KASAN: slab-use-after-free Read in xfs_inode_item_push

Status: fixed on 2026/04/06 08:33
Reported-by: syzbot+652af2b3c5569c4ab63c@syzkaller.appspotmail.com
Fix commit: 7121b22b0bac xfs: avoid dereferencing log items after push callbacks 75669e987137 xfs: save ailp before dropping the AIL lock in push callbacks d38135af04a3 xfs: stop reclaim before pushing AIL during unmount
First crash: 204d, last: 204d
▶ ▼ Discussions (8)
Title Replies (including bot) Last reply
[PATCH v4 2/4] xfs: avoid dereferencing log items after push callbacks 2 (2) 2026/03/10 20:40
[PATCH v4 1/4] xfs: stop reclaim before pushing AIL during unmount 2 (2) 2026/03/10 20:39
[PATCH v4 3/4] xfs: save ailp before dropping the AIL lock in push callbacks 1 (1) 2026/03/10 18:38
[PATCH v3 3/4] xfs: avoid dereferencing log items after push callbacks 6 (6) 2026/03/10 17:56
[PATCH v3 1/4] xfs: stop reclaim before pushing AIL during unmount 3 (3) 2026/03/10 17:33
[PATCH v3 4/4] xfs: save ailp before dropping the AIL lock in push callbacks 3 (3) 2026/03/10 05:27
[PATCH v2] xfs: fix use-after-free of log items during AIL pushing 3 (3) 2026/03/08 18:35
[PATCH] xfs: fix use-after-free in xfs_inode_item_push() 5 (5) 2026/03/05 18:28
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in xfs_inode_item_push xfs 19 syz, C error 430 146d 861d 0/29 auto-obsoleted due to no activity on 2026/06/19 13:32
upstream KASAN: use-after-free Read in xfs_inode_item_push xfs 19 16 1060d 1286d 0/29 auto-obsoleted due to no activity on 2024/01/02 00:00
linux-6.6 KFENCE: use-after-free read in xfs_inode_item_push 19 2 311d 318d 0/2 auto-obsoleted due to no activity on 2026/01/20 14:10
linux-6.1 KASAN: use-after-free Read in xfs_inode_item_push (2) 19 1 713d 713d 0/3 auto-obsoleted due to no activity on 2024/12/14 11:37
linux-6.1 KASAN: use-after-free Read in xfs_inode_item_push 19 1 1208d 1208d 0/3 auto-obsoleted due to no activity on 2023/08/23 09:03
linux-5.15 KASAN: use-after-free Read in xfs_inode_item_push (2) origin:lts-only 19 syz, C inconclusive 2 438d 565d 0/3 upstream: reported C repro on 2025/01/31 01:44
linux-5.15 KASAN: use-after-free Read in xfs_inode_item_push 19 2 1187d 1190d 0/3 auto-obsoleted due to no activity on 2023/08/28 08:02
linux-6.1 KASAN: use-after-free Read in xfs_inode_item_push (3) 19 1 209d 209d 0/3 auto-obsoleted due to no activity on 2026/05/02 12:51

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in xfs_inode_item_push+0x28a/0x2e0 fs/xfs/xfs_inode_item.c:776
Read of size 8 at addr ffff88805ebe87e0 by task xfsaild/loop5/10155

CPU: 1 PID: 10155 Comm: xfsaild/loop5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 xfs_inode_item_push+0x28a/0x2e0 fs/xfs/xfs_inode_item.c:776
 xfsaild_push_item fs/xfs/xfs_trans_ail.c:414 [inline]
 xfsaild_push fs/xfs/xfs_trans_ail.c:486 [inline]
 xfsaild+0xc84/0x25e0 fs/xfs/xfs_trans_ail.c:671
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Allocated by task 10120:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x11a/0x2d0 mm/slub.c:3519
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 xfs_inode_item_init+0x33/0xc0 fs/xfs/xfs_inode_item.c:871
 xfs_trans_ijoin+0xd8/0x120 fs/xfs/libxfs/xfs_trans_inode.c:36
 xfs_trans_alloc_ichange+0xd8/0x530 fs/xfs/xfs_trans.c:1297
 xfs_ioctl_setattr_get_trans fs/xfs/xfs_ioctl.c:1220 [inline]
 xfs_fileattr_set+0x5e7/0x17d0 fs/xfs/xfs_ioctl.c:1367
 vfs_fileattr_set+0x85d/0xb10 fs/ioctl.c:697
 ioctl_setflags fs/ioctl.c:729 [inline]
 do_vfs_ioctl+0x1449/0x1cc0 fs/ioctl.c:840
 __do_sys_ioctl fs/ioctl.c:869 [inline]
 __se_sys_ioctl+0x83/0x170 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 3:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 kmem_cache_free+0xf8/0x270 mm/slub.c:3852
 xfs_inode_free_callback+0x14f/0x1c0 fs/xfs/xfs_icache.c:145
 rcu_do_batch kernel/rcu/tree.c:2194 [inline]
 rcu_core+0xcfb/0x1770 kernel/rcu/tree.c:2467
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687

The buggy address belongs to the object at ffff88805ebe87b0
 which belongs to the cache xfs_ili of size 264
The buggy address is located 48 bytes inside of
 freed 264-byte region [ffff88805ebe87b0, ffff88805ebe88b8)

The buggy address belongs to the physical page:
page:ffffea00017afa00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5ebe8
flags: 0xfff00000000800(slab|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000800 ffff888018fbe280 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Reclaimable, gfp_mask 0x112c50(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 5914, tgid 5913 (syz.0.26), ts 95807326330, free_ts 27432984022
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x1951/0x19e0 mm/page_alloc.c:3191
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4457
 alloc_slab_page+0x5d/0x160 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2081
 ___slab_alloc+0xc5d/0x12f0 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x1b3/0x2d0 mm/slub.c:3519
 kmem_cache_zalloc include/linux/slab.h:711 [inline]
 xfs_inode_item_init+0x33/0xc0 fs/xfs/xfs_inode_item.c:871
 xfs_trans_ijoin+0xd8/0x120 fs/xfs/libxfs/xfs_trans_inode.c:36
 xfs_init_new_inode+0xacb/0xd70 fs/xfs/xfs_inode.c:901
 xfs_qm_qino_alloc+0x4a4/0x990 fs/xfs/xfs_qm.c:790
 xfs_qm_init_quotainos+0x4a9/0x6d0 fs/xfs/xfs_qm.c:1576
 xfs_qm_init_quotainfo+0x11b/0x11a0 fs/xfs/xfs_qm.c:643
 xfs_qm_mount_quotas+0xa0/0x600 fs/xfs/xfs_qm.c:1460
 xfs_mountfs+0x165b/0x1d40 fs/xfs/xfs_mount.c:962
 xfs_fs_fill_super+0x112f/0x13a0 fs/xfs/xfs_super.c:1747
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2336
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
 free_contig_range+0xa1/0x150 mm/page_alloc.c:6369
 destroy_args+0x80/0x850 mm/debug_vm_pgtable.c:1015
 debug_vm_pgtable+0x411/0x440 mm/debug_vm_pgtable.c:1400
 do_one_initcall+0x242/0x790 init/main.c:1250
 do_initcall_level+0x137/0x1f0 init/main.c:1312
 do_initcalls+0x69/0xd0 init/main.c:1328
 kernel_init_freeable+0x3ed/0x580 init/main.c:1565
 kernel_init+0x1d/0x1c0 init/main.c:1455
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Memory state around the buggy address:
 ffff88805ebe8680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805ebe8700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc
>ffff88805ebe8780: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff88805ebe8800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805ebe8880: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/27 13:32 linux-6.6.y cbb31f77b879 9a514c2f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in xfs_inode_item_push
* Struck through repros no longer work on HEAD.