[v5.15] INFO: task hung in lock_buffer

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c957cbb87315 Linux 5.15.105
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1517bb71c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=852dc3de44ba1f3f
dashboard link: https://syzkaller.appspot.com/bug?extid=103feceb41039a3948c2
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/91d0cf1fc5fb/disk-c957cbb8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/346dc1169521/vmlinux-c957cbb8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f7005bdc0e20/Image-c957cbb8.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+103fec...@syzkaller.appspotmail.com

INFO: task syz-executor.5:7029 blocked for more than 143 seconds.
Not tainted 5.15.105-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.5 state:D stack: 0 pid: 7029 ppid: 4091 flags:0x00000009
Call trace:
__switch_to+0x308/0x5e8 arch/arm64/kernel/process.c:518
context_switch kernel/sched/core.c:5026 [inline]
__schedule+0xf10/0x1e38 kernel/sched/core.c:6372
schedule+0x11c/0x1c8 kernel/sched/core.c:6455
io_schedule+0x8c/0x194 kernel/sched/core.c:8472
bit_wait_io+0x1c/0xac kernel/sched/wait_bit.c:209
__wait_on_bit_lock+0xcc/0x1f0 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 fs/buffer.c:69 [inline]
lock_buffer+0x108/0x174 include/linux/buffer_head.h:402
__sync_dirty_buffer+0x6c/0x350 fs/buffer.c:3144
sync_dirty_buffer+0x24/0x34 fs/buffer.c:3170
__ext4_handle_dirty_metadata+0x198/0x740 fs/ext4/ext4_jbd2.c:381
ext4_convert_inline_data_nolock+0x680/0xc18 fs/ext4/inline.c:1262
ext4_convert_inline_data+0x390/0x53c fs/ext4/inline.c:2045
ext4_fallocate+0x12c/0x1d1c fs/ext4/extents.c:4707
vfs_fallocate+0x478/0x5b4 fs/open.c:308
ioctl_preallocate+0x2a0/0x34c fs/ioctl.c:294
do_vfs_ioctl+0x1d00/0x2a38 fs/ioctl.c:853
__do_sys_ioctl fs/ioctl.c:872 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__arm64_sys_ioctl+0xe4/0x1c8 fs/ioctl.c:860
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

Showing all locks held in the system:
1 lock held by khungtaskd/27:
#0: ffff800014a91660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:268
2 locks held by getty/3735:
#0: ffff0000d4090098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
#1: ffff80001a27b2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1200 drivers/tty/n_tty.c:2147
1 lock held by syz-fuzzer/4050:
4 locks held by kworker/u4:12/4361:
3 locks held by syz-executor.5/7029:
#0: ffff0000da682460 (sb_writers#3){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2966 [inline]
#0: ffff0000da682460 (sb_writers#3){.+.+}-{0:0}, at: vfs_fallocate+0x404/0x5b4 fs/open.c:307
#1: ffff00012b24f198 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#1: ffff00012b24f198 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_fallocate+0x124/0x1d1c fs/ext4/extents.c:4706
#2: ffff00012b24ee70 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
#2: ffff00012b24ee70 (&ei->xattr_sem){++++}-{3:3}, at: ext4_convert_inline_data+0x2dc/0x53c fs/ext4/inline.c:2043
3 locks held by syz-executor.3/7113:
#0: ffff0000c9b50460 (sb_writers#3){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2966 [inline]
#0: ffff0000c9b50460 (sb_writers#3){.+.+}-{0:0}, at: vfs_fallocate+0x404/0x5b4 fs/open.c:307
#1: ffff00012b0667a0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#1: ffff00012b0667a0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_fallocate+0x124/0x1d1c fs/ext4/extents.c:4706
#2: ffff00012b066478 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
#2: ffff00012b066478 (&ei->xattr_sem){++++}-{3:3}, at: ext4_convert_inline_data+0x2dc/0x53c fs/ext4/inline.c:2043
2 locks held by kworker/u4:20/8035:
2 locks held by syz-executor.5/8167:

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



---
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[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 543aff194ab6 Linux 6.1.23
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12ad9003c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=9ccbc3d5467efd1
dashboard link: https://syzkaller.appspot.com/bug?extid=32673b66035b3fda5955

compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:

disk image: https://storage.googleapis.com/syzbot-assets/7fe538fc87bf/disk-543aff19.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8df93997601a/vmlinux-543aff19.xz
kernel image: https://storage.googleapis.com/syzbot-assets/03ad7e3bf859/Image-543aff19.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by: syzbot+32673b...@syzkaller.appspotmail.com

INFO: task syz-executor.2:11874 blocked for more than 143 seconds.
Not tainted 6.1.23-syzkaller #0

"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.

task:syz-executor.2 state:D stack:0 pid:11874 ppid:4347 flags:0x00000009
Call trace:
__switch_to+0x320/0x754 arch/arm64/kernel/process.c:553
context_switch kernel/sched/core.c:5241 [inline]
__schedule+0xee4/0x1c98 kernel/sched/core.c:6554
schedule+0xc4/0x170 kernel/sched/core.c:6630
io_schedule+0x8c/0x188 kernel/sched/core.c:8774
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 fs/buffer.c:69 [inline]

lock_buffer+0xf8/0x14c include/linux/buffer_head.h:397
__sync_dirty_buffer+0x6c/0x300 fs/buffer.c:2732
sync_dirty_buffer+0x24/0x34 fs/buffer.c:2758
__ext4_handle_dirty_metadata+0x188/0x70c fs/ext4/ext4_jbd2.c:381
ext4_convert_inline_data_nolock+0x66c/0xbc4 fs/ext4/inline.c:1255
ext4_convert_inline_data+0x388/0x508 fs/ext4/inline.c:2066
ext4_page_mkwrite+0x198/0x1120 fs/ext4/inode.c:6165
do_page_mkwrite+0x144/0x37c mm/memory.c:2973
wp_page_shared+0x148/0x550 mm/memory.c:3319
do_wp_page+0xcbc/0xf44 mm/memory.c:3469
handle_pte_fault mm/memory.c:4968 [inline]
__handle_mm_fault mm/memory.c:5092 [inline]
handle_mm_fault+0x1aa4/0x3d18 mm/memory.c:5213
__do_page_fault arch/arm64/mm/fault.c:512 [inline]
do_page_fault+0x634/0xac4 arch/arm64/mm/fault.c:612
do_mem_abort+0x74/0x200 arch/arm64/mm/fault.c:831
el0_da+0x70/0x184 arch/arm64/kernel/entry-common.c:515
el0t_64_sync_handler+0xcc/0xf0 arch/arm64/kernel/entry-common.c:658
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:581

Showing all locks held in the system:

1 lock held by rcu_tasks_kthre/12:
#0: ffff800015754a30 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:510
1 lock held by rcu_tasks_trace/13:
#0: ffff800015755230 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x44/0xcf4 kernel/rcu/tasks.h:510
1 lock held by khungtaskd/28:
#0: ffff800015754860 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:305
1 lock held by udevd/3837:
2 locks held by getty/3988:
#0: ffff0000d43c6098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
#1: ffff80001ca002f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1210 drivers/tty/n_tty.c:2177
1 lock held by syz-executor.4/4345:
#0: ffff800015759e38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:292 [inline]
#0: ffff800015759e38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3e0/0x768 kernel/rcu/tree_exp.h:948
1 lock held by syz-executor.3/4346:
#0: ffff800015759e38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:324 [inline]
#0: ffff800015759e38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x394/0x768 kernel/rcu/tree_exp.h:948
2 locks held by kworker/0:4/4401:
#0: ffff0000c0021d38 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2262
#1: ffff80001e077c20 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2264
2 locks held by kworker/0:6/4403:
#0: ffff0000c0020d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x664/0x1404 kernel/workqueue.c:2262
#1: ffff80001e097c20 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x6a8/0x1404 kernel/workqueue.c:2264
3 locks held by kworker/u4:13/4996:
4 locks held by syz-executor.2/11874:
#0: ffff0000d7306748 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
#0: ffff0000d7306748 (&mm->mmap_lock){++++}-{3:3}, at: do_page_fault+0x2dc/0xac4 arch/arm64/mm/fault.c:593
#1: ffff000123ce6558 (sb_pagefaults){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1832 [inline]
#1: ffff000123ce6558 (sb_pagefaults){.+.+}-{0:0}, at: sb_start_pagefault include/linux/fs.h:1936 [inline]
#1: ffff000123ce6558 (sb_pagefaults){.+.+}-{0:0}, at: ext4_page_mkwrite+0x168/0x1120 fs/ext4/inode.c:6160
#2: ffff0001266fa3b8 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:811 [inline]
#2: ffff0001266fa3b8 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_page_mkwrite+0x190/0x1120 fs/ext4/inode.c:6163
#3: ffff0001266f9ee0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
#3: ffff0001266f9ee0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_convert_inline_data+0x2d8/0x508 fs/ext4/inline.c:2064
1 lock held by udevd/11965:
#0: ffff0000c049d5d8 (mapping.invalidate_lock#2){.+.+}-{3:3}, at: filemap_invalidate_lock_shared include/linux/fs.h:811 [inline]
#0: ffff0000c049d5d8 (mapping.invalidate_lock#2){.+.+}-{3:3}, at: page_cache_ra_unbounded+0xc8/0x58c mm/readahead.c:226
2 locks held by udevd/11980:
1 lock held by udevd/11981:
1 lock held by udevd/11982:
1 lock held by syz-executor.0/16090:

[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.

[syzbot]