[syzbot] [xfs?] possible deadlock in xfs_ilock_data_map_shared

From: syzbot
Date: Thu Apr 25 2024 - 10:46:44 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 977b1ef51866 Merge tag 'block-6.9-20240420' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=126497cd180000
kernel config: https://syzkaller.appspot.com/x/.config?x=d239903bd07761e5
dashboard link: https://syzkaller.appspot.com/bug?extid=b7e8d799f0ab724876f9
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/08d7b6e107aa/disk-977b1ef5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9c5e543ffdcf/vmlinux-977b1ef5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/04a6d79d2f69/bzImage-977b1ef5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b7e8d799f0ab724876f9@xxxxxxxxxxxxxxxxxxxxxxxxx

XFS (loop2): Ending clean mount
======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc4-syzkaller-00266-g977b1ef51866 #0 Not tainted
------------------------------------------------------
syz-executor.2/7915 is trying to acquire lock:
ffffffff8e42a800 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:312 [inline]
ffffffff8e42a800 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:3746 [inline]
ffffffff8e42a800 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:3827 [inline]
ffffffff8e42a800 (fs_reclaim){+.+.}-{0:0}, at: kmalloc_trace+0x47/0x360 mm/slub.c:3992

but task is already holding lock:
ffff888056da8118 (&xfs_dir_ilock_class){++++}-{3:3}, at: xfs_ilock_data_map_shared+0x4f/0x70 fs/xfs/xfs_inode.c:114

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&xfs_dir_ilock_class){++++}-{3:3}:
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
down_write_nested+0x3d/0x50 kernel/locking/rwsem.c:1695
xfs_reclaim_inode fs/xfs/xfs_icache.c:945 [inline]
xfs_icwalk_process_inode fs/xfs/xfs_icache.c:1631 [inline]
xfs_icwalk_ag+0x120e/0x1ad0 fs/xfs/xfs_icache.c:1713
xfs_icwalk fs/xfs/xfs_icache.c:1762 [inline]
xfs_reclaim_inodes_nr+0x257/0x360 fs/xfs/xfs_icache.c:1011
super_cache_scan+0x411/0x4b0 fs/super.c:227
do_shrink_slab+0x707/0x1160 mm/shrinker.c:435
shrink_slab+0x1092/0x14d0 mm/shrinker.c:662
shrink_one+0x453/0x880 mm/vmscan.c:4774
shrink_many mm/vmscan.c:4835 [inline]
lru_gen_shrink_node mm/vmscan.c:4935 [inline]
shrink_node+0x3b17/0x4310 mm/vmscan.c:5894
kswapd_shrink_node mm/vmscan.c:6704 [inline]
balance_pgdat mm/vmscan.c:6895 [inline]
kswapd+0x1882/0x38a0 mm/vmscan.c:7164
kthread+0x2f2/0x390 kernel/kthread.c:388
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 (fs_reclaim){+.+.}-{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
__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_bulk+0x729/0xd40 mm/page_alloc.c:4523
alloc_pages_bulk_array include/linux/gfp.h:202 [inline]
xfs_buf_alloc_pages+0x1a7/0x860 fs/xfs/xfs_buf.c:398
xfs_buf_find_insert+0x19a/0x1540 fs/xfs/xfs_buf.c:650
xfs_buf_get_map+0x149c/0x1ae0 fs/xfs/xfs_buf.c:755
xfs_buf_read_map+0x111/0xa60 fs/xfs/xfs_buf.c:860
xfs_trans_read_buf_map+0x260/0xad0 fs/xfs/xfs_trans_buf.c:289
xfs_da_read_buf+0x2b1/0x470 fs/xfs/libxfs/xfs_da_btree.c:2674
xfs_dir3_block_read+0x92/0x1a0 fs/xfs/libxfs/xfs_dir2_block.c:145
xfs_dir2_block_lookup_int+0x109/0x7d0 fs/xfs/libxfs/xfs_dir2_block.c:700
xfs_dir2_block_lookup+0x19a/0x630 fs/xfs/libxfs/xfs_dir2_block.c:650
xfs_dir_lookup+0x633/0xaf0 fs/xfs/libxfs/xfs_dir2.c:399
xfs_lookup+0x298/0x550 fs/xfs/xfs_inode.c:640
xfs_vn_lookup+0x192/0x290 fs/xfs/xfs_iops.c:303
lookup_open fs/namei.c:3475 [inline]
open_last_lookups fs/namei.c:3566 [inline]
path_openat+0x1035/0x3240 fs/namei.c:3796
do_filp_open+0x235/0x490 fs/namei.c:3826
do_sys_openat2+0x13e/0x1d0 fs/open.c:1406
do_sys_open fs/open.c:1421 [inline]
__do_sys_openat fs/open.c:1437 [inline]
__se_sys_openat fs/open.c:1432 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1432
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

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
rlock(&xfs_dir_ilock_class);
lock(fs_reclaim);
lock(&xfs_dir_ilock_class);
lock(fs_reclaim);

*** DEADLOCK ***

3 locks held by syz-executor.2/7915:
#0: ffff8881d0472420 (sb_writers#14){.+.+}-{0:0}, at: mnt_want_write+0x3f/0x90 fs/namespace.c:409
#1: ffff888056da8338 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{3:3}, at: inode_lock include/linux/fs.h:795 [inline]
#1: ffff888056da8338 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{3:3}, at: open_last_lookups fs/namei.c:3563 [inline]
#1: ffff888056da8338 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{3:3}, at: path_openat+0x7d3/0x3240 fs/namei.c:3796
#2: ffff888056da8118 (&xfs_dir_ilock_class){++++}-{3:3}, at: xfs_ilock_data_map_shared+0x4f/0x70 fs/xfs/xfs_inode.c:114

stack backtrace:
CPU: 1 PID: 7915 Comm: syz-executor.2 Not tainted 6.9.0-rc4-syzkaller-00266-g977b1ef51866 #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
__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_bulk+0x729/0xd40 mm/page_alloc.c:4523
alloc_pages_bulk_array include/linux/gfp.h:202 [inline]
xfs_buf_alloc_pages+0x1a7/0x860 fs/xfs/xfs_buf.c:398
xfs_buf_find_insert+0x19a/0x1540 fs/xfs/xfs_buf.c:650
xfs_buf_get_map+0x149c/0x1ae0 fs/xfs/xfs_buf.c:755
xfs_buf_read_map+0x111/0xa60 fs/xfs/xfs_buf.c:860
xfs_trans_read_buf_map+0x260/0xad0 fs/xfs/xfs_trans_buf.c:289
xfs_da_read_buf+0x2b1/0x470 fs/xfs/libxfs/xfs_da_btree.c:2674
xfs_dir3_block_read+0x92/0x1a0 fs/xfs/libxfs/xfs_dir2_block.c:145
xfs_dir2_block_lookup_int+0x109/0x7d0 fs/xfs/libxfs/xfs_dir2_block.c:700
xfs_dir2_block_lookup+0x19a/0x630 fs/xfs/libxfs/xfs_dir2_block.c:650
xfs_dir_lookup+0x633/0xaf0 fs/xfs/libxfs/xfs_dir2.c:399
xfs_lookup+0x298/0x550 fs/xfs/xfs_inode.c:640
xfs_vn_lookup+0x192/0x290 fs/xfs/xfs_iops.c:303
lookup_open fs/namei.c:3475 [inline]
open_last_lookups fs/namei.c:3566 [inline]
path_openat+0x1035/0x3240 fs/namei.c:3796
do_filp_open+0x235/0x490 fs/namei.c:3826
do_sys_openat2+0x13e/0x1d0 fs/open.c:1406
do_sys_open fs/open.c:1421 [inline]
__do_sys_openat fs/open.c:1437 [inline]
__se_sys_openat fs/open.c:1432 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1432
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
RIP: 0033:0x7f23c887dea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f23c95950c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f23c89abf80 RCX: 00007f23c887dea9
RDX: 000000000000275a RSI: 0000000020000080 RDI: ffffffffffffff9c
RBP: 00007f23c88ca4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f23c89abf80 R15: 00007fff62a26428
</TASK>

---
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Next message: Sean Christopherson: "Re: [PATCH 1/4] KVM: x86: Add a struct to consolidate host values, e.g. EFER, XCR0, etc..."
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Next in thread: Darrick J. Wong: "Re: [syzbot] [xfs?] possible deadlock in xfs_ilock_data_map_shared"
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