[syzbot] [xfs?] possible deadlock in xfs_fs_dirty_inode

syzbot
2024-04-26T05:15:29Z

Hello,

syzbot found the following issue on:

HEAD commit: 3b68086599f8 Merge tag 'sched_urgent_for_v6.9_rc5' of git:..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=158206bb180000
kernel config: https://syzkaller.appspot.com/x/.config?x=f47e5e015c177e57
dashboard link: https://syzkaller.appspot.com/bug?extid=1619d847a7b9ba3a9137
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/caa90b55d476/disk-3b680865.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/17940f1c5e8f/vmlinux-3b680865.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b03bd6929a1c/bzImage-3b680865.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1619d847a7b9ba3a9137@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc4-syzkaller-00274-g3b68086599f8 #0 Not tainted
------------------------------------------------------
kswapd0/81 is trying to acquire lock:
ffff8881a895a610 (sb_internal#3){.+.+}-{0:0}, at: xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:689

but task is already holding lock:
ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6782 [inline]
ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb20/0x30c0 mm/vmscan.c:7164

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (fs_reclaim){+.+.}-{0:0}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
__fs_reclaim_acquire mm/page_alloc.c:3698 [inline]
fs_reclaim_acquire+0x88/0x140 mm/page_alloc.c:3712
might_alloc include/linux/sched/mm.h:312 [inline]
slab_pre_alloc_hook mm/slub.c:3746 [inline]
slab_alloc_node mm/slub.c:3827 [inline]
kmalloc_trace+0x47/0x360 mm/slub.c:3992
kmalloc include/linux/slab.h:628 [inline]
add_stack_record_to_list mm/page_owner.c:177 [inline]
inc_stack_record_count mm/page_owner.c:219 [inline]
__set_page_owner+0x561/0x810 mm/page_owner.c:334
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1534
prep_new_page mm/page_alloc.c:1541 [inline]
get_page_from_freelist+0x3410/0x35b0 mm/page_alloc.c:3317
__alloc_pages+0x256/0x6c0 mm/page_alloc.c:4575
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page+0x5f/0x160 mm/slub.c:2175
allocate_slab mm/slub.c:2338 [inline]
new_slab+0x84/0x2f0 mm/slub.c:2391
___slab_alloc+0xc73/0x1260 mm/slub.c:3525
__slab_alloc mm/slub.c:3610 [inline]
__slab_alloc_node mm/slub.c:3663 [inline]
slab_alloc_node mm/slub.c:3835 [inline]
kmem_cache_alloc+0x252/0x340 mm/slub.c:3852
kmem_cache_zalloc include/linux/slab.h:739 [inline]
xfs_btree_alloc_cursor fs/xfs/libxfs/xfs_btree.h:679 [inline]
xfs_refcountbt_init_cursor+0x65/0x2a0 fs/xfs/libxfs/xfs_refcount_btree.c:367
xfs_reflink_find_shared fs/xfs/xfs_reflink.c:147 [inline]
xfs_reflink_trim_around_shared+0x53a/0x9d0 fs/xfs/xfs_reflink.c:194
xfs_buffered_write_iomap_begin+0xebf/0x1b40 fs/xfs/xfs_iomap.c:1062
iomap_iter+0x691/0xf60 fs/iomap/iter.c:91
iomap_file_unshare+0x17a/0x710 fs/iomap/buffered-io.c:1364
xfs_reflink_unshare+0x173/0x5f0 fs/xfs/xfs_reflink.c:1710
xfs_file_fallocate+0x87c/0xd00 fs/xfs/xfs_file.c:1082
vfs_fallocate+0x564/0x6c0 fs/open.c:330
ksys_fallocate fs/open.c:353 [inline]
__do_sys_fallocate fs/open.c:361 [inline]
__se_sys_fallocate fs/open.c:359 [inline]
__x64_sys_fallocate+0xbd/0x110 fs/open.c:359
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&xfs_nondir_ilock_class#3){++++}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
down_write_nested+0x3d/0x50 kernel/locking/rwsem.c:1695
xfs_dquot_disk_alloc+0x399/0xe50 fs/xfs/xfs_dquot.c:332
xfs_qm_dqread+0x1a3/0x650 fs/xfs/xfs_dquot.c:693
xfs_qm_dqget+0x2bb/0x6f0 fs/xfs/xfs_dquot.c:905
xfs_qm_quotacheck_dqadjust+0xea/0x5a0 fs/xfs/xfs_qm.c:1096
xfs_qm_dqusage_adjust+0x4db/0x6f0 fs/xfs/xfs_qm.c:1215
xfs_iwalk_ag_recs+0x4e0/0x860 fs/xfs/xfs_iwalk.c:213
xfs_iwalk_run_callbacks+0x218/0x470 fs/xfs/xfs_iwalk.c:372
xfs_iwalk_ag+0xa39/0xb50 fs/xfs/xfs_iwalk.c:478
xfs_iwalk_ag_work+0xfb/0x1b0 fs/xfs/xfs_iwalk.c:620
xfs_pwork_work+0x7f/0x190 fs/xfs/xfs_pwork.c:47
process_one_work kernel/workqueue.c:3254 [inline]
process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3335
worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (sb_internal#3){.+.+}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1664 [inline]
sb_start_intwrite include/linux/fs.h:1847 [inline]
xfs_trans_alloc+0xe5/0x830 fs/xfs/xfs_trans.c:264
xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:689
__mark_inode_dirty+0x325/0xe20 fs/fs-writeback.c:2477
mark_inode_dirty_sync include/linux/fs.h:2410 [inline]
iput+0x1fe/0x930 fs/inode.c:1764
__dentry_kill+0x20d/0x630 fs/dcache.c:603
shrink_kill+0xa9/0x2c0 fs/dcache.c:1048
shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1075
prune_dcache_sb+0x10f/0x180 fs/dcache.c:1156
super_cache_scan+0x34f/0x4b0 fs/super.c:221
do_shrink_slab+0x705/0x1160 mm/shrinker.c:435
shrink_slab_memcg mm/shrinker.c:548 [inline]
shrink_slab+0x883/0x14d0 mm/shrinker.c:626
shrink_node_memcgs mm/vmscan.c:5875 [inline]
shrink_node+0x11f5/0x2d60 mm/vmscan.c:5908
kswapd_shrink_node mm/vmscan.c:6704 [inline]
balance_pgdat mm/vmscan.c:6895 [inline]
kswapd+0x1a25/0x30c0 mm/vmscan.c:7164
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

Chain exists of:
sb_internal#3 --> &xfs_nondir_ilock_class#3 --> fs_reclaim

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(fs_reclaim);
lock(&xfs_nondir_ilock_class#3);
lock(fs_reclaim);
rlock(sb_internal#3);

*** DEADLOCK ***

2 locks held by kswapd0/81:
#0: ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat mm/vmscan.c:6782 [inline]
#0: ffffffff8e428e80 (fs_reclaim){+.+.}-{0:0}, at: kswapd+0xb20/0x30c0 mm/vmscan.c:7164
#1: ffff8881a895a0e0 (&type->s_umount_key#65){++++}-{3:3}, at: super_trylock_shared fs/super.c:561 [inline]
#1: ffff8881a895a0e0 (&type->s_umount_key#65){++++}-{3:3}, at: super_cache_scan+0x94/0x4b0 fs/super.c:196

stack backtrace:
CPU: 1 PID: 81 Comm: kswapd0 Not tainted 6.9.0-rc4-syzkaller-00274-g3b68086599f8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869
__lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1664 [inline]
sb_start_intwrite include/linux/fs.h:1847 [inline]
xfs_trans_alloc+0xe5/0x830 fs/xfs/xfs_trans.c:264
xfs_fs_dirty_inode+0x158/0x250 fs/xfs/xfs_super.c:689
__mark_inode_dirty+0x325/0xe20 fs/fs-writeback.c:2477
mark_inode_dirty_sync include/linux/fs.h:2410 [inline]
iput+0x1fe/0x930 fs/inode.c:1764
__dentry_kill+0x20d/0x630 fs/dcache.c:603
shrink_kill+0xa9/0x2c0 fs/dcache.c:1048
shrink_dentry_list+0x2c0/0x5b0 fs/dcache.c:1075
prune_dcache_sb+0x10f/0x180 fs/dcache.c:1156
super_cache_scan+0x34f/0x4b0 fs/super.c:221
do_shrink_slab+0x705/0x1160 mm/shrinker.c:435
shrink_slab_memcg mm/shrinker.c:548 [inline]
shrink_slab+0x883/0x14d0 mm/shrinker.c:626
shrink_node_memcgs mm/vmscan.c:5875 [inline]
shrink_node+0x11f5/0x2d60 mm/vmscan.c:5908
kswapd_shrink_node mm/vmscan.c:6704 [inline]
balance_pgdat mm/vmscan.c:6895 [inline]
kswapd+0x1a25/0x30c0 mm/vmscan.c:7164
kthread+0x2f0/0x390 kernel/kthread.c:388
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
NILFS (loop4): discard dirty page: offset=98304, ino=3
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty block: blocknr=0, size=1024
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty page: offset=0, ino=12
NILFS (loop4): discard dirty block: blocknr=17, size=1024
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty page: offset=0, ino=3
NILFS (loop4): discard dirty block: blocknr=42, size=1024
NILFS (loop4): discard dirty block: blocknr=43, size=1024
NILFS (loop4): discard dirty block: blocknr=44, size=1024
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty page: offset=4096, ino=6
NILFS (loop4): discard dirty block: blocknr=39, size=1024
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty page: offset=196608, ino=3
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024
NILFS (loop4): discard dirty block: blocknr=49, size=1024
NILFS (loop4): discard dirty block: blocknr=18446744073709551615, size=1024

---
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