syzbot


INFO: rcu detected stall in cleanup_mnt (2)

Status: auto-obsoleted due to no activity on 2024/09/23 19:34
Reported-by: syzbot+0dcdc7316d0f74e1a5b6@syzkaller.appspotmail.com
First crash: 171d, last: 171d
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in cleanup_mnt 1 542d 542d 0/3 auto-obsoleted due to no activity on 2023/09/19 04:00
upstream INFO: rcu detected stall in cleanup_mnt (2) block 1 1078d 1078d 0/28 closed as invalid on 2022/02/08 10:10
linux-6.1 INFO: rcu detected stall in cleanup_mnt 1 487d 487d 0/3 auto-obsoleted due to no activity on 2023/11/13 00:06
upstream INFO: rcu detected stall in cleanup_mnt exfat 1 1609d 1609d 0/28 auto-closed as invalid on 2020/09/06 14:28
upstream INFO: rcu detected stall in cleanup_mnt (3) reiserfs block 2 553d 563d 0/28 auto-obsoleted due to no activity on 2023/08/29 03:36
linux-5.15 INFO: rcu detected stall in cleanup_mnt (2) origin:lts-only syz done 4 43d 115d 0/3 upstream: reported syz repro on 2024/08/10 23:43

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5517/1:b..l
	(detected by 1, t=10502 jiffies, g=25933, q=15 ncpus=2)
task:syz-executor.2  state:R  running task     stack:21224 pid:5517  ppid:5505   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 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:memset_erms+0x6/0x10 arch/x86/lib/memset_64.S:63
Code: e2 07 48 c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 <48> 89 d1 f3 aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01
RSP: 0018:ffffc900037374a0 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffff88801f768fb8 RCX: ffffffff854f9525
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffff88801f7690f8
RBP: ffff88801f768f80 R08: dffffc0000000000 R09: ffff88801f7690f8
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff88801f7690f8 R14: ffff88801f6c7800 R15: ffffc90003737580
 loop_queue_rq+0x165/0xaf0 drivers/block/loop.c:1863
 __blk_mq_issue_directly block/blk-mq.c:2622 [inline]
 __blk_mq_try_issue_directly+0x4fe/0x820 block/blk-mq.c:2675
 blk_mq_request_issue_directly block/blk-mq.c:2709 [inline]
 blk_mq_plug_issue_direct+0x230/0x5d0 block/blk-mq.c:2729
 blk_mq_flush_plug_list+0x5a3/0xb40 block/blk-mq.c:2829
 __blk_flush_plug+0x442/0x4c0 block/blk-core.c:1153
 blk_finish_plug+0x59/0x80 block/blk-core.c:1177
 generic_writepages+0x105/0x160 mm/page-writeback.c:2452
 do_writepages+0x3a2/0x670 mm/page-writeback.c:2469
 filemap_fdatawrite_wbc+0x121/0x180 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 __filemap_fdatawrite mm/filemap.c:427 [inline]
 filemap_flush+0x11a/0x170 mm/filemap.c:454
 sync_filesystem+0x142/0x220 fs/sync.c:60
 generic_shutdown_super+0x6b/0x340 fs/super.c:474
 kill_block_super+0x7a/0xe0 fs/super.c:1459
 deactivate_locked_super+0xa0/0x110 fs/super.c:332
 cleanup_mnt+0x490/0x520 fs/namespace.c:1186
 task_work_run+0x246/0x300 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177
 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: 0033:0x7eff4287e1d7
RSP: 002b:00007ffeca76d7a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007eff4287e1d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffeca76d860
RBP: 00007ffeca76d860 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffeca76e910
R13: 00007eff428d9636 R14: 0000000000030634 R15: 0000000000000004
 </TASK>
rcu: rcu_preempt kthread starved for 10509 jiffies! g25933 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:25528 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x142d/0x4550 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:308
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 6938 Comm: syz-executor.1 Not tainted 6.1.93-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:finish_task_switch+0x1d3/0x810 kernel/sched/core.c:5124
Code: 2e 0b 00 48 83 c4 08 4c 89 f7 e8 98 30 00 00 e9 8f 04 00 00 4c 89 f7 e8 0b 32 36 09 e8 06 1e 32 00 fb 49 8d bc 24 f8 15 00 00 <48> 89 f8 48 c1 e8 03 49 bd 00 00 00 00 00 fc ff df 42 0f b6 04 28
RSP: 0018:ffffc900045ff108 EFLAGS: 00000286
RAX: 17ddf0ad10030100 RBX: ffff8880b993b748 RCX: ffffffff816ad3ca
RDX: dffffc0000000000 RSI: ffffffff8aec0240 RDI: ffff8880257c33b8
RBP: ffffc900045ff150 R08: dffffc0000000000 R09: fffffbfff2093a59
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880257c1dc0
R13: 1ffff110173276eb R14: ffff8880b983aa00 R15: ffff8880b993b758
FS:  00007fcbc5e1f6c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcbc5e3ff00 CR3: 0000000027310000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 context_switch kernel/sched/core.c:5248 [inline]
 __schedule+0x1435/0x4550 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_call_function_single+0x16/0x20 arch/x86/include/asm/idtentry.h:661
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:need_resched include/linux/sched.h:2231 [inline]
RIP: 0010:preempt_schedule_common+0x91/0xd0 kernel/sched/core.c:6735
Code: 42 80 3c 38 00 74 08 48 89 df e8 ba 67 4e f7 4c 89 33 bf 01 00 00 00 e8 1d b7 ff ff 65 8b 05 8e c3 6e 75 65 ff 0d 87 c3 6e 75 <65> 48 8b 1d 77 c3 6e 75 48 89 df be 08 00 00 00 e8 9a 68 4e f7 48
RSP: 0018:ffffc900045ff4a0 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffff8880257c3298 RCX: 1ffff920008bfe7c
RDX: dffffc0000000000 RSI: ffffffff8aec0240 RDI: ffff8880257c33b8
RBP: ffffc900045ff558 R08: dffffc0000000000 R09: fffffbfff2093a59
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920008bfe9c
R13: 1ffff920008bfeb8 R14: ffffffff8a93ab29 R15: dffffc0000000000
 preempt_schedule+0xd9/0xe0 kernel/sched/core.c:6751
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0x128/0x130 kernel/locking/spinlock.c:194
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 __wake_up_common_lock kernel/sched/wait.c:140 [inline]
 __wake_up_sync_key+0x121/0x1c0 kernel/sched/wait.c:208
 __unix_dgram_recvmsg+0x5fe/0x1260 net/unix/af_unix.c:2478
 ____sys_recvmsg+0x285/0x530
 ___sys_recvmsg net/socket.c:2775 [inline]
 do_recvmmsg+0x46d/0xad0 net/socket.c:2869
 __sys_recvmmsg net/socket.c:2948 [inline]
 __do_sys_recvmmsg net/socket.c:2971 [inline]
 __se_sys_recvmmsg net/socket.c:2964 [inline]
 __x64_sys_recvmmsg+0x195/0x240 net/socket.c:2964
 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: 0033:0x7fcbc507cea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fcbc5e1f0c8 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007fcbc51b4050 RCX: 00007fcbc507cea9
RDX: 0000000000010106 RSI: 00000000200000c0 RDI: 0000000000000004
RBP: 00007fcbc50ebff4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007fcbc51b4050 R15: 00007fffc9fa3de8
 </TASK>
vkms_vblank_simulate: vblank timer overrun

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/15 19:33 linux-6.1.y ae9f2a70d69e f429ab00 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: rcu detected stall in cleanup_mnt
* Struck through repros no longer work on HEAD.