syzbot


INFO: task hung in ext4_quota_write (2)

Status: upstream: reported C repro on 2024/12/19 10:44
Reported-by: syzbot+ec7cb5db60b4d8e2071b@syzkaller.appspotmail.com
First crash: 55d, last: 2d23h
Bug presence (1)
Date Name Commit Repro Result
2025/02/10 upstream (ToT) a64dcfb451e2 C Failed due to an error; will retry later
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in ext4_quota_write (2) origin:lts-only C error 11 59d 284d 0/3 upstream: reported C repro on 2024/05/03 23:59
linux-6.1 INFO: task hung in ext4_quota_write origin:upstream missing-backport C done 9 173d 413d 3/3 fixed on 2024/10/08 03:39
upstream INFO: task hung in ext4_quota_write ext4 C inconclusive 22 303d 408d 25/28 fixed on 2024/06/05 13:52
linux-5.15 INFO: task hung in ext4_quota_write 2 413d 413d 0/3 auto-obsoleted due to no activity on 2024/04/05 13:59

Sample crash report:
INFO: task syz-executor360:4308 blocked for more than 143 seconds.
      Not tainted 6.1.128-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor360 state:D stack:0     pid:4308  ppid:4307   flags:0x00000005
Call trace:
 __switch_to+0x308/0x598 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5241 [inline]
 __schedule+0xef4/0x1d44 kernel/sched/core.c:6558
 schedule+0xc4/0x170 kernel/sched/core.c:6634
 io_schedule+0x8c/0x188 kernel/sched/core.c:8786
 bit_wait_io+0x1c/0xac kernel/sched/wait_bit.c:209
 __wait_on_bit_lock+0xcc/0x1e8 kernel/sched/wait_bit.c:90
 out_of_line_wait_on_bit_lock+0x194/0x21c kernel/sched/wait_bit.c:117
 wait_on_bit_lock_io include/linux/wait_bit.h:208 [inline]
 __lock_buffer+0x78/0xac fs/buffer.c:69
 lock_buffer include/linux/buffer_head.h:397 [inline]
 ext4_quota_write+0x36c/0x54c fs/ext4/super.c:7180
 qtree_write_dquot+0x1e0/0x4d8 fs/quota/quota_tree.c:462
 v2_write_dquot+0xf4/0x188 fs/quota/quota_v2.c:361
 dquot_commit+0x14c/0x240 fs/quota/dquot.c:514
 ext4_write_dquot+0x1b4/0x314 fs/ext4/super.c:6771
 ext4_mark_dquot_dirty+0xe8/0x140 fs/ext4/super.c:6831
 mark_dquot_dirty fs/quota/dquot.c:372 [inline]
 mark_all_dquot_dirty+0x108/0x424 fs/quota/dquot.c:412
 __dquot_free_space+0x840/0xce4 fs/quota/dquot.c:1942
 dquot_free_space_nodirty include/linux/quotaops.h:379 [inline]
 ext4_xattr_inode_free_quota+0x11c/0x188 fs/ext4/xattr.c:899
 ext4_xattr_set_entry+0xb2c/0x1694 fs/ext4/xattr.c:1677
 ext4_xattr_block_set+0x634/0x2d10 fs/ext4/xattr.c:1910
 ext4_xattr_set_handle+0xae8/0x1294 fs/ext4/xattr.c:2404
 ext4_xattr_set+0x220/0x340 fs/ext4/xattr.c:2506
 ext4_xattr_trusted_set+0x4c/0x64 fs/ext4/xattr_trusted.c:38
 __vfs_setxattr+0x388/0x3a4 fs/xattr.c:182
 __vfs_setxattr_noperm+0x110/0x528 fs/xattr.c:216
 __vfs_setxattr_locked+0x1ec/0x218 fs/xattr.c:277
 vfs_setxattr+0x1a8/0x344 fs/xattr.c:309
 do_setxattr fs/xattr.c:594 [inline]
 setxattr+0x230/0x294 fs/xattr.c:617
 path_setxattr+0x17c/0x258 fs/xattr.c:636
 __do_sys_setxattr fs/xattr.c:652 [inline]
 __se_sys_setxattr fs/xattr.c:648 [inline]
 __arm64_sys_setxattr+0xbc/0xd8 fs/xattr.c:648
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffff800015c65530 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffff800015c65d30 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffff800015c65360 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
2 locks held by getty/4054:
 #0: ffff0000d647e098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80001d8202f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1214 drivers/tty/n_tty.c:2198
6 locks held by syz-executor360/4308:
 #0: ffff0000de152460 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:393
 #1: ffff0000def5a218 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff0000def5a218 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: vfs_setxattr+0x17c/0x344 fs/xattr.c:308
 #2: ffff0000def59ee0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
 #2: ffff0000def59ee0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x1e0/0x1294 fs/ext4/xattr.c:2319
 #3: ffff800015d98ee8 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:349
 #4: ffff0000e17020a8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x54/0x240 fs/quota/dquot.c:507
 #5: ffff0000de152208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x84/0x188 fs/quota/quota_v2.c:359

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


Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/02/09 21:58 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-1-kasan-arm64 INFO: task hung in ext4_quota_write
2024/12/19 10:44 linux-6.1.y 52f863f820fd 1432fc84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 INFO: task hung in ext4_quota_write
* Struck through repros no longer work on HEAD.