KASAN: slab-use-after-free Read in v4l2_release (2)

Status: fixed on 2026/05/21 07:50
Subsystems: media
[Documentation on labels]
Reported-by: syzbot+a658d41cf8564471775e@syzkaller.appspotmail.com
Fix commit: 3b7da2b4d0fe media: hackrf: fix to not free memory after the device is registered in hackrf_probe()
First crash: 355d, last: 113d
Cause bisection: failed (error log, bisect log)
  
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Discussions (5)
Title Replies (including bot) Last reply
[PATCH v3] media: hackrf: fix to not free memory after the device is registered in hackrf_probe() 2 (2) 2026/01/10 15:06
[PATCH v2 RESEND] media: hackrf: fix to not free memory after the device is registered in hackrf_probe() 3 (3) 2026/01/10 03:46
[syzbot] [media?] [usb?] KASAN: slab-use-after-free Read in v4l2_release (2) 1 (3) 2025/08/24 08:37
[PATCH v2] media: hackrf: fix to not free memory after the device is registered in hackrf_probe() 1 (1) 2025/08/23 12:00
[PATCH] media: hackrf: fix to not free memory after the device is registered in hackrf_probe() 1 (1) 2025/08/22 14:27
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in v4l2_release media usb 19 syz, C error inconclusive 1 556d 619d 0/29 auto-obsoleted due to no activity on 2025/07/14 22:25
upstream KASAN: use-after-free Read in v4l2_release (3) usb media 19 syz, C error error 34 1840d 2396d 0/29 auto-obsoleted due to no activity on 2023/04/15 03:26
▶ ▼ Last patch testing requests (2)
Created Duration User Patch Repo Result
2025/09/07 08:11 54m retest repro upstream report log
2025/08/24 08:09 27m hdanton@sina.com patch upstream OK log
▶ ▼ Fix bisection attempts (4)
Created Duration User Patch Repo Result
2026/01/22 02:54 1m bisect fix upstream error job log
2025/12/14 21:22 3h27m bisect fix upstream OK (0) job log log
2025/11/14 16:06 3h34m bisect fix upstream OK (0) job log log
2025/10/10 17:30 6h52m bisect fix upstream OK (0) job log log

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in v4l2_release+0xb5/0x370 drivers/media/v4l2-core/v4l2-dev.c:466
Read of size 8 at addr ffff88807bed4598 by task v4l_id/8439

CPU: 0 UID: 0 PID: 8439 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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
 v4l2_release+0xb5/0x370 drivers/media/v4l2-core/v4l2-dev.c:466
 __fput+0x44f/0xa70 fs/file_table.c:469
 fput_close_sync+0x11f/0x240 fs/file_table.c:574
 __do_sys_close fs/open.c:1509 [inline]
 __se_sys_close fs/open.c:1494 [inline]
 __x64_sys_close+0x7e/0x110 fs/open.c:1494
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffa99ea7407
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:00007ffe800b4760 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007ffa9a55f880 RCX: 00007ffa99ea7407
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffa9a55f6e8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000002
R13: 00007ffe800b4990 R14: 00007ffa9a6c6000 R15: 0000561ea53d14d8
 </TASK>

Allocated by task 6165:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5380
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 hackrf_probe+0xe6/0x13a0 drivers/media/usb/hackrf/hackrf.c:1351
 usb_probe_interface+0x668/0xc90 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x267/0xaf0 drivers/base/dd.c:721
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:863
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:893
 __device_attach_driver+0x279/0x430 drivers/base/dd.c:1021
 bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
 __device_attach+0x2c5/0x450 drivers/base/dd.c:1093
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1148
 bus_probe_device+0x12a/0x220 drivers/base/bus.c:613
 device_add+0x7b6/0xb70 drivers/base/core.c:3691
 usb_set_configuration+0x1a87/0x2110 drivers/usb/core/message.c:2266
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
 usb_probe_device+0x1c4/0x3b0 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x267/0xaf0 drivers/base/dd.c:721
 __driver_probe_device+0x18c/0x320 drivers/base/dd.c:863
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:893
 __device_attach_driver+0x279/0x430 drivers/base/dd.c:1021
 bus_for_each_drv+0x258/0x2f0 drivers/base/bus.c:500
 __device_attach+0x2c5/0x450 drivers/base/dd.c:1093
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1148
 bus_probe_device+0x12a/0x220 drivers/base/bus.c:613
 device_add+0x7b6/0xb70 drivers/base/core.c:3691
 usb_new_device+0xa08/0x16f0 drivers/usb/core/hub.c:2695
 hub_port_connect drivers/usb/core/hub.c:5567 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x2a1c/0x4f30 drivers/usb/core/hub.c:5953
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff88807bed4000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 1432 bytes inside of
 freed 8192-byte region [ffff88807bed4000, ffff88807bed6000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7bed0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813fea6280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fea6280 dead000000000100 dead000000000122
head: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0001efb401 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5943, tgid 5943 (syz-executor), ts 114523858350, free_ts 114424532620
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1889
 prep_new_page mm/page_alloc.c:1897 [inline]
 get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3962
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5250
 alloc_slab_page mm/slub.c:3292 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3481
 new_slab mm/slub.c:3539 [inline]
 refill_objects+0x331/0x3c0 mm/slub.c:7175
 refill_sheaf mm/slub.c:2812 [inline]
 __pcs_replace_empty_main+0x2e6/0x730 mm/slub.c:4615
 alloc_from_pcs mm/slub.c:4717 [inline]
 slab_alloc_node mm/slub.c:4851 [inline]
 __do_kmalloc_node mm/slub.c:5259 [inline]
 __kvmalloc_node_noprof+0x657/0x8a0 mm/slub.c:6752
 kvmalloc_array_node_noprof include/linux/slab.h:1216 [inline]
 __ptr_ring_init_queue_alloc_noprof include/linux/ptr_ring.h:481 [inline]
 ptr_ring_init_noprof include/linux/ptr_ring.h:499 [inline]
 skb_array_init_noprof include/linux/skb_array.h:182 [inline]
 pfifo_fast_init+0x372/0x6c0 net/sched/sch_generic.c:870
 qdisc_create_dflt+0x13b/0x510 net/sched/sch_generic.c:1013
 mq_init_common+0x25c/0x440 net/sched/sch_mq.c:91
 mq_init+0x84/0x270 net/sched/sch_mq.c:112
 qdisc_create_dflt+0x13b/0x510 net/sched/sch_generic.c:1013
 attach_default_qdiscs net/sched/sch_generic.c:1195 [inline]
 dev_activate+0x1ce/0x1150 net/sched/sch_generic.c:1249
 __dev_open+0x67a/0x830 net/core/dev.c:1711
 __dev_change_flags+0x1f7/0x690 net/core/dev.c:9764
 netif_change_flags+0x88/0x1a0 net/core/dev.c:9827
page last free pid 29 tgid 29 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1433 [inline]
 __free_frozen_pages+0xc2b/0xdb0 mm/page_alloc.c:2978
 __slab_free+0x263/0x2b0 mm/slub.c:5573
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4538 [inline]
 slab_alloc_node mm/slub.c:4866 [inline]
 kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4918
 __alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
 alloc_skb include/linux/skbuff.h:1383 [inline]
 mld_newpack+0x14c/0xc90 net/ipv6/mcast.c:1775
 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1886
 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2025
 mld_send_cr net/ipv6/mcast.c:2148 [inline]
 mld_ifc_work+0x6e6/0xe70 net/ipv6/mcast.c:2693
 process_one_work kernel/workqueue.c:3276 [inline]
 process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88807bed4480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807bed4500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807bed4580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88807bed4600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88807bed4680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/23 21:36 upstream c369299895a5 5e3db351 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root KASAN: slab-use-after-free Read in v4l2_release
2025/08/24 06:16 upstream 8d245acc1e88 bf27483f .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Read in v4l2_release
2026/04/09 08:00 upstream 7f87a5ea75f0 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Read in v4l2_release
2026/02/19 01:01 upstream 2961f841b025 77d4d919 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in v4l2_release
2025/12/23 00:44 upstream 9448598b22c5 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in v4l2_release
2025/08/10 03:57 upstream 561c80369df0 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in v4l2_release
* Struck through repros no longer work on HEAD.