[v5.15] KASAN: use-after-free Read in ocfs2_claim_suballoc_bits

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0c935c049b5c Linux 5.15.179
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=128d23e4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=bcb6af887426ce59
dashboard link: https://syzkaller.appspot.com/bug?extid=7ee70fbe2ae94f89be13
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/75b060834e1e/disk-0c935c04.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d42b06ae465d/vmlinux-0c935c04.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d5217676cd35/bzImage-0c935c04.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7ee70f...@syzkaller.appspotmail.com

ocfs2: Slot 0 on device (7,2) was already allocated to this node!
ocfs2: Mounting device (7,2) on (node local, slot 0) with ordered data mode.
==================================================================
BUG: KASAN: use-after-free in ocfs2_find_victim_chain fs/ocfs2/suballoc.c:1391 [inline]
BUG: KASAN: use-after-free in ocfs2_claim_suballoc_bits+0xfb5/0x24b0 fs/ocfs2/suballoc.c:1927
Read of size 4 at addr ffff888069bc8000 by task syz.2.3157/6412

CPU: 0 PID: 6412 Comm: syz.2.3157 Not tainted 5.15.179-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
ocfs2_find_victim_chain fs/ocfs2/suballoc.c:1391 [inline]
ocfs2_claim_suballoc_bits+0xfb5/0x24b0 fs/ocfs2/suballoc.c:1927
__ocfs2_claim_clusters+0x327/0xa30 fs/ocfs2/suballoc.c:2338
ocfs2_local_alloc_new_window fs/ocfs2/localalloc.c:1170 [inline]
ocfs2_local_alloc_slide_window fs/ocfs2/localalloc.c:1299 [inline]
ocfs2_reserve_local_alloc_bits+0x1411/0x27a0 fs/ocfs2/localalloc.c:668
ocfs2_reserve_clusters_with_limit+0x1b4/0xb50 fs/ocfs2/suballoc.c:1162
ocfs2_mknod+0x1535/0x2cd0 fs/ocfs2/namei.c:354
ocfs2_mkdir+0x194/0x430 fs/ocfs2/namei.c:657
vfs_mkdir+0x3b6/0x590 fs/namei.c:4065
do_mkdirat+0x260/0x520 fs/namei.c:4090
__do_sys_mkdirat fs/namei.c:4105 [inline]
__se_sys_mkdirat fs/namei.c:4103 [inline]
__x64_sys_mkdirat+0x85/0x90 fs/namei.c:4103
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: 0033:0x7fbcaffae169
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:00007fbcade17038 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fbcb01c6fa0 RCX: 00007fbcaffae169
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: ffffffffffffff9c
RBP: 00007fbcb002f2a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fbcb01c6fa0 R15: 00007ffc9b472008
</TASK>

The buggy address belongs to the page:
page:ffffea0001a6f200 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x100 pfn:0x69bc8
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0000c42108 ffffea0001310e08 0000000000000000
raw: 0000000000000100 0000000000000002 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask 0x1100cca(GFP_HIGHUSER_MOVABLE), pid 30796, ts 908609926383, free_ts 911174992083
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_pages_vma+0x39a/0x800 mm/mempolicy.c:2146
shmem_alloc_page mm/shmem.c:1586 [inline]
shmem_alloc_and_acct_page+0x4d1/0xd10 mm/shmem.c:1611
shmem_getpage_gfp+0x17b1/0x3190 mm/shmem.c:1906
shmem_getpage mm/shmem.c:151 [inline]
shmem_write_begin+0xce/0x1a0 mm/shmem.c:2474
generic_perform_write+0x2bf/0x5b0 mm/filemap.c:3785
__generic_file_write_iter+0x243/0x4f0 mm/filemap.c:3912
generic_file_write_iter+0xa7/0x1b0 mm/filemap.c:3944
__kernel_write+0x5b1/0xa60 fs/read_write.c:539
__dump_emit+0x264/0x3a0 fs/coredump.c:875
dump_user_range+0x91/0x320 fs/coredump.c:949
elf_core_dump+0x3c7d/0x4570 fs/binfmt_elf.c:2285
do_coredump+0x1852/0x31e0 fs/coredump.c:826
get_signal+0xc06/0x14e0 kernel/signal.c:2886
arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867
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_list+0x1f7/0x8e0 mm/page_alloc.c:3433
release_pages+0x1bb9/0x1f40 mm/swap.c:963
__pagevec_release+0x80/0xf0 mm/swap.c:983
pagevec_release include/linux/pagevec.h:81 [inline]
shmem_undo_range+0x67a/0x1b50 mm/shmem.c:964
shmem_truncate_range mm/shmem.c:1063 [inline]
shmem_evict_inode+0x21b/0xa00 mm/shmem.c:1145
evict+0x529/0x930 fs/inode.c:647
__dentry_kill+0x436/0x650 fs/dcache.c:586
dentry_kill+0xbb/0x290 fs/dcache.c:-1
dput+0xd8/0x1a0 fs/dcache.c:893
__fput+0x636/0x8e0 fs/file_table.c:319
task_work_run+0x129/0x1a0 kernel/task_work.c:188
exit_task_work include/linux/task_work.h:33 [inline]
do_exit+0x6a3/0x2480 kernel/exit.c:874
do_group_exit+0x144/0x310 kernel/exit.c:996
get_signal+0xc66/0x14e0 kernel/signal.c:2900
arch_do_signal_or_restart+0xc3/0x1890 arch/x86/kernel/signal.c:867

Memory state around the buggy address:
ffff888069bc7f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888069bc7f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888069bc8000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff888069bc8080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888069bc8100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 0c935c049b5c Linux 5.15.179
git tree: linux-5.15.y

console output: https://syzkaller.appspot.com/x/log.txt?x=172d47b0580000

kernel config: https://syzkaller.appspot.com/x/.config?x=bcb6af887426ce59
dashboard link: https://syzkaller.appspot.com/bug?extid=7ee70fbe2ae94f89be13
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=152bb198580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=114b23e4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/75b060834e1e/disk-0c935c04.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d42b06ae465d/vmlinux-0c935c04.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d5217676cd35/bzImage-0c935c04.xz

mounted in repro: https://storage.googleapis.com/syzbot-assets/74094181ec8e/mount_0.gz
fsck result: OK (log: https://syzkaller.appspot.com/x/fsck.log?x=112bb198580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7ee70f...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 32768
ocfs2: Slot 0 on device (7,0) was already allocated to this node!
ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode.

==================================================================
BUG: KASAN: use-after-free in ocfs2_find_victim_chain fs/ocfs2/suballoc.c:1391 [inline]
BUG: KASAN: use-after-free in ocfs2_claim_suballoc_bits+0xfb5/0x24b0 fs/ocfs2/suballoc.c:1927

Read of size 4 at addr ffff88806ea58000 by task syz-executor830/4168

CPU: 1 PID: 4168 Comm: syz-executor830 Not tainted 5.15.179-syzkaller #0

RIP: 0033:0x7f94713cb129
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd77634438 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f94713cb129
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: 00000000ffffff9c
RBP: 0000000000000004 R08: 0000000000004458 R09: 0000000000000000
R10: 00007ffd776344d0 R11: 0000000000000246 R12: 0000000001000000
R13: 00007ffd776344d0 R14: 0000200000000240 R15: 0000000000000003

</TASK>

The buggy address belongs to the page:

page:ffffea0001ba9600 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x6ea58
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001ba9648 ffffea0001ba95c8 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000

page dumped because: kasan: bad access detected
page_owner tracks the page as freed

page last allocated via order 0, migratetype Movable, gfp_mask 0x1100cca(GFP_HIGHUSER_MOVABLE), pid 4163, ts 54889812237, free_ts 55378275758

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_pages_vma+0x39a/0x800 mm/mempolicy.c:2146
shmem_alloc_page mm/shmem.c:1586 [inline]
shmem_alloc_and_acct_page+0x4d1/0xd10 mm/shmem.c:1611
shmem_getpage_gfp+0x17b1/0x3190 mm/shmem.c:1906
shmem_getpage mm/shmem.c:151 [inline]
shmem_write_begin+0xce/0x1a0 mm/shmem.c:2474
generic_perform_write+0x2bf/0x5b0 mm/filemap.c:3785
__generic_file_write_iter+0x243/0x4f0 mm/filemap.c:3912
generic_file_write_iter+0xa7/0x1b0 mm/filemap.c:3944

call_write_iter include/linux/fs.h:2172 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0xacd/0xe50 fs/read_write.c:594
ksys_write+0x1a2/0x2c0 fs/read_write.c:647

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_list+0x1f7/0x8e0 mm/page_alloc.c:3433
release_pages+0x1bb9/0x1f40 mm/swap.c:963
__pagevec_release+0x80/0xf0 mm/swap.c:983
pagevec_release include/linux/pagevec.h:81 [inline]
shmem_undo_range+0x67a/0x1b50 mm/shmem.c:964
shmem_truncate_range mm/shmem.c:1063 [inline]
shmem_evict_inode+0x21b/0xa00 mm/shmem.c:1145
evict+0x529/0x930 fs/inode.c:647
__dentry_kill+0x436/0x650 fs/dcache.c:586
dentry_kill+0xbb/0x290 fs/dcache.c:-1
dput+0xd8/0x1a0 fs/dcache.c:893
__fput+0x636/0x8e0 fs/file_table.c:319
task_work_run+0x129/0x1a0 kernel/task_work.c:188

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

Memory state around the buggy address:

ffff88806ea57f00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88806ea57f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88806ea58000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff88806ea58080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff88806ea58100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


---
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