[v5.15] KASAN: use-after-free Write in gfs2_qd_shrink_scan

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 284087d4f7d5 Linux 5.15.158
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14c04338980000
kernel config: https://syzkaller.appspot.com/x/.config?x=b0dd54e4b5171ebc
dashboard link: https://syzkaller.appspot.com/bug?extid=00ceb73a2aae5696f09d
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/c2e33c1db6bf/disk-284087d4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d9f77284af1d/vmlinux-284087d4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a600323dd149/bzImage-284087d4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+00ceb7...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
BUG: KASAN: use-after-free in atomic_dec include/linux/atomic/atomic-instrumented.h:244 [inline]
BUG: KASAN: use-after-free in gfs2_qd_dispose fs/gfs2/quota.c:137 [inline]
BUG: KASAN: use-after-free in gfs2_qd_shrink_scan+0x63d/0x860 fs/gfs2/quota.c:175
Write of size 4 at addr ffff888074104a70 by task syz-executor.4/7265

CPU: 1 PID: 7265 Comm: syz-executor.4 Not tainted 5.15.158-syzkaller #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+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
kasan_check_range+0x27e/0x290 mm/kasan/generic.c:189
instrument_atomic_read_write include/linux/instrumented.h:101 [inline]
atomic_dec include/linux/atomic/atomic-instrumented.h:244 [inline]
gfs2_qd_dispose fs/gfs2/quota.c:137 [inline]
gfs2_qd_shrink_scan+0x63d/0x860 fs/gfs2/quota.c:175
do_shrink_slab+0x542/0xda0 mm/vmscan.c:758
shrink_slab+0x233/0x960 mm/vmscan.c:918
drop_slab_node+0xed/0x180 mm/vmscan.c:953
drop_slab+0x8b/0x120 mm/vmscan.c:963
drop_caches_sysctl_handler+0xb3/0x160 fs/drop_caches.c:66
proc_sys_call_handler+0x541/0x8a0 fs/proc/proc_sysctl.c:587
do_iter_readv_writev+0x594/0x7a0
do_iter_write+0x1ea/0x760 fs/read_write.c:855
vfs_writev fs/read_write.c:928 [inline]
do_writev+0x281/0x470 fs/read_write.c:971
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f678fde4ca9
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:00007f678e3570c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f678ff12f80 RCX: 00007f678fde4ca9
RDX: 0000000000000001 RSI: 00000000200000c0 RDI: 0000000000000005
RBP: 00007f678fe3047e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f678ff12f80 R15: 00007ffd4a4cbe18
</TASK>

Allocated by task 7202:
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_kmalloc+0xba/0xf0 mm/kasan/common.c:513
kasan_kmalloc include/linux/kasan.h:264 [inline]
kmem_cache_alloc_trace+0x143/0x290 mm/slub.c:3247
kmalloc include/linux/slab.h:591 [inline]
kzalloc include/linux/slab.h:721 [inline]
init_sbd fs/gfs2/ops_fstype.c:77 [inline]
gfs2_fill_super+0x15a/0x2750 fs/gfs2/ops_fstype.c:1151
get_tree_bdev+0x3fe/0x620 fs/super.c:1312
gfs2_get_tree+0x50/0x210 fs/gfs2/ops_fstype.c:1332
vfs_get_tree+0x88/0x270 fs/super.c:1517
do_new_mount+0x2ba/0xb40 fs/namespace.c:3005
do_mount fs/namespace.c:3348 [inline]
__do_sys_mount fs/namespace.c:3556 [inline]
__se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3533
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 5926:
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]
kfree+0xf1/0x270 mm/slub.c:4559
generic_shutdown_super+0x136/0x2c0 fs/super.c:475
kill_block_super+0x7a/0xe0 fs/super.c:1414
deactivate_locked_super+0xa0/0x110 fs/super.c:335
cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
task_work_run+0x129/0x1a0 kernel/task_work.c:164
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff888074104000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2672 bytes inside of
8192-byte region [ffff888074104000, ffff888074106000)
The buggy address belongs to the page:
page:ffffea0001d04000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x74100
head:ffffea0001d04000 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888011c42280
raw: 0000000000000000 0000000080020002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 7225, ts 201567891525, free_ts 201532372375
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x322a/0x33c0 mm/page_alloc.c:4159
__alloc_pages+0x272/0x700 mm/page_alloc.c:5423
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_trace+0x1a0/0x290 mm/slub.c:3245
kmalloc include/linux/slab.h:591 [inline]
kzalloc include/linux/slab.h:721 [inline]
bpf_check+0x16a/0x12d00 kernel/bpf/verifier.c:14000
bpf_prog_load+0x12b3/0x1b60 kernel/bpf/syscall.c:2353
__sys_bpf+0x343/0x670 kernel/bpf/syscall.c:4651
__do_sys_bpf kernel/bpf/syscall.c:4755 [inline]
__se_sys_bpf kernel/bpf/syscall.c:4753 [inline]
__x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:4753
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 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
getname fs/namei.c:217 [inline]
__do_sys_symlinkat fs/namei.c:4475 [inline]
__se_sys_symlinkat fs/namei.c:4472 [inline]
__x64_sys_symlinkat+0x78/0xa0 fs/namei.c:4472
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

Memory state around the buggy address:
ffff888074104900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888074104980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888074104a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888074104a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888074104b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


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