syzbot


INFO: task hung in ext4_sync_file (2)

Status: auto-obsoleted due to no activity on 2025/11/17 04:30
Subsystems: fs mm
[Documentation on labels]
First crash: 286d, last: 151d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in ext4_sync_file fs mm 1 1 422d 422d 0/29 auto-obsoleted due to no activity on 2025/02/19 03:39

Sample crash report:
INFO: task syz.1.1666:13653 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.1666      state:D stack:26888 pid:13653 tgid:13651 ppid:5856   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 io_schedule+0xbf/0x130 kernel/sched/core.c:7903
 folio_wait_bit_common+0x3d6/0x9e0 mm/filemap.c:1317
 folio_wait_writeback+0x3c/0x90 mm/page-writeback.c:3124
 __filemap_fdatawait_range+0x11f/0x200 mm/filemap.c:539
 file_write_and_wait_range+0x101/0x140 mm/filemap.c:798
 ext4_sync_file+0x310/0xf10 fs/ext4/fsync.c:154
 vfs_fsync_range+0x136/0x220 fs/sync.c:187
 __do_sys_msync+0x3cb/0x5c0 mm/msync.c:96
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f655558ebe9
RSP: 002b:00007f65563b5038 EFLAGS: 00000246 ORIG_RAX: 000000000000001a
RAX: ffffffffffffffda RBX: 00007f65557b6090 RCX: 00007f655558ebe9
RDX: 0000000400000004 RSI: 01800000000000fe RDI: 000000001ffff000
RBP: 00007f6555611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f65557b6128 R14: 00007f65557b6090 R15: 00007fffe24cd4c8
 </TASK>
INFO: task syz.0.1667:13660 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1667      state:D stack:29336 pid:13660 tgid:13654 ppid:5859   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 io_schedule+0xbf/0x130 kernel/sched/core.c:7903
 folio_wait_bit_common+0x3d6/0x9e0 mm/filemap.c:1317
 folio_wait_writeback+0x3c/0x90 mm/page-writeback.c:3124
 __filemap_fdatawait_range+0x11f/0x200 mm/filemap.c:539
 file_write_and_wait_range+0x101/0x140 mm/filemap.c:798
 ext4_sync_file+0x310/0xf10 fs/ext4/fsync.c:154
 vfs_fsync_range+0x136/0x220 fs/sync.c:187
 __do_sys_msync+0x3cb/0x5c0 mm/msync.c:96
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f07bef8ebe9
RSP: 002b:00007f07bfd5e038 EFLAGS: 00000246 ORIG_RAX: 000000000000001a
RAX: ffffffffffffffda RBX: 00007f07bf1b6090 RCX: 00007f07bef8ebe9
RDX: 0000000400000004 RSI: 0180000000000000 RDI: 000000001ffff000
RBP: 00007f07bf011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f07bf1b6128 R14: 00007f07bf1b6090 R15: 00007ffcf1217b38
 </TASK>
INFO: task syz.4.1670:13676 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.1670      state:D stack:27424 pid:13676 tgid:13674 ppid:13035  task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 io_schedule+0xbf/0x130 kernel/sched/core.c:7903
 folio_wait_bit_common+0x3d6/0x9e0 mm/filemap.c:1317
 folio_wait_writeback+0x3c/0x90 mm/page-writeback.c:3124
 __filemap_fdatawait_range+0x11f/0x200 mm/filemap.c:539
 file_write_and_wait_range+0x101/0x140 mm/filemap.c:798
 ext4_sync_file+0x310/0xf10 fs/ext4/fsync.c:154
 vfs_fsync_range+0x136/0x220 fs/sync.c:187
 __do_sys_msync+0x3cb/0x5c0 mm/msync.c:96
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f19cd58ebe9
RSP: 002b:00007f19ce3d4038 EFLAGS: 00000246 ORIG_RAX: 000000000000001a
RAX: ffffffffffffffda RBX: 00007f19cd7b6090 RCX: 00007f19cd58ebe9
RDX: 0000000400000004 RSI: 0180000000000000 RDI: 000000001ffff000
RBP: 00007f19cd611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f19cd7b6128 R14: 00007f19cd7b6090 R15: 00007ffd1f061cb8
 </TASK>
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
 watchdog+0xf0e/0x1260 kernel/hung_task.c:491
 kthread+0x3c2/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 12811 Comm: syz.3.1482 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:lock_release+0x6/0x2f0 kernel/locking/lockdep.c:5876
Code: 44 24 1c 44 8b 4c 24 18 4c 8b 54 24 10 44 8b 5c 24 0c eb 8c 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 <41> 56 41 55 41 54 49 89 f4 53 48 89 fb 48 83 ec 18 65 48 8b 05 49
RSP: 0018:ffffc90003b870b8 EFLAGS: 00000246
RAX: 0000000000080000 RBX: 0000000000000000 RCX: ffffc9000c93c000
RDX: 0000000000080000 RSI: ffffffff81f1dfa7 RDI: ffffffff8e5c1060
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 00000000754b406b R12: 1ffff92000770e19
R13: ffffc90003b870e8 R14: 0000000000000009 R15: 0000000000000002
FS:  00007f66330796c0(0000) GS:ffff8881247c4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055f4061f7168 CR3: 000000007bd2c000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:871 [inline]
 filemap_get_entry+0x1ac/0x3b0 mm/filemap.c:1889
 __filemap_get_folio+0x59/0xc30 mm/filemap.c:1916
 filemap_lock_folio include/linux/pagemap.h:812 [inline]
 filemap_lock_hugetlb_folio include/linux/hugetlb.h:809 [inline]
 hugetlbfs_read_iter+0x3e4/0x8f0 fs/hugetlbfs/inode.c:264
 __kernel_read+0x3f0/0xbf0 fs/read_write.c:530
 integrity_kernel_read+0x7e/0xb0 security/integrity/iint.c:28
 ima_calc_file_hash_tfm+0x25c/0x350 security/integrity/ima/ima_crypto.c:480
 ima_calc_file_shash security/integrity/ima/ima_crypto.c:511 [inline]
 ima_calc_file_hash+0x1ba/0x490 security/integrity/ima/ima_crypto.c:568
 ima_collect_measurement+0x899/0xa40 security/integrity/ima/ima_api.c:293
 process_measurement+0x11fa/0x23e0 security/integrity/ima/ima_main.c:405
 ima_file_mmap+0x1b1/0x1d0 security/integrity/ima/ima_main.c:495
 security_mmap_file+0x88c/0x990 security/security.c:3012
 vm_mmap_pgoff+0xec/0x470 mm/util.c:574
 ksys_mmap_pgoff+0x1c8/0x5c0 mm/mmap.c:604
 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline]
 __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline]
 __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f663218ebe9
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:00007f6633079038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f66323b5fa0 RCX: 00007f663218ebe9
RDX: 0000000000000006 RSI: 0010000000200006 RDI: ffffffffffffffff
RBP: 00007f6632211e19 R08: 0000000000000602 R09: 0000300000000000
R10: 0000000000040eb1 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f66323b6038 R14: 00007f66323b5fa0 R15: 00007ffd73ecfca8
 </TASK>

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/19 04:26 upstream be48bcf004f9 6e8d317a .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in ext4_sync_file
2025/07/09 18:52 upstream 733923397fd9 956bd956 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in ext4_sync_file
2025/04/30 00:15 upstream ca91b9500108 4a62c0b1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in ext4_sync_file
2025/04/29 20:32 upstream ca91b9500108 4a62c0b1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in ext4_sync_file
2025/04/28 05:28 upstream b4432656b36e c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in ext4_sync_file
2025/04/27 22:06 upstream 5bc1018675ec c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in ext4_sync_file
2025/04/15 19:34 upstream 1a1d569a75f3 85125322 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in ext4_sync_file
2025/04/10 07:48 upstream 3b07108ada81 988b336c .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in ext4_sync_file
2025/04/06 17:44 upstream f4d2ef48250a 1c65791e .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.