syzbot


INFO: task hung in ext4_sync_file

Status: auto-obsoleted due to no activity on 2025/02/19 03:39
Subsystems: fs mm
[Documentation on labels]
First crash: 324d, last: 324d

Sample crash report:
INFO: task syz.7.2769:29201 blocked for more than 143 seconds.
      Not tainted 6.12.0-syzkaller-01892-g8f7c8b88bda4 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.2769      state:D stack:26944 pid:29201 tgid:29188 ppid:27659  flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0xe5a/0x5ae0 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6848
 io_schedule+0xbf/0x130 kernel/sched/core.c:7681
 folio_wait_bit_common+0x3d8/0x9b0 mm/filemap.c:1309
 folio_wait_writeback+0x3c/0x90 mm/page-writeback.c:3189
 __filemap_fdatawait_range+0x123/0x210 mm/filemap.c:533
 file_write_and_wait_range+0x101/0x140 mm/filemap.c:792
 ext4_sync_file+0x290/0xf30 fs/ext4/fsync.c:158
 vfs_fsync_range+0x136/0x220 fs/sync.c:187
 __do_sys_msync+0x3c6/0x5b0 mm/msync.c:96
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f03e637e819
RSP: 002b:00007f03e41f6038 EFLAGS: 00000246 ORIG_RAX: 000000000000001a
RAX: ffffffffffffffda RBX: 00007f03e6536080 RCX: 00007f03e637e819
RDX: 0000000400000004 RSI: 0080100000000002 RDI: 000000001ffff000
RBP: 00007f03e63f175e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f03e6536080 R15: 00007ffca305be08
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8ddba680 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8ddba680 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8ddba680 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x7f/0x390 kernel/locking/lockdep.c:6744
2 locks held by getty/5600:
 #0: ffff88814eb380a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0xfba/0x1480 drivers/tty/n_tty.c:2211
3 locks held by syz-executor/5829:
 #0: ffff888033416ec8 (&vma->vm_lock->lock){++++}-{4:4}, at: vma_start_read include/linux/mm.h:716 [inline]
 #0: ffff888033416ec8 (&vma->vm_lock->lock){++++}-{4:4}, at: lock_vma_under_rcu+0x13e/0x980 mm/memory.c:6243
 #1: ffff888034f60518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x177/0x380 mm/memory.c:3162
 #2: ffff888034f64958 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xf6c/0x1430 fs/jbd2/transaction.c:448
6 locks held by kworker/u8:13/6064:
 #0: ffff88801d6eb148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x1212/0x1b30 kernel/workqueue.c:3204
 #1: ffffc90004667d80 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3205
 #2: ffff888034f600e0 (&type->s_umount_key#32){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:562
 #3: ffff888034f62b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x1b3/0x820 mm/page-writeback.c:2683
 #4: ffff888034f64958 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xf6c/0x1430 fs/jbd2/transaction.c:448
 #5: ffff88807ef6c7e0 (&ei->i_data_sem){++++}-{4:4}, at: ext4_map_blocks+0x352/0x1370 fs/ext4/inode.c:701
2 locks held by kworker/u8:2/14184:
 #0: ffff8880b863ef18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:598
 #1: ffffc9000d9cfd80 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1b30 kernel/workqueue.c:3205
3 locks held by syz.5.2915/31845:
 #0: ffff88808c5c3148 (&vma->vm_lock->lock){++++}-{4:4}, at: vma_start_read include/linux/mm.h:716 [inline]
 #0: ffff88808c5c3148 (&vma->vm_lock->lock){++++}-{4:4}, at: lock_vma_under_rcu+0x13e/0x980 mm/memory.c:6243
 #1: ffff888034f60518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x177/0x380 mm/memory.c:3162
 #2: ffff888034f64958 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xf6c/0x1430 fs/jbd2/transaction.c:448
3 locks held by syz.3.2923/31882:
 #0: ffff888029203808 (&vma->vm_lock->lock){++++}-{4:4}, at: vma_start_read include/linux/mm.h:716 [inline]
 #0: ffff888029203808 (&vma->vm_lock->lock){++++}-{4:4}, at: lock_vma_under_rcu+0x13e/0x980 mm/memory.c:6243
 #1: ffff888034f60518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x177/0x380 mm/memory.c:3162
 #2: ffff888034f64958 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xf6c/0x1430 fs/jbd2/transaction.c:448
3 locks held by syz.4.2924/31884:
 #0: ffff888028130658 (&vma->vm_lock->lock){++++}-{4:4}, at: vma_start_read include/linux/mm.h:716 [inline]
 #0: ffff888028130658 (&vma->vm_lock->lock){++++}-{4:4}, at: lock_vma_under_rcu+0x13e/0x980 mm/memory.c:6243
 #1: ffff888034f60518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x177/0x380 mm/memory.c:3162
 #2: ffff888034f64958 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xf6c/0x1430 fs/jbd2/transaction.c:448
3 locks held by syz.1.2922/31886:
 #0: ffff8880303432f8 (&vma->vm_lock->lock){++++}-{4:4}, at: vma_start_read include/linux/mm.h:716 [inline]
 #0: ffff8880303432f8 (&vma->vm_lock->lock){++++}-{4:4}, at: lock_vma_under_rcu+0x13e/0x980 mm/memory.c:6243
 #1: ffff888034f60518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x177/0x380 mm/memory.c:3162
 #2: ffff888034f64958 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0xf6c/0x1430 fs/jbd2/transaction.c:448

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 30 Comm: khungtaskd Not tainted 6.12.0-syzkaller-01892-g8f7c8b88bda4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xf0c/0x1240 kernel/hung_task.c:379
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31722 Comm: kworker/u8:23 Not tainted 6.12.0-syzkaller-01892-g8f7c8b88bda4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Workqueue: bat_events batadv_nc_worker
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4866 [inline]
RIP: 0010:__lock_acquire+0x54e/0x3c40 kernel/locking/lockdep.c:5176
Code: ff 0f 84 a2 0b 00 00 49 8d 4c 24 df 4c 89 e2 4c 89 e6 48 c1 ea 03 83 e6 07 0f b6 14 2a 40 38 f2 7f 08 84 d2 0f 85 19 23 00 00 <0f> b6 51 21 44 31 f2 83 e2 60 74 c1 83 c3 01 65 8b 15 d4 83 98 7e
RSP: 0018:ffffc90002d5f960 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffff888062a328e0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff888062a32951
RBP: dffffc0000000000 R08: 0000000000000002 R09: fffffbfff2d35598
R10: ffffffff969aacc7 R11: 0000000000000002 R12: ffff888062a32901
R13: ffff888062a31e00 R14: 0000000000000000 R15: ffff888062a32930
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556a44beb730 CR3: 000000000db7e000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0x16a/0x1060 net/batman-adv/network-coding.c:719
 process_one_work+0x958/0x1b30 kernel/workqueue.c:3229
 process_scheduled_works kernel/workqueue.c:3310 [inline]
 worker_thread+0x6c8/0xf00 kernel/workqueue.c:3391
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/11/21 03:29 upstream 8f7c8b88bda4 4b25d554 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in ext4_sync_file
* Struck through repros no longer work on HEAD.