[syzbot] [ext4?] INFO: task hung in find_inode_fast (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1c7873e33645 mm: lock newly mapped VMA with corrected orde..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10d2771ca80000
kernel config: https://syzkaller.appspot.com/x/.config?x=15873d91ff37a949
dashboard link: https://syzkaller.appspot.com/bug?extid=adfd362e7719c02b3015
compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=136b54c4a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=179ec9d8a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/266e35c3f21e/disk-1c7873e3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9cf36dfe8b31/vmlinux-1c7873e3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a274cf2ce4d3/bzImage-1c7873e3.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/3d70fcee5ad3/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+adfd36...@syzkaller.appspotmail.com

INFO: task syz-executor173:7462 blocked for more than 143 seconds.
Not tainted 6.4.0-syzkaller-12454-g1c7873e33645 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor173 state:D stack:25544 pid:7462 ppid:5046 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1873/0x48f0 kernel/sched/core.c:6710
schedule+0xc3/0x180 kernel/sched/core.c:6786
__wait_on_freeing_inode fs/inode.c:2240 [inline]
find_inode_fast+0x319/0x450 fs/inode.c:950
iget_locked+0xcb/0x830 fs/inode.c:1317
__ext4_iget+0x261/0x3f30 fs/ext4/inode.c:4670
ext4_xattr_inode_cache_find fs/ext4/xattr.c:1542 [inline]
ext4_xattr_inode_lookup_create fs/ext4/xattr.c:1577 [inline]
ext4_xattr_set_entry+0x219f/0x3e80 fs/ext4/xattr.c:1719
ext4_xattr_block_set+0xb12/0x3630 fs/ext4/xattr.c:2025
ext4_xattr_set_handle+0xcd4/0x15c0 fs/ext4/xattr.c:2442
ext4_xattr_set+0x241/0x3d0 fs/ext4/xattr.c:2544
__vfs_setxattr+0x460/0x4a0 fs/xattr.c:201
__vfs_setxattr_noperm+0x12e/0x5e0 fs/xattr.c:235
vfs_setxattr+0x221/0x420 fs/xattr.c:322
do_setxattr fs/xattr.c:630 [inline]
setxattr+0x25d/0x2f0 fs/xattr.c:653
path_setxattr+0x1c0/0x2a0 fs/xattr.c:672
__do_sys_setxattr fs/xattr.c:688 [inline]
__se_sys_setxattr fs/xattr.c:684 [inline]
__x64_sys_setxattr+0xbb/0xd0 fs/xattr.c:684
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f9b8cd80509
RSP: 002b:00007f9b841472f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007f9b8ce0c550 RCX: 00007f9b8cd80509
RDX: 00000000200005c0 RSI: 0000000020000180 RDI: 00000000200000c0
RBP: 0030656c69662f2e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000002000 R11: 0000000000000246 R12: 00007f9b8cdd2360
R13: 66763d746d66716a R14: 2f30656c69662f2e R15: 00007f9b8ce0c558
</TASK>
INFO: task syz-executor173:7468 blocked for more than 143 seconds.
Not tainted 6.4.0-syzkaller-12454-g1c7873e33645 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor173 state:D stack:25768 pid:7468 ppid:5046 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1873/0x48f0 kernel/sched/core.c:6710
schedule+0xc3/0x180 kernel/sched/core.c:6786
mb_cache_entry_wait_unused+0x166/0x250 fs/mbcache.c:148
ext4_evict_ea_inode+0x14a/0x2f0 fs/ext4/xattr.c:480
ext4_evict_inode+0x184/0xf20 fs/ext4/inode.c:180
evict+0x2a4/0x620 fs/inode.c:665
ext4_xattr_set_entry+0x13d4/0x3e80 fs/ext4/xattr.c:1856
ext4_xattr_block_set+0x69c/0x3630 fs/ext4/xattr.c:1956
ext4_xattr_set_handle+0xcd4/0x15c0 fs/ext4/xattr.c:2442
ext4_xattr_set+0x241/0x3d0 fs/ext4/xattr.c:2544
__vfs_setxattr+0x460/0x4a0 fs/xattr.c:201
__vfs_setxattr_noperm+0x12e/0x5e0 fs/xattr.c:235
vfs_setxattr+0x221/0x420 fs/xattr.c:322
do_setxattr fs/xattr.c:630 [inline]
setxattr+0x25d/0x2f0 fs/xattr.c:653
path_setxattr+0x1c0/0x2a0 fs/xattr.c:672
__do_sys_setxattr fs/xattr.c:688 [inline]
__se_sys_setxattr fs/xattr.c:684 [inline]
__x64_sys_setxattr+0xbb/0xd0 fs/xattr.c:684
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f9b8cd80509
RSP: 002b:00007f9b841262f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007f9b8ce0c560 RCX: 00007f9b8cd80509
RDX: 0000000000000000 RSI: 0000000020000200 RDI: 00000000200001c0
RBP: 0030656c69662f2e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9b8cdd2360
R13: 66763d746d66716a R14: 2f30656c69662f2e R15: 00007f9b8ce0c568
</TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/13:
#0: ffffffff8d328af0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:522
1 lock held by rcu_tasks_trace/14:
#0: ffffffff8d328eb0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xd20 kernel/rcu/tasks.h:522
1 lock held by khungtaskd/28:
#0: ffffffff8d328920 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/1:2/2094:
#0: ffff888012870d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7e3/0x12c0 kernel/workqueue.c:2569
#1: ffffc9000786fd20 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x82b/0x12c0 kernel/workqueue.c:2571
#2: ffffffff8d32dfb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:325 [inline]
#2: ffffffff8d32dfb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x46c/0x890 kernel/rcu/tree_exp.h:992
3 locks held by kworker/0:3/4759:
#0: ffff888012870d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7e3/0x12c0 kernel/workqueue.c:2569
#1: ffffc9000379fd20 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x82b/0x12c0 kernel/workqueue.c:2571
#2: ffffffff8d32dfb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:293 [inline]
#2: ffffffff8d32dfb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3a3/0x890 kernel/rcu/tree_exp.h:992
2 locks held by getty/4772:
#0: ffff88802d3c2098
(&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900015b02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b1/0x1dc0 drivers/tty/n_tty.c:2187
1 lock held by udevd/5050:
2 locks held by kworker/0:2/5052:
#0: ffff888012870d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7e3/0x12c0 kernel/workqueue.c:2569
#1: ffffc90003c0fd20 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x82b/0x12c0 kernel/workqueue.c:2571
2 locks held by kworker/1:3/5060:
#0: ffff888012870d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7e3/0x12c0 kernel/workqueue.c:2569
#1: ffffc90003c9fd20 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x82b/0x12c0 kernel/workqueue.c:2571
1 lock held by udevd/5105:
2 locks held by kworker/0:4/5115:
#0: ffff888012872538 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7e3/0x12c0 kernel/workqueue.c:2569
#1: ffffc90003e6fd20 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x82b/0x12c0 kernel/workqueue.c:2571
3 locks held by syz-executor173/7462:
#0: ffff8880220f2410 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:403
#1: ffff8880783cf200 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: inode_lock include/linux/fs.h:771 [inline]
#1: ffff8880783cf200 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: vfs_setxattr+0x1e1/0x420 fs/xattr.c:321
#2: ffff8880783ceec8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
#2: ffff8880783ceec8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x274/0x15c0 fs/ext4/xattr.c:2357
3 locks held by syz-executor173/7468:
#0: ffff8880220f2410 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:403
#1: ffff88806aed8400 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: inode_lock include/linux/fs.h:771 [inline]
#1: ffff88806aed8400 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: vfs_setxattr+0x1e1/0x420 fs/xattr.c:321
#2: ffff88806aed80c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_write_lock_xattr fs/ext4/xattr.h:155 [inline]
#2: ffff88806aed80c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_xattr_set_handle+0x274/0x15c0 fs/ext4/xattr.c:2357

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.4.0-syzkaller-12454-g1c7873e33645 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/03/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
nmi_cpu_backtrace+0x498/0x4d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x187/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
watchdog+0xec2/0xf00 kernel/hung_task.c:379
kthread+0x2b8/0x350 kernel/kthread.c:389
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 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline]
NMI backtrace for cpu 1 skipped: idling at __intel_idle_hlt drivers/idle/intel_idle.c:205 [inline]
NMI backtrace for cpu 1 skipped: idling at intel_idle_hlt+0x15/0x20 drivers/idle/intel_idle.c:224


---
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If the bug is already fixed, let syzbot know by replying with:
#syz fix: exact-commit-title

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#syz test: git://repo/address.git branch-or-commit-hash
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If you want to change bug's subsystems, reply with:
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#syz dup: exact-subject-of-another-report

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#syz undup

[syzbot]

syzbot suspects this issue was fixed by commit:

commit 6f861765464f43a71462d52026fbddfc858239a5
Author: Jan Kara <ja...@suse.cz>
Date: Wed Nov 1 17:43:10 2023 +0000

fs: Block writes to mounted block devices

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17852f7be80000
start commit: 2a5a4326e583 Merge tag 'scsi-misc' of git://git.kernel.org..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=d5e7bcb9a41fc9b3
dashboard link: https://syzkaller.appspot.com/bug?extid=adfd362e7719c02b3015
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11d27994680000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: fs: Block writes to mounted block devices

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[Aleksandr Nogikh]

#syz fix: fs: Block writes to mounted block devices