[v5.15] KASAN: use-after-free Read in lockref_put_or_lock

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f7347f400572 Linux 5.15.180
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14e1b568580000
kernel config: https://syzkaller.appspot.com/x/.config?x=346c19688de58d89
dashboard link: https://syzkaller.appspot.com/bug?extid=d601919f47cdae876037
compiler: Debian clang version 15.0.6, Debian LLD 15.0.6

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2685682aa24a/disk-f7347f40.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f01e2fad1237/vmlinux-f7347f40.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cbcd92b62b9a/bzImage-f7347f40.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d60191...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x74/0x1ff0 kernel/locking/lockdep.c:4882
Read of size 8 at addr ffff888061a02048 by task syz.4.101/4574

CPU: 0 PID: 4574 Comm: syz.4.101 Not tainted 5.15.180-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
print_address_description+0x63/0x3b0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0x16b/0x1c0 mm/kasan/report.c:451
__lock_acquire+0x74/0x1ff0 kernel/locking/lockdep.c:4882
lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:363 [inline]
lockref_put_or_lock+0x22/0xb0 lib/lockref.c:173
qd_put fs/gfs2/quota.c:309 [inline]
gfs2_set_dqblk+0x47e/0xd00 fs/gfs2/quota.c:1780
quota_setquota+0x6d3/0x840 fs/quota/quota.c:309
__do_sys_quotactl fs/quota/quota.c:959 [inline]
__se_sys_quotactl+0x2b1/0x770 fs/quota/quota.c:915
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0x80 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6121128169
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f611ef6f038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007f6121350080 RCX: 00007f6121128169
RDX: 0000000000000000 RSI: 0000200000001a80 RDI: ffffffff80000801
RBP: 00007f61211aaa68 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000006140 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f6121350080 R15: 00007ffe0f88c3a8
</TASK>

Allocated by task 4525:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
__kasan_slab_alloc+0x8e/0xc0 mm/kasan/common.c:467
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x53/0x380 mm/slab.h:519
slab_alloc_node mm/slub.c:3220 [inline]
slab_alloc mm/slub.c:3228 [inline]
kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233
kmem_cache_zalloc include/linux/slab.h:725 [inline]
qd_alloc+0x51/0x250 fs/gfs2/quota.c:216
gfs2_quota_init+0x7ea/0x1110 fs/gfs2/quota.c:1426
gfs2_make_fs_rw+0x436/0x5b0 fs/gfs2/super.c:155
gfs2_fill_super+0x23e8/0x2750 fs/gfs2/ops_fstype.c:1276
get_tree_bdev+0x3fe/0x620 fs/super.c:1325
gfs2_get_tree+0x50/0x210 fs/gfs2/ops_fstype.c:1332
vfs_get_tree+0x88/0x270 fs/super.c:1530
do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
do_mount fs/namespace.c:3355 [inline]
__do_sys_mount fs/namespace.c:3563 [inline]
__se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0x80 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 14:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x80 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1705 [inline]
slab_free_freelist_hook+0xdd/0x160 mm/slub.c:1731
slab_free mm/slub.c:3499 [inline]
kmem_cache_free+0x91/0x1f0 mm/slub.c:3515
rcu_do_batch kernel/rcu/tree.c:2523 [inline]
rcu_core+0xa15/0x1650 kernel/rcu/tree.c:2763
handle_softirqs+0x3a7/0x930 kernel/softirq.c:558
run_ksoftirqd+0xc6/0x120 kernel/softirq.c:925
smpboot_thread_fn+0x51b/0x9d0 kernel/smpboot.c:164
kthread+0x3f6/0x4f0 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Last potentially related work creation:
kasan_save_stack+0x36/0x60 mm/kasan/common.c:38
kasan_record_aux_stack+0xba/0x100 mm/kasan/generic.c:348
__call_rcu kernel/rcu/tree.c:3007 [inline]
call_rcu+0x1c4/0xa70 kernel/rcu/tree.c:3087
gfs2_quota_cleanup+0x43e/0x6a0 fs/gfs2/quota.c:1490
gfs2_make_fs_ro+0x4ad/0x5f0 fs/gfs2/super.c:557
signal_our_withdraw fs/gfs2/util.c:166 [inline]
gfs2_withdraw+0x5fb/0x14e0 fs/gfs2/util.c:343
gfs2_dirent_scan+0x512/0x640 fs/gfs2/dir.c:602
gfs2_dirent_search+0x30a/0x8c0 fs/gfs2/dir.c:850
gfs2_dir_search+0xae/0x2f0 fs/gfs2/dir.c:1651
gfs2_lookupi+0x45b/0x5e0 fs/gfs2/inode.c:332
__gfs2_lookup+0xa0/0x270 fs/gfs2/inode.c:873
gfs2_atomic_open+0x9a/0x220 fs/gfs2/inode.c:1277
atomic_open fs/namei.c:3325 [inline]
lookup_open fs/namei.c:3433 [inline]
open_last_lookups fs/namei.c:3532 [inline]
path_openat+0xf75/0x2f20 fs/namei.c:3739
do_filp_open+0x21c/0x460 fs/namei.c:3769
do_sys_openat2+0x13b/0x4f0 fs/open.c:1253
do_sys_open fs/open.c:1269 [inline]
__do_sys_openat fs/open.c:1285 [inline]
__se_sys_openat fs/open.c:1280 [inline]
__x64_sys_openat+0x243/0x290 fs/open.c:1280
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0x80 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff888061a02000
which belongs to the cache gfs2_quotad of size 272
The buggy address is located 72 bytes inside of
272-byte region [ffff888061a02000, ffff888061a02110)
The buggy address belongs to the page:
page:ffffea0001868080 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x61a02
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 dead000000000122 ffff88801ec6fb40
raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Reclaimable, gfp_mask 0x112c50(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 4525, ts 68671521239, free_ts 64259917923
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x3b78/0x3d40 mm/page_alloc.c:4192
__alloc_pages+0x272/0x700 mm/page_alloc.c:5466
alloc_slab_page mm/slub.c:1775 [inline]
allocate_slab mm/slub.c:1912 [inline]
new_slab+0xbb/0x4b0 mm/slub.c:1975
___slab_alloc+0x6f6/0xe10 mm/slub.c:3008
__slab_alloc mm/slub.c:3095 [inline]
slab_alloc_node mm/slub.c:3186 [inline]
slab_alloc mm/slub.c:3228 [inline]
kmem_cache_alloc+0x18e/0x280 mm/slub.c:3233
kmem_cache_zalloc include/linux/slab.h:725 [inline]
qd_alloc+0x51/0x250 fs/gfs2/quota.c:216
gfs2_quota_init+0x7ea/0x1110 fs/gfs2/quota.c:1426
gfs2_make_fs_rw+0x436/0x5b0 fs/gfs2/super.c:155
gfs2_fill_super+0x23e8/0x2750 fs/gfs2/ops_fstype.c:1276
get_tree_bdev+0x3fe/0x620 fs/super.c:1325
gfs2_get_tree+0x50/0x210 fs/gfs2/ops_fstype.c:1332
vfs_get_tree+0x88/0x270 fs/super.c:1530
do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
do_mount fs/namespace.c:3355 [inline]
__do_sys_mount fs/namespace.c:3563 [inline]
__se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0x80 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1340 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0xc34/0xcf0 mm/page_alloc.c:3317
free_unref_page+0x95/0x2d0 mm/page_alloc.c:3396
free_slab mm/slub.c:2015 [inline]
discard_slab mm/slub.c:2021 [inline]
__unfreeze_partials+0x1b7/0x210 mm/slub.c:2507
put_cpu_partial+0x132/0x1a0 mm/slub.c:2587
do_slab_free mm/slub.c:3487 [inline]
___cache_free+0xe3/0x100 mm/slub.c:3506
qlist_free_all+0x36/0x90 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x162/0x180 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x2f/0xc0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x53/0x380 mm/slab.h:519
slab_alloc_node mm/slub.c:3220 [inline]
slab_alloc mm/slub.c:3228 [inline]
kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233
getname_flags+0xb8/0x4e0 fs/namei.c:138
user_path_at_empty+0x2a/0x180 fs/namei.c:2882
user_path_at include/linux/namei.h:57 [inline]
vfs_statx+0x106/0x3b0 fs/stat.c:221
vfs_fstatat fs/stat.c:243 [inline]
__do_sys_newfstatat fs/stat.c:411 [inline]
__se_sys_newfstatat fs/stat.c:405 [inline]
__x64_sys_newfstatat+0x12c/0x1b0 fs/stat.c:405
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0x80 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
ffff888061a01f00: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
ffff888061a01f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888061a02000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888061a02080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888061a02100: fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.