syzbot


INFO: task hung in vfs_rename (2)

Status: upstream: reported C repro on 2025/04/22 21:28
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+321477fad98ea6dd35b7@syzkaller.appspotmail.com
First crash: 5d22h, last: 5d06h
Cause bisection: failed (error log, bisect log)
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [fs?] INFO: task hung in vfs_rename (2) 1 (2) 2025/04/23 11:35
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in vfs_rename 1 346d 346d 0/3 auto-obsoleted due to no activity on 2024/08/20 18:33
upstream INFO: task hung in vfs_rename bcachefs 80 105d 220d 0/28 auto-obsoleted due to no activity on 2025/03/20 07:53
linux-5.15 INFO: task hung in vfs_rename (2) 2 213d 213d 0/3 auto-obsoleted due to no activity on 2025/01/01 05:06
Last patch testing requests (2)
Created Duration User Patch Repo Result
2025/04/24 11:06 16m hdanton@sina.com patch upstream report log
2025/04/23 11:05 1h33m hdanton@sina.com patch upstream report log

Sample crash report:
INFO: task syz-executor362:5849 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00278-gfc96b232f8e7 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor362 state:D stack:24280 pid:5849  tgid:5849  ppid:5848   task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x1b33/0x51f0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x163/0x360 kernel/sched/core.c:6860
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 rwsem_down_write_slowpath+0xedd/0x1420 kernel/locking/rwsem.c:1176
 __down_write_common kernel/locking/rwsem.c:1304 [inline]
 __down_write kernel/locking/rwsem.c:1313 [inline]
 down_write+0x1da/0x220 kernel/locking/rwsem.c:1578
 inode_lock include/linux/fs.h:867 [inline]
 vfs_rename+0x6b9/0xf10 fs/namei.c:5051
 do_renameat2+0xc8d/0x1290 fs/namei.c:5235
 __do_sys_renameat2 fs/namei.c:5269 [inline]
 __se_sys_renameat2 fs/namei.c:5266 [inline]
 __x64_sys_renameat2+0xce/0xe0 fs/namei.c:5266
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc3678ce519
RSP: 002b:00007ffc519cacb8 EFLAGS: 00000246 ORIG_RAX: 000000000000013c
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc3678ce519
RDX: 0000000000000004 RSI: 0000200000000240 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffc519cacf0
R10: 00002000000001c0 R11: 0000000000000246 R12: 00007ffc519cacf0
R13: 00007ffc519caf78 R14: 431bde82d7b634db R15: 00007fc36791703b
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x30/0x180 kernel/locking/lockdep.c:6764
2 locks held by getty/5587:
 #0: ffff8880366f20a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900036d62f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x5bb/0x1700 drivers/tty/n_tty.c:2222
6 locks held by syz-executor362/5849:
 #0: ffff88807f054420 (sb_writers#8){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:556
 #1: ffff88807f054730 (&type->s_vfs_rename_key){+.+.}-{4:4}, at: lock_rename fs/namei.c:3234 [inline]
 #1: ffff88807f054730 (&type->s_vfs_rename_key){+.+.}-{4:4}, at: do_renameat2+0x5d6/0x1290 fs/namei.c:5181
 #2: ffff88807b3e8910 (&sb->s_type->i_mutex_key#14/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline]
 #2: ffff88807b3e8910 (&sb->s_type->i_mutex_key#14/1){+.+.}-{4:4}, at: lock_two_directories+0x1a8/0x220 fs/namei.c:3210
 #3: ffff88807b2b8910 (&sb->s_type->i_mutex_key#14/5){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline]
 #3: ffff88807b2b8910 (&sb->s_type->i_mutex_key#14/5){+.+.}-{4:4}, at: lock_two_directories+0x1d1/0x220 fs/namei.c:3211
 #4: ffff88807b2b82a0 (&sb->s_type->i_mutex_key#14/2){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:902 [inline]
 #4: ffff88807b2b82a0 (&sb->s_type->i_mutex_key#14/2){+.+.}-{4:4}, at: vfs_rename+0x63f/0xf10 fs/namei.c:5049
 #5: ffff88807b2b8910 (&sb->s_type->i_mutex_key#14){++++}-{4:4}, at: inode_lock include/linux/fs.h:867 [inline]
 #5: ffff88807b2b8910 (&sb->s_type->i_mutex_key#14){++++}-{4:4}, at: vfs_rename+0x6b9/0xf10 fs/namei.c:5051

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc2-syzkaller-00278-gfc96b232f8e7 #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+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x4ab/0x4e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 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+0x1058/0x10a0 kernel/hung_task.c:437
 kthread+0x7b7/0x940 kernel/kthread.c:464
 ret_from_fork+0x4b/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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.15.0-rc2-syzkaller-00278-gfc96b232f8e7 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
Code: cc cc cc cc cc cc cc 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 73 5f 20 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8ea07d60 EFLAGS: 000002c2
RAX: 5fa1c341e9d1cd00 RBX: ffffffff8197267e RCX: ffffffff8c27d93c
RDX: 0000000000000001 RSI: ffffffff8e6356dd RDI: ffffffff8ca0e2e0
RBP: ffffffff8ea07eb8 R08: ffff8880b8632b5b R09: 1ffff110170c656b
R10: dffffc0000000000 R11: ffffed10170c656c R12: 1ffffffff1d40fc6
R13: 1ffffffff1d52cb0 R14: 0000000000000000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888124fcf000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005597c9480600 CR3: 000000000eb38000 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+0x74/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x22e/0x5d0 kernel/sched/idle.c:325
 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423
 rest_init+0x2dc/0x300 init/main.c:743
 start_kernel+0x484/0x510 init/main.c:1099
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:513
 x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:494
 common_startup_64+0x13e/0x147
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/18 21:19 upstream fc96b232f8e7 2a20f901 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-upstream-fs INFO: task hung in vfs_rename
2025/04/19 08:15 upstream 3088d26962e8 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in vfs_rename
2025/04/18 16:12 upstream fc96b232f8e7 2a20f901 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs INFO: task hung in vfs_rename
* Struck through repros no longer work on HEAD.