[moderation] [media?] KASAN: slab-use-after-free Read in vb2_core_queue_release (2)

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Apr 8, 2026, 2:17:22 AM (3 days ago) Apr 8
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Hello,

syzbot found the following issue on:

HEAD commit: 631919fb12fe Merge tag 'sched_ext-for-7.0-rc6-fixes-2' of ..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17fef3d6580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5a3e5e8c17cc174e
dashboard link: https://syzkaller.appspot.com/bug?extid=dea72621ea41b0a18217
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
CC: [linux-...@vger.kernel.org linux...@vger.kernel.org m.szyp...@samsung.com mch...@kernel.org tf...@chromium.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b1c4c524a601/disk-631919fb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f9b882f1f558/vmlinux-631919fb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4c82d30da7f9/bzImage-631919fb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dea726...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in vb2_core_queue_release+0x150/0x190 drivers/media/common/videobuf2/videobuf2-core.c:2679
Read of size 4 at addr ffff88802d000f48 by task v4l_id/21137

CPU: 0 UID: 0 PID: 21137 Comm: v4l_id Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x156/0x4c9 mm/kasan/report.c:482
kasan_report+0xdf/0x1e0 mm/kasan/report.c:595
vb2_core_queue_release+0x150/0x190 drivers/media/common/videobuf2/videobuf2-core.c:2679
vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:956 [inline]
_vb2_fop_release+0xe8/0x280 drivers/media/common/videobuf2/videobuf2-v4l2.c:1159
v4l2_release+0x280/0x390 drivers/media/v4l2-core/v4l2-dev.c:471
__fput+0x3ff/0xb40 fs/file_table.c:469
fput_close_sync+0x118/0x250 fs/file_table.c:574
__do_sys_close fs/open.c:1509 [inline]
__se_sys_close fs/open.c:1494 [inline]
__x64_sys_close+0x8b/0x120 fs/open.c:1494
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1adb8a7407
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:00007ffe883bdfc0 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007f1adbff2880 RCX: 00007f1adb8a7407
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f1adbff26e8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffe883be1f0 R14: 00007f1adc159000 R15: 0000562e7d91b4d8
</TASK>

Allocated by task 29:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
hackrf_probe+0xcf/0x5d0 drivers/media/usb/hackrf/hackrf.c:1351
usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:643 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:721
__driver_probe_device+0x1de/0x400 drivers/base/dd.c:863
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:893
__device_attach_driver+0x1df/0x340 drivers/base/dd.c:1021
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1093
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1148
bus_probe_device+0x64/0x160 drivers/base/bus.c:613
device_add+0x11d9/0x1950 drivers/base/core.c:3691
usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2266
usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291
call_driver_probe drivers/base/dd.c:643 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:721
__driver_probe_device+0x1de/0x400 drivers/base/dd.c:863
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:893
__device_attach_driver+0x1df/0x340 drivers/base/dd.c:1021
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1093
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1148
bus_probe_device+0x64/0x160 drivers/base/bus.c:613
device_add+0x11d9/0x1950 drivers/base/core.c:3691
usb_new_device.cold+0x685/0x115c 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+0x314d/0x4af0 drivers/usb/core/hub.c:5953
process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
process_scheduled_works kernel/workqueue.c:3359 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 29:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2685 [inline]
slab_free mm/slub.c:6165 [inline]
kfree+0x1f6/0x6b0 mm/slub.c:6483
hackrf_probe.cold+0x40/0x12f9 drivers/media/usb/hackrf/hackrf.c:1523
usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:643 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:721
__driver_probe_device+0x1de/0x400 drivers/base/dd.c:863
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:893
__device_attach_driver+0x1df/0x340 drivers/base/dd.c:1021
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1093
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1148
bus_probe_device+0x64/0x160 drivers/base/bus.c:613
device_add+0x11d9/0x1950 drivers/base/core.c:3691
usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2266
usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291
call_driver_probe drivers/base/dd.c:643 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:721
__driver_probe_device+0x1de/0x400 drivers/base/dd.c:863
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:893
__device_attach_driver+0x1df/0x340 drivers/base/dd.c:1021
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1093
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1148
bus_probe_device+0x64/0x160 drivers/base/bus.c:613
device_add+0x11d9/0x1950 drivers/base/core.c:3691
usb_new_device.cold+0x685/0x115c 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+0x314d/0x4af0 drivers/usb/core/hub.c:5953
process_one_work+0xa23/0x19a0 kernel/workqueue.c:3276
process_scheduled_works kernel/workqueue.c:3359 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3440
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x754/0xd80 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 ffff88802d000000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 3912 bytes inside of
freed 8192-byte region [ffff88802d000000, ffff88802d002000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2d000
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 ffff88813fe41280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fe41280 dead000000000100 dead000000000122
head: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0000b40001 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 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 11594, tgid 11586 (syz.1.1536), ts 456308172457, free_ts 456186809005
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x153/0x170 mm/page_alloc.c:1889
prep_new_page mm/page_alloc.c:1897 [inline]
get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3962
__alloc_frozen_pages_noprof+0x27c/0x2ba0 mm/page_alloc.c:5250
alloc_slab_page mm/slub.c:3292 [inline]
allocate_slab mm/slub.c:3481 [inline]
new_slab+0xa6/0x6b0 mm/slub.c:3539
refill_objects+0x26b/0x400 mm/slub.c:7175
refill_sheaf mm/slub.c:2812 [inline]
__pcs_replace_empty_main+0x1ab/0x660 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]
__kmalloc_noprof+0x688/0x850 mm/slub.c:5272
kmalloc_noprof include/linux/slab.h:954 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
tomoyo_init_log+0x1224/0x20c0 security/tomoyo/audit.c:275
tomoyo_supervisor+0x506/0x1340 security/tomoyo/common.c:2232
tomoyo_audit_path_log security/tomoyo/file.c:169 [inline]
tomoyo_path_permission security/tomoyo/file.c:592 [inline]
tomoyo_path_permission+0x270/0x3b0 security/tomoyo/file.c:577
tomoyo_path_perm+0x3d6/0x460 security/tomoyo/file.c:843
tomoyo_path_symlink+0x97/0xe0 security/tomoyo/tomoyo.c:212
security_path_symlink+0x152/0x2d0 security/security.c:1477
filename_symlinkat+0x122/0x560 fs/namei.c:5644
__do_sys_symlink fs/namei.c:5673 [inline]
__se_sys_symlink fs/namei.c:5669 [inline]
__x64_sys_symlink+0x79/0xb0 fs/namei.c:5669
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
page last free pid 5181 tgid 5181 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
__free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 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]
__do_kmalloc_node mm/slub.c:5259 [inline]
__kvmalloc_node_noprof+0x316/0xa00 mm/slub.c:6752
seq_buf_alloc fs/seq_file.c:39 [inline]
seq_read_iter+0x819/0x1270 fs/seq_file.c:211
kernfs_fop_read_iter+0x46c/0x610 fs/kernfs/file.c:297
new_sync_read fs/read_write.c:493 [inline]
vfs_read+0x825/0xb30 fs/read_write.c:574
ksys_read+0x12a/0x250 fs/read_write.c:717
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff88802d000e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802d000e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802d000f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802d000f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802d001000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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