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KASAN: use-after-free Read in v4l2_fh_open

Status: upstream: reported C repro on 2024/08/01 11:01
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+545d6080425f1f289ca9@syzkaller.appspotmail.com
First crash: 545d, last: 15h02m
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2024/08/02 upstream (ToT) c0ecd6388360 C [report] KASAN: slab-use-after-free Read in v4l2_fh_open
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in v4l2_fh_open usb media 19 C unreliable inconclusive 3403 15h18m 1808d 0/29 upstream: reported C repro on 2021/02/15 15:18
linux-6.1 KASAN: use-after-free Read in v4l2_fh_open origin:upstream 19 C 59 6d21h 524d 0/3 upstream: reported C repro on 2024/08/22 03:36
linux-6.6 KASAN: slab-use-after-free Read in v4l2_fh_open origin:upstream 19 C 34 7d00h 213d 0/2 upstream: reported C repro on 2025/06/29 09:48
▶ ▼ Last patch testing requests (4)
Created Duration User Patch Repo Result
2025/05/16 14:23 13m retest repro linux-5.15.y report log
2025/05/16 14:23 1h17m retest repro linux-5.15.y report log
2025/05/16 14:23 10m retest repro linux-5.15.y report log
2024/11/26 20:18 14m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (1)
Created Duration User Patch Repo Result
2024/09/06 00:23 1h29m bisect fix linux-5.15.y OK (0) job log log

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline]
BUG: KASAN: use-after-free in v4l2_fh_open+0xc6/0x430 drivers/media/v4l2-core/v4l2-fh.c:63
Read of size 8 at addr ffff8880594cc900 by task v4l_id/4594

CPU: 1 PID: 4594 Comm: v4l_id Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 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
 v4l2_fh_init drivers/media/v4l2-core/v4l2-fh.c:25 [inline]
 v4l2_fh_open+0xc6/0x430 drivers/media/v4l2-core/v4l2-fh.c:63
 em28xx_v4l2_open+0x152/0x990 drivers/media/usb/em28xx/em28xx-video.c:2163
 v4l2_open+0x20b/0x360 drivers/media/v4l2-core/v4l2-dev.c:427
 chrdev_open+0x5c5/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x7ff/0xf80 fs/open.c:826
 do_open fs/namei.c:3616 [inline]
 path_openat+0x26f5/0x2fa0 fs/namei.c:3750
 do_filp_open+0x1e2/0x410 fs/namei.c:3777
 do_sys_openat2+0x150/0x4b0 fs/open.c:1255
 do_sys_open fs/open.c:1271 [inline]
 __do_sys_openat fs/open.c:1287 [inline]
 __se_sys_openat fs/open.c:1282 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1282
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fde7059d407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007ffdf5bb3040 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fde704af880 RCX: 00007fde7059d407
RDX: 0000000000000000 RSI: 00007ffdf5bb4f1c RDI: ffffffffffffff9c
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffdf5bb3290 R14: 00007fde70d2b000 R15: 000055f3ddbdd4d8
 </TASK>

The buggy address belongs to the page:
page:ffffea0001653300 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x594cc
head:ffffea0001653300 order:2 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010000(head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x140dc0(GFP_USER|__GFP_COMP|__GFP_ZERO), pid 4358, ts 101372226901, free_ts 101344170705
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
 __alloc_pages+0x1ee/0x480 mm/page_alloc.c:5487
 kmalloc_order+0x40/0x150 mm/slab_common.c:986
 kmalloc_order_trace+0x14/0xf0 mm/slab_common.c:1002
 kmalloc_large include/linux/slab.h:536 [inline]
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:738 [inline]
 em28xx_v4l2_init+0xe2/0x2e50 drivers/media/usb/em28xx/em28xx-video.c:2542
 em28xx_init_extension+0x118/0x1b0 drivers/media/usb/em28xx/em28xx-core.c:1126
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 process_scheduled_works kernel/workqueue.c:2373 [inline]
 worker_thread+0xdcf/0x1290 kernel/workqueue.c:2462
 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+0x8f/0x2a0 mm/page_alloc.c:3396
 free_nonslab_page+0xe2/0x150 mm/slub.c:3540
 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2128 [inline]
 kref_put include/linux/kref.h:65 [inline]
 em28xx_v4l2_init+0x1649/0x2e50 drivers/media/usb/em28xx/em28xx-video.c:2911
 em28xx_init_extension+0x118/0x1b0 drivers/media/usb/em28xx/em28xx-core.c:1126
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 process_scheduled_works kernel/workqueue.c:2373 [inline]
 worker_thread+0xdcf/0x1290 kernel/workqueue.c:2462
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff8880594cc800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880594cc880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880594cc900: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff8880594cc980: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880594cca00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (205):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/28 09:36 linux-5.15.y 9eec9a14ee10 3029c699 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/10/27 00:12 linux-5.15.y ac56c046adf4 c0460fcd .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/21 08:01 linux-5.15.y c79648372d02 0b9605c8 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/21 07:16 linux-5.15.y c79648372d02 0b9605c8 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/06/01 01:32 linux-5.15.y 98f47d0e9b8c 3d2f584d .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/03/14 13:30 linux-5.15.y 0c935c049b5c e2826670 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2024/12/01 14:37 linux-5.15.y 0a51d2d4527b 68914665 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2024/08/02 07:45 linux-5.15.y 7e89efd3ae1c 1e9c4cf3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2026/01/22 00:12 linux-5.15.y 9eec9a14ee10 8fc37797 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2026/01/19 20:59 linux-5.15.y 9eec9a14ee10 a9fc5226 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2026/01/18 05:38 linux-5.15.y 68efe5a6c16a 20d37d28 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2026/01/11 06:01 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2026/01/11 04:55 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2026/01/08 15:48 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2026/01/08 00:25 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2026/01/05 00:09 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2026/01/01 20:53 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/31 12:17 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/30 20:54 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/29 19:46 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/28 02:52 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/25 18:52 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/23 12:30 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/21 17:18 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/20 16:22 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/16 04:36 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/14 05:18 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/13 01:51 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/10 14:19 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/07 06:31 linux-5.15.y 68efe5a6c16a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/06 09:38 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/03 15:50 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/02 21:01 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/12/02 07:30 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/30 10:43 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/29 20:44 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/28 18:42 linux-5.15.y cc5ec8769306 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/25 07:30 linux-5.15.y cc5ec8769306 64219f15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/21 12:39 linux-5.15.y cc5ec8769306 280ea308 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/20 21:44 linux-5.15.y cc5ec8769306 2cc4c24a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/18 04:57 linux-5.15.y cc5ec8769306 ef766cd7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/12 12:41 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/11 06:39 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/10 01:17 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/09 19:09 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/07 12:56 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/07 04:57 linux-5.15.y cc5ec8769306 4e1406b4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/02 16:26 linux-5.15.y cc5ec8769306 2c50b6a9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/10/27 19:31 linux-5.15.y ac56c046adf4 fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/10/24 20:28 linux-5.15.y ac56c046adf4 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/10/24 16:43 linux-5.15.y ac56c046adf4 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/10/24 00:23 linux-5.15.y ac56c046adf4 c0460fcd .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/10/17 14:08 linux-5.15.y 29e53a5b1c4f 7adf5298 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2024/08/01 11:00 linux-5.15.y 7e89efd3ae1c 1e9c4cf3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/16 12:34 linux-5.15.y cc5ec8769306 f7988ea4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: out-of-bounds Read in v4l2_fh_open
* Struck through repros no longer work on HEAD.