[syzbot] [xfs?] INFO: task hung in xfs_file_fsync

[syzbot] [xfs?] INFO: task hung in xfs_file_fsync

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    d006330be3f7 Merge tag 'sound-6.16-rc6' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17d17f70580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b309c907eaab29da
dashboard link: https://syzkaller.appspot.com/bug?extid=9bc8c0586b39708784d9
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15e24a8c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10ed3582580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/589c382b9e63/disk-d006330b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/756fa29cc5a7/vmlinux-d006330b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/41f40b8b4afc/bzImage-d006330b.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/f0df0d993fe8/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=11e24a8c580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+9bc8c0586b39708784d9@syzkaller.appspotmail.com

INFO: task syz.6.141:7477 blocked for more than 143 seconds.
      Not tainted 6.16.0-rc5-syzkaller-00025-gd006330be3f7 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.141       state:D stack:21864 pid:7477  tgid:7476  ppid:6658   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5401 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6790
 __schedule_loop kernel/sched/core.c:6868 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6883
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6940
 rwsem_down_read_slowpath+0x552/0x880 kernel/locking/rwsem.c:1084
 __down_read_common kernel/locking/rwsem.c:1248 [inline]
 __down_read kernel/locking/rwsem.c:1261 [inline]
 down_read_nested+0x9a/0x2f0 kernel/locking/rwsem.c:1650
 xfs_fsync_flush_log fs/xfs/xfs_file.c:112 [inline]
 xfs_file_fsync+0x422/0xa30 fs/xfs/xfs_file.c:167
 generic_write_sync include/linux/fs.h:3031 [inline]
 xfs_file_buffered_write+0x713/0x890 fs/xfs/xfs_file.c:1018
 do_iter_readv_writev+0x56e/0x7f0 fs/read_write.c:-1
 vfs_writev+0x31a/0x960 fs/read_write.c:1057
 do_pwritev fs/read_write.c:1153 [inline]
 __do_sys_pwritev2 fs/read_write.c:1211 [inline]
 __se_sys_pwritev2+0x179/0x290 fs/read_write.c:1202
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fccbdb8e929
RSP: 002b:00007fccbe9f2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000148
RAX: ffffffffffffffda RBX: 00007fccbddb5fa0 RCX: 00007fccbdb8e929
RDX: 0000000000000001 RSI: 00002000000001c0 RDI: 0000000000000004
RBP: 00007fccbdc10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000e7b R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fccbddb5fa0 R15: 00007ffd671078d8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: 
ffffffff8e13f160 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
ffffffff8e13f160 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
ffffffff8e13f160 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6770
2 locks held by kworker/u8:5/969:
2 locks held by getty/5603:
 #0: ffff88803539a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000333b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/5979:
 #0: ffffffff8e144c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
 #0: ffffffff8e144c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:998
1 lock held by syz-executor/5980:
 #0: ffffffff8e144c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:336 [inline]
 #0: ffffffff8e144c78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:998
4 locks held by syz.2.46/6517:
 #0: ffff88802386a428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff888022d85870 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff888022d85870 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff88802386a618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc_inode+0x13c/0x4a0 fs/xfs/xfs_trans.c:1098
 #3: ffff888022d85658 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_trans_alloc_inode+0x161/0x4a0 fs/xfs/xfs_trans.c:1104
4 locks held by syz.5.114/7216:
 #0: ffff8880734a2428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff88804fbfc8f0 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff88804fbfc8f0 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff8880734a2618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc_inode+0x13c/0x4a0 fs/xfs/xfs_trans.c:1098
 #3: ffff88804fbfc6d8 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_trans_alloc_inode+0x161/0x4a0 fs/xfs/xfs_trans.c:1104
2 locks held by syz.6.141/7477:
 #0: ffff88805c398428 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline]
 #0: ffff88805c398428 (sb_writers#12){.+.+}-{0:0}, at: vfs_writev+0x288/0x960 fs/read_write.c:1055
 #1: ffff88807f90a7d8 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_fsync_flush_log fs/xfs/xfs_file.c:112 [inline]
 #1: ffff88807f90a7d8 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_file_fsync+0x422/0xa30 fs/xfs/xfs_file.c:167
4 locks held by syz.6.141/7520:
 #0: ffff88805c398428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff88807f90a9f0 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff88807f90a9f0 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff88805c398618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc_inode+0x13c/0x4a0 fs/xfs/xfs_trans.c:1098
 #3: ffff88807f90a7d8 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_trans_alloc_inode+0x161/0x4a0 fs/xfs/xfs_trans.c:1104
4 locks held by syz.0.144/7510:
 #0: ffff88807b726428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff88804fbfb1b0 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff88804fbfb1b0 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff88807b726618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc_inode+0x13c/0x4a0 fs/xfs/xfs_trans.c:1098
 #3: ffff88804fbfaf98 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_trans_alloc_inode+0x161/0x4a0 fs/xfs/xfs_trans.c:1104
4 locks held by syz.7.184/8027:
 #0: ffff888074d8c428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff88807f90d870 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff88807f90d870 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff888074d8c618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc_inode+0x13c/0x4a0 fs/xfs/xfs_trans.c:1098
 #3: ffff88807f90d658 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_trans_alloc_inode+0x161/0x4a0 fs/xfs/xfs_trans.c:1104
4 locks held by syz.9.222/8459:
 #0: ffff88802f5f8428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff88804fa20330 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff88804fa20330 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff88802f5f8618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc_inode+0x13c/0x4a0 fs/xfs/xfs_trans.c:1098
 #3: ffff88804fa20118 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_trans_alloc_inode+0x161/0x4a0 fs/xfs/xfs_trans.c:1104
4 locks held by syz.8.287/8943:
 #0: ffff8880310d6428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff88804fac0330 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff88804fac0330 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff8880310d6618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc_inode+0x13c/0x4a0 fs/xfs/xfs_trans.c:1098
 #3: ffff88804fac0118 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_trans_alloc_inode+0x161/0x4a0 fs/xfs/xfs_trans.c:1104
5 locks held by syz-executor/9036:
 #0: ffff88807b534428 (sb_writers#9){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3096 [inline]
 #0: ffff88807b534428 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x211/0xa90 fs/read_write.c:682
 #1: ffff88804f649088 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e0/0x4f0 fs/kernfs/file.c:325
 #2: ffffffff8e176708 (cgroup_mutex){+.+.}-{4:4}, at: cgroup_lock include/linux/cgroup.h:387 [inline]
 #2: ffffffff8e176708 (cgroup_mutex){+.+.}-{4:4}, at: cgroup_kn_lock_live+0x13c/0x230 kernel/cgroup/cgroup.c:1686
 #3: ffffffff8dfd72d0 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2480 [inline]
 #3: ffffffff8dfd72d0 (cpu_hotplug_lock){++++}-{0:0}, at: cgroup_procs_write_start+0x186/0x610 kernel/cgroup/cgroup.c:2984
 #4: ffffffff8e1769b0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_attach_lock kernel/cgroup/cgroup.c:2482 [inline]
 #4: ffffffff8e1769b0 (cgroup_threadgroup_rwsem){++++}-{0:0}, at: cgroup_procs_write_start+0x19c/0x610 kernel/cgroup/cgroup.c:2984
4 locks held by syz.1.340/9228:
 #0: ffff888030946428 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:557
 #1: ffff88804fa26fb0 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: inode_lock include/linux/fs.h:869 [inline]
 #1: ffff88804fa26fb0 (&sb->s_type->i_mutex_key#20){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
 #2: ffff888030946618 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc_inode+0x13c/0x4a0 fs/xfs/xfs_trans.c:1098
 #3: ffff88804fa26d98 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_trans_alloc_inode+0x161/0x4a0 fs/xfs/xfs_trans.c:1104
4 locks held by syz.2.347/9266:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc5-syzkaller-00025-gd006330be3f7 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:470
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 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: 9264 Comm: syz.5.346 Not tainted 6.16.0-rc5-syzkaller-00025-gd006330be3f7 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4857 [inline]
RIP: 0010:__lock_acquire+0x332/0xd20 kernel/locking/lockdep.c:5190
Code: e5 15 09 d5 09 cd 44 09 f5 41 89 6c c7 20 45 89 44 c7 24 4c 89 7c 24 10 4d 8d 34 c7 81 e5 ff 1f 00 00 48 0f a3 2d 3e ce 09 12 <73> 10 48 69 c5 c8 00 00 00 48 8d 80 f0 02 49 93 eb 40 83 3d 85 5d
RSP: 0018:ffffc90004d8f028 EFLAGS: 00000003
RAX: 0000000000000000 RBX: ffffffff8e13f160 RCX: 0000000000000007
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888048581e00
RBP: 0000000000000007 R08: 0000000000000000 R09: ffffffff81729ae5
R10: dffffc0000000000 R11: ffffffff81acf330 R12: 0000000000020000
R13: 0000000000000000 R14: ffff8880485828f0 R15: ffff8880485828f0
FS:  00007fec077e56c0(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f83ec5b7bac CR3: 00000000489aa000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 save_stack+0xf5/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 free_unref_folios+0xc66/0x14d0 mm/page_alloc.c:2763
 folios_put_refs+0x559/0x640 mm/swap.c:992
 folio_batch_release include/linux/pagevec.h:101 [inline]
 shmem_undo_range+0x49e/0x14b0 mm/shmem.c:1125
 shmem_truncate_range mm/shmem.c:1237 [inline]
 shmem_evict_inode+0x272/0xa70 mm/shmem.c:1365
 evict+0x504/0x9c0 fs/inode.c:810
 __dentry_kill+0x209/0x660 fs/dcache.c:669
 dput+0x19f/0x2b0 fs/dcache.c:911
 __fput+0x68e/0xa70 fs/file_table.c:473
 fput_close_sync+0x119/0x200 fs/file_table.c:570
 __do_sys_close fs/open.c:1589 [inline]
 __se_sys_close fs/open.c:1574 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1574
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fec0698d58a
Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 43 91 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 a3 91 02 00 8b 44 24
RSP: 002b:00007fec077e4e00 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007fec0698d58a
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000010 R08: 0000000000000000 R09: 000000000000985e
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 00007fec077e4ef0 R14: 00007fec077e4eb0 R15: 00007febfd600000
 </TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

Re: [syzbot] [xfs?] INFO: task hung in xfs_file_fsync

[syzbot]

syzbot has bisected this issue to:

commit 0161e2d6950fe66cf6ac1c10d945bae971f33667
Author: John Ogness <john.ogness@linutronix.de>
Date:   Mon Dec 9 11:17:46 2024 +0000

    printk: Defer legacy printing when holding printk_cpu_sync

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14b19a8c580000
start commit:   d006330be3f7 Merge tag 'sound-6.16-rc6' of git://git.kerne..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=16b19a8c580000
console output: https://syzkaller.appspot.com/x/log.txt?x=12b19a8c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b309c907eaab29da
dashboard link: https://syzkaller.appspot.com/bug?extid=9bc8c0586b39708784d9
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15e24a8c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10ed3582580000

Reported-by: syzbot+9bc8c0586b39708784d9@syzkaller.appspotmail.com
Fixes: 0161e2d6950f ("printk: Defer legacy printing when holding printk_cpu_sync")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: [syzbot] [xfs?] INFO: task hung in xfs_file_fsync

[syzbot]

syzbot suspects this issue was fixed by commit:

commit b9a176e54162f890aaf50ac8a467d725ed2f00df
Author: Darrick J. Wong <djwong@kernel.org>
Date:   Tue Sep 2 21:33:53 2025 +0000

    xfs: remove deprecated mount options

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1481829a580000
start commit:   d006330be3f7 Merge tag 'sound-6.16-rc6' of git://git.kerne..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=b309c907eaab29da
dashboard link: https://syzkaller.appspot.com/bug?extid=9bc8c0586b39708784d9
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15e24a8c580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10ed3582580000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: xfs: remove deprecated mount options

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: [syzbot] [xfs?] INFO: task hung in xfs_file_fsync

[Petr Mladek]

On Wed 2025-07-09 17:44:03, syzbot wrote:
> syzbot has bisected this issue to:
> 
> commit 0161e2d6950fe66cf6ac1c10d945bae971f33667
> Author: John Ogness <john.ogness@linutronix.de>
> Date:   Mon Dec 9 11:17:46 2024 +0000
> 
>     printk: Defer legacy printing when holding printk_cpu_sync
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14b19a8c580000

Just for record. It looks to me that the bisection was wrong.
The original problem was:

ci starts bisection 2025-07-09 13:22:22.587055103 +0000 UTC m=+182.380303436
bisecting cause commit starting from d006330be3f782ff3fb7c3ed51e617e01f29a465
building syzkaller on abade7941e7b8a888e052cda1a92805ab785c77e
ensuring issue is reproducible on original commit d006330be3f782ff3fb7c3ed51e617e01f29a465

testing commit d006330be3f782ff3fb7c3ed51e617e01f29a465 gcc
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: fd86d90e0d4e2b546bda0ba5ad3009b1c803f92f35eefc7a5a9a6a9779edb44a
run #0: crashed: INFO: task hung in xfs_setfilesize
run #1: crashed: INFO: task hung in xfs_setfilesize
run #2: crashed: INFO: task hung in xfs_setfilesize
run #3: crashed: INFO: task hung in process_measurement
run #4: crashed: INFO: task hung in xfs_setfilesize
run #5: crashed: INFO: task hung in process_measurement
run #6: crashed: INFO: task hung in xfs_setfilesize
run #7: crashed: INFO: task hung in process_measurement
run #8: crashed: INFO: task hung in process_measurement
run #9: crashed: INFO: task hung in xfs_setfilesize
run #10: crashed: INFO: task hung in xfs_setfilesize
run #11: crashed: INFO: task hung in xfs_setfilesize
run #12: crashed: INFO: task hung in xfs_setfilesize
run #13: crashed: INFO: task hung in xfs_setfilesize
run #14: crashed: INFO: task hung in xfs_trans_alloc_inode
run #15: crashed: INFO: task hung in xfs_trans_alloc_inode
run #16: crashed: INFO: task hung in xfs_setfilesize
run #17: crashed: INFO: task hung in xfs_setfilesize
run #18: crashed: INFO: task hung in xfs_setfilesize
run #19: crashed: INFO: task hung in xfs_setfilesize
representative crash: INFO: task hung in xfs_setfilesize, types: [HANG]


But the end of the bisection looks like:

testing commit 4ca6c022279dddba1eca8ea580c82ea510ecf690 gcc
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: 03f8650641fe155806b39e47c854b91bf96ee0d5e9d18ff940235c5a21c89620
run #0: OK
run #1: OK
run #2: OK
run #3: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #4: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #5: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #6: OK
run #7: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #8: OK
run #9: OK
run #10: OK
run #11: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
representative crash: BUG: MAX_LOCKDEP_KEYS too low!, types: [UNKNOWN]
# git bisect bad 4ca6c022279dddba1eca8ea580c82ea510ecf690
Bisecting: 4 revisions left to test after this (roughly 2 steps)
[62de6e1685269e1637a6c6684c8be58cc8d4ff38] Merge tag 'sched-core-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

testing commit 62de6e1685269e1637a6c6684c8be58cc8d4ff38 gcc
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: 8e4e982610da69c055ecca8aaca23f23a454eb4db0ee20d8bf6d5ae22aeebb01
run #0: ignore: lost connection to test machine
run #1: OK
run #2: OK
run #3: OK
run #4: OK
run #5: OK
run #6: OK
run #7: OK
run #8: OK
run #9: OK
run #10: OK
run #11: OK
run #12: OK
run #13: OK
run #14: OK
run #15: OK
run #16: OK
run #17: OK
run #18: OK
run #19: OK
false negative chance: 0.001
# git bisect good 62de6e1685269e1637a6c6684c8be58cc8d4ff38
Bisecting: 2 revisions left to test after this (roughly 1 step)
[0161e2d6950fe66cf6ac1c10d945bae971f33667] printk: Defer legacy printing when holding printk_cpu_sync

testing commit 0161e2d6950fe66cf6ac1c10d945bae971f33667 gcc
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: 7566994b210981fb429e3b5e9ed670407710135484fee131b57299dc8b3071f7
run #0: OK
run #1: OK
run #2: OK
run #3: OK
run #4: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #5: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #6: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #7: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #8: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #9: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #10: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #11: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #12: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #13: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #14: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #15: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #16: crashed: BUG: MAX_LOCKDEP_KEYS too low!
run #17: OK
run #18: OK
run #19: OK
representative crash: BUG: MAX_LOCKDEP_KEYS too low!, types: [UNKNOWN]
# git bisect bad 0161e2d6950fe66cf6ac1c10d945bae971f33667
Bisecting: 0 revisions left to test after this (roughly 0 steps)
[f1c21cf470595c4561d4671fd499af94152175d5] printk: Remove redundant deferred check in vprintk()

testing commit f1c21cf470595c4561d4671fd499af94152175d5 gcc
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
kernel signature: a7cc6b185bdb5074103099a969663e598b6c2f53f61168a0f2e7c1d9bc9e8426
all runs: OK
false negative chance: 0.001
# git bisect good f1c21cf470595c4561d4671fd499af94152175d5
0161e2d6950fe66cf6ac1c10d945bae971f33667 is the first bad commit
commit 0161e2d6950fe66cf6ac1c10d945bae971f33667
Author: John Ogness <john.ogness@linutronix.de>
Date:   Mon Dec 9 12:23:46 2024 +0106

    printk: Defer legacy printing when holding printk_cpu_sync


Notice:
=======

The original test crashed with:

    crashed: INFO: task hung in xfs_setfilesize

But the bad commits around the potential bad commit are failing
with

    crashed: BUG: MAX_LOCKDEP_KEYS too low!


Conclusion:
===========

I believe that the bisection went into a wrong direction.
And the printk() change has nothing to do with a hung task.

Best Regards,
Petr

> start commit:   d006330be3f7 Merge tag 'sound-6.16-rc6' of git://git.kerne..
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=16b19a8c580000
> console output: https://syzkaller.appspot.com/x/log.txt?x=12b19a8c580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=b309c907eaab29da
> dashboard link: https://syzkaller.appspot.com/bug?extid=9bc8c0586b39708784d9
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15e24a8c580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10ed3582580000
> 
> Reported-by: syzbot+9bc8c0586b39708784d9@syzkaller.appspotmail.com
> Fixes: 0161e2d6950f ("printk: Defer legacy printing when holding printk_cpu_sync")
> 
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection