[v6.1] KASAN: use-after-free Read in release_metapage (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cd9b81672742 Linux 6.1.161
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14007d22580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b1adc0bfde2d8a4a
dashboard link: https://syzkaller.appspot.com/bug?extid=6bc485fffddbab44f2f3
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d21df4411014/disk-cd9b8167.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/246aed0358fb/vmlinux-cd9b8167.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a6f546504ec2/Image-cd9b8167.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6bc485...@syzkaller.appspotmail.com

bn = 0, index = 0
bn = 72c, index = 96
bn = 0, index = 0
bn = 0, index = 0
==================================================================
BUG: KASAN: use-after-free in drop_metapage fs/jfs/jfs_metapage.c:223 [inline]
BUG: KASAN: use-after-free in release_metapage+0x718/0xc6c fs/jfs/jfs_metapage.c:757
Read of size 8 at addr ffff0000f15cabc8 by task syz.3.15/4529

CPU: 0 PID: 4529 Comm: syz.3.15 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Call trace:
dump_backtrace+0x1c0/0x1ec arch/arm64/kernel/stacktrace.c:158
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
__dump_stack+0x30/0x40 lib/dump_stack.c:88
dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
print_address_description+0x88/0x218 mm/kasan/report.c:316
print_report+0x50/0x68 mm/kasan/report.c:420
kasan_report+0xa8/0xfc mm/kasan/report.c:524
__asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351
drop_metapage fs/jfs/jfs_metapage.c:223 [inline]
release_metapage+0x718/0xc6c fs/jfs/jfs_metapage.c:757
dtSearch+0x169c/0x1b18 fs/jfs/jfs_dtree.c:793
jfs_symlink+0x64c/0xdb0 fs/jfs/namei.c:1016
vfs_symlink+0x238/0x3b0 fs/namei.c:4479
do_symlinkat+0x178/0x35c fs/namei.c:4508
__do_sys_symlinkat fs/namei.c:4525 [inline]
__se_sys_symlinkat fs/namei.c:4522 [inline]
__arm64_sys_symlinkat+0xa4/0xbc fs/namei.c:4522
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Allocated by task 4529:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
__kasan_slab_alloc+0x70/0x88 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x74/0x430 mm/slab.h:737
slab_alloc_node mm/slub.c:3359 [inline]
slab_alloc mm/slub.c:3367 [inline]
__kmem_cache_alloc_lru mm/slub.c:3374 [inline]
kmem_cache_alloc+0x22c/0x308 mm/slub.c:3383
mempool_alloc_slab+0x58/0x74 mm/mempool.c:532
mempool_alloc+0x150/0x3fc mm/mempool.c:412
alloc_metapage fs/jfs/jfs_metapage.c:176 [inline]
__get_metapage+0x5c4/0xfac fs/jfs/jfs_metapage.c:651
dtSplitRoot+0x178/0x1174 fs/jfs/jfs_dtree.c:1910
dtSplitUp fs/jfs/jfs_dtree.c:993 [inline]
dtInsert+0xb44/0x5720 fs/jfs/jfs_dtree.c:871
jfs_create+0x5e4/0x920 fs/jfs/namei.c:137
lookup_open fs/namei.c:3490 [inline]
open_last_lookups fs/namei.c:3558 [inline]
path_openat+0xe18/0x26bc fs/namei.c:3788
do_filp_open+0x194/0x384 fs/namei.c:3818
do_sys_openat2+0x134/0x3f4 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__arm64_sys_openat+0x118/0x14c fs/open.c:1347
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Freed by task 4544:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516
____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237
__kasan_slab_free+0x18/0x28 mm/kasan/common.c:245
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1729 [inline]
slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755
slab_free mm/slub.c:3687 [inline]
kmem_cache_free+0x118/0x314 mm/slub.c:3709
mempool_free_slab+0x28/0x38 mm/mempool.c:539
mempool_free+0xbc/0x2e0 mm/mempool.c:521
free_metapage fs/jfs/jfs_metapage.c:191 [inline]
metapage_release_folio+0x44c/0x5b4 fs/jfs/jfs_metapage.c:551
metapage_invalidate_folio+0x140/0x1d8 fs/jfs/jfs_metapage.c:563
folio_invalidate mm/truncate.c:158 [inline]
truncate_cleanup_folio+0x1b4/0x32c mm/truncate.c:178
truncate_inode_folio mm/truncate.c:194 [inline]
truncate_inode_pages_range+0x8c8/0xd68 mm/truncate.c:450
truncate_inode_pages+0x2c/0x3c mm/truncate.c:476
jfs_remount+0x284/0x490 fs/jfs/super.c:451
legacy_reconfigure+0xf8/0x110 fs/fs_context.c:655
reconfigure_super+0x1d4/0x79c fs/super.c:977
do_remount fs/namespace.c:2741 [inline]
path_mount+0xbdc/0xe80 fs/namespace.c:3400
do_mount fs/namespace.c:3421 [inline]
__do_sys_mount fs/namespace.c:3629 [inline]
__se_sys_mount fs/namespace.c:3606 [inline]
__arm64_sys_mount+0x49c/0x59c fs/namespace.c:3606
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the object at ffff0000f15caba0
which belongs to the cache jfs_mp of size 184
The buggy address is located 40 bytes inside of
184-byte region [ffff0000f15caba0, ffff0000f15cac58)

The buggy address belongs to the physical page:
page:000000006d2d582a refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1315ca
flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000200 0000000000000000 dead000000000122 ffff0000c4bb1980
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000f15caa80: fc fc fc fc fc 00 00 00 00 00 00 00 00 00 00 00
ffff0000f15cab00: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
>ffff0000f15cab80: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb
^
ffff0000f15cac00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
ffff0000f15cac80: fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


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