[v6.1] KASAN: use-after-free Read in ocfs2_fault

Hello,

syzbot found the following issue on:

HEAD commit: da3c5173c55f Linux 6.1.140
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11050ff4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2bfe5a2f04bb30e3
dashboard link: https://syzkaller.appspot.com/bug?extid=80b869690c5c1d5c9e95
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
userspace arch: arm64

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2c3ee4de68a1/disk-da3c5173.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/19742d73f52b/vmlinux-da3c5173.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0ffdd39d32ee/Image-da3c5173.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

==================================================================
BUG: KASAN: use-after-free in ocfs2_fault+0xc8/0x4a4 fs/ocfs2/mmap.c:41
Read of size 8 at addr ffff0000ce1ab070 by task syz.4.14/4433

CPU: 0 PID: 4433 Comm: syz.4.14 Not tainted 6.1.140-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call trace:
dump_backtrace+0x1c8/0x1f4 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+0xf8/0x160 lib/dump_stack.c:106
print_address_description+0x88/0x220 mm/kasan/report.c:316
print_report+0x50/0x68 mm/kasan/report.c:427
kasan_report+0xa8/0x100 mm/kasan/report.c:531
__asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351
ocfs2_fault+0xc8/0x4a4 fs/ocfs2/mmap.c:41
__do_fault+0x11c/0x3d8 mm/memory.c:4280
do_read_fault mm/memory.c:4631 [inline]
do_fault mm/memory.c:4760 [inline]
handle_pte_fault mm/memory.c:5031 [inline]
__handle_mm_fault mm/memory.c:5173 [inline]
handle_mm_fault+0x1ac0/0x2fd4 mm/memory.c:5294
__do_page_fault arch/arm64/mm/fault.c:499 [inline]
do_page_fault+0x310/0x99c arch/arm64/mm/fault.c:583
do_translation_fault+0x94/0xc8 arch/arm64/mm/fault.c:667
do_mem_abort+0x70/0x194 arch/arm64/mm/fault.c:803
el1_abort+0x3c/0x5c arch/arm64/kernel/entry-common.c:367
el1h_64_sync_handler+0x80/0xcc arch/arm64/kernel/entry-common.c:427
el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:580
fault_in_readable+0x2c8/0x3e0 mm/gup.c:1915
fault_in_iov_iter_readable+0xc0/0x2c4 lib/iov_iter.c:356
generic_perform_write+0x35c/0x4b0 mm/filemap.c:3836
__generic_file_write_iter+0x168/0x37c mm/filemap.c:3974
ocfs2_file_write_iter+0x1300/0x1bf4 fs/ocfs2/file.c:2469
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x5ac/0x7c4 fs/read_write.c:584
ksys_write+0x120/0x210 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 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 4457:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:52
kasan_save_alloc_info+0x28/0x34 mm/kasan/generic.c:505
__kasan_slab_alloc+0x70/0x88 mm/kasan/common.c:328
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook+0x74/0x43c mm/slab.h:737
slab_alloc_node mm/slub.c:3398 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc+0x234/0x318 mm/slub.c:3422
vm_area_alloc+0x2c/0xe0 kernel/fork.c:459
__mmap_region mm/mmap.c:2741 [inline]
mmap_region+0xb64/0x1860 mm/mmap.c:2904
do_mmap+0x978/0x10dc mm/mmap.c:1424
vm_mmap_pgoff+0x184/0x284 mm/util.c:520
ksys_mmap_pgoff+0x3b8/0x5a0 mm/mmap.c:1470
__do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
__se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
__arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 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 4461:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:52
kasan_save_free_info+0x3c/0x60 mm/kasan/generic.c:516
____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:236
__kasan_slab_free+0x18/0x28 mm/kasan/common.c:244
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1724 [inline]
slab_free_freelist_hook+0x16c/0x1ec mm/slub.c:1750
slab_free mm/slub.c:3661 [inline]
kmem_cache_free+0x11c/0x324 mm/slub.c:3683
vm_area_free+0x58/0x12c kernel/fork.c:486
remove_vma mm/mmap.c:143 [inline]
remove_mt mm/mmap.c:2307 [inline]
do_mas_align_munmap+0xc1c/0xeec mm/mmap.c:2583
do_mas_munmap mm/mmap.c:2638 [inline]
__mmap_region mm/mmap.c:2686 [inline]
mmap_region+0x64c/0x1860 mm/mmap.c:2904
do_mmap+0x978/0x10dc mm/mmap.c:1424
vm_mmap_pgoff+0x184/0x284 mm/util.c:520
ksys_mmap_pgoff+0x3b8/0x5a0 mm/mmap.c:1470
__do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
__se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
__arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 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 ffff0000ce1ab000
which belongs to the cache vm_area_struct of size 152
The buggy address is located 112 bytes inside of
152-byte region [ffff0000ce1ab000, ffff0000ce1ab098)

The buggy address belongs to the physical page:
page:000000003cd2817d refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff0000ce1ab0d8 pfn:0x10e1ab
memcg:ffff0000d5541401
flags: 0x5ffc00000000200(slab|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000000200 fffffc000360c148 fffffc0003753ac8 ffff0000c0851680
raw: ffff0000ce1ab0d8 0000000000120007 00000001ffffffff ffff0000d5541401
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000ce1aaf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff0000ce1aaf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff0000ce1ab000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff0000ce1ab080: fb fb fb fc fc fc fc fc fc fc fc fb fb fb fb fb
ffff0000ce1ab100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
==================================================================


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