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Subject: Private message regarding: [syzbot] [xfs?] inconsistent lock state in igrab
Author: kapoorarnav43@gmail.com

#syz test
From 7e7a6c0e2d9a2d7b9f9a4f5b1b0f2a1c7f0a1234 Mon Sep 17 00:00:00 2001
From: Your Name <you@example.com>
Date: Sat, 14 Feb 2026 12:00:00 +0000
Subject: [PATCH] fs: fserror: avoid igrab in atomic contexts
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

fserror_report() can be called from softirq/atomic contexts (e.g. I/O
endio paths). Using igrab() there takes i_lock, which is also acquired
with softirqs enabled in process context, triggering lockdep warnings
and a potential softirq recursion deadlock.

All fserror_report() callers already hold a live reference to the inode,
so use ihold() to take a safe reference without grabbing i_lock.

Reported-by: syzbot+5eb0d61dfb76ca12670c@syzkaller.appspotmail.com
Signed-off-by: Your Name <you@example.com>
---
 fs/fserror.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/fs/fserror.c b/fs/fserror.c
index 0123456789ab..fedcba987654 100644
--- a/fs/fserror.c
+++ b/fs/fserror.c
@@ -159,16 +159,13 @@ void fserror_report(struct super_block *sb, struct 
inode *inode,
     event->len = len;
     event->error = error;

     /*
-  * Can't iput from non-sleeping context, so grabbing another reference
-  * to the inode must be the last thing before submitting the event.
+  * Can't iput from non-sleeping context, so grabbing another reference
+  * to the inode must be the last thing before submitting the event.
+  * The caller must hold a live reference if @inode is provided.
      */
     if (inode) {
- event->inode = igrab(inode);
- if (!event->inode)
- goto lost_event;
+ ihold(inode);
+ event->inode = inode;
     }

     /*
@@ -184,9 +181,7 @@ void fserror_report(struct super_block *sb, struct 
inode *inode,
     schedule_work(&event->work);
     return;

-lost_event:
- fserror_free_event(event);
 lost:
     if (inode)
         pr_err_ratelimited("%s: lost file I/O error report for ino %lu 
type %u pos 0x%llx len 0x%llx error %d",
--
2.43.0

On Saturday, 14 February 2026 at 13:48:38 UTC+5:30 syzbot wrote:

syzbot has found a reproducer for the following issue on: 

HEAD commit: cd7a5651db26 alpha: add missing address argument in call t.. 
git tree: upstream 
console output: https://syzkaller.appspot.com/x/log.txt?x=13b47e5a580000 
kernel config: https://syzkaller.appspot.com/x/.config?x=e600149b13c010eb 
dashboard link: https://syzkaller.appspot.com/bug?extid=5eb0d61dfb76ca12670c 
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 
2.44 
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15df8722580000 
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17f362aa580000 

Downloadable assets: 
disk image: 
https://storage.googleapis.com/syzbot-assets/ea46ed04f19d/disk-cd7a5651.raw.xz 
vmlinux: 
https://storage.googleapis.com/syzbot-assets/ee7aa4ba7700/vmlinux-cd7a5651.xz 
kernel image: 
https://storage.googleapis.com/syzbot-assets/70280d10edbe/bzImage-cd7a5651.xz 
mounted in repro: 
https://storage.googleapis.com/syzbot-assets/41cb64e4f612/mount_0.gz 
fsck result: failed (log: 
https://syzkaller.appspot.com/x/fsck.log?x=1105a6e6580000) 

IMPORTANT: if you fix the issue, please add the following tag to the 
commit: 
Reported-by: syzbot+5eb0d6...@syzkaller.appspotmail.com 

I/O error, dev loop0, sector 512 op 0x0:(READ) flags 0x880700 phys_seg 1 
prio class 2 
I/O error, dev loop0, sector 18692 op 0x0:(READ) flags 0x880700 phys_seg 1 
prio class 2 
================================ 
WARNING: inconsistent lock state 
syzkaller #0 Not tainted 
-------------------------------- 
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. 
ksoftirqd/0/15 [HC0[0]:SC1[1]:HE1:SE0] takes: 
ffff888059619180 (&sb->s_type->i_lock_key#36){+.?.}-{3:3}, at: spin_lock 
include/linux/spinlock.h:341 [inline] 
ffff888059619180 (&sb->s_type->i_lock_key#36){+.?.}-{3:3}, at: 
igrab+0x2a/0x230 fs/inode.c:1583 
{SOFTIRQ-ON-W} state was registered at: 
lock_acquire kernel/locking/lockdep.c:5868 [inline] 
lock_acquire+0x17c/0x330 kernel/locking/lockdep.c:5825 
__raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline] 
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 
spin_lock include/linux/spinlock.h:341 [inline] 
unlock_new_inode+0x7a/0x330 fs/inode.c:1222 
xfs_finish_inode_setup fs/xfs/xfs_inode.h:630 [inline] 
xfs_setup_existing_inode fs/xfs/xfs_inode.h:637 [inline] 
xfs_iget+0x1196/0x30f0 fs/xfs/xfs_icache.c:814 
xfs_mountfs+0x108c/0x20b0 fs/xfs/xfs_mount.c:1072 
xfs_fs_fill_super+0x153f/0x1f20 fs/xfs/xfs_super.c:1938 
get_tree_bdev_flags+0x38c/0x620 fs/super.c:1694 
vfs_get_tree+0x92/0x320 fs/super.c:1754 
fc_mount fs/namespace.c:1193 [inline] 
do_new_mount_fc fs/namespace.c:3760 [inline] 
do_new_mount fs/namespace.c:3836 [inline] 
path_mount+0x7d0/0x23d0 fs/namespace.c:4146 
do_mount fs/namespace.c:4159 [inline] 
__do_sys_mount fs/namespace.c:4348 [inline] 
__se_sys_mount fs/namespace.c:4325 [inline] 
__x64_sys_mount+0x293/0x310 fs/namespace.c:4325 
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] 
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 
entry_SYSCALL_64_after_hwframe+0x77/0x7f 
irq event stamp: 972992 
hardirqs last enabled at (972992): [<ffffffff8b820072>] 
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:178 [inline] 
hardirqs last enabled at (972992): [<ffffffff8b820072>] 
_raw_spin_unlock_irqrestore+0x52/0x80 kernel/locking/spinlock.c:194 
hardirqs last disabled at (972991): [<ffffffff8b81fd82>] 
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:130 [inline] 
hardirqs last disabled at (972991): [<ffffffff8b81fd82>] 
_raw_spin_lock_irqsave+0x52/0x60 kernel/locking/spinlock.c:162 
softirqs last enabled at (972968): [<ffffffff81c7bb68>] run_ksoftirqd 
kernel/softirq.c:1063 [inline] 
softirqs last enabled at (972968): [<ffffffff81c7bb68>] 
run_ksoftirqd+0x38/0x60 kernel/softirq.c:1055 
softirqs last disabled at (972973): [<ffffffff81c7bb68>] run_ksoftirqd 
kernel/softirq.c:1063 [inline] 
softirqs last disabled at (972973): [<ffffffff81c7bb68>] 
run_ksoftirqd+0x38/0x60 kernel/softirq.c:1055 

other info that might help us debug this: 
Possible unsafe locking scenario: 

CPU0 
---- 
lock(&sb->s_type->i_lock_key#36); 
<Interrupt> 
lock(&sb->s_type->i_lock_key#36); 

*** DEADLOCK *** 

no locks held by ksoftirqd/0/15. 

stack backtrace: 
CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted syzkaller #0 
PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS 
Google 02/12/2026 
Call Trace: 
<TASK> 
__dump_stack lib/dump_stack.c:94 [inline] 
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 
print_usage_bug.part.0+0x257/0x340 kernel/locking/lockdep.c:4042 
print_usage_bug kernel/locking/lockdep.c:4010 [inline] 
valid_state kernel/locking/lockdep.c:4056 [inline] 
mark_lock_irq kernel/locking/lockdep.c:4267 [inline] 
mark_lock+0x74a/0xa20 kernel/locking/lockdep.c:4753 
mark_usage kernel/locking/lockdep.c:4642 [inline] 
__lock_acquire+0x103a/0x2630 kernel/locking/lockdep.c:5191 
lock_acquire kernel/locking/lockdep.c:5868 [inline] 
lock_acquire+0x17c/0x330 kernel/locking/lockdep.c:5825 
__raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline] 
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 
spin_lock include/linux/spinlock.h:341 [inline] 
igrab+0x2a/0x230 fs/inode.c:1583 
fserror_report+0x3fd/0x750 fs/fserror.c:159 
fserror_report_io include/linux/fserror.h:48 [inline] 
iomap_finish_folio_read+0x168/0x2c0 fs/iomap/buffered-io.c:407 
iomap_read_end_io+0x11a/0x430 fs/iomap/bio.c:17 
bio_endio+0x755/0x8b0 block/bio.c:1790 
blk_update_request+0x741/0x1330 block/blk-mq.c:1016 
blk_mq_end_request+0x5b/0x420 block/blk-mq.c:1178 
lo_complete_rq+0x1d4/0x2a0 drivers/block/loop.c:314 
blk_complete_reqs+0xb1/0xf0 block/blk-mq.c:1253 
handle_softirqs+0x1ea/0x910 kernel/softirq.c:622 
run_ksoftirqd kernel/softirq.c:1063 [inline] 
run_ksoftirqd+0x38/0x60 kernel/softirq.c:1055 
smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160 
kthread+0x370/0x450 kernel/kthread.c:467 
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 
</TASK> 


--- 
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#syz test: git://repo/address.git branch-or-commit-hash 
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