From: syzbot <syzbot+c32ff62cf4913d345d0c@syzkaller.appspotmail.com>
To: cem@kernel.org, linux-kernel@vger.kernel.org,
linux-xfs@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [xfs?] KASAN: slab-use-after-free Write in xlog_cil_push_work
Date: Fri, 25 Sep 2026 18:31:28 -0700 [thread overview]
Message-ID: <6ab72070.dc2998a4.2261f5.004f.GAE@google.com> (raw)
In-Reply-To: <6ab1c82d.514bccd6.255447.0018.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: aa98230e410f Merge tag 'vfs-7.3-rc5.fixes' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15b4025e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=718e346eb0b8f38
dashboard link: https://syzkaller.appspot.com/bug?extid=c32ff62cf4913d345d0c
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11440a05580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12a99d25580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e111cbedae47/disk-aa98230e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/448db8740448/vmlinux-aa98230e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bf2dee21a792/bzImage-aa98230e.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/e1fe55618d28/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=12ab2a05580000)
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c32ff62cf4913d345d0c@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: slab-use-after-free in __list_splice include/linux/list.h:577 [inline]
BUG: KASAN: slab-use-after-free in list_splice_init include/linux/list.h:619 [inline]
BUG: KASAN: slab-use-after-free in xlog_cil_push_pcp_aggregate fs/xfs/xfs_log_cil.c:137 [inline]
BUG: KASAN: slab-use-after-free in xlog_cil_push_work+0x986/0x2a90 fs/xfs/xfs_log_cil.c:1417
Write of size 8 at addr ffff88803ac995b0 by task kworker/u8:8/1160
CPU: 1 UID: 0 PID: 1160 Comm: kworker/u8:8 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Workqueue: xfs-cil/loop0 xlog_cil_push_work
Call Trace:
<TASK>
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_address_description+0x55/0x1e0 mm/kasan/report.c:378
print_report+0x58/0x70 mm/kasan/report.c:482
kasan_report+0x117/0x150 mm/kasan/report.c:595
__list_splice include/linux/list.h:577 [inline]
list_splice_init include/linux/list.h:619 [inline]
xlog_cil_push_pcp_aggregate fs/xfs/xfs_log_cil.c:137 [inline]
xlog_cil_push_work+0x986/0x2a90 fs/xfs/xfs_log_cil.c:1417
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Allocated by task 6137:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
kmem_cache_alloc_noprof+0x360/0x690 mm/slub.c:5010
xfs_buf_item_init+0x6a/0x6e0 fs/xfs/xfs_buf_item.c:872
_xfs_trans_bjoin+0x46/0x110 fs/xfs/xfs_trans_buf.c:75
__xfs_trans_getsb+0x65/0x4a0 fs/xfs/xfs_trans_buf.c:191
xfs_log_sb+0x43/0x200 fs/xfs/libxfs/xfs_sb.c:1327
xfs_sync_sb_buf+0xc2/0x290 fs/xfs/libxfs/xfs_sb.c:1479
xfs_ioc_setlabel+0x1d7/0x340 fs/xfs/xfs_ioctl.c:1081
xfs_file_ioctl+0x901/0x1590 fs/xfs/xfs_ioctl.c:1238
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 6137:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2748 [inline]
slab_free mm/slub.c:6508 [inline]
kmem_cache_free+0x187/0x6d0 mm/slub.c:6635
xfs_buf_ioend+0x235/0x790 fs/xfs/xfs_buf.c:1167
xfs_buf_iowait+0x133/0x420 fs/xfs/xfs_buf.c:1336
xfs_bwrite+0x5f/0xe0 fs/xfs/xfs_buf.c:1239
xfs_sync_sb_buf+0x172/0x290 fs/xfs/libxfs/xfs_sb.c:1489
xfs_ioc_setlabel+0x1d7/0x340 fs/xfs/xfs_ioctl.c:1081
xfs_file_ioctl+0x901/0x1590 fs/xfs/xfs_ioctl.c:1238
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff88803ac99540
which belongs to the cache xfs_buf_item of size 272
The buggy address is located 112 bytes inside of
freed 272-byte region [ffff88803ac99540, ffff88803ac99650)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x3ac99
flags: 0x80000000000000(node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000000 ffff88801e348b40 dead000000000122 0000000000000000
raw: 0000000000000000 00000002000c000c 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6116, tgid 6106 (syz.4.30), ts 150746597616
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x2591/0x2600 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x230/0x5c0 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab+0x7d/0x620 mm/slub.c:3462
new_slab mm/slub.c:3513 [inline]
refill_objects+0x2d8/0x350 mm/slub.c:7417
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x339/0x690 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
kmem_cache_alloc_noprof+0x45d/0x690 mm/slub.c:5010
xfs_buf_item_init+0x6a/0x6e0 fs/xfs/xfs_buf_item.c:872
_xfs_trans_bjoin+0x46/0x110 fs/xfs/xfs_trans_buf.c:75
xfs_trans_read_buf_map+0x2ee/0x820 fs/xfs/xfs_trans_buf.c:294
xfs_trans_read_buf fs/xfs/xfs_trans.h:212 [inline]
xfs_read_icluster+0x218/0x3e0 fs/xfs/libxfs/xfs_inode_buf.c:139
xfs_iget_cache_miss fs/xfs/xfs_icache.c:663 [inline]
xfs_iget+0xc34/0x2f00 fs/xfs/xfs_icache.c:804
xfs_trans_metafile_iget+0x77/0x330 fs/xfs/xfs_icache.c:853
xfs_rtginode_load+0x3a3/0x920 fs/xfs/libxfs/xfs_rtgroup.c:469
xfs_rtmount_rtg fs/xfs/xfs_rtalloc.c:1684 [inline]
xfs_rtmount_inodes+0x245/0x7a0 fs/xfs/xfs_rtalloc.c:1721
xfs_mountfs+0x1254/0x2380 fs/xfs/xfs_mount.c:1095
page last free pid 6120 tgid 6072 ts 149440641538 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
free_unref_folios+0xd0f/0x1950 mm/page_alloc.c:3022
folios_put_refs+0x815/0x920 mm/folio.c:1036
folio_batch_release include/linux/folio_batch.h:101 [inline]
mapping_try_invalidate+0x3b7/0x4b0 mm/truncate.c:579
xfs_ioc_setlabel+0x262/0x340 fs/xfs/xfs_ioctl.c:1091
xfs_file_ioctl+0x901/0x1590 fs/xfs/xfs_ioctl.c:1238
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xff/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff88803ac99480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88803ac99500: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
>ffff88803ac99580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88803ac99600: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc
ffff88803ac99680: fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
prev parent reply other threads:[~2026-09-26 1:31 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-22 0:13 [syzbot] [xfs?] KASAN: slab-use-after-free Write in xlog_cil_push_work syzbot
2026-09-26 1:31 ` syzbot [this message]
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