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

Status: auto-obsoleted due to no activity on 2026/04/28 05:38
Subsystems: xfs
[Documentation on labels]
Reported-by: syzbot+95170b2e7d9e80b8a7d7@syzkaller.appspotmail.com
First crash: 344d, last: 191d
Cause bisection: failed (error log, bisect log)
  
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[syzbot] Monthly xfs report (Jan 2026) 0 (1) 2026/01/30 10:09
[syzbot] Monthly xfs report (Aug 2025) 0 (1) 2025/08/27 08:15
[syzbot] [xfs?] KASAN: slab-use-after-free Read in xlog_cil_push_work 0 (1) 2025/08/21 13:03
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in xlog_cil_push_work (2) prio:high xfs 19 5 77d 74d 0/29 upstream: reported on 2026/05/15 04:01
upstream BUG: unable to handle kernel paging request in xlog_cil_push_work xfs 8 5 453d 453d 0/29 auto-obsoleted due to no activity on 2025/08/08 19:37
upstream KASAN: slab-out-of-bounds Write in xlog_cil_push_work xfs 22 3 779d 785d 0/29 auto-obsoleted due to no activity on 2024/09/06 14:39
▶ ▼ Last patch testing requests (6)
Created Duration User Patch Repo Result
2026/02/01 12:46 1h08m retest repro linux-next OK log
2026/02/01 12:46 56m retest repro linux-next OK log
2025/11/09 23:37 20m retest repro linux-next report log
2025/11/09 23:37 23m retest repro linux-next report log
2025/08/31 22:47 22m retest repro linux-next error
2025/08/31 22:47 17m retest repro linux-next error

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in __list_del_entry_valid_or_report+0xb5/0x190 lib/list_debug.c:65
Read of size 8 at addr ffff888034d0d310 by task kworker/u8:2/41

CPU: 1 UID: 0 PID: 41 Comm: kworker/u8:2 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: xfs-cil/loop4 xlog_cil_push_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xba/0x230 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 __list_del_entry_valid_or_report+0xb5/0x190 lib/list_debug.c:65
 __list_del_entry_valid include/linux/list.h:132 [inline]
 __list_del_entry include/linux/list.h:223 [inline]
 list_del_init include/linux/list.h:295 [inline]
 xlog_cil_build_lv_chain fs/xfs/xfs_log_cil.c:1246 [inline]
 xlog_cil_push_work+0x1221/0x2670 fs/xfs/xfs_log_cil.c:1374
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
 worker_thread+0x89f/0xd90 kernel/workqueue.c:3421
 kthread+0x726/0x8b0 kernel/kthread.c:463
 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Allocated by task 6346:
 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:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_noprof+0x188/0x6a0 mm/slub.c:5270
 xfs_buf_item_init+0x6a/0x6d0 fs/xfs/xfs_buf_item.c:878
 _xfs_trans_bjoin+0x46/0x110 fs/xfs/xfs_trans_buf.c:75
 xfs_trans_read_buf_map+0x294/0x8a0 fs/xfs/xfs_trans_buf.c:325
 xfs_trans_read_buf fs/xfs/xfs_trans.h:210 [inline]
 xfs_btree_read_buf_block+0x2b0/0x490 fs/xfs/libxfs/xfs_btree.c:1402
 xfs_btree_lookup_get_block+0x297/0x510 fs/xfs/libxfs/xfs_btree.c:1907
 xfs_btree_lookup+0x45a/0x1350 fs/xfs/libxfs/xfs_btree.c:2018
 xfs_alloc_lookup fs/xfs/libxfs/xfs_alloc.c:166 [inline]
 xfs_alloc_lookup_eq fs/xfs/libxfs/xfs_alloc.c:184 [inline]
 xfs_alloc_fixup_trees+0x219/0xd30 fs/xfs/libxfs/xfs_alloc.c:626
 xfs_alloc_cur_finish+0xd5/0x480 fs/xfs/libxfs/xfs_alloc.c:1117
 xfs_alloc_ag_vextent_near+0xd4b/0x1200 fs/xfs/libxfs/xfs_alloc.c:1776
 xfs_alloc_vextent_iterate_ags+0x61c/0x910 fs/xfs/libxfs/xfs_alloc.c:3764
 xfs_alloc_vextent_start_ag+0x378/0x830 fs/xfs/libxfs/xfs_alloc.c:3839
 xfs_bmap_btalloc_best_length fs/xfs/libxfs/xfs_bmap.c:3619 [inline]
 xfs_bmap_btalloc fs/xfs/libxfs/xfs_bmap.c:3663 [inline]
 xfs_bmapi_allocate+0x17c1/0x2da0 fs/xfs/libxfs/xfs_bmap.c:3938
 xfs_bmapi_write+0x843/0x1330 fs/xfs/libxfs/xfs_bmap.c:4267
 xfs_iomap_write_direct+0x3ba/0x6b0 fs/xfs/xfs_iomap.c:335
 xfs_direct_write_iomap_begin+0xfbf/0x1410 fs/xfs/xfs_iomap.c:1009
 iomap_iter+0x600/0xf30 fs/iomap/iter.c:110
 __iomap_dio_rw+0xcc7/0x1e10 fs/iomap/direct-io.c:752
 iomap_dio_rw+0x45/0xb0 fs/iomap/direct-io.c:847
 xfs_file_dio_write_aligned+0x174/0x1e0 fs/xfs/xfs_file.c:707
 xfs_file_dio_write fs/xfs/xfs_file.c:910 [inline]
 xfs_file_write_iter+0x7ea/0x920 fs/xfs/xfs_file.c:1122
 iter_file_splice_write+0x9a0/0x1100 fs/splice.c:738
 do_splice_from fs/splice.c:938 [inline]
 direct_splice_actor+0x104/0x160 fs/splice.c:1161
 splice_direct_to_actor+0x545/0xc80 fs/splice.c:1105
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0x19b/0x2a0 fs/splice.c:1230
 do_sendfile+0x547/0x7d0 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1417
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6346:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 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:2540 [inline]
 slab_free mm/slub.c:6670 [inline]
 kmem_cache_free+0x18d/0x8c0 mm/slub.c:6781
 __xfs_buf_ioend+0x28c/0x6d0 fs/xfs/xfs_buf.c:1199
 xfs_buf_iowait+0x143/0x440 fs/xfs/xfs_buf.c:1381
 _xfs_buf_read fs/xfs/xfs_buf.c:643 [inline]
 xfs_buf_read_map+0x325/0xa20 fs/xfs/xfs_buf.c:709
 xfs_trans_read_buf_map+0x1db/0x8a0 fs/xfs/xfs_trans_buf.c:304
 xfs_trans_read_buf fs/xfs/xfs_trans.h:210 [inline]
 xfs_btree_read_buf_block+0x2b0/0x490 fs/xfs/libxfs/xfs_btree.c:1402
 xfs_btree_lookup_get_block+0x297/0x510 fs/xfs/libxfs/xfs_btree.c:1907
 xfs_btree_lookup+0x45a/0x1350 fs/xfs/libxfs/xfs_btree.c:2018
 xfs_alloc_lookup fs/xfs/libxfs/xfs_alloc.c:166 [inline]
 xfs_alloc_lookup_eq fs/xfs/libxfs/xfs_alloc.c:184 [inline]
 xfs_alloc_fixup_trees+0x219/0xd30 fs/xfs/libxfs/xfs_alloc.c:626
 xfs_alloc_cur_finish+0xd5/0x480 fs/xfs/libxfs/xfs_alloc.c:1117
 xfs_alloc_ag_vextent_near+0xd4b/0x1200 fs/xfs/libxfs/xfs_alloc.c:1776
 xfs_alloc_vextent_iterate_ags+0x61c/0x910 fs/xfs/libxfs/xfs_alloc.c:3764
 xfs_alloc_vextent_start_ag+0x378/0x830 fs/xfs/libxfs/xfs_alloc.c:3839
 xfs_bmap_btalloc_best_length fs/xfs/libxfs/xfs_bmap.c:3619 [inline]
 xfs_bmap_btalloc fs/xfs/libxfs/xfs_bmap.c:3663 [inline]
 xfs_bmapi_allocate+0x17c1/0x2da0 fs/xfs/libxfs/xfs_bmap.c:3938
 xfs_bmapi_write+0x843/0x1330 fs/xfs/libxfs/xfs_bmap.c:4267
 xfs_iomap_write_direct+0x3ba/0x6b0 fs/xfs/xfs_iomap.c:335
 xfs_direct_write_iomap_begin+0xfbf/0x1410 fs/xfs/xfs_iomap.c:1009
 iomap_iter+0x600/0xf30 fs/iomap/iter.c:110
 __iomap_dio_rw+0xcc7/0x1e10 fs/iomap/direct-io.c:752
 iomap_dio_rw+0x45/0xb0 fs/iomap/direct-io.c:847
 xfs_file_dio_write_aligned+0x174/0x1e0 fs/xfs/xfs_file.c:707
 xfs_file_dio_write fs/xfs/xfs_file.c:910 [inline]
 xfs_file_write_iter+0x7ea/0x920 fs/xfs/xfs_file.c:1122
 iter_file_splice_write+0x9a0/0x1100 fs/splice.c:738
 do_splice_from fs/splice.c:938 [inline]
 direct_splice_actor+0x104/0x160 fs/splice.c:1161
 splice_direct_to_actor+0x545/0xc80 fs/splice.c:1105
 do_splice_direct_actor fs/splice.c:1204 [inline]
 do_splice_direct+0x19b/0x2a0 fs/splice.c:1230
 do_sendfile+0x547/0x7d0 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1417
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888034d0d2a0
 which belongs to the cache xfs_buf_item of size 272
The buggy address is located 112 bytes inside of
 freed 272-byte region [ffff888034d0d2a0, ffff888034d0d3b0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34d0d
flags: 0x80000000000000(node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000000 ffff888143af1a00 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800c000c 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 0x52c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 6346, tgid 6345 (syz.4.74), ts 139080494270, free_ts 138174925054
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x228/0x280 mm/page_alloc.c:1884
 prep_new_page mm/page_alloc.c:1892 [inline]
 get_page_from_freelist+0x28bb/0x2950 mm/page_alloc.c:3945
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5240
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab+0x86/0x3a0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xaf8/0x13d0 mm/slub.c:4656
 __slab_alloc+0xc5/0x1f0 mm/slub.c:4779
 __slab_alloc_node mm/slub.c:4855 [inline]
 slab_alloc_node mm/slub.c:5251 [inline]
 kmem_cache_alloc_noprof+0x100/0x6a0 mm/slub.c:5270
 xfs_buf_item_init+0x6a/0x6d0 fs/xfs/xfs_buf_item.c:878
 _xfs_trans_bjoin+0x46/0x110 fs/xfs/xfs_trans_buf.c:75
 xfs_trans_read_buf_map+0x294/0x8a0 fs/xfs/xfs_trans_buf.c:325
 xfs_trans_read_buf fs/xfs/xfs_trans.h:210 [inline]
 xfs_alloc_read_agfl+0x233/0x430 fs/xfs/libxfs/xfs_alloc.c:885
 xfs_alloc_fix_freelist+0xbe7/0x13d0 fs/xfs/libxfs/xfs_alloc.c:2961
 xfs_alloc_vextent_prepare_ag+0xdb/0x5f0 fs/xfs/libxfs/xfs_alloc.c:3566
 xfs_alloc_vextent_iterate_ags+0x140/0x910 fs/xfs/libxfs/xfs_alloc.c:3750
 xfs_alloc_vextent_start_ag+0x378/0x830 fs/xfs/libxfs/xfs_alloc.c:3839
page last free pid 5798 tgid 5798 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1433 [inline]
 free_unref_folios+0xc13/0x17f0 mm/page_alloc.c:3030
 folios_put_refs+0x56f/0x680 mm/swap.c:1002
 folio_batch_release include/linux/pagevec.h:101 [inline]
 mapping_try_invalidate+0x3c2/0x4c0 mm/truncate.c:579
 generic_shutdown_super+0x135/0x2c0 fs/super.c:643
 kill_block_super+0x44/0x90 fs/super.c:1722
 xfs_kill_sb+0x15/0x50 fs/xfs/xfs_super.c:2297
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1318
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888034d0d200: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc
 ffff888034d0d280: fc fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb
>ffff888034d0d300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888034d0d380: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fa fb
 ffff888034d0d400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/18 05:37 upstream d12453c7e281 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: slab-use-after-free Read in xlog_cil_push_work
2026/01/16 20:40 upstream 983d014aafb1 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: slab-use-after-free Read in xlog_cil_push_work
2025/08/17 15:10 linux-next 931e46dcbc7e 1804e95e .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in xlog_cil_push_work
2025/08/17 12:59 linux-next 931e46dcbc7e 1804e95e .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-linux-next-kasan-gce-root KASAN: slab-use-after-free Read in xlog_cil_push_work
* Struck through repros no longer work on HEAD.