234 Comm: syz.4.7558 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__lock_acquire+0xe01/0x7c40 kernel/locking/lockdep.c:5033
Code: fc ff df 85 c0 0f 84 88 1a 00 00 4c 8b 6c 24 20 4c 89 ef 4c 89 f6 ba 08 00 00 00 e8 39 a6 00 00 31 db 85 c0 0f 84 4d 02 00 00 <48> c7 c0 40 a1 c1 96 48 c1 e8 03 49 b8 00 00 00 00 00 fc ff df 42
RSP: 0018:ffffc90000007940 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff8164c3c4
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90b13240
RBP: ffffc90000007b70 R08: ffffffff90b13247 R09: 1ffffffff2162648
R10: dffffc0000000000 R11: fffffbfff2162649 R12: ffff88804d1428d8
R13: ffff88804d141e00 R14: ffff88804d142980 R15: ffff88804d1429a0
FS:  00007ff3781bf6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff3711f6000 CR3: 0000000054fd3000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 advance_sched+0x6d0/0x950 net/sched/sch_taprio.c:755
 __run_hrtimer kernel/time/hrtimer.c:1751 [inline]
 __hrtimer_run_queues+0x522/0xc90 kernel/time/hrtimer.c:1815
 hrtimer_interrupt+0x399/0x980 kernel/time/hrtimer.c:1877
 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:lock_acquire+0x225/0x4a0 kernel/locking/lockdep.c:5680
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 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 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04
RSP: 0018:ffffc9000578f660 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 87d9d74723438500
RDX: 0000000000000000 RSI: ffffffff8a8c2a20 RDI: ffffffff8adf6420
RBP: ffffc9000578f768 R08: dffffc0000000000 R09: 1ffffffff2162648
R10: dffffc0000000000 R11: fffffbfff2162649 R12: 0000000000000000
R13: 1ffff92000af1ed8 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 percpu_ref_tryget_many include/linux/percpu-refcount.h:241 [inline]
 percpu_ref_tryget+0x31/0x180 include/linux/percpu-refcount.h:266
 css_tryget include/linux/cgroup.h:357 [inline]
 get_mem_cgroup_from_mm+0xfe/0x290 mm/memcontrol.c:1041
 __mem_cgroup_charge+0x11/0x80 mm/memcontrol.c:6943
 mem_cgroup_charge include/linux/memcontrol.h:672 [inline]
 shmem_add_to_page_cache+0x8d7/0x1c90 mm/shmem.c:708
 shmem_get_folio_gfp+0x1663/0x35e0 mm/shmem.c:1971
 shmem_get_folio mm/shmem.c:2072 [inline]
 shmem_write_begin+0xee/0x3f0 mm/shmem.c:2556
 generic_perform_write+0x2fa/0x5c0 mm/filemap.c:3862
 __generic_file_write_iter+0x148/0x2a0 mm/filemap.c:3960
 generic_file_write_iter+0xab/0x2e0 mm/filemap.c:3989
 call_write_iter include/linux/fs.h:2271 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x482/0x9a0 fs/read_write.c:584
 ksys_write+0x14d/0x260 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff37735e98e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007ff3781beda8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ff3781bf6c0 RCX: 00007ff37735e98e
RDX: 0000000004000000 RSI: 00007ff36d1f7000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007ff3781beee0 R14: 00007ff3781beea0 R15: 00007ff36d1f7000
 </TASK>
rcu: rcu_preempt kthread starved for 10386 jiffies! g121737 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:28112 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x99/0x3b0 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:
CPU: 1 PID: 24219 Comm: syz.3.7550 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline]
RIP: 0010:smp_call_function_many_cond+0x114d/0x1250 kernel/smp.c:998
Code: 83 e6 01 31 ff e8 23 02 0b 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 0a e8 af fe 0a 00 e9 34 ff ff ff f3 90 41 0f b6 04 1c <84> c0 75 14 41 f7 07 01 00 00 00 0f 84 17 ff ff ff e8 8d fe 0a 00
RSP: 0018:ffffc90005a4fac0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000080000
RDX: ffffc9000e62a000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc90005a4fc10 R08: ffff8880b8f3bd97 R09: 1ffff110171e77b2
R10: dffffc0000000000 R11: ffffed10171e77b3 R12: 1ffff110171c85f5
R13: ffff8880b8f3bd80 R14: 0000000000000000 R15: ffff8880b8e42fa8
FS:  00007fc89f19a6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2fd23ffc CR3: 0000000072756000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 clock_was_set+0x7ee/0x8d0 kernel/time/hrtimer.c:988
 do_settimeofday64+0x597/0x740 kernel/time/timekeeping.c:1345
 __do_sys_clock_settime kernel/time/posix-timers.c:1125 [inline]
 __se_sys_clock_settime kernel/time/posix-timers.c:1113 [inline]
 __x64_sys_clock_settime+0x25a/0x2a0 kernel/time/posix-timers.c:1113
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc89e39e159
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:00007fc89f19a028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 00007fc89e625fa0 RCX: 00007fc89e39e159
RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000
RBP: 00007fc89e435024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc89e626038 R14: 00007fc89e625fa0 R15: 00007ffea66b3978
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/02 17:55 linux-6.1.y cf82dcca9634 85995287 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in generic_file_write_iter
2026/08/04 07:51 linux-6.1.y fb28aa725e05 9451e17e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in generic_file_write_iter
2026/07/11 18:32 linux-6.1.y 090666d3cc90 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in generic_file_write_iter
* Struck through repros no longer work on HEAD.