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KASAN: use-after-free Read in v4l2_fh_open

Status: upstream: reported C repro on 2024/08/22 03:36
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+d6ac1201f2492c7eda10@syzkaller.appspotmail.com
First crash: 462d, last: 4d03h
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2025/03/10 upstream (ToT) 4d872d51bc9d 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 3005 9h08m 1745d 0/29 upstream: reported C repro on 2021/02/15 15:18
linux-5.15 KASAN: use-after-free Read in v4l2_fh_open origin:upstream 19 C 174 1d23h 482d 0/3 upstream: reported C repro on 2024/08/01 11:01
linux-6.6 KASAN: slab-use-after-free Read in v4l2_fh_open origin:upstream 19 C 24 9d00h 150d 0/2 upstream: reported C repro on 2025/06/29 09:48
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2025/05/28 05:23 2h09m bisect fix linux-6.1.y OK (0) job log log
2025/04/23 20:54 1h43m bisect fix linux-6.1.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 ffff88805cf80738 by task v4l_id/4591

CPU: 1 PID: 4591 Comm: v4l_id Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 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:2153
 v4l2_open+0x20b/0x360 drivers/media/v4l2-core/v4l2-dev.c:427
 chrdev_open+0x597/0x670 fs/char_dev.c:414
 do_dentry_open+0x7e9/0x10d0 fs/open.c:882
 do_open fs/namei.c:3626 [inline]
 path_openat+0x25c6/0x2e70 fs/namei.c:3783
 do_filp_open+0x1c1/0x3c0 fs/namei.c:3810
 do_sys_openat2+0x142/0x490 fs/open.c:1318
 do_sys_open fs/open.c:1334 [inline]
 __do_sys_openat fs/open.c:1350 [inline]
 __se_sys_openat fs/open.c:1345 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1345
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa0f68a7407
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:00007ffeed88e5f0 EFLAGS: 00000202
 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fa0f6f65880 RCX: 00007fa0f68a7407
RDX: 0000000000000000 RSI: 00007ffeed88ef1c RDI: ffffffffffffff9c
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffeed88e840 R14: 00007fa0f70c4000 R15: 00005622f4beb4d8
 </TASK>

Allocated by task 14:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:383
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 em28xx_v4l2_init+0x107/0x2e70 drivers/media/usb/em28xx/em28xx-video.c:2532
 em28xx_init_extension+0x118/0x1b0 drivers/media/usb/em28xx/em28xx-core.c:1116
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

Freed by task 14:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 __kmem_cache_free+0xb6/0x1f0 mm/slub.c:3700
 em28xx_free_v4l2 drivers/media/usb/em28xx/em28xx-video.c:2118 [inline]
 kref_put include/linux/kref.h:65 [inline]
 em28xx_v4l2_init+0x166c/0x2e70 drivers/media/usb/em28xx/em28xx-video.c:2901
 em28xx_init_extension+0x118/0x1b0 drivers/media/usb/em28xx/em28xx-core.c:1116
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

The buggy address belongs to the object at ffff88805cf80000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 1848 bytes inside of
 8192-byte region [ffff88805cf80000, ffff88805cf82000)

The buggy address belongs to the physical page:
page:ffffea000173e000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5cf80
head:ffffea000173e000 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea0001d26600 dead000000000006 ffff888017442280
raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 4330, tgid 4330 (syz-executor), ts 85447362916, free_ts 85427637976
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328
 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614
 alloc_slab_page+0x5d/0x160 mm/slub.c:1799
 allocate_slab mm/slub.c:1944 [inline]
 new_slab+0x87/0x2c0 mm/slub.c:1997
 ___slab_alloc+0xbc6/0x1230 mm/slub.c:3154
 __slab_alloc mm/slub.c:3240 [inline]
 slab_alloc_node mm/slub.c:3325 [inline]
 __kmem_cache_alloc_node+0x1a0/0x260 mm/slub.c:3398
 __do_kmalloc_node mm/slab_common.c:935 [inline]
 __kmalloc+0xa0/0x240 mm/slab_common.c:949
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 ops_init+0x8b/0x5f0 net/core/net_namespace.c:128
 setup_net+0x4e1/0xbb0 net/core/net_namespace.c:336
 copy_net_ns+0x348/0x5b0 net/core/net_namespace.c:508
 create_new_namespaces+0x3d3/0x6f0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x116/0x160 kernel/nsproxy.c:226
 ksys_unshare+0x4bc/0x890 kernel/fork.c:3277
 __do_sys_unshare kernel/fork.c:3348 [inline]
 __se_sys_unshare kernel/fork.c:3346 [inline]
 __x64_sys_unshare+0x34/0x40 kernel/fork.c:3346
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3384
 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3479
 __vunmap+0x856/0xa00 mm/vmalloc.c:2726
 kcov_put kernel/kcov.c:437 [inline]
 kcov_close+0x27/0x50 kernel/kcov.c:533
 __fput+0x22c/0x920 fs/file_table.c:320
 task_work_run+0x1ca/0x250 kernel/task_work.c:203
 exit_task_work include/linux/task_work.h:39 [inline]
 do_exit+0x93e/0x2400 kernel/exit.c:880
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 get_signal+0x1272/0x1350 kernel/signal.c:2871
 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffff88805cf80600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805cf80680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805cf80700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff88805cf80780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88805cf80800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (49):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/20 10:34 linux-6.1.y 363a599da6d9 67c37560 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/06/04 01:10 linux-6.1.y da3c5173c55f a30356b7 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/02/09 00:34 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/11/23 04:03 linux-6.1.y f6e38ae624cf 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/10/29 19:26 linux-6.1.y f6e38ae624cf fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/10/01 19:45 linux-6.1.y 7b34dc04e4ff a1859138 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/09/24 19:35 linux-6.1.y 363a599da6d9 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/09/20 05:07 linux-6.1.y 363a599da6d9 67c37560 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/09/14 00:37 linux-6.1.y 3db754f56897 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/09/06 14:25 linux-6.1.y 28c695c365e1 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/09/03 03:03 linux-6.1.y f89b6e15694c 96a211bc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/09/01 22:54 linux-6.1.y f89b6e15694c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/31 04:01 linux-6.1.y f89b6e15694c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/31 03:59 linux-6.1.y f89b6e15694c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/31 03:55 linux-6.1.y f89b6e15694c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/31 03:54 linux-6.1.y f89b6e15694c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/30 16:47 linux-6.1.y f89b6e15694c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/21 12:20 linux-6.1.y 0bc96de781b4 0b9605c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/19 12:40 linux-6.1.y 0bc96de781b4 523f460e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/16 02:41 linux-6.1.y 0bc96de781b4 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/12 15:42 linux-6.1.y 3594f306da12 c06e8995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/12 15:40 linux-6.1.y 3594f306da12 c06e8995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/11 01:58 linux-6.1.y 3594f306da12 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/09 08:24 linux-6.1.y 3594f306da12 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/08/01 11:29 linux-6.1.y 3594f306da12 40127d41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/07/29 14:01 linux-6.1.y 3594f306da12 c4a95487 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/07/29 13:20 linux-6.1.y 3594f306da12 c4a95487 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/07/29 02:20 linux-6.1.y 3594f306da12 6654ea9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/07/23 10:57 linux-6.1.y 3369c6df2fae e1dd4f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/07/22 13:11 linux-6.1.y 3369c6df2fae 1555463b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/07/14 10:50 linux-6.1.y dfc486ec9cce d8fc7335 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/07/11 08:07 linux-6.1.y dfc486ec9cce 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/07/03 17:56 linux-6.1.y 7e69c33e4858 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/07/02 03:44 linux-6.1.y 7e69c33e4858 bc80e4f0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/06/03 22:13 linux-6.1.y da3c5173c55f a30356b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/06/03 22:12 linux-6.1.y da3c5173c55f a30356b7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/03/20 04:23 linux-6.1.y 344a09659766 9209bc22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/03/17 18:25 linux-6.1.y 344a09659766 948c34e4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/02/22 19:17 linux-6.1.y 3a8358583626 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/02/22 02:48 linux-6.1.y 3a8358583626 d34966d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/02/08 23:55 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/02/08 23:49 linux-6.1.y 0cbb5f65e52f ef44b750 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2025/02/01 11:11 linux-6.1.y 75cefdf153f5 aa47157c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2024/12/29 07:20 linux-6.1.y 563edd786f0a d3ccff63 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2024/11/27 04:55 linux-6.1.y e4d90d63d385 52b38cc1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2024/11/20 15:57 linux-6.1.y b67dc5c9ade9 4fca1650 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2024/09/04 01:30 linux-6.1.y 311d8503ef9f 326f9c5a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2024/08/25 14:08 linux-6.1.y ee5e09825b81 d7d32352 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
2024/08/22 03:35 linux-6.1.y ee5e09825b81 ca02180f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: use-after-free Read in v4l2_fh_open
* Struck through repros no longer work on HEAD.