[v6.1] KASAN: use-after-free Read in dvb_device_open
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syzbot
Feb 7, 2026, 5:59:29 AM (2 days ago) Feb 7
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 0182cb5b74ee Linux 6.1.162
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16243d3a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=e90b3d2c21add5ffde1c
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/91a9c745b7a1/disk-0182cb5b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a26ca15eb2ec/vmlinux-0182cb5b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/767cda5049bb/bzImage-0182cb5b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e90b3d...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:99
Read of size 8 at addr ffff888147bdce18 by task syz.4.4215/24321
CPU: 1 PID: 24321 Comm: syz.4.4215 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e 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
dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:99
chrdev_open+0x5c5/0x6a0 fs/char_dev.c:414
do_dentry_open+0x7e9/0x10d0 fs/open.c:882
do_open fs/namei.c:3634 [inline]
path_openat+0x2635/0x2ee0 fs/namei.c:3791
do_filp_open+0x1f1/0x430 fs/namei.c:3818
do_sys_openat2+0x150/0x4b0 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb00a15b78e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007fb00affab28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fb00affb6c0 RCX: 00007fb00a15b78e
RDX: 0000000000040002 RSI: 00007fb00affac00 RDI: ffffffffffffff9c
RBP: 00007fb00affac00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007fb00a416038 R14: 00007fb00a415fa0 R15: 00007ffc665ef558
</TASK>
Allocated by task 1:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
dvb_register_device+0x311/0x2150 drivers/media/dvb-core/dvbdev.c:478
dvb_register_frontend+0x645/0x920 drivers/media/dvb-core/dvb_frontend.c:3035
vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline]
vidtv_bridge_probe+0x9a1/0xf70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
platform_probe+0x137/0x1c0 drivers/base/platform.c:1400
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2aa/0xc70 drivers/base/dd.c:639
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:785
driver_probe_device+0x4f/0x420 drivers/base/dd.c:815
__driver_attach+0x44a/0x6e0 drivers/base/dd.c:1201
bus_for_each_dev+0x182/0x1f0 drivers/base/bus.c:303
bus_add_driver+0x30a/0x5a0 drivers/base/bus.c:620
driver_register+0x32d/0x430 drivers/base/driver.c:246
vidtv_bridge_init+0x39/0x67 drivers/media/test-drivers/vidtv/vidtv_bridge.c:600
do_one_initcall+0x26a/0x840 init/main.c:1310
do_initcall_level+0x137/0x1e4 init/main.c:1383
do_initcalls+0x4b/0x8a init/main.c:1399
kernel_init_freeable+0x415/0x5be init/main.c:1638
kernel_init+0x19/0x1b0 init/main.c:1526
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
The buggy address belongs to the object at ffff888147bdce00
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 24 bytes inside of
256-byte region [ffff888147bdce00, ffff888147bdcf00)
The buggy address belongs to the physical page:
page:ffffea00051ef700 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888147bdce00 pfn:0x147bdc
head:ffffea00051ef700 order:1 compound_mapcount:0 compound_pincount:0
flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000010200 ffffea0000639100 dead000000000003 ffff888017441b40
raw: ffff888147bdce00 000000008010000f 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 12235332926, free_ts 0
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559
prep_new_page mm/page_alloc.c:2566 [inline]
get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357
__alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5643
alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2115
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+0xbc6/0x1240 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
kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
bus_add_driver+0xda/0x5a0 drivers/base/bus.c:604
driver_register+0x32d/0x430 drivers/base/driver.c:246
usb_register_driver+0x202/0x3d0 drivers/usb/core/driver.c:1062
uvc_init+0x23/0x4a drivers/media/usb/uvc/uvc_driver.c:3087
do_one_initcall+0x26a/0x840 init/main.c:1310
do_initcall_level+0x137/0x1e4 init/main.c:1383
do_initcalls+0x4b/0x8a init/main.c:1399
page_owner free stack trace missing
Memory state around the buggy address:
ffff888147bdcd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888147bdcd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888147bdce00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888147bdce80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888147bdcf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot found the following issue on:
HEAD commit: 0182cb5b74ee Linux 6.1.162
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16243d3a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=e90b3d2c21add5ffde1c
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/91a9c745b7a1/disk-0182cb5b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a26ca15eb2ec/vmlinux-0182cb5b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/767cda5049bb/bzImage-0182cb5b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e90b3d...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:99
Read of size 8 at addr ffff888147bdce18 by task syz.4.4215/24321
CPU: 1 PID: 24321 Comm: syz.4.4215 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e 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
dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:99
chrdev_open+0x5c5/0x6a0 fs/char_dev.c:414
do_dentry_open+0x7e9/0x10d0 fs/open.c:882
do_open fs/namei.c:3634 [inline]
path_openat+0x2635/0x2ee0 fs/namei.c:3791
do_filp_open+0x1f1/0x430 fs/namei.c:3818
do_sys_openat2+0x150/0x4b0 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb00a15b78e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007fb00affab28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fb00affb6c0 RCX: 00007fb00a15b78e
RDX: 0000000000040002 RSI: 00007fb00affac00 RDI: ffffffffffffff9c
RBP: 00007fb00affac00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007fb00a416038 R14: 00007fb00a415fa0 R15: 00007ffc665ef558
</TASK>
Allocated by task 1:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0x8e/0xa0 mm/kasan/common.c:384
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
dvb_register_device+0x311/0x2150 drivers/media/dvb-core/dvbdev.c:478
dvb_register_frontend+0x645/0x920 drivers/media/dvb-core/dvb_frontend.c:3035
vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline]
vidtv_bridge_probe+0x9a1/0xf70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
platform_probe+0x137/0x1c0 drivers/base/platform.c:1400
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x2aa/0xc70 drivers/base/dd.c:639
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:785
driver_probe_device+0x4f/0x420 drivers/base/dd.c:815
__driver_attach+0x44a/0x6e0 drivers/base/dd.c:1201
bus_for_each_dev+0x182/0x1f0 drivers/base/bus.c:303
bus_add_driver+0x30a/0x5a0 drivers/base/bus.c:620
driver_register+0x32d/0x430 drivers/base/driver.c:246
vidtv_bridge_init+0x39/0x67 drivers/media/test-drivers/vidtv/vidtv_bridge.c:600
do_one_initcall+0x26a/0x840 init/main.c:1310
do_initcall_level+0x137/0x1e4 init/main.c:1383
do_initcalls+0x4b/0x8a init/main.c:1399
kernel_init_freeable+0x415/0x5be init/main.c:1638
kernel_init+0x19/0x1b0 init/main.c:1526
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
The buggy address belongs to the object at ffff888147bdce00
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 24 bytes inside of
256-byte region [ffff888147bdce00, ffff888147bdcf00)
The buggy address belongs to the physical page:
page:ffffea00051ef700 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888147bdce00 pfn:0x147bdc
head:ffffea00051ef700 order:1 compound_mapcount:0 compound_pincount:0
flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000010200 ffffea0000639100 dead000000000003 ffff888017441b40
raw: ffff888147bdce00 000000008010000f 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 12235332926, free_ts 0
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559
prep_new_page mm/page_alloc.c:2566 [inline]
get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357
__alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5643
alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2115
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+0xbc6/0x1240 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
kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
bus_add_driver+0xda/0x5a0 drivers/base/bus.c:604
driver_register+0x32d/0x430 drivers/base/driver.c:246
usb_register_driver+0x202/0x3d0 drivers/usb/core/driver.c:1062
uvc_init+0x23/0x4a drivers/media/usb/uvc/uvc_driver.c:3087
do_one_initcall+0x26a/0x840 init/main.c:1310
do_initcall_level+0x137/0x1e4 init/main.c:1383
do_initcalls+0x4b/0x8a init/main.c:1399
page_owner free stack trace missing
Memory state around the buggy address:
ffff888147bdcd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888147bdcd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888147bdce00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888147bdce80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888147bdcf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title
If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)
If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report
If you want to undo deduplication, reply with:
#syz undup
syzbot
Feb 7, 2026, 12:35:24 PM (2 days ago) Feb 7
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: 0182cb5b74ee Linux 6.1.162
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=16a5fa5a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17b867fa580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/91a9c745b7a1/disk-0182cb5b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a26ca15eb2ec/vmlinux-0182cb5b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/767cda5049bb/bzImage-0182cb5b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e90b3d...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:99
Read of size 8 at addr ffff888029746618 by task syz.0.19/4422
CPU: 0 PID: 4422 Comm: syz.0.19 Not tainted syzkaller #0
RAX: ffffffffffffffda RBX: 000055555ceb2500 RCX: 00007f592215b78e
RDX: 0000000000000002 RSI: 00007fff377b5b90 RDI: ffffffffffffff9c
RBP: 00007fff377b5b90 R08: 0000000000000000 R09: 0000000000000000
Freed by task 4421:
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
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
dvb_free_device drivers/media/dvb-core/dvbdev.c:625 [inline]
kref_put include/linux/kref.h:65 [inline]
dvb_device_put drivers/media/dvb-core/dvbdev.c:640 [inline]
dvb_device_open+0x2e7/0x370 drivers/media/dvb-core/dvbdev.c:113
The buggy address belongs to the physical page:
page:ffffea0000a5d180 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x29746
head:ffffea0000a5d180 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888017441b40
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
ffff888029746580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888029746600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888029746680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888029746700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
HEAD commit: 0182cb5b74ee Linux 6.1.162
git tree: linux-6.1.y
kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=e90b3d2c21add5ffde1c
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1636ab22580000
dashboard link: https://syzkaller.appspot.com/bug?extid=e90b3d2c21add5ffde1c
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17b867fa580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/91a9c745b7a1/disk-0182cb5b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a26ca15eb2ec/vmlinux-0182cb5b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/767cda5049bb/bzImage-0182cb5b.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e90b3d...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:99
CPU: 0 PID: 4422 Comm: syz.0.19 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e 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
dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:99
chrdev_open+0x5c5/0x6a0 fs/char_dev.c:414
do_dentry_open+0x7e9/0x10d0 fs/open.c:882
do_open fs/namei.c:3634 [inline]
path_openat+0x2635/0x2ee0 fs/namei.c:3791
do_filp_open+0x1f1/0x430 fs/namei.c:3818
do_sys_openat2+0x150/0x4b0 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f592215b78e
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x24e 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
dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:99
chrdev_open+0x5c5/0x6a0 fs/char_dev.c:414
do_dentry_open+0x7e9/0x10d0 fs/open.c:882
do_open fs/namei.c:3634 [inline]
path_openat+0x2635/0x2ee0 fs/namei.c:3791
do_filp_open+0x1f1/0x430 fs/namei.c:3818
do_sys_openat2+0x150/0x4b0 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007fff377b5ab8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000055555ceb2500 RCX: 00007f592215b78e
RDX: 0000000000000002 RSI: 00007fff377b5b90 RDI: ffffffffffffff9c
RBP: 00007fff377b5b90 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f5922415fac R14: 00007f5922415fa0 R15: 00007f5922415fa0
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
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
dvb_free_device drivers/media/dvb-core/dvbdev.c:625 [inline]
kref_put include/linux/kref.h:65 [inline]
dvb_device_put drivers/media/dvb-core/dvbdev.c:640 [inline]
dvb_device_open+0x2e7/0x370 drivers/media/dvb-core/dvbdev.c:113
chrdev_open+0x5c5/0x6a0 fs/char_dev.c:414
do_dentry_open+0x7e9/0x10d0 fs/open.c:882
do_open fs/namei.c:3634 [inline]
path_openat+0x2635/0x2ee0 fs/namei.c:3791
do_filp_open+0x1f1/0x430 fs/namei.c:3818
do_sys_openat2+0x150/0x4b0 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
The buggy address belongs to the object at ffff888029746600
do_dentry_open+0x7e9/0x10d0 fs/open.c:882
do_open fs/namei.c:3634 [inline]
path_openat+0x2635/0x2ee0 fs/namei.c:3791
do_filp_open+0x1f1/0x430 fs/namei.c:3818
do_sys_openat2+0x150/0x4b0 fs/open.c:1320
do_sys_open fs/open.c:1336 [inline]
__do_sys_openat fs/open.c:1352 [inline]
__se_sys_openat fs/open.c:1347 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1347
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 24 bytes inside of
256-byte region [ffff888029746600, ffff888029746700)
The buggy address is located 24 bytes inside of
The buggy address belongs to the physical page:
head:ffffea0000a5d180 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888017441b40
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 17986844941, free_ts 0
page_owner tracks the page as allocated
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559
prep_new_page mm/page_alloc.c:2566 [inline]
get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357
__alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5643
alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2115
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+0xbc6/0x1240 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
kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
bus_add_driver+0xda/0x5a0 drivers/base/bus.c:604
driver_register+0x32d/0x430 drivers/base/driver.c:246
i2c_register_driver+0xb6/0x160 drivers/i2c/i2c-core-base.c:2021
post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2559
prep_new_page mm/page_alloc.c:2566 [inline]
get_page_from_freelist+0x1a1e/0x1ab0 mm/page_alloc.c:4357
__alloc_pages+0x1ec/0x4f0 mm/page_alloc.c:5643
alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2115
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+0xbc6/0x1240 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
kmalloc_trace+0x26/0xe0 mm/slab_common.c:1026
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:699 [inline]
bus_add_driver+0xda/0x5a0 drivers/base/bus.c:604
driver_register+0x32d/0x430 drivers/base/driver.c:246
do_one_initcall+0x26a/0x840 init/main.c:1310
do_initcall_level+0x137/0x1e4 init/main.c:1383
do_initcalls+0x4b/0x8a init/main.c:1399
kernel_init_freeable+0x415/0x5be init/main.c:1638
do_initcall_level+0x137/0x1e4 init/main.c:1383
do_initcalls+0x4b/0x8a init/main.c:1399
kernel_init_freeable+0x415/0x5be init/main.c:1638
page_owner free stack trace missing
Memory state around the buggy address:
ffff888029746500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
Memory state around the buggy address:
ffff888029746580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888029746600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888029746680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888029746700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
syzbot
Feb 8, 2026, 11:16:26 AM (yesterday) Feb 8
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: 7b232985052f Linux 5.15.199
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1571e7fa580000
kernel config: https://syzkaller.appspot.com/x/.config?x=353ae28c40b35af5
dashboard link: https://syzkaller.appspot.com/bug?extid=77c81ec5baefe5b53fd2
disk image: https://storage.googleapis.com/syzbot-assets/97a23052e207/disk-7b232985.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e9871fb1bda3/vmlinux-7b232985.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b08e48f5be44/bzImage-7b232985.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+77c81e...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:109
Read of size 8 at addr ffff8880298b9218 by task syz.2.905/7959
CPU: 1 PID: 7959 Comm: syz.2.905 Not tainted syzkaller #0
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
dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:109
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: 0033:0x7faae2eb278e
RAX: ffffffffffffffda RBX: 00007faae110b6c0 RCX: 00007faae2eb278e
RDX: 0000000000040002 RSI: 00007faae110ac00 RDI: ffffffffffffff9c
RBP: 00007faae110ac00 R08: 0000000000000000 R09: 0000000000000000
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
kmalloc include/linux/slab.h:607 [inline]
kzalloc include/linux/slab.h:738 [inline]
dvb_register_device+0x311/0x2170 drivers/media/dvb-core/dvbdev.c:488
dvb_register_frontend+0x645/0x920 drivers/media/dvb-core/dvb_frontend.c:3034
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
__driver_attach+0x46b/0x670 drivers/base/dd.c:1164
vidtv_bridge_init+0x39/0x70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:600
do_one_initcall+0x272/0x730 init/main.c:1316
do_initcall_level+0x137/0x1f0 init/main.c:1389
do_initcalls+0x4b/0x90 init/main.c:1405
kernel_init_freeable+0x3e9/0x570 init/main.c:1629
kernel_init+0x19/0x1b0 init/main.c:1520
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Freed by task 7931:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1710 [inline]
slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
dvb_free_device drivers/media/dvb-core/dvbdev.c:635 [inline]
kref_put include/linux/kref.h:65 [inline]
dvb_device_put drivers/media/dvb-core/dvbdev.c:650 [inline]
dvb_device_open+0x2e7/0x370 drivers/media/dvb-core/dvbdev.c:123
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
The buggy address belongs to the object at ffff8880298b9200
The buggy address belongs to the page:
page:ffffea0000a62e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x298b8
head:ffffea0000a62e00 order:1 compound_mapcount:0
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
alloc_slab_page mm/slub.c:1780 [inline]
allocate_slab mm/slub.c:1917 [inline]
new_slab+0xc0/0x4b0 mm/slub.c:1980
___slab_alloc+0x80a/0xdd0 mm/slub.c:3013
__slab_alloc mm/slub.c:3100 [inline]
slab_alloc_node mm/slub.c:3191 [inline]
slab_alloc mm/slub.c:3233 [inline]
kmem_cache_alloc_trace+0x1a5/0x2a0 mm/slub.c:3250
kmalloc include/linux/slab.h:607 [inline]
kzalloc include/linux/slab.h:738 [inline]
set_kthread_struct kernel/kthread.c:103 [inline]
kthread+0x10b/0x520 kernel/kthread.c:296
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
ffff8880298b9180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880298b9200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880298b9280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880298b9300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
syzbot found the following issue on:
HEAD commit: 7b232985052f Linux 5.15.199
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1571e7fa580000
kernel config: https://syzkaller.appspot.com/x/.config?x=353ae28c40b35af5
dashboard link: https://syzkaller.appspot.com/bug?extid=77c81ec5baefe5b53fd2
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/97a23052e207/disk-7b232985.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e9871fb1bda3/vmlinux-7b232985.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b08e48f5be44/bzImage-7b232985.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
==================================================================
BUG: KASAN: use-after-free in dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:109
Read of size 8 at addr ffff8880298b9218 by task syz.2.905/7959
CPU: 1 PID: 7959 Comm: syz.2.905 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
Call Trace:
<TASK>
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
dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:109
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: 0033:0x7faae2eb278e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007faae110ab28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007faae110b6c0 RCX: 00007faae2eb278e
RDX: 0000000000040002 RSI: 00007faae110ac00 RDI: ffffffffffffff9c
RBP: 00007faae110ac00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007faae316d218 R14: 00007faae316d180 R15: 00007ffea32dcdd8
</TASK>
Allocated by task 1:
kasan_save_stack mm/kasan/common.c:38 [inline]
Allocated by task 1:
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
kmalloc include/linux/slab.h:607 [inline]
kzalloc include/linux/slab.h:738 [inline]
dvb_register_device+0x311/0x2170 drivers/media/dvb-core/dvbdev.c:488
dvb_register_frontend+0x645/0x920 drivers/media/dvb-core/dvb_frontend.c:3034
vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline]
vidtv_bridge_probe+0x9a1/0xf70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
platform_probe+0x137/0x1c0 drivers/base/platform.c:1391
vidtv_bridge_probe+0x9a1/0xf70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
driver_probe_device+0x4f/0x420 drivers/base/dd.c:785
__driver_attach+0x46b/0x670 drivers/base/dd.c:1164
bus_for_each_dev+0x182/0x1f0 drivers/base/bus.c:303
bus_add_driver+0x30a/0x5a0 drivers/base/bus.c:620
driver_register+0x32d/0x430 drivers/base/driver.c:240
bus_add_driver+0x30a/0x5a0 drivers/base/bus.c:620
vidtv_bridge_init+0x39/0x70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:600
do_one_initcall+0x272/0x730 init/main.c:1316
do_initcall_level+0x137/0x1f0 init/main.c:1389
do_initcalls+0x4b/0x90 init/main.c:1405
kernel_init_freeable+0x3e9/0x570 init/main.c:1629
kernel_init+0x19/0x1b0 init/main.c:1520
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
Freed by task 7931:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1710 [inline]
slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
dvb_free_device drivers/media/dvb-core/dvbdev.c:635 [inline]
kref_put include/linux/kref.h:65 [inline]
dvb_device_put drivers/media/dvb-core/dvbdev.c:650 [inline]
dvb_device_open+0x2e7/0x370 drivers/media/dvb-core/dvbdev.c:123
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
The buggy address belongs to the object at ffff8880298b9200
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 24 bytes inside of
256-byte region [ffff8880298b9200, ffff8880298b9300)
The buggy address is located 24 bytes inside of
The buggy address belongs to the page:
page:ffffea0000a62e00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x298b8
head:ffffea0000a62e00 order:1 compound_mapcount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea000530df80 0000000600000006 ffff888016c41b40
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 2803, ts 19920933034, free_ts 0
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
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
alloc_slab_page mm/slub.c:1780 [inline]
allocate_slab mm/slub.c:1917 [inline]
new_slab+0xc0/0x4b0 mm/slub.c:1980
___slab_alloc+0x80a/0xdd0 mm/slub.c:3013
__slab_alloc mm/slub.c:3100 [inline]
slab_alloc_node mm/slub.c:3191 [inline]
slab_alloc mm/slub.c:3233 [inline]
kmem_cache_alloc_trace+0x1a5/0x2a0 mm/slub.c:3250
kmalloc include/linux/slab.h:607 [inline]
kzalloc include/linux/slab.h:738 [inline]
set_kthread_struct kernel/kthread.c:103 [inline]
kthread+0x10b/0x520 kernel/kthread.c:296
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
page_owner free stack trace missing
Memory state around the buggy address:
ffff8880298b9100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
Memory state around the buggy address:
ffff8880298b9180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880298b9200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880298b9280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880298b9300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
syzbot
Feb 8, 2026, 11:39:30 PM (18 hours ago) Feb 8
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: 7b232985052f Linux 5.15.199
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14f4d402580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/97a23052e207/disk-7b232985.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e9871fb1bda3/vmlinux-7b232985.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b08e48f5be44/bzImage-7b232985.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+77c81e...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:109
Read of size 8 at addr ffff88814be81218 by task syz.1.112/4702
CPU: 0 PID: 4702 Comm: syz.1.112 Not tainted syzkaller #0
RAX: ffffffffffffffda RBX: 00007fbe851276c0 RCX: 00007fbe85a8478e
RDX: 0000000000040002 RSI: 00007fbe85126c00 RDI: ffffffffffffff9c
RBP: 00007fbe85126c00 R08: 0000000000000000 R09: 0000000000000000
Freed by task 4700:
The buggy address belongs to the object at ffff88814be81200
head:ffffea00052fa000 order:1 compound_mapcount:0
kmalloc_node include/linux/slab.h:630 [inline]
kvmalloc_node+0x84/0x130 mm/util.c:619
kvmalloc include/linux/mm.h:816 [inline]
kvzalloc include/linux/mm.h:824 [inline]
v4l2_ctrl_new+0x70f/0x1310 drivers/media/v4l2-core/v4l2-ctrls-core.c:1306
v4l2_ctrl_new_std+0x247/0x300 drivers/media/v4l2-core/v4l2-ctrls-core.c:1429
handler_new_ref+0x14a/0x950 drivers/media/v4l2-core/v4l2-ctrls-core.c:1098
v4l2_ctrl_add_handler+0x197/0x280 drivers/media/v4l2-core/v4l2-ctrls-core.c:1573
vivid_create_controls+0x27f2/0x3460 drivers/media/test-drivers/vivid/vivid-ctrls.c:1900
vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:1860 [inline]
vivid_probe+0x3c47/0x67a0 drivers/media/test-drivers/vivid/vivid-core.c:2031
ffff88814be81180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88814be81200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88814be81280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88814be81300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
HEAD commit: 7b232985052f Linux 5.15.199
git tree: linux-5.15.y
kernel config: https://syzkaller.appspot.com/x/.config?x=353ae28c40b35af5
dashboard link: https://syzkaller.appspot.com/bug?extid=77c81ec5baefe5b53fd2
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11ce17fa580000
dashboard link: https://syzkaller.appspot.com/bug?extid=77c81ec5baefe5b53fd2
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/97a23052e207/disk-7b232985.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e9871fb1bda3/vmlinux-7b232985.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b08e48f5be44/bzImage-7b232985.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+77c81e...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:109
CPU: 0 PID: 4702 Comm: syz.1.112 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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
dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:109
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: 0033:0x7fbe85a8478e
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
dvb_device_open+0xc6/0x370 drivers/media/dvb-core/dvbdev.c:109
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
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007fbe85126b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fbe851276c0 RCX: 00007fbe85a8478e
RDX: 0000000000040002 RSI: 00007fbe85126c00 RDI: ffffffffffffff9c
RBP: 00007fbe85126c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007fbe85d3f038 R14: 00007fbe85d3efa0 R15: 00007ffc8b528bc8
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 24 bytes inside of
256-byte region [ffff88814be81200, ffff88814be81300)
The buggy address is located 24 bytes inside of
The buggy address belongs to the page:
page:ffffea00052fa000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14be80
head:ffffea00052fa000 order:1 compound_mapcount:0
flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000010200 ffffea00052f1600 0000000300000002 ffff888016c41b40
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, ts 10824112251, free_ts 0
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
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
alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2031
get_page_from_freelist+0x1bbd/0x1ca0 mm/page_alloc.c:4192
__alloc_pages+0x1ee/0x480 mm/page_alloc.c:5487
alloc_slab_page mm/slub.c:1780 [inline]
allocate_slab mm/slub.c:1917 [inline]
new_slab+0xc0/0x4b0 mm/slub.c:1980
___slab_alloc+0x80a/0xdd0 mm/slub.c:3013
__slab_alloc mm/slub.c:3100 [inline]
slab_alloc_node mm/slub.c:3191 [inline]
__kmalloc_node+0x200/0x3b0 mm/slub.c:4456
allocate_slab mm/slub.c:1917 [inline]
new_slab+0xc0/0x4b0 mm/slub.c:1980
___slab_alloc+0x80a/0xdd0 mm/slub.c:3013
__slab_alloc mm/slub.c:3100 [inline]
slab_alloc_node mm/slub.c:3191 [inline]
kmalloc_node include/linux/slab.h:630 [inline]
kvmalloc_node+0x84/0x130 mm/util.c:619
kvmalloc include/linux/mm.h:816 [inline]
kvzalloc include/linux/mm.h:824 [inline]
v4l2_ctrl_new+0x70f/0x1310 drivers/media/v4l2-core/v4l2-ctrls-core.c:1306
v4l2_ctrl_new_std+0x247/0x300 drivers/media/v4l2-core/v4l2-ctrls-core.c:1429
handler_new_ref+0x14a/0x950 drivers/media/v4l2-core/v4l2-ctrls-core.c:1098
v4l2_ctrl_add_handler+0x197/0x280 drivers/media/v4l2-core/v4l2-ctrls-core.c:1573
vivid_create_controls+0x27f2/0x3460 drivers/media/test-drivers/vivid/vivid-ctrls.c:1900
vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:1860 [inline]
vivid_probe+0x3c47/0x67a0 drivers/media/test-drivers/vivid/vivid-core.c:2031
platform_probe+0x137/0x1c0 drivers/base/platform.c:1391
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x284/0xc80 drivers/base/dd.c:595
__driver_probe_device+0x18c/0x330 drivers/base/dd.c:755
page_owner free stack trace missing
Memory state around the buggy address:
ffff88814be81100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
Memory state around the buggy address:
ffff88814be81180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88814be81200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88814be81280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88814be81300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
---
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