syzbot


INFO: task hung in __ext4_get_inode_loc (2)

Status: auto-obsoleted due to no activity on 2025/07/12 23:33
Subsystems: ext4
[Documentation on labels]
First crash: 133d, last: 133d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in __ext4_get_inode_loc ext4 1 2 676d 749d 0/29 auto-obsoleted due to no activity on 2024/01/16 07:44

Sample crash report:
INFO: task dhcpcd:5506 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc1-syzkaller-00333-g5aaaedb0cb54 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:dhcpcd          state:D stack:23064 pid:5506  tgid:5506  ppid:5505   task_flags:0x440140 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x116f/0x5de0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6860
 io_schedule+0xbf/0x130 kernel/sched/core.c:7742
 bit_wait_io+0x15/0xe0 kernel/sched/wait_bit.c:247
 __wait_on_bit+0x62/0x180 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0xd9/0x110 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:105 [inline]
 __wait_on_buffer+0x64/0x70 fs/buffer.c:123
 wait_on_buffer include/linux/buffer_head.h:413 [inline]
 __ext4_get_inode_loc+0x1085/0x1540 fs/ext4/inode.c:4550
 ext4_get_inode_loc+0xbd/0x160 fs/ext4/inode.c:4583
 ext4_reserve_inode_write+0x14c/0x320 fs/ext4/inode.c:5889
 __ext4_mark_inode_dirty+0x197/0x870 fs/ext4/inode.c:6066
 ext4_dirty_inode+0xd9/0x130 fs/ext4/inode.c:6103
 __mark_inode_dirty+0x1eb/0xe50 fs/fs-writeback.c:2527
 generic_update_time+0xcf/0xf0 fs/inode.c:2064
 inode_update_time fs/inode.c:2077 [inline]
 touch_atime+0x4ee/0x5d0 fs/inode.c:2149
 file_accessed include/linux/fs.h:2599 [inline]
 filemap_read+0xc85/0xe90 mm/filemap.c:2773
 generic_file_read_iter+0x344/0x450 mm/filemap.c:2893
 ext4_file_read_iter+0x1d6/0x6a0 fs/ext4/file.c:147
 new_sync_read fs/read_write.c:489 [inline]
 vfs_read+0x8c8/0xc70 fs/read_write.c:570
 ksys_read+0x12a/0x240 fs/read_write.c:713
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5aa5ce0b6a
RSP: 002b:00007ffc06b66a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00000000000100a0 RCX: 00007f5aa5ce0b6a
RDX: 00000000000100a0 RSI: 00007ffc06b66ad8 RDI: 0000000000000018
RBP: 0000000000000018 R08: 0000000000000000 R09: 00007ffc06b76bc8
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 00007ffc06b66ad8 R14: 00007ffc06b66ad8 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u8:0/12:
 #0: ffff88801f682948 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
 #1: ffffc90000117d18 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
 #2: ffff88814e7120e0 (&type->s_umount_key#31){++++}-{4:4}, at: super_trylock_shared+0x1e/0xf0 fs/super.c:562
 #3: ffff88814e714b98 (&sbi->s_writepages_rwsem){++++}-{0:0}, at: do_writepages+0x1b2/0x820 mm/page-writeback.c:2656
1 lock held by khungtaskd/31:
 #0: ffffffff8e3c15c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e3c15c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e3c15c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6764
3 locks held by kworker/u8:8/3021:
 #0: ffff88801c2f6148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
 #1: ffffc9000b737d18 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
 #2: ffffffff90118690 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xc9/0xb30 net/core/net_namespace.c:608
2 locks held by dhcpcd/5506:
 #0: ffff88814e712420 (sb_writers#4){.+.+}-{0:0}, at: file_accessed include/linux/fs.h:2599 [inline]
 #0: ffff88814e712420 (sb_writers#4){.+.+}-{0:0}, at: filemap_read+0xc85/0xe90 mm/filemap.c:2773
 #1: ffff88814e716950 (jbd2_handle){++++}-{0:0}, at: start_this_handle+0x5e4/0x1410 fs/jbd2/transaction.c:444
2 locks held by syz-executor/5828:
 #0: ffff88807abcb588 (vm_lock){++++}-{0:0}, at: do_user_addr_fault+0x452/0x1370 arch/x86/mm/fault.c:1328
 #1: ffff88814e712518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x171/0x380 mm/memory.c:3287
2 locks held by getty/7019:
 #0: ffff888031b1c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000b24b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
2 locks held by syz-executor/7320:
 #0: ffff88814e712420 (sb_writers#4){.+.+}-{0:0}, at: filename_create+0x10e/0x4a0 fs/namei.c:4090
 #1: ffff88805f4e8e20 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline]
 #1: ffff88805f4e8e20 (&type->i_mutex_dir_key#3/1){+.+.}-{4:4}, at: filename_create+0x1bb/0x4a0 fs/namei.c:4097
2 locks held by syz.0.340/7450:
 #0: ffff88805ea9c1c8 (vm_lock){++++}-{0:0}, at: do_user_addr_fault+0x452/0x1370 arch/x86/mm/fault.c:1328
 #1: ffff88814e712518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x171/0x380 mm/memory.c:3287
2 locks held by syz.1.342/7465:
 #0: ffff888026b8d1c8 (vm_lock){++++}-{0:0}, at: do_user_addr_fault+0x452/0x1370 arch/x86/mm/fault.c:1328
 #1: ffff88814e712518 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x171/0x380 mm/memory.c:3287

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc1-syzkaller-00333-g5aaaedb0cb54 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
 watchdog+0xf70/0x12c0 kernel/hung_task.c:437
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 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: 0 Comm: swapper/1 Not tainted 6.15.0-rc1-syzkaller-00333-g5aaaedb0cb54 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:81
Code: 55 5f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 93 bc 19 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df8 EFLAGS: 000002c6
RAX: 000000000010915b RBX: 0000000000000001 RCX: ffffffff8b703439
RDX: 0000000000000000 RSI: ffffffff8dbeb4de RDI: ffffffff8bf44f80
RBP: ffffed1003b59b40 R08: 0000000000000001 R09: ffffed10170a65bd
R10: ffff8880b8532deb R11: 0000000000000000 R12: 0000000000000001
R13: ffff88801dacda00 R14: ffffffff90867f10 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124ab9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ffc5378e00 CR3: 000000000e182000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:748
 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x391/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423
 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315
 common_startup_64+0x13e/0x148
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/13 23:23 upstream 5aaaedb0cb54 0bd6db41 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: task hung in __ext4_get_inode_loc
* Struck through repros no longer work on HEAD.