==================================================================
BUG: KASAN: slab-use-after-free in v4l2_open+0x351/0x490 drivers/media/v4l2-core/v4l2-dev.c:444
Read of size 4 at addr ffff888078448860 by task v4l_id/19113
CPU: 0 UID: 0 PID: 19113 Comm: v4l_id Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
__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+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
v4l2_open+0x351/0x490 drivers/media/v4l2-core/v4l2-dev.c:444
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6ab/0x14d0 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1079
do_open fs/namei.c:4700 [inline]
path_openat+0x2873/0x4280 fs/namei.c:4859
do_file_open+0x20e/0x430 fs/namei.c:4888
do_sys_openat2+0x10f/0x1e0 fs/open.c:1395
do_sys_open fs/open.c:1401 [inline]
__do_sys_openat fs/open.c:1417 [inline]
__se_sys_openat fs/open.c:1412 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1412
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4f78aa7407
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:00007ffc852622f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f4f7929b880 RCX: 00007f4f78aa7407
RDX: 0000000000000000 RSI: 00007ffc85262f1b RDI: ffffffffffffff9c
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffc85262540 R14: 00007f4f79402000 R15: 00005597b471e4d8
Allocated by task 5772:
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:969 [inline]
_kzalloc_noprof include/linux/slab.h:1286 [inline]
em28xx_v4l2_init.cold+0x94/0x3a40 drivers/media/usb/em28xx/em28xx-video.c:2709
em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1248
request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3660
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Freed by task 5772:
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:2700 [inline]
slab_free mm/slub.c:6310 [inline]
kfree+0x22b/0x6c0 mm/slub.c:6625
kref_put.isra.0+0x53/0x75 include/linux/kref.h:65
em28xx_v4l2_init.cold+0x280/0x3a40 drivers/media/usb/em28xx/em28xx-video.c:3080
em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1248
request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3660
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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 ffff888078448000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2144 bytes inside of
freed 8192-byte region [ffff888078448000, ffff88807844a000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78448
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 ffff88813fe3d280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fe3d280 dead000000000100 dead000000000122
head: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000003 fffffffffffffe01 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 0x1d28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 7425, tgid 7425 (syz-executor), ts 202605798064, free_ts 202598336134
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1853
prep_new_page mm/page_alloc.c:1861 [inline]
get_page_from_freelist+0x812/0x3d20 mm/page_alloc.c:3941
__alloc_frozen_pages_noprof+0x27c/0x2b60 mm/page_alloc.c:5221
alloc_slab_page mm/slub.c:3289 [inline]
allocate_slab mm/slub.c:3404 [inline]
new_slab+0xa2/0x670 mm/slub.c:3447
refill_objects+0xe3/0x430 mm/slub.c:7241
refill_sheaf mm/slub.c:2827 [inline]
__pcs_replace_empty_main+0x375/0x660 mm/slub.c:4692
alloc_from_pcs mm/slub.c:4790 [inline]
slab_alloc_node mm/slub.c:4924 [inline]
__do_kmalloc_node mm/slub.c:5333 [inline]
__kvmalloc_node_noprof+0x809/0xa60 mm/slub.c:6833
_kvmalloc_array_node_noprof include/linux/slab.h:1348 [inline]
__ptr_ring_init_queue_alloc_noprof include/linux/ptr_ring.h:497 [inline]
ptr_ring_init_noprof include/linux/ptr_ring.h:515 [inline]
skb_array_init_noprof include/linux/skb_array.h:182 [inline]
pfifo_fast_init+0x177/0x3b0 net/sched/sch_generic.c:920
qdisc_create_dflt+0x124/0x490 net/sched/sch_generic.c:1063
mq_init_common+0x1f4/0x490 net/sched/sch_mq.c:91
mq_init+0x26/0x60 net/sched/sch_mq.c:112
qdisc_create_dflt+0x124/0x490 net/sched/sch_generic.c:1063
attach_default_qdiscs net/sched/sch_generic.c:1245 [inline]
dev_activate+0xaa9/0xce0 net/sched/sch_generic.c:1299
__dev_open+0x490/0x8f0 net/core/dev.c:1711
__dev_change_flags+0x596/0x850 net/core/dev.c:9754
netif_change_flags+0x8d/0x160 net/core/dev.c:9817
page last free pid 3328 tgid 3328 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1397 [inline]
__free_frozen_pages+0x794/0x10a0 mm/page_alloc.c:2938
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x47/0xf0 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:4610 [inline]
slab_alloc_node mm/slub.c:4939 [inline]
__do_kmalloc_node mm/slub.c:5333 [inline]
__kmalloc_noprof+0x2ba/0x840 mm/slub.c:5347
_kmalloc_noprof include/linux/slab.h:973 [inline]
_kzalloc_noprof include/linux/slab.h:1286 [inline]
ieee80211_alloc_chanctx+0xa5/0x4c0 net/mac80211/chan.c:1006
ieee80211_new_chanctx+0x84/0x320 net/mac80211/chan.c:1059
ieee80211_find_or_create_chanctx+0x279/0x2d0 net/mac80211/chan.c:2213
_ieee80211_link_use_channel+0x459/0xbc0 net/mac80211/chan.c:2319
ieee80211_link_use_channel net/mac80211/ieee80211_i.h:2823 [inline]
__ieee80211_sta_join_ibss+0x607/0x1940 net/mac80211/ibss.c:292
ieee80211_sta_create_ibss.cold+0xaf/0x104 net/mac80211/ibss.c:1286
ieee80211_sta_find_ibss net/mac80211/ibss.c:1415 [inline]
ieee80211_ibss_work.cold+0x253/0x431 net/mac80211/ibss.c:1636
ieee80211_iface_work+0xac4/0x1070 net/mac80211/iface.c:1839
cfg80211_wiphy_work+0x2b7/0x550 net/wireless/core.c:538
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
Memory state around the buggy address:
ffff888078448700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888078448780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888078448800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888078448880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888078448900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in kobject_put+0x590/0x640 lib/kobject.c:733
Read of size 1 at addr ffff8880784482f4 by task v4l_id/19113
CPU: 0 UID: 0 PID: 19113 Comm: v4l_id Tainted: G B syzkaller #0 PREEMPT(full)
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
__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+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
kobject_put+0x590/0x640 lib/kobject.c:733
put_device+0x1f/0x30 drivers/base/core.c:3880
video_put drivers/media/v4l2-core/v4l2-dev.c:173 [inline]
v4l2_open+0x2e5/0x490 drivers/media/v4l2-core/v4l2-dev.c:450
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6ab/0x14d0 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1079
do_open fs/namei.c:4700 [inline]
path_openat+0x2873/0x4280 fs/namei.c:4859
do_file_open+0x20e/0x430 fs/namei.c:4888
do_sys_openat2+0x10f/0x1e0 fs/open.c:1395
do_sys_open fs/open.c:1401 [inline]
__do_sys_openat fs/open.c:1417 [inline]
__se_sys_openat fs/open.c:1412 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1412
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4f78aa7407
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:00007ffc852622f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f4f7929b880 RCX: 00007f4f78aa7407
RDX: 0000000000000000 RSI: 00007ffc85262f1b RDI: ffffffffffffff9c
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffc85262540 R14: 00007f4f79402000 R15: 00005597b471e4d8
Allocated by task 5772:
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:969 [inline]
_kzalloc_noprof include/linux/slab.h:1286 [inline]
em28xx_v4l2_init.cold+0x94/0x3a40 drivers/media/usb/em28xx/em28xx-video.c:2709
em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1248
request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3660
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Freed by task 5772:
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:2700 [inline]
slab_free mm/slub.c:6310 [inline]
kfree+0x22b/0x6c0 mm/slub.c:6625
kref_put.isra.0+0x53/0x75 include/linux/kref.h:65
em28xx_v4l2_init.cold+0x280/0x3a40 drivers/media/usb/em28xx/em28xx-video.c:3080
em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1248
request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3660
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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 ffff888078448000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 756 bytes inside of
freed 8192-byte region [ffff888078448000, ffff88807844a000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78448
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 ffff88813fe3d280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fe3d280 dead000000000100 dead000000000122
head: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000003 fffffffffffffe01 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 0x1d28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 7425, tgid 7425 (syz-executor), ts 202605798064, free_ts 202598336134
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1853
prep_new_page mm/page_alloc.c:1861 [inline]
get_page_from_freelist+0x812/0x3d20 mm/page_alloc.c:3941
__alloc_frozen_pages_noprof+0x27c/0x2b60 mm/page_alloc.c:5221
alloc_slab_page mm/slub.c:3289 [inline]
allocate_slab mm/slub.c:3404 [inline]
new_slab+0xa2/0x670 mm/slub.c:3447
refill_objects+0xe3/0x430 mm/slub.c:7241
refill_sheaf mm/slub.c:2827 [inline]
__pcs_replace_empty_main+0x375/0x660 mm/slub.c:4692
alloc_from_pcs mm/slub.c:4790 [inline]
slab_alloc_node mm/slub.c:4924 [inline]
__do_kmalloc_node mm/slub.c:5333 [inline]
__kvmalloc_node_noprof+0x809/0xa60 mm/slub.c:6833
_kvmalloc_array_node_noprof include/linux/slab.h:1348 [inline]
__ptr_ring_init_queue_alloc_noprof include/linux/ptr_ring.h:497 [inline]
ptr_ring_init_noprof include/linux/ptr_ring.h:515 [inline]
skb_array_init_noprof include/linux/skb_array.h:182 [inline]
pfifo_fast_init+0x177/0x3b0 net/sched/sch_generic.c:920
qdisc_create_dflt+0x124/0x490 net/sched/sch_generic.c:1063
mq_init_common+0x1f4/0x490 net/sched/sch_mq.c:91
mq_init+0x26/0x60 net/sched/sch_mq.c:112
qdisc_create_dflt+0x124/0x490 net/sched/sch_generic.c:1063
attach_default_qdiscs net/sched/sch_generic.c:1245 [inline]
dev_activate+0xaa9/0xce0 net/sched/sch_generic.c:1299
__dev_open+0x490/0x8f0 net/core/dev.c:1711
__dev_change_flags+0x596/0x850 net/core/dev.c:9754
netif_change_flags+0x8d/0x160 net/core/dev.c:9817
page last free pid 3328 tgid 3328 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1397 [inline]
__free_frozen_pages+0x794/0x10a0 mm/page_alloc.c:2938
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x47/0xf0 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:4610 [inline]
slab_alloc_node mm/slub.c:4939 [inline]
__do_kmalloc_node mm/slub.c:5333 [inline]
__kmalloc_noprof+0x2ba/0x840 mm/slub.c:5347
_kmalloc_noprof include/linux/slab.h:973 [inline]
_kzalloc_noprof include/linux/slab.h:1286 [inline]
ieee80211_alloc_chanctx+0xa5/0x4c0 net/mac80211/chan.c:1006
ieee80211_new_chanctx+0x84/0x320 net/mac80211/chan.c:1059
ieee80211_find_or_create_chanctx+0x279/0x2d0 net/mac80211/chan.c:2213
_ieee80211_link_use_channel+0x459/0xbc0 net/mac80211/chan.c:2319
ieee80211_link_use_channel net/mac80211/ieee80211_i.h:2823 [inline]
__ieee80211_sta_join_ibss+0x607/0x1940 net/mac80211/ibss.c:292
ieee80211_sta_create_ibss.cold+0xaf/0x104 net/mac80211/ibss.c:1286
ieee80211_sta_find_ibss net/mac80211/ibss.c:1415 [inline]
ieee80211_ibss_work.cold+0x253/0x431 net/mac80211/ibss.c:1636
ieee80211_iface_work+0xac4/0x1070 net/mac80211/iface.c:1839
cfg80211_wiphy_work+0x2b7/0x550 net/wireless/core.c:538
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
Memory state around the buggy address:
ffff888078448180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888078448200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888078448280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888078448300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888078448380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
BUG: KASAN: slab-use-after-free in atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline]
BUG: KASAN: slab-use-after-free in __refcount_sub_and_test include/linux/refcount.h:389 [inline]
BUG: KASAN: slab-use-after-free in __refcount_dec_and_test include/linux/refcount.h:432 [inline]
BUG: KASAN: slab-use-after-free in refcount_dec_and_test include/linux/refcount.h:450 [inline]
BUG: KASAN: slab-use-after-free in kref_put include/linux/kref.h:64 [inline]
BUG: KASAN: slab-use-after-free in kobject_put+0x88/0x640 lib/kobject.c:737
Write of size 4 at addr ffff8880784482f0 by task v4l_id/19113
CPU: 1 UID: 0 PID: 19113 Comm: v4l_id Tainted: G B syzkaller #0 PREEMPT(full)
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
__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+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:186 [inline]
kasan_check_range+0x10f/0x1e0 mm/kasan/generic.c:200
instrument_atomic_read_write include/linux/instrumented.h:112 [inline]
atomic_fetch_sub_release include/linux/atomic/atomic-instrumented.h:400 [inline]
__refcount_sub_and_test include/linux/refcount.h:389 [inline]
__refcount_dec_and_test include/linux/refcount.h:432 [inline]
refcount_dec_and_test include/linux/refcount.h:450 [inline]
kref_put include/linux/kref.h:64 [inline]
kobject_put+0x88/0x640 lib/kobject.c:737
put_device+0x1f/0x30 drivers/base/core.c:3880
video_put drivers/media/v4l2-core/v4l2-dev.c:173 [inline]
v4l2_open+0x2e5/0x490 drivers/media/v4l2-core/v4l2-dev.c:450
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6ab/0x14d0 fs/open.c:947
vfs_open+0x82/0x3f0 fs/open.c:1079
do_open fs/namei.c:4700 [inline]
path_openat+0x2873/0x4280 fs/namei.c:4859
do_file_open+0x20e/0x430 fs/namei.c:4888
do_sys_openat2+0x10f/0x1e0 fs/open.c:1395
do_sys_open fs/open.c:1401 [inline]
__do_sys_openat fs/open.c:1417 [inline]
__se_sys_openat fs/open.c:1412 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1412
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4f78aa7407
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:00007ffc852622f0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f4f7929b880 RCX: 00007f4f78aa7407
RDX: 0000000000000000 RSI: 00007ffc85262f1b RDI: ffffffffffffff9c
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 00007ffc85262540 R14: 00007f4f79402000 R15: 00005597b471e4d8
Allocated by task 5772:
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:969 [inline]
_kzalloc_noprof include/linux/slab.h:1286 [inline]
em28xx_v4l2_init.cold+0x94/0x3a40 drivers/media/usb/em28xx/em28xx-video.c:2709
em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1248
request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3660
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Freed by task 5772:
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:2700 [inline]
slab_free mm/slub.c:6310 [inline]
kfree+0x22b/0x6c0 mm/slub.c:6625
kref_put.isra.0+0x53/0x75 include/linux/kref.h:65
em28xx_v4l2_init.cold+0x280/0x3a40 drivers/media/usb/em28xx/em28xx-video.c:3080
em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1248
request_module_async+0x61/0x80 drivers/media/usb/em28xx/em28xx-cards.c:3660
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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 ffff888078448000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 752 bytes inside of
freed 8192-byte region [ffff888078448000, ffff88807844a000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78448
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 ffff88813fe3d280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fe3d280 dead000000000100 dead000000000122
head: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 00fff00000000003 fffffffffffffe01 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 0x1d28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 7425, tgid 7425 (syz-executor), ts 202605798064, free_ts 202598336134
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1853
prep_new_page mm/page_alloc.c:1861 [inline]
get_page_from_freelist+0x812/0x3d20 mm/page_alloc.c:3941
__alloc_frozen_pages_noprof+0x27c/0x2b60 mm/page_alloc.c:5221
alloc_slab_page mm/slub.c:3289 [inline]
allocate_slab mm/slub.c:3404 [inline]
new_slab+0xa2/0x670 mm/slub.c:3447
refill_objects+0xe3/0x430 mm/slub.c:7241
refill_sheaf mm/slub.c:2827 [inline]
__pcs_replace_empty_main+0x375/0x660 mm/slub.c:4692
alloc_from_pcs mm/slub.c:4790 [inline]
slab_alloc_node mm/slub.c:4924 [inline]
__do_kmalloc_node mm/slub.c:5333 [inline]
__kvmalloc_node_noprof+0x809/0xa60 mm/slub.c:6833
_kvmalloc_array_node_noprof include/linux/slab.h:1348 [inline]
__ptr_ring_init_queue_alloc_noprof include/linux/ptr_ring.h:497 [inline]
ptr_ring_init_noprof include/linux/ptr_ring.h:515 [inline]
skb_array_init_noprof include/linux/skb_array.h:182 [inline]
pfifo_fast_init+0x177/0x3b0 net/sched/sch_generic.c:920
qdisc_create_dflt+0x124/0x490 net/sched/sch_generic.c:1063
mq_init_common+0x1f4/0x490 net/sched/sch_mq.c:91
mq_init+0x26/0x60 net/sched/sch_mq.c:112
qdisc_create_dflt+0x124/0x490 net/sched/sch_generic.c:1063
attach_default_qdiscs net/sched/sch_generic.c:1245 [inline]
dev_activate+0xaa9/0xce0 net/sched/sch_generic.c:1299
__dev_open+0x490/0x8f0 net/core/dev.c:1711
__dev_change_flags+0x596/0x850 net/core/dev.c:9754
netif_change_flags+0x8d/0x160 net/core/dev.c:9817
page last free pid 3328 tgid 3328 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1397 [inline]
__free_frozen_pages+0x794/0x10a0 mm/page_alloc.c:2938
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x47/0xf0 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:4610 [inline]
slab_alloc_node mm/slub.c:4939 [inline]
__do_kmalloc_node mm/slub.c:5333 [inline]
__kmalloc_noprof+0x2ba/0x840 mm/slub.c:5347
_kmalloc_noprof include/linux/slab.h:973 [inline]
_kzalloc_noprof include/linux/slab.h:1286 [inline]
ieee80211_alloc_chanctx+0xa5/0x4c0 net/mac80211/chan.c:1006
ieee80211_new_chanctx+0x84/0x320 net/mac80211/chan.c:1059
ieee80211_find_or_create_chanctx+0x279/0x2d0 net/mac80211/chan.c:2213
_ieee80211_link_use_channel+0x459/0xbc0 net/mac80211/chan.c:2319
ieee80211_link_use_channel net/mac80211/ieee80211_i.h:2823 [inline]
__ieee80211_sta_join_ibss+0x607/0x1940 net/mac80211/ibss.c:292
ieee80211_sta_create_ibss.cold+0xaf/0x104 net/mac80211/ibss.c:1286
ieee80211_sta_find_ibss net/mac80211/ibss.c:1415 [inline]
ieee80211_ibss_work.cold+0x253/0x431 net/mac80211/ibss.c:1636
ieee80211_iface_work+0xac4/0x1070 net/mac80211/iface.c:1839
cfg80211_wiphy_work+0x2b7/0x550 net/wireless/core.c:538
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
Memory state around the buggy address:
ffff888078448180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888078448200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888078448280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888078448300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888078448380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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