[syzbot] [btrfs?] INFO: task hung in extent_write_cache_pages

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7c6984405241 Merge tag 'iommu-fixes-v6.2-rc3' of git://git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1785447e480000
kernel config: https://syzkaller.appspot.com/x/.config?x=ebc110f9741920ed
dashboard link: https://syzkaller.appspot.com/bug?extid=cc35f55c41e34c30dcb5
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=105b4136480000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12d4ba0e480000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b8f356c8d898/disk-7c698440.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6c7adfab3239/vmlinux-7c698440.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a5638e170c40/bzImage-7c698440.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/09ab9b4cd0af/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cc35f5...@syzkaller.appspotmail.com

INFO: task kworker/u4:5:1106 blocked for more than 143 seconds.
Not tainted 6.2.0-rc3-syzkaller-00376-g7c6984405241 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:5 state:D stack:17088 pid:1106 ppid:2 flags:0x00004000
Workqueue: writeback wb_workfn
(flush-btrfs-21)
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5293 [inline]
__schedule+0x995/0xe20 kernel/sched/core.c:6606
schedule+0xcb/0x190 kernel/sched/core.c:6682
io_schedule+0x83/0x100 kernel/sched/core.c:8862
folio_wait_bit_common+0x83a/0x12a0 mm/filemap.c:1297
extent_write_cache_pages+0x6c8/0x1220 fs/btrfs/extent_io.c:3071
extent_writepages+0x219/0x540 fs/btrfs/extent_io.c:3211
do_writepages+0x3c3/0x680 mm/page-writeback.c:2581
__writeback_single_inode+0xd1/0x670 fs/fs-writeback.c:1598
writeback_sb_inodes+0x812/0x1050 fs/fs-writeback.c:1889
__writeback_inodes_wb+0x11d/0x260 fs/fs-writeback.c:1960
wb_writeback+0x440/0x7b0 fs/fs-writeback.c:2065
wb_check_background_flush fs/fs-writeback.c:2131 [inline]
wb_do_writeback fs/fs-writeback.c:2219 [inline]
wb_workfn+0xb3f/0xef0 fs/fs-writeback.c:2246
process_one_work+0x877/0xdb0 kernel/workqueue.c:2289
worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>
INFO: task syz-executor361:5668 blocked for more than 144 seconds.
Not tainted 6.2.0-rc3-syzkaller-00376-g7c6984405241 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor361 state:D stack:20264 pid:5668 ppid:5119 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5293 [inline]
__schedule+0x995/0xe20 kernel/sched/core.c:6606
schedule+0xcb/0x190 kernel/sched/core.c:6682
wait_on_state fs/btrfs/extent-io-tree.c:707 [inline]
wait_extent_bit+0x577/0x6f0 fs/btrfs/extent-io-tree.c:751
lock_extent+0x1c2/0x280 fs/btrfs/extent-io-tree.c:1742
find_lock_delalloc_range+0x4e6/0x9c0 fs/btrfs/extent_io.c:488
writepage_delalloc+0x1ef/0x540 fs/btrfs/extent_io.c:1863
__extent_writepage+0x736/0x14e0 fs/btrfs/extent_io.c:2174
extent_write_cache_pages+0x983/0x1220 fs/btrfs/extent_io.c:3091
extent_writepages+0x219/0x540 fs/btrfs/extent_io.c:3211
do_writepages+0x3c3/0x680 mm/page-writeback.c:2581
filemap_fdatawrite_wbc+0x11e/0x170 mm/filemap.c:388
__filemap_fdatawrite_range mm/filemap.c:421 [inline]
filemap_fdatawrite_range+0x175/0x200 mm/filemap.c:439
btrfs_fdatawrite_range fs/btrfs/file.c:3850 [inline]
start_ordered_ops fs/btrfs/file.c:1737 [inline]
btrfs_sync_file+0x4ff/0x1190 fs/btrfs/file.c:1839
generic_write_sync include/linux/fs.h:2885 [inline]
btrfs_do_write_iter+0xcd3/0x1280 fs/btrfs/file.c:1684
call_write_iter include/linux/fs.h:2189 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x7dc/0xc50 fs/read_write.c:584
ksys_write+0x177/0x2a0 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f7d4054e9b9
RSP: 002b:00007f7d404fa2f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f7d405d87a0 RCX: 00007f7d4054e9b9
RDX: 0000000000000090 RSI: 0000000020000000 RDI: 0000000000000006
RBP: 00007f7d405a51d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 61635f65646f6e69
R13: 65646f7475616f6e R14: 7261637369646f6e R15: 00007f7d405d87a8
</TASK>
INFO: task syz-executor361:5697 blocked for more than 145 seconds.
Not tainted 6.2.0-rc3-syzkaller-00376-g7c6984405241 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor361 state:D stack:21216 pid:5697 ppid:5119 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5293 [inline]
__schedule+0x995/0xe20 kernel/sched/core.c:6606
schedule+0xcb/0x190 kernel/sched/core.c:6682
rwsem_down_read_slowpath+0x5f9/0x930 kernel/locking/rwsem.c:1095
__down_read_common+0x54/0x2a0 kernel/locking/rwsem.c:1260
btrfs_page_mkwrite+0x417/0xc80 fs/btrfs/inode.c:8526
do_page_mkwrite+0x19e/0x5e0 mm/memory.c:2947
wp_page_shared+0x15e/0x380 mm/memory.c:3295
handle_pte_fault mm/memory.c:4949 [inline]
__handle_mm_fault mm/memory.c:5073 [inline]
handle_mm_fault+0x1b79/0x26b0 mm/memory.c:5219
do_user_addr_fault+0x69b/0xcb0 arch/x86/mm/fault.c:1428
handle_page_fault arch/x86/mm/fault.c:1519 [inline]
exc_page_fault+0x7a/0x110 arch/x86/mm/fault.c:1575
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0010:copy_user_short_string+0xd/0x40 arch/x86/lib/copy_user_64.S:233
Code: 74 0a 89 d1 f3 a4 89 c8 0f 01 ca c3 89 d0 0f 01 ca c3 01 ca eb e7 0f 1f 80 00 00 00 00 89 d1 83 e2 07 c1 e9 03 74 12 4c 8b 06 <4c> 89 07 48 8d 76 08 48 8d 7f 08 ff c9 75 ee 21 d2 74 10 89 d1 8a
RSP: 0018:ffffc9000570f330 EFLAGS: 00050202
RAX: ffffffff843e6601 RBX: 00007fffffffefc8 RCX: 0000000000000007
RDX: 0000000000000000 RSI: ffffc9000570f3e0 RDI: 0000000020000120
RBP: ffffc9000570f490 R08: 0000000000000000 R09: fffff52000ae1e83
R10: fffff52000ae1e83 R11: 1ffff92000ae1e7c R12: 0000000000000038
R13: ffffc9000570f3e0 R14: 0000000020000120 R15: ffffc9000570f3e0
copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
_copy_to_user+0xe9/0x130 lib/usercopy.c:34
copy_to_user include/linux/uaccess.h:169 [inline]
fiemap_fill_next_extent+0x22e/0x410 fs/ioctl.c:144
emit_fiemap_extent+0x22d/0x3c0 fs/btrfs/extent_io.c:3458
fiemap_process_hole+0xa00/0xad0 fs/btrfs/extent_io.c:3716
extent_fiemap+0xe27/0x2100 fs/btrfs/extent_io.c:3922
btrfs_fiemap+0x172/0x1e0 fs/btrfs/inode.c:8209
ioctl_fiemap fs/ioctl.c:219 [inline]
do_vfs_ioctl+0x185b/0x2980 fs/ioctl.c:810
__do_sys_ioctl fs/ioctl.c:868 [inline]
__se_sys_ioctl+0x83/0x170 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f7d4054e9b9
RSP: 002b:00007f7d390d92f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7d405d87b0 RCX: 00007f7d4054e9b9
RDX: 0000000020000100 RSI: 00000000c020660b RDI: 0000000000000005
RBP: 00007f7d405a51d0 R08: 00007f7d390d9700 R09: 0000000000000000
R10: 00007f7d390d9700 R11: 0000000000000246 R12: 61635f65646f6e69
R13: 65646f7475616f6e R14: 7261637369646f6e R15: 00007f7d405d87b8
</TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffffffff8d326fd0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x30/0xd00 kernel/rcu/tasks.h:507
1 lock held by rcu_tasks_trace/13:
#0: ffffffff8d3277d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x30/0xd00 kernel/rcu/tasks.h:507
1 lock held by khungtaskd/28:
#0: ffffffff8d326e00 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
5 locks held by kworker/u4:4/56:
3 locks held by kworker/u4:5/1106:
#0: ffff888144e2b138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7f2/0xdb0
#1: ffffc9000592fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x831/0xdb0 kernel/workqueue.c:2264
#2: ffff88807847c0e0 (&type->s_umount_key#42){++++}-{3:3}, at: trylock_super+0x1b/0xf0 fs/super.c:415
2 locks held by getty/4745:
#0: ffff88802c0b3098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc900015902f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x53b/0x1650 drivers/tty/n_tty.c:2177
4 locks held by syz-executor361/5668:
#0: ffff88807a09f9e8 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x242/0x2e0 fs/file.c:1046
#1: ffff88807847c460 (sb_writers#9){.+.+}-{0:0}, at: vfs_write+0x287/0xc50 fs/read_write.c:580
#2: ffff888075485c80 (&sb->s_type->i_mutex_key#15){++++}-{3:3}, at: inode_lock include/linux/fs.h:756 [inline]
#2: ffff888075485c80 (&sb->s_type->i_mutex_key#15){++++}-{3:3}, at: btrfs_inode_lock+0x49/0xd0 fs/btrfs/inode.c:192
#3: ffff888075485b08 (&ei->i_mmap_lock){++++}-{3:3}, at: btrfs_inode_lock+0xc1/0xd0 fs/btrfs/inode.c:195
3 locks held by syz-executor361/5697:
#0: ffff8880280b0a18 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff8880280b0a18 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2e2/0xcb0 arch/x86/mm/fault.c:1369
#1: ffff88807847c558 (sb_pagefaults){.+.+}-{0:0}, at: do_page_mkwrite+0x19e/0x5e0 mm/memory.c:2947
#2: ffff888075485b08 (&ei->i_mmap_lock){++++}-{3:3}, at: btrfs_page_mkwrite+0x417/0xc80 fs/btrfs/inode.c:8526
2 locks held by syz-executor361/7986:

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.2.0-rc3-syzkaller-00376-g7c6984405241 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106
nmi_cpu_backtrace+0x46f/0x4f0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x1ba/0x420 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
watchdog+0xcd5/0xd20 kernel/hung_task.c:377
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
</TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7984 Comm: syz-executor361 Not tainted 6.2.0-rc3-syzkaller-00376-g7c6984405241 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
RIP: 0033:0x7f7d4050527c
Code: 01 c2 49 3b 55 08 77 56 8d 55 ff 85 ed 74 35 0f 1f 80 00 00 00 00 48 39 c1 77 1c 49 8b 75 00 49 89 c1 49 29 c9 46 0f b6 0c 0e <45> 84 c9 74 08 44 88 0c 06 49 8b 45 10 48 83 c0 01 49 89 45 10 83
RSP: 002b:00007f7d404f9830 EFLAGS: 00000206
RAX: 0000000000da5bbf RBX: 00007f7d404f9890 RCX: 0000000000000001
RDX: 0000000000000016 RSI: 00007f7d380da000 RDI: 00007f7d404f9930
RBP: 0000000000000102 R08: 0000000000000015 R09: 0000000000000000
R10: 0000000000000000 R11: 00007f7d404f98a0 R12: 00007f7d404f98a0
R13: 00007f7d404f9930 R14: 0000000000000001 R15: 0000000000000000
FS: 00007f7d404fa700 GS: 0000000000000000


---
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