INFO: rcu detected stall in ext4_file_write_iter

Status: upstream: reported C repro on 2019/04/12 16:30
Reported-by: syzbot+0f14e80e289d4997740f@syzkaller.appspotmail.com
First crash: 2685d, last: 1276d
▶ ▼ Similar bugs (14)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in ext4_file_write_iter (8) mm 1 3 977d 1032d 0/29 auto-obsoleted due to no activity on 2024/03/14 12:59
linux-5.15 INFO: rcu detected stall in ext4_file_write_iter 1 1 1000d 1000d 0/3 auto-obsoleted due to no activity on 2024/02/29 20:44
upstream INFO: rcu detected stall in ext4_file_write_iter (10) ext4 1 1 342d 342d 0/29 auto-obsoleted due to no activity on 2025/12/09 11:43
upstream INFO: rcu detected stall in ext4_file_write_iter (3) block 1 5 1835d 1924d 0/29 auto-closed as invalid on 2021/11/07 19:52
upstream INFO: rcu detected stall in ext4_file_write_iter (5) mm 1 3 1575d 1575d 0/29 auto-closed as invalid on 2022/06/25 07:58
linux-6.1 INFO: rcu detected stall in ext4_file_write_iter 1 1 869d 869d 0/3 auto-obsoleted due to no activity on 2024/07/10 06:27
upstream INFO: rcu detected stall in ext4_file_write_iter (7) mm bpf ext4 1 3 1083d 1125d 23/29 fixed on 2023/10/12 12:47
upstream INFO: rcu detected stall in ext4_file_write_iter (4) mm 1 syz, C unreliable 58 1670d 1700d 0/29 closed as invalid on 2022/02/08 10:32
android-49 INFO: rcu detected stall in ext4_file_write_iter 1 syz 2 2633d 2674d 0/3 public: reported syz repro on 2019/04/23 08:58
upstream INFO: rcu detected stall in ext4_file_write_iter (2) ext4 1 1 2136d 2136d 0/29 auto-closed as invalid on 2021/01/10 12:58
upstream INFO: rcu detected stall in ext4_file_write_iter 1 syz, C inconclusive done 93 2198d 2730d 15/29 fixed on 2020/09/25 01:17
linux-4.19 INFO: rcu detected stall in ext4_file_write_iter 1 syz, C error 9 1336d 2677d 0/1 upstream: reported C repro on 2019/04/20 13:09
upstream INFO: rcu detected stall in ext4_file_write_iter (6) ext4 1 syz, C error 8 1224d 1287d 22/29 fixed on 2023/06/08 14:41
upstream INFO: rcu detected stall in ext4_file_write_iter (9) mm 1 8 793d 857d 0/29 auto-obsoleted due to no activity on 2024/09/14 13:24
▶ ▼ Fix bisection attempts (25)
Created Duration User Patch Repo Result
2023/02/19 16:44 26m bisect fix linux-4.14.y OK (0) job log log
2023/01/20 06:26 22m bisect fix linux-4.14.y OK (0) job log log
2022/10/27 15:08 24m bisect fix linux-4.14.y OK (0) job log log
2022/09/19 14:43 28m bisect fix linux-4.14.y OK (0) job log log
2022/08/20 11:52 22m bisect fix linux-4.14.y OK (0) job log log
2022/07/21 11:20 31m bisect fix linux-4.14.y OK (0) job log log
2022/06/21 10:47 31m bisect fix linux-4.14.y OK (0) job log log
2022/05/22 09:59 22m bisect fix linux-4.14.y OK (0) job log log
2022/04/22 06:14 21m bisect fix linux-4.14.y OK (0) job log log
2022/03/23 05:03 28m bisect fix linux-4.14.y OK (0) job log log
2022/02/20 14:40 29m bisect fix linux-4.14.y OK (0) job log log
2022/01/21 12:51 25m bisect fix linux-4.14.y OK (0) job log log
2021/12/22 12:12 26m bisect fix linux-4.14.y OK (0) job log log
2021/11/22 11:28 26m bisect fix linux-4.14.y OK (0) job log log
2021/10/23 10:14 26m bisect fix linux-4.14.y OK (0) job log log
2021/09/22 22:17 27m bisect fix linux-4.14.y OK (0) job log log
2021/08/23 19:08 29m bisect fix linux-4.14.y OK (0) job log log
2021/07/24 18:36 26m bisect fix linux-4.14.y OK (0) job log log
2021/06/24 18:09 21m bisect fix linux-4.14.y OK (0) job log log
2021/05/25 13:16 28m bisect fix linux-4.14.y OK (0) job log log
2021/04/25 12:02 25m bisect fix linux-4.14.y OK (0) job log log
2021/03/26 05:03 21m bisect fix linux-4.14.y OK (0) job log log
2021/02/24 04:07 24m bisect fix linux-4.14.y OK (0) job log log
2021/01/24 03:24 25m bisect fix linux-4.14.y OK (0) job log log
2020/12/25 02:56 25m bisect fix linux-4.14.y OK (0) job log log

Sample crash report:
audit: type=1400 audit(1561786044.356:37): avc:  denied  { map } for  pid=7099 comm="syz-executor232" path="/root/syz-executor232886150" dev="sda1" ino=1426 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
INFO: rcu_sched self-detected stall on CPU
	0-...: (10499 ticks this GP) idle=6e6/140000000000001/0 softirq=23189/23194 fqs=0 
	 (t=10500 jiffies g=925 c=924 q=4)
rcu_sched kthread starved for 10500 jiffies! g925 c924 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0
rcu_sched       R  running task    29824     9      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_timeout+0x43e/0xe10 kernel/time/timer.c:1744
 rcu_gp_kthread+0xbf4/0x1ec0 kernel/rcu/tree.c:2255
 kthread+0x319/0x430 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
NMI backtrace for cpu 0
CPU: 0 PID: 7107 Comm: syz-executor232 Not tainted 4.14.131 #25
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x138/0x19c lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:158 [inline]
 rcu_dump_cpu_stacks+0x186/0x1d2 kernel/rcu/tree.c:1396
 print_cpu_stall kernel/rcu/tree.c:1542 [inline]
 check_cpu_stall kernel/rcu/tree.c:1610 [inline]
 __rcu_pending kernel/rcu/tree.c:3390 [inline]
 rcu_pending kernel/rcu/tree.c:3452 [inline]
 rcu_check_callbacks.cold+0x43d/0xd0a kernel/rcu/tree.c:2792
 update_process_times+0x31/0x70 kernel/time/timer.c:1588
 tick_sched_handle+0x85/0x160 kernel/time/tick-sched.c:161
 tick_sched_timer+0x43/0x130 kernel/time/tick-sched.c:1219
 __run_hrtimer kernel/time/hrtimer.c:1220 [inline]
 __hrtimer_run_queues+0x270/0xbc0 kernel/time/hrtimer.c:1284
 hrtimer_interrupt+0x1d8/0x5d0 kernel/time/hrtimer.c:1318
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline]
 smp_apic_timer_interrupt+0x11c/0x5e0 arch/x86/kernel/apic/apic.c:1062
 apic_timer_interrupt+0x8e/0xa0 arch/x86/entry/entry_64.S:789
 </IRQ>
RIP: 0010:debug_smp_processor_id+0x1c/0x20 lib/smp_processor_id.c:58
RSP: 0018:ffff88808fb7f470 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10
RAX: 0000000000000000 RBX: ffffffff87ab2740 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff869d29a0 RDI: ffffffff869d29e0
RBP: ffff88808fb7f470 R08: 000000000000001c R09: ffffea00021c8a40
R10: ffff8880a5849a40 R11: ffff8880872297e3 R12: 0000000000000001
R13: 0000000000000000 R14: ffff888095f255f0 R15: 000000000000001c
 rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1186 [inline]
 rcu_lockdep_current_cpu_online+0x3a/0x140 kernel/rcu/tree.c:1177
 rcu_read_lock_sched_held+0x97/0x130 kernel/rcu/update.c:113
 trace_writeback_mark_inode_dirty include/trace/events/writeback.h:114 [inline]
 __mark_inode_dirty+0x8f4/0x1040 fs/fs-writeback.c:2125
 mark_inode_dirty include/linux/fs.h:2019 [inline]
 generic_write_end+0x1b7/0x290 fs/buffer.c:2218
 ext4_da_write_end+0x344/0x8e0 fs/ext4/inode.c:3181
 generic_perform_write+0x29f/0x480 mm/filemap.c:3035
 __generic_file_write_iter+0x239/0x5b0 mm/filemap.c:3149
 ext4_file_write_iter+0x2ac/0xe90 fs/ext4/file.c:264
 call_write_iter include/linux/fs.h:1777 [inline]
 do_iter_readv_writev+0x418/0x670 fs/read_write.c:675
 do_iter_write fs/read_write.c:954 [inline]
 do_iter_write+0x154/0x540 fs/read_write.c:935
 vfs_iter_write+0x77/0xb0 fs/read_write.c:967
 iter_file_splice_write+0x572/0xad0 fs/splice.c:749
 do_splice_from fs/splice.c:851 [inline]
 direct_splice_actor+0x123/0x190 fs/splice.c:1018
 splice_direct_to_actor+0x29e/0x7b0 fs/splice.c:973
 do_splice_direct+0x18d/0x230 fs/splice.c:1061
 do_sendfile+0x4db/0xbd0 fs/read_write.c:1441
 SYSC_sendfile64 fs/read_write.c:1496 [inline]
 SyS_sendfile64+0x9d/0x110 fs/read_write.c:1488
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4417a9
RSP: 002b:00007fff5f5841a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fff5f584350 RCX: 00000000004417a9
RDX: 0000000020000000 RSI: 0000000000000003 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00008080fffffffe R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000402480 R14: 0000000000000000 R15: 0000000000000000
INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10554 jiffies, g=1220, c=1219, q=23)
All QSes seen, last rcu_preempt kthread activity 10554 (4295013694-4295003140), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor232 R  running task    26976  7107   7103 0x00000008
Call Trace:
 <IRQ>
 sched_show_task kernel/sched/core.c:5167 [inline]
 sched_show_task.cold+0x294/0x2ff kernel/sched/core.c:5142
 print_other_cpu_stall kernel/rcu/tree.c:1501 [inline]
 check_cpu_stall kernel/rcu/tree.c:1616 [inline]
 __rcu_pending kernel/rcu/tree.c:3390 [inline]
 rcu_pending kernel/rcu/tree.c:3452 [inline]
 rcu_check_callbacks.cold+0xcb1/0xd0a kernel/rcu/tree.c:2792
 update_process_times+0x31/0x70 kernel/time/timer.c:1588
 tick_sched_handle+0x85/0x160 kernel/time/tick-sched.c:161
 tick_sched_timer+0x43/0x130 kernel/time/tick-sched.c:1219
 __run_hrtimer kernel/time/hrtimer.c:1220 [inline]
 __hrtimer_run_queues+0x270/0xbc0 kernel/time/hrtimer.c:1284
 hrtimer_interrupt+0x1d8/0x5d0 kernel/time/hrtimer.c:1318
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1037 [inline]
 smp_apic_timer_interrupt+0x11c/0x5e0 arch/x86/kernel/apic/apic.c:1062
 apic_timer_interrupt+0x8e/0xa0 arch/x86/entry/entry_64.S:789
 </IRQ>
RIP: 0010:debug_smp_processor_id+0x1c/0x20 lib/smp_processor_id.c:58
RSP: 0018:ffff88808fb7f470 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff10
RAX: 0000000000000000 RBX: ffffffff87ab2740 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff869d29a0 RDI: ffffffff869d29e0
RBP: ffff88808fb7f470 R08: 000000000000001c R09: ffffea00021c8a40
R10: ffff8880a5849a40 R11: ffff8880872297e3 R12: 0000000000000001
R13: 0000000000000000 R14: ffff888095f255f0 R15: 000000000000001c
 rcu_lockdep_current_cpu_online kernel/rcu/tree.c:1186 [inline]
 rcu_lockdep_current_cpu_online+0x3a/0x140 kernel/rcu/tree.c:1177
 rcu_read_lock_sched_held+0x97/0x130 kernel/rcu/update.c:113
 trace_writeback_mark_inode_dirty include/trace/events/writeback.h:114 [inline]
 __mark_inode_dirty+0x8f4/0x1040 fs/fs-writeback.c:2125
 mark_inode_dirty include/linux/fs.h:2019 [inline]
 generic_write_end+0x1b7/0x290 fs/buffer.c:2218
 ext4_da_write_end+0x344/0x8e0 fs/ext4/inode.c:3181
 generic_perform_write+0x29f/0x480 mm/filemap.c:3035
 __generic_file_write_iter+0x239/0x5b0 mm/filemap.c:3149
 ext4_file_write_iter+0x2ac/0xe90 fs/ext4/file.c:264
 call_write_iter include/linux/fs.h:1777 [inline]
 do_iter_readv_writev+0x418/0x670 fs/read_write.c:675
 do_iter_write fs/read_write.c:954 [inline]
 do_iter_write+0x154/0x540 fs/read_write.c:935
 vfs_iter_write+0x77/0xb0 fs/read_write.c:967
 iter_file_splice_write+0x572/0xad0 fs/splice.c:749
 do_splice_from fs/splice.c:851 [inline]
 direct_splice_actor+0x123/0x190 fs/splice.c:1018
 splice_direct_to_actor+0x29e/0x7b0 fs/splice.c:973
 do_splice_direct+0x18d/0x230 fs/splice.c:1061
 do_sendfile+0x4db/0xbd0 fs/read_write.c:1441
 SYSC_sendfile64 fs/read_write.c:1496 [inline]
 SyS_sendfile64+0x9d/0x110 fs/read_write.c:1488
 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4417a9
RSP: 002b:00007fff5f5841a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fff5f584350 RCX: 00000000004417a9
RDX: 0000000020000000 RSI: 0000000000000003 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00008080fffffffe R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000402480 R14: 0000000000000000 R15: 0000000000000000
rcu_preempt kthread starved for 10554 jiffies! g1220 c1219 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0
rcu_preempt     R  running task    29776     8      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2807 [inline]
 __schedule+0x7b8/0x1cd0 kernel/sched/core.c:3383
 schedule+0x92/0x1c0 kernel/sched/core.c:3427
 schedule_timeout+0x43e/0xe10 kernel/time/timer.c:1744
 rcu_gp_kthread+0xbf4/0x1ec0 kernel/rcu/tree.c:2255
 kthread+0x319/0x430 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/06/29 05:32 linux-4.14.y f4cc0ed9b2c7 7509bf36 .config console log report syz C ci2-linux-4-14
2020/06/27 23:48 linux-4.14.y b850307b279c a2cdad9d .config console log report ci2-linux-4-14
2020/06/24 11:31 linux-4.14.y b850307b279c 41694dbf .config console log report ci2-linux-4-14
2020/03/04 12:51 linux-4.14.y 78d697fc93f9 712198ac .config console log report ci2-linux-4-14
2019/09/08 20:12 linux-4.14.y 414510bc00a5 a60cb4cd .config console log report ci2-linux-4-14
2019/04/23 00:06 linux-4.14.y 68d7a45eec10 53199d6e .config console log report ci2-linux-4-14
2019/04/12 15:29 linux-4.14.y 1ec8f1f0bffe 4f421599 .config console log report ci2-linux-4-14
* Struck through repros no longer work on HEAD.