syzbot


INFO: rcu detected stall in kernfs_fop_write_iter (2)

Status: auto-obsoleted due to no activity on 2024/11/14 04:13
Reported-by: syzbot+6a3035b78ed235eb5e2a@syzkaller.appspotmail.com
First crash: 204d, last: 107d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in kernfs_fop_write_iter 1 24d 24d 0/3 upstream: reported on 2024/10/28 10:26
upstream INFO: rcu detected stall in kernfs_fop_write_iter fs sctp 7 100d 196d 0/28 auto-obsoleted due to no activity on 2024/11/10 20:48
linux-6.1 INFO: rcu detected stall in kernfs_fop_write_iter 1 483d 483d 0/3 auto-obsoleted due to no activity on 2023/11/03 22:13

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3091/1:b..l
	(detected by 0, t=10502 jiffies, g=26393, q=1411 ncpus=2)
task:udevd           state:R  running task     stack:22600 pid:3091  ppid:1      flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6558
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6870
 irqentry_exit+0x53/0x80 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:653
RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5666
Code: 2b 00 74 08 4c 89 f7 e8 9f a8 77 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc900031cf8e0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000639f28 RCX: 1ffff92000639ec8
RDX: dffffc0000000000 RSI: ffffffff8b0c13e0 RDI: ffffffff8b5d5de0
RBP: ffffc900031cfa30 R08: dffffc0000000000 R09: fffffbfff20e7245
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000639f24
R13: dffffc0000000000 R14: ffffc900031cf940 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 netlink_has_listeners+0x8b/0x390 net/netlink/af_netlink.c:1378
 uevent_net_broadcast_untagged lib/kobject_uevent.c:321 [inline]
 kobject_uevent_net_broadcast+0x2ad/0x560 lib/kobject_uevent.c:409
 kobject_uevent_env+0x576/0x8c0 lib/kobject_uevent.c:608
 kobject_synth_uevent+0x4eb/0xae0 lib/kobject_uevent.c:208
 uevent_store+0x20/0x60 drivers/base/core.c:2681
 kernfs_fop_write_iter+0x3a2/0x4f0 fs/kernfs/file.c:334
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x857/0xbc0 fs/read_write.c:584
 ksys_write+0x19c/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5957570bf2
RSP: 002b:00007ffdcec1cbc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000055b18d0f2fd0 RCX: 00007f5957570bf2
RDX: 0000000000000007 RSI: 000055b18d0fee30 RDI: 000000000000000c
RBP: 0000000000000007 R08: 000055b18d0fee30 R09: 0000000000000020
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000007
R13: 000055b18d0fee30 R14: 00007ffdcec1cfa8 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10536 jiffies! g26393 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=17192
rcu: rcu_preempt kthread starved for 10537 jiffies! g26393 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:25016 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0x143f/0x4570 kernel/sched/core.c:6558
 schedule+0xbf/0x180 kernel/sched/core.c:6634
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2d2/0x1150 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xa3/0x3b0 kernel/rcu/tree.c:1905
 kthread+0x28d/0x320 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: 0 PID: 6804 Comm: syz.1.888 Not tainted 6.1.103-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: a1 9d f5 ff 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 6e 1a bb f6 48 89 df e8 d6 57 bc f6 e8 c1 e5 e1 f6 fb bf 01 00 00 00 <e8> c6 e8 ae f6 65 8b 05 67 f1 52 75 85 c0 74 02 5b c3 e8 14 15 51
RSP: 0018:ffffc9000311fb30 EFLAGS: 00000286
RAX: b976a17446fb6000 RBX: ffff88801bbd40c0 RCX: ffffffff91f31103
RDX: dffffc0000000000 RSI: ffffffff8b0c0260 RDI: 0000000000000001
RBP: ffffc9000311fc70 R08: dffffc0000000000 R09: ffffed100377a819
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff1100377a8ab
R13: 000000001c000004 R14: 0000000000000021 R15: ffff88801bbd4558
FS:  00005555559d2500(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb22ca69601 CR3: 0000000075be3000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x154b/0x17d0 kernel/signal.c:2873
 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f25303779f9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc1613a9c8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f2530505f80 RCX: 00007f25303779f9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f2530505f88
RBP: 00007f2530505f8c R08: 00007f2530505f80 R09: 00007ffc1613acaf
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2530505f80 R14: 0000000000000003 R15: 000000000000097d
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/08/06 04:12 linux-6.1.y 48d525b0e463 e1bdb00a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in kernfs_fop_write_iter
2024/04/30 16:50 linux-6.1.y dcbc050cb0d3 3ce4924c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in kernfs_fop_write_iter
* Struck through repros no longer work on HEAD.