[syzbot] [xfs?] possible deadlock in xfs_can_free_eofblocks (3)
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syzbot
Dec 7, 2025, 1:07:35 PM (yesterday) Dec 7
to c...@kernel.org, linux-...@vger.kernel.org, linu...@vger.kernel.org, syzkall...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: c06c303832ec ocfs2: fix xattr array entry __counted_by error
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1688a992580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d3ce1cfe3996fc8b
dashboard link: https://syzkaller.appspot.com/bug?extid=a8a73f25200041b89d40
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-c06c3038.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/aa14148a2ef4/vmlinux-c06c3038.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d2d5f3a106bf/bzImage-c06c3038.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a8a73f...@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kswapd0/79 is trying to acquire lock:
ffff88800083d798 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_can_free_eofblocks+0x693/0x8e0 fs/xfs/xfs_bmap_util.c:562
but task is already holding lock:
ffffffff8e251780 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6973 [inline]
ffffffff8e251780 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x92a/0x2820 mm/vmscan.c:7352
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}-{0:0}:
__fs_reclaim_acquire mm/page_alloc.c:4301 [inline]
fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4315
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4899 [inline]
slab_alloc_node mm/slub.c:5234 [inline]
__kmalloc_cache_noprof+0x40/0x700 mm/slub.c:5766
kmalloc_noprof include/linux/slab.h:957 [inline]
iomap_fill_dirty_folios+0xf4/0x260 fs/iomap/buffered-io.c:1557
xfs_buffered_write_iomap_begin+0xa23/0x1a70 fs/xfs/xfs_iomap.c:1857
iomap_iter+0x5ef/0xeb0 fs/iomap/iter.c:110
iomap_zero_range+0x1cc/0xa30 fs/iomap/buffered-io.c:1590
xfs_zero_range+0x9a/0x100 fs/xfs/xfs_iomap.c:2289
xfs_setattr_size+0x48b/0xed0 fs/xfs/xfs_iops.c:993
__xfs_file_fallocate+0x10ca/0x15f0 include/linux/fs.h:-1
xfs_file_fallocate+0x27b/0x340 fs/xfs/xfs_file.c:1462
vfs_fallocate+0x669/0x7e0 fs/open.c:339
ksys_fallocate fs/open.c:363 [inline]
__do_sys_fallocate fs/open.c:368 [inline]
__se_sys_fallocate fs/open.c:366 [inline]
__x64_sys_fallocate+0xc0/0x110 fs/open.c:366
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&xfs_nondir_ilock_class){++++}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
down_read_nested+0x49/0x2e0 kernel/locking/rwsem.c:1662
xfs_can_free_eofblocks+0x693/0x8e0 fs/xfs/xfs_bmap_util.c:562
xfs_inode_mark_reclaimable+0x21d/0x1030 fs/xfs/xfs_icache.c:2244
destroy_inode fs/inode.c:396 [inline]
evict+0x8aa/0xae0 fs/inode.c:861
dispose_list fs/inode.c:879 [inline]
prune_icache_sb+0x21b/0x2c0 fs/inode.c:1027
super_cache_scan+0x39b/0x4b0 fs/super.c:224
do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437
shrink_slab_memcg mm/shrinker.c:550 [inline]
shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628
shrink_one+0x2d9/0x720 mm/vmscan.c:4919
shrink_many mm/vmscan.c:4980 [inline]
lru_gen_shrink_node mm/vmscan.c:5058 [inline]
shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6045
kswapd_shrink_node mm/vmscan.c:6899 [inline]
balance_pgdat mm/vmscan.c:7082 [inline]
kswapd+0x145a/0x2820 mm/vmscan.c:7352
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&xfs_nondir_ilock_class);
lock(fs_reclaim);
rlock(&xfs_nondir_ilock_class);
*** DEADLOCK ***
2 locks held by kswapd0/79:
#0: ffffffff8e251780 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6973 [inline]
#0: ffffffff8e251780 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x92a/0x2820 mm/vmscan.c:7352
#1: ffff88803639a0e0 (&type->s_umount_key#51){.+.+}-{4:4}, at: super_trylock_shared fs/super.c:563 [inline]
#1: ffff88803639a0e0 (&type->s_umount_key#51){.+.+}-{4:4}, at: super_cache_scan+0x91/0x4b0 fs/super.c:197
stack backtrace:
CPU: 0 UID: 0 PID: 79 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043
check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
down_read_nested+0x49/0x2e0 kernel/locking/rwsem.c:1662
xfs_can_free_eofblocks+0x693/0x8e0 fs/xfs/xfs_bmap_util.c:562
xfs_inode_mark_reclaimable+0x21d/0x1030 fs/xfs/xfs_icache.c:2244
destroy_inode fs/inode.c:396 [inline]
evict+0x8aa/0xae0 fs/inode.c:861
dispose_list fs/inode.c:879 [inline]
prune_icache_sb+0x21b/0x2c0 fs/inode.c:1027
super_cache_scan+0x39b/0x4b0 fs/super.c:224
do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437
shrink_slab_memcg mm/shrinker.c:550 [inline]
shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628
shrink_one+0x2d9/0x720 mm/vmscan.c:4919
shrink_many mm/vmscan.c:4980 [inline]
lru_gen_shrink_node mm/vmscan.c:5058 [inline]
shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6045
kswapd_shrink_node mm/vmscan.c:6899 [inline]
balance_pgdat mm/vmscan.c:7082 [inline]
kswapd+0x145a/0x2820 mm/vmscan.c:7352
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: c06c303832ec ocfs2: fix xattr array entry __counted_by error
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1688a992580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d3ce1cfe3996fc8b
dashboard link: https://syzkaller.appspot.com/bug?extid=a8a73f25200041b89d40
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-c06c3038.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/aa14148a2ef4/vmlinux-c06c3038.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d2d5f3a106bf/bzImage-c06c3038.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a8a73f...@syzkaller.appspotmail.com
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kswapd0/79 is trying to acquire lock:
ffff88800083d798 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_can_free_eofblocks+0x693/0x8e0 fs/xfs/xfs_bmap_util.c:562
but task is already holding lock:
ffffffff8e251780 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6973 [inline]
ffffffff8e251780 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x92a/0x2820 mm/vmscan.c:7352
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (fs_reclaim){+.+.}-{0:0}:
__fs_reclaim_acquire mm/page_alloc.c:4301 [inline]
fs_reclaim_acquire+0x72/0x100 mm/page_alloc.c:4315
might_alloc include/linux/sched/mm.h:317 [inline]
slab_pre_alloc_hook mm/slub.c:4899 [inline]
slab_alloc_node mm/slub.c:5234 [inline]
__kmalloc_cache_noprof+0x40/0x700 mm/slub.c:5766
kmalloc_noprof include/linux/slab.h:957 [inline]
iomap_fill_dirty_folios+0xf4/0x260 fs/iomap/buffered-io.c:1557
xfs_buffered_write_iomap_begin+0xa23/0x1a70 fs/xfs/xfs_iomap.c:1857
iomap_iter+0x5ef/0xeb0 fs/iomap/iter.c:110
iomap_zero_range+0x1cc/0xa30 fs/iomap/buffered-io.c:1590
xfs_zero_range+0x9a/0x100 fs/xfs/xfs_iomap.c:2289
xfs_setattr_size+0x48b/0xed0 fs/xfs/xfs_iops.c:993
__xfs_file_fallocate+0x10ca/0x15f0 include/linux/fs.h:-1
xfs_file_fallocate+0x27b/0x340 fs/xfs/xfs_file.c:1462
vfs_fallocate+0x669/0x7e0 fs/open.c:339
ksys_fallocate fs/open.c:363 [inline]
__do_sys_fallocate fs/open.c:368 [inline]
__se_sys_fallocate fs/open.c:366 [inline]
__x64_sys_fallocate+0xc0/0x110 fs/open.c:366
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
-> #0 (&xfs_nondir_ilock_class){++++}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
down_read_nested+0x49/0x2e0 kernel/locking/rwsem.c:1662
xfs_can_free_eofblocks+0x693/0x8e0 fs/xfs/xfs_bmap_util.c:562
xfs_inode_mark_reclaimable+0x21d/0x1030 fs/xfs/xfs_icache.c:2244
destroy_inode fs/inode.c:396 [inline]
evict+0x8aa/0xae0 fs/inode.c:861
dispose_list fs/inode.c:879 [inline]
prune_icache_sb+0x21b/0x2c0 fs/inode.c:1027
super_cache_scan+0x39b/0x4b0 fs/super.c:224
do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437
shrink_slab_memcg mm/shrinker.c:550 [inline]
shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628
shrink_one+0x2d9/0x720 mm/vmscan.c:4919
shrink_many mm/vmscan.c:4980 [inline]
lru_gen_shrink_node mm/vmscan.c:5058 [inline]
shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6045
kswapd_shrink_node mm/vmscan.c:6899 [inline]
balance_pgdat mm/vmscan.c:7082 [inline]
kswapd+0x145a/0x2820 mm/vmscan.c:7352
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&xfs_nondir_ilock_class);
lock(fs_reclaim);
rlock(&xfs_nondir_ilock_class);
*** DEADLOCK ***
2 locks held by kswapd0/79:
#0: ffffffff8e251780 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6973 [inline]
#0: ffffffff8e251780 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0x92a/0x2820 mm/vmscan.c:7352
#1: ffff88803639a0e0 (&type->s_umount_key#51){.+.+}-{4:4}, at: super_trylock_shared fs/super.c:563 [inline]
#1: ffff88803639a0e0 (&type->s_umount_key#51){.+.+}-{4:4}, at: super_cache_scan+0x91/0x4b0 fs/super.c:197
stack backtrace:
CPU: 0 UID: 0 PID: 79 Comm: kswapd0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043
check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0x117/0x340 kernel/locking/lockdep.c:5868
down_read_nested+0x49/0x2e0 kernel/locking/rwsem.c:1662
xfs_can_free_eofblocks+0x693/0x8e0 fs/xfs/xfs_bmap_util.c:562
xfs_inode_mark_reclaimable+0x21d/0x1030 fs/xfs/xfs_icache.c:2244
destroy_inode fs/inode.c:396 [inline]
evict+0x8aa/0xae0 fs/inode.c:861
dispose_list fs/inode.c:879 [inline]
prune_icache_sb+0x21b/0x2c0 fs/inode.c:1027
super_cache_scan+0x39b/0x4b0 fs/super.c:224
do_shrink_slab+0x6df/0x10d0 mm/shrinker.c:437
shrink_slab_memcg mm/shrinker.c:550 [inline]
shrink_slab+0x7ef/0x10d0 mm/shrinker.c:628
shrink_one+0x2d9/0x720 mm/vmscan.c:4919
shrink_many mm/vmscan.c:4980 [inline]
lru_gen_shrink_node mm/vmscan.c:5058 [inline]
shrink_node+0x2f7d/0x35b0 mm/vmscan.c:6045
kswapd_shrink_node mm/vmscan.c:6899 [inline]
balance_pgdat mm/vmscan.c:7082 [inline]
kswapd+0x145a/0x2820 mm/vmscan.c:7352
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
</TASK>
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
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