syzbot

INFO: task kworker/u4:0:9 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:0    state:D stack:24720 pid:    9 ppid:     2 flags:0x00004000
Workqueue: events_unbound quota_release_workfn
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:1890
 do_wait_for_common+0x2a2/0x450 kernel/sched/completion.c:85
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x48/0x60 kernel/sched/completion.c:138
 __synchronize_srcu+0x2bb/0x350 kernel/rcu/srcutree.c:930
 quota_release_workfn+0x106/0x610 fs/quota/dquot.c:828
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task syz.2.19:4393 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19        state:D stack:21360 pid: 4393 ppid:  4336 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
 __wait_on_bit_lock+0xbc/0x1a0 kernel/sched/wait_bit.c:90
 out_of_line_wait_on_bit_lock+0x138/0x190 kernel/sched/wait_bit.c:117
 lock_buffer include/linux/buffer_head.h:402 [inline]
 ext4_quota_write+0x36d/0x580 fs/ext4/super.c:6636
 qtree_write_dquot+0x203/0x4b0 fs/quota/quota_tree.c:422
 v2_write_dquot+0x108/0x190 fs/quota/quota_v2.c:358
 dquot_commit+0x34b/0x410 fs/quota/dquot.c:514
 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6210
 mark_dquot_dirty fs/quota/dquot.c:372 [inline]
 mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412
 dquot_alloc_inode+0x717/0x9c0 fs/quota/dquot.c:1801
 ext4_xattr_inode_alloc_quota fs/ext4/xattr.c:866 [inline]
 ext4_xattr_set_entry+0xfb2/0x3ea0 fs/ext4/xattr.c:1669
 ext4_xattr_block_set+0x4fd/0x2d20 fs/ext4/xattr.c:1924
 ext4_xattr_set_handle+0xbc4/0x12b0 fs/ext4/xattr.c:2407
 ext4_xattr_set+0x242/0x320 fs/ext4/xattr.c:2508
 __vfs_setxattr+0x3e0/0x420 fs/xattr.c:182
 __vfs_setxattr_noperm+0x129/0x5e0 fs/xattr.c:216
 vfs_setxattr+0x167/0x2e0 fs/xattr.c:303
 do_setxattr fs/xattr.c:588 [inline]
 setxattr+0x36c/0x390 fs/xattr.c:611
 path_setxattr+0x147/0x290 fs/xattr.c:630
 __do_sys_setxattr fs/xattr.c:646 [inline]
 __se_sys_setxattr fs/xattr.c:642 [inline]
 __x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:642
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fb747521eb9
RSP: 002b:00007ffe297efd38 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007fb74779cfa0 RCX: 00007fb747521eb9
RDX: 0000200000000380 RSI: 0000200000000340 RDI: 00002000000002c0
RBP: 00007fb74758fc1f R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000ffed R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb74779cfac R14: 00007fb74779cfa0 R15: 00007fb74779cfa0
 </TASK>
INFO: task syz.0.17:4397 blocked for more than 147 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:21840 pid: 4397 ppid:  4328 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8503
 bit_wait_io+0xd/0xc0 kernel/sched/wait_bit.c:209
 __wait_on_bit_lock+0xbc/0x1a0 kernel/sched/wait_bit.c:90
 out_of_line_wait_on_bit_lock+0x138/0x190 kernel/sched/wait_bit.c:117
 lock_buffer include/linux/buffer_head.h:402 [inline]
 ext4_quota_write+0x36d/0x580 fs/ext4/super.c:6636
 qtree_write_dquot+0x203/0x4b0 fs/quota/quota_tree.c:422
 v2_write_dquot+0x108/0x190 fs/quota/quota_v2.c:358
 dquot_commit+0x34b/0x410 fs/quota/dquot.c:514
 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6210
 mark_dquot_dirty fs/quota/dquot.c:372 [inline]
 mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412
 dquot_alloc_inode+0x717/0x9c0 fs/quota/dquot.c:1801
 ext4_xattr_inode_alloc_quota fs/ext4/xattr.c:866 [inline]
 ext4_xattr_set_entry+0xfb2/0x3ea0 fs/ext4/xattr.c:1669
 ext4_xattr_block_set+0x4fd/0x2d20 fs/ext4/xattr.c:1924
 ext4_xattr_set_handle+0xbc4/0x12b0 fs/ext4/xattr.c:2407
 ext4_xattr_set+0x242/0x320 fs/ext4/xattr.c:2508
 __vfs_setxattr+0x3e0/0x420 fs/xattr.c:182
 __vfs_setxattr_noperm+0x129/0x5e0 fs/xattr.c:216
 vfs_setxattr+0x167/0x2e0 fs/xattr.c:303
 do_setxattr fs/xattr.c:588 [inline]
 setxattr+0x36c/0x390 fs/xattr.c:611
 path_setxattr+0x147/0x290 fs/xattr.c:630
 __do_sys_setxattr fs/xattr.c:646 [inline]
 __se_sys_setxattr fs/xattr.c:642 [inline]
 __x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:642
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6c78218eb9
RSP: 002b:00007ffd483d5a18 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007f6c78493fa0 RCX: 00007f6c78218eb9
RDX: 0000200000000380 RSI: 0000200000000340 RDI: 00002000000002c0
RBP: 00007f6c78286c1f R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000ffed R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6c78493fac R14: 00007f6c78493fa0 R15: 00007f6c78493fa0
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u4:0/9:
 #0: ffff888016c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc90000ce7d00 ((quota_release_work).work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
1 lock held by khungtaskd/27:
 #0: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:4/1262:
 #0: ffff888016dcd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc90005107d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffffffff8d430850 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:589
 #3: ffffffff8c31eaa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
1 lock held by udevd/3560:
2 locks held by getty/3945:
 #0: ffff88802bebd098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900025ce2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
3 locks held by kworker/0:3/4292:
 #0: ffff888016c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000307fd00 (fqdir_free_work){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffffffff8c323430 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0xa1/0x4c0 kernel/rcu/tree.c:4043
3 locks held by kworker/1:4/4298:
 #0: ffff88802aee7138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc9000316fd00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
 #2: ffffffff8d43c748 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xca/0x1540 net/ipv6/addrconf.c:4110
3 locks held by kworker/u4:5/4370:
3 locks held by kworker/0:7/4384:
6 locks held by syz.2.19/4393:
 #0: ffff88807ac3c460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
 #1: ffff88805605f198 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff88805605f198 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: vfs_setxattr+0x140/0x2e0 fs/xattr.c:302
 #2: ffff88805605ee70 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline]
 #2: ffff88805605ee70 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x190/0x12b0 fs/ext4/xattr.c:2322
 #3: ffffffff8c441538 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
 #4: ffff888068b960a8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
 #5: ffff88807ac3c208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x88/0x190 fs/quota/quota_v2.c:356
6 locks held by syz.0.17/4397:
 #0: ffff88807a68a460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
 #1: ffff8880560603f0 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff8880560603f0 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: vfs_setxattr+0x140/0x2e0 fs/xattr.c:302
 #2: ffff8880560600c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline]
 #2: ffff8880560600c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x190/0x12b0 fs/ext4/xattr.c:2322
 #3: ffffffff8c441538 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
 #4: ffff888068b96268 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
 #5: ffff88807a68a208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x88/0x190 fs/quota/quota_v2.c:356
4 locks held by kworker/0:8/4398:
6 locks held by syz.3.20/4443:
 #0: ffff88802558e460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
 #1: ffff8880560667a0 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff8880560667a0 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: vfs_setxattr+0x140/0x2e0 fs/xattr.c:302
 #2: ffff888056066478 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline]
 #2: ffff888056066478 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x190/0x12b0 fs/ext4/xattr.c:2322
 #3: ffffffff8c441538 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
 #4: ffff888070f620a8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
 #5: ffff88802558e208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x88/0x190 fs/quota/quota_v2.c:356
6 locks held by syz.1.18/4444:
 #0: ffff888025a5e460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
 #1: ffff888056065da8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff888056065da8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: vfs_setxattr+0x140/0x2e0 fs/xattr.c:302
 #2: ffff888056065a80 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline]
 #2: ffff888056065a80 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x190/0x12b0 fs/ext4/xattr.c:2322
 #3: ffffffff8c441538 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
 #4: ffff888068b967a8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
 #5: ffff888025a5e208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x88/0x190 fs/quota/quota_v2.c:356
6 locks held by syz.4.21/4450:
 #0: ffff888078926460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
 #1: ffff8880689621d8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff8880689621d8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: vfs_setxattr+0x140/0x2e0 fs/xattr.c:302
 #2: ffff888068961eb0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline]
 #2: ffff888068961eb0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x190/0x12b0 fs/ext4/xattr.c:2322
 #3: ffffffff8c441538 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
 #4: ffff888068b96b28 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
 #5: ffff888078926208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x88/0x190 fs/quota/quota_v2.c:356
6 locks held by syz.5.22/4500:
 #0: ffff88801ee32460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
 #1: ffff888068a2dda8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff888068a2dda8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: vfs_setxattr+0x140/0x2e0 fs/xattr.c:302
 #2: ffff888068a2da80 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline]
 #2: ffff888068a2da80 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x190/0x12b0 fs/ext4/xattr.c:2322
 #3: ffffffff8c441538 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
 #4: ffff888068b96ea8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
 #5: ffff88801ee32208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x88/0x190 fs/quota/quota_v2.c:356
6 locks held by syz.6.23/4514:
 #0: ffff888022e72460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
 #1: ffff88805627abd0 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
 #1: ffff88805627abd0 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: vfs_setxattr+0x140/0x2e0 fs/xattr.c:302
 #2: ffff88805627a8a8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:158 [inline]
 #2: ffff88805627a8a8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x190/0x12b0 fs/ext4/xattr.c:2322
 #3: ffffffff8c441538 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312
 #4: ffff888068b97228 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
 #5: ffff888022e72208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x88/0x190 fs/quota/quota_v2.c:356