KASAN: use-after-free Read in udf_sync_fs

Status: upstream: reported C repro on 2023/06/16 18:53
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+d8d08094ff268799bae7@syzkaller.appspotmail.com
First crash: 1138d, last: 31d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2023/06/16 upstream (ToT) 4973ca295528 C [report] KASAN: use-after-free Read in udf_sync_fs
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 KASAN: use-after-free Read in udf_sync_fs 19 1 219d 219d 0/2 auto-obsoleted due to no activity on 2026/03/31 04:31
linux-6.1 KASAN: use-after-free Read in udf_sync_fs origin:upstream 19 syz, C error 59 115d 1136d 0/3 upstream: reported C repro on 2023/06/18 11:33
upstream KASAN: use-after-free Read in udf_sync_fs udf 19 syz, C done done 37 942d 1081d 25/29 fixed on 2024/02/03 12:44
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2026/06/27 06:57 15m retest repro linux-5.15.y report log
2026/06/27 06:57 15m retest repro linux-5.15.y report log
2026/06/07 21:11 17m retest repro linux-5.15.y report log
2026/06/07 21:11 15m retest repro linux-5.15.y report log
2026/06/07 21:11 13m retest repro linux-5.15.y report log
2026/06/07 21:11 15m retest repro linux-5.15.y report log
2026/05/10 03:51 18m retest repro linux-5.15.y report log
2026/05/10 03:51 15m retest repro linux-5.15.y report log
2026/05/10 03:51 15m retest repro linux-5.15.y report log
2026/05/10 03:51 18m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (12)
Created Duration User Patch Repo Result
2026/05/05 14:50 11m bisect fix linux-5.15.y error job log
2025/06/20 10:15 1h45m bisect fix linux-5.15.y OK (0) job log log
2025/04/12 00:13 1h14m bisect fix linux-5.15.y OK (0) job log log
2025/02/02 21:20 1h10m bisect fix linux-5.15.y OK (0) job log log
2024/07/29 16:11 2h19m bisect fix linux-5.15.y OK (0) job log log
2024/06/12 10:26 1h41m bisect fix linux-5.15.y OK (0) job log log
2024/03/31 22:48 1h24m bisect fix linux-5.15.y OK (0) job log log
2024/03/01 11:46 1h59m bisect fix linux-5.15.y OK (0) job log log
2024/01/21 12:34 1h50m bisect fix linux-5.15.y OK (0) job log log
2023/12/07 04:17 1h08m bisect fix linux-5.15.y OK (0) job log log
2023/10/21 19:29 1h00m bisect fix linux-5.15.y OK (0) job log log
2023/09/21 07:23 1h18m bisect fix linux-5.15.y OK (0) job log log

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in crc_itu_t+0x1ad/0x280 lib/crc-itu-t.c:60
Read of size 1 at addr ffff888073a26000 by task syz-executor/4304

CPU: 0 PID: 4304 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 crc_itu_t+0x1ad/0x280 lib/crc-itu-t.c:60
 udf_finalize_lvid fs/udf/super.c:2057 [inline]
 udf_sync_fs+0x194/0x350 fs/udf/super.c:2413
 sync_filesystem+0xe6/0x220 fs/sync.c:56
 generic_shutdown_super+0x6b/0x300 fs/super.c:448
 kill_block_super+0x7c/0xe0 fs/super.c:1427
 deactivate_locked_super+0x93/0xf0 fs/super.c:335
 cleanup_mnt+0x418/0x4d0 fs/namespace.c:1148
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 exit_task_work include/linux/task_work.h:33 [inline]
 do_exit+0x61e/0x20a0 kernel/exit.c:883
 do_group_exit+0x12e/0x300 kernel/exit.c:997
 get_signal+0x6ca/0x12c0 kernel/signal.c:2900
 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd17908a1ff
Code: Unable to access opcode bytes at RIP 0x7fd17908a1d5.
RSP: 002b:00007ffc9e7084c0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: 0000000000000004 RBX: 0000000000000003 RCX: 00007fd17908a1ff
RDX: 0000000000000004 RSI: 00007ffc9e708580 RDI: 00000000000000f8
RBP: 00007ffc9e70852c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00000000000927c0 R14: 00000000000102f7 R15: 00007ffc9e708580
 </TASK>

Allocated by task 21:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x9c/0xd0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3225 [inline]
 kmem_cache_alloc_node+0x12d/0x2d0 mm/slub.c:3261
 __alloc_skb+0xf4/0x750 net/core/skbuff.c:415
 alloc_skb include/linux/skbuff.h:1162 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:664 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:721 [inline]
 nsim_dev_trap_report_work+0x2a1/0xb40 drivers/net/netdevsim/dev.c:762
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Freed by task 21:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3520
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:737 [inline]
 nsim_dev_trap_report_work+0x7cb/0xb40 drivers/net/netdevsim/dev.c:762
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

The buggy address belongs to the object at ffff888073a26000
 which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 0 bytes inside of
 232-byte region [ffff888073a26000, ffff888073a260e8)
The buggy address belongs to the page:
page:ffffea0001ce8980 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x73a26
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888144bf0140
raw: 0000000000000000 00000000000c000c 00000001ffffffff 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 0x112a20(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 21, ts 65944486496, free_ts 65820324772
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192
 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5487
 alloc_slab_page mm/slub.c:1780 [inline]
 allocate_slab mm/slub.c:1917 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1980
 ___slab_alloc+0x81e/0xdf0 mm/slub.c:3013
 __slab_alloc mm/slub.c:3100 [inline]
 slab_alloc_node mm/slub.c:3191 [inline]
 kmem_cache_alloc_node+0x1c3/0x2d0 mm/slub.c:3261
 __alloc_skb+0xf4/0x750 net/core/skbuff.c:415
 alloc_skb include/linux/skbuff.h:1162 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:664 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:721 [inline]
 nsim_dev_trap_report_work+0x2a1/0xb40 drivers/net/netdevsim/dev.c:762
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
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+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x94/0x280 mm/page_alloc.c:3396
 free_slab mm/slub.c:2020 [inline]
 discard_slab mm/slub.c:2026 [inline]
 __unfreeze_partials+0x1a5/0x200 mm/slub.c:2512
 put_cpu_partial+0x12d/0x190 mm/slub.c:2592
 qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3225 [inline]
 kmem_cache_alloc_node+0x12d/0x2d0 mm/slub.c:3261
 __alloc_skb+0xf4/0x750 net/core/skbuff.c:415
 alloc_skb include/linux/skbuff.h:1162 [inline]
 nlmsg_new include/net/netlink.h:953 [inline]
 inet_netconf_notify_devconf+0x16f/0x230 net/ipv4/devinet.c:2121
 __devinet_sysctl_register+0x321/0x380 net/ipv4/devinet.c:2609
 devinet_sysctl_register+0x17c/0x1f0 net/ipv4/devinet.c:2643
 inetdev_init+0x28c/0x4d0 net/ipv4/devinet.c:277
 inetdev_event+0x280/0x1360 net/ipv4/devinet.c:1543
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391

Memory state around the buggy address:
 ffff888073a25f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888073a25f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888073a26000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888073a26080: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
 ffff888

Crashes (26):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/12 13:23 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2025/09/16 14:03 linux-5.15.y 43bb85222e53 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2025/07/07 22:32 linux-5.15.y 3dea0e7f549e 4f67c4ae .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2024/09/01 23:48 linux-5.15.y fa93fa65db6e 1eda0d14 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2024/05/13 03:37 linux-5.15.y 284087d4f7d5 9026e142 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2024/04/25 16:45 linux-5.15.y c52b9710c83d 8bdc0f22 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2024/04/23 00:14 linux-5.15.y c52b9710c83d 36c961ad .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2023/06/28 04:46 linux-5.15.y f67653019430 4cd5bb25 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2023/06/23 17:52 linux-5.15.y f67653019430 79782afc .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2023/06/20 20:35 linux-5.15.y 471e639e59d1 09ffe269 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2023/06/16 18:52 linux-5.15.y 471e639e59d1 f3921d4d .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2026/01/07 20:54 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2025/07/07 20:12 linux-5.15.y 3dea0e7f549e 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2024/08/15 19:10 linux-5.15.y 7e89efd3ae1c e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2024/08/15 19:08 linux-5.15.y 7e89efd3ae1c e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2024/08/15 19:06 linux-5.15.y 7e89efd3ae1c e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2024/08/15 18:34 linux-5.15.y 7e89efd3ae1c e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2024/07/29 18:04 linux-5.15.y 7e89efd3ae1c 5187fc86 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2024/04/22 22:40 linux-5.15.y c52b9710c83d 36c961ad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2024/04/22 22:39 linux-5.15.y c52b9710c83d 36c961ad .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2023/12/22 04:25 linux-5.15.y 1d146b1875fc 4f9530a3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2023/11/06 20:44 linux-5.15.y 12952a23a5da 78fae24e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2023/07/07 21:52 linux-5.15.y d54cfc420586 668cb1fa .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in udf_sync_fs
2026/01/07 12:44 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in udf_sync_fs
2024/11/15 14:32 linux-5.15.y d98fd109f827 f6ede3a3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in udf_sync_fs
2024/08/15 19:04 linux-5.15.y 7e89efd3ae1c e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: slab-out-of-bounds Read in udf_sync_fs
* Struck through repros no longer work on HEAD.