[v5.15] INFO: task hung in fuse_simple_request

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syzbot

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Jul 20, 2023, 7:10:13 AM7/20/23
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Hello,

syzbot found the following issue on:

HEAD commit: d54cfc420586 Linux 5.15.120
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12e08c52a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=1cbb66d8f24dbb30
dashboard link: https://syzkaller.appspot.com/bug?extid=8b80be47d93784f776de
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a7edb50fe106/disk-d54cfc42.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6d9892e76c6e/vmlinux-d54cfc42.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0fd11af6d33e/Image-d54cfc42.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8b80be...@syzkaller.appspotmail.com

INFO: task syz-executor.4:21861 blocked for more than 143 seconds.
Not tainted 5.15.120-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4 state:D stack: 0 pid:21861 ppid: 4017 flags:0x0000000d
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
request_wait_answer fs/fuse/dev.c:411 [inline]
__fuse_request_send fs/fuse/dev.c:430 [inline]
fuse_simple_request+0xea8/0x1758 fs/fuse/dev.c:515
fuse_setxattr+0x2f4/0x56c fs/fuse/xattr.c:40
fuse_xattr_set+0x88/0xc0 fs/fuse/xattr.c:205
__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:303
do_setxattr fs/xattr.c:588 [inline]
setxattr+0x250/0x2b4 fs/xattr.c:611
path_setxattr+0x17c/0x258 fs/xattr.c:630
__do_sys_setxattr fs/xattr.c:646 [inline]
__se_sys_setxattr fs/xattr.c:642 [inline]
__arm64_sys_setxattr+0xbc/0xd8 fs/xattr.c:642
__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: ffff800014ac19a0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:268
1 lock held by klogd/3576:
2 locks held by getty/3728:
#0: ffff0000d3895098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x40/0x50 drivers/tty/tty_ldsem.c:340
#1: ffff80001a29b2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x414/0x1200 drivers/tty/n_tty.c:2147
2 locks held by syz-executor.4/21861:
#0: ffff0000d8ce4460 (sb_writers#16){.+.+}-{0:0}, at: mnt_want_write+0x44/0x9c fs/namespace.c:377
#1: ffff00011be75fd0 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#1: ffff00011be75fd0 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: vfs_setxattr+0x17c/0x344 fs/xattr.c:302

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



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syzbot

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Feb 3, 2024, 8:59:16 AMFeb 3
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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