==================================================================
BUG: KASAN: slab-use-after-free in dvb_device_open+0x33f/0x3b0 drivers/media/dvb-core/dvbdev.c:99
Read of size 8 at addr ffff88802b978218 by task syz.4.607/8832
CPU: 0 UID: 0 PID: 8832 Comm: syz.4.607 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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+0x156/0x4c9 mm/kasan/report.c:482
kasan_report+0xdf/0x1a0 mm/kasan/report.c:595
dvb_device_open+0x33f/0x3b0 drivers/media/dvb-core/dvbdev.c:99
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6d8/0x1660 fs/open.c:949
vfs_open+0x82/0x3f0 fs/open.c:1081
do_open fs/namei.c:4671 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4830
do_file_open+0x20e/0x430 fs/namei.c:4859
do_sys_openat2+0x10d/0x1e0 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1383
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: 0033:0x7fed7615c84e
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 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007fed770c7b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fed770c86c0 RCX: 00007fed7615c84e
RDX: 0000000000040402 RSI: 00007fed770c7c00 RDI: ffffffffffffff9c
RBP: 00007fed770c7c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007fed76416218 R14: 00007fed76416180 R15: 00007ffcc5dfe0c8
Allocated by task 1:
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:962 [inline]
kzalloc_noprof include/linux/slab.h:1204 [inline]
dvb_register_device+0x1d6/0x1e60 drivers/media/dvb-core/dvbdev.c:475
dvb_register_frontend+0x5a8/0x8a0 drivers/media/dvb-core/dvb_frontend.c:3051
vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline]
vidtv_bridge_probe+0x44b/0xa30 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
platform_probe+0x106/0x1d0 drivers/base/platform.c:1446
call_driver_probe drivers/base/dd.c:583 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:661
__driver_probe_device+0x1de/0x400 drivers/base/dd.c:803
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833
__driver_attach+0x217/0x5c0 drivers/base/dd.c:1227
bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:383
bus_add_driver+0x305/0x5b0 drivers/base/bus.c:715
driver_register+0x1e2/0x360 drivers/base/driver.c:249
vidtv_bridge_init+0x38/0x70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598
do_one_initcall+0x11d/0x690 init/main.c:1378
do_initcall_level init/main.c:1440 [inline]
do_initcalls init/main.c:1456 [inline]
do_basic_setup init/main.c:1475 [inline]
kernel_init_freeable+0x6e5/0x790 init/main.c:1688
kernel_init+0x1f/0x1e0 init/main.c:1578
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 8786:
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:2670 [inline]
slab_free mm/slub.c:6082 [inline]
kfree+0x1aa/0x670 mm/slub.c:6399
dvb_free_device drivers/media/dvb-core/dvbdev.c:619 [inline]
kref_put include/linux/kref.h:65 [inline]
dvb_device_put.part.0+0x57/0x90 drivers/media/dvb-core/dvbdev.c:632
dvb_device_put drivers/media/dvb-core/dvbdev.c:631 [inline]
dvb_device_open+0x2ba/0x3b0 drivers/media/dvb-core/dvbdev.c:113
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6d8/0x1660 fs/open.c:949
vfs_open+0x82/0x3f0 fs/open.c:1081
do_open fs/namei.c:4671 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4830
do_file_open+0x20e/0x430 fs/namei.c:4859
do_sys_openat2+0x10d/0x1e0 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1383
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
The buggy address belongs to the object at ffff88802b978200
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 24 bytes inside of
freed 256-byte region [ffff88802b978200, ffff88802b978300)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b978
head: order:1 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 ffff88813ff30b40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ff30b40 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea0000ae5e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
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 27637351492, free_ts 0
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1e1/0x250 mm/page_alloc.c:1884
prep_new_page mm/page_alloc.c:1892 [inline]
get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3950
__alloc_frozen_pages_noprof+0x26c/0x2410 mm/page_alloc.c:5245
alloc_slab_page mm/slub.c:3238 [inline]
allocate_slab mm/slub.c:3411 [inline]
new_slab+0xa6/0x6e0 mm/slub.c:3469
refill_objects+0x26b/0x400 mm/slub.c:7091
refill_sheaf mm/slub.c:2787 [inline]
alloc_full_sheaf mm/slub.c:2808 [inline]
__pcs_replace_empty_main+0x19f/0x600 mm/slub.c:4546
alloc_from_pcs mm/slub.c:4639 [inline]
slab_alloc_node mm/slub.c:4773 [inline]
__kmalloc_cache_noprof+0x493/0x6f0 mm/slub.c:5292
kmalloc_noprof include/linux/slab.h:962 [inline]
kzalloc_noprof include/linux/slab.h:1204 [inline]
bus_add_driver+0x92/0x5b0 drivers/base/bus.c:699
driver_register+0x1e2/0x360 drivers/base/driver.c:249
usb_register_driver drivers/usb/core/driver.c:1078 [inline]
usb_register_driver+0x21c/0x3e0 drivers/usb/core/driver.c:1060
do_one_initcall+0x11d/0x690 init/main.c:1378
do_initcall_level init/main.c:1440 [inline]
do_initcalls init/main.c:1456 [inline]
do_basic_setup init/main.c:1475 [inline]
kernel_init_freeable+0x6e5/0x790 init/main.c:1688
kernel_init+0x1f/0x1e0 init/main.c:1578
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing
Memory state around the buggy address:
ffff88802b978100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802b978180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802b978200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802b978280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802b978300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
BUG: KASAN: slab-use-after-free in atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline]
BUG: KASAN: slab-use-after-free in __refcount_add include/linux/refcount.h:283 [inline]
BUG: KASAN: slab-use-after-free in __refcount_inc include/linux/refcount.h:366 [inline]
BUG: KASAN: slab-use-after-free in refcount_inc include/linux/refcount.h:383 [inline]
BUG: KASAN: slab-use-after-free in kref_get include/linux/kref.h:45 [inline]
BUG: KASAN: slab-use-after-free in dvb_device_get drivers/media/dvb-core/dvbdev.c:624 [inline]
BUG: KASAN: slab-use-after-free in dvb_device_open+0x152/0x3b0 drivers/media/dvb-core/dvbdev.c:106
Write of size 4 at addr ffff88802b978210 by task syz.4.607/8832
CPU: 0 UID: 0 PID: 8832 Comm: syz.4.607 Tainted: G B syzkaller #0 PREEMPT(full)
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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+0x156/0x4c9 mm/kasan/report.c:482
kasan_report+0xdf/0x1a0 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:96 [inline]
atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline]
__refcount_add include/linux/refcount.h:283 [inline]
__refcount_inc include/linux/refcount.h:366 [inline]
refcount_inc include/linux/refcount.h:383 [inline]
kref_get include/linux/kref.h:45 [inline]
dvb_device_get drivers/media/dvb-core/dvbdev.c:624 [inline]
dvb_device_open+0x152/0x3b0 drivers/media/dvb-core/dvbdev.c:106
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6d8/0x1660 fs/open.c:949
vfs_open+0x82/0x3f0 fs/open.c:1081
do_open fs/namei.c:4671 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4830
do_file_open+0x20e/0x430 fs/namei.c:4859
do_sys_openat2+0x10d/0x1e0 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1383
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: 0033:0x7fed7615c84e
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 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007fed770c7b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fed770c86c0 RCX: 00007fed7615c84e
RDX: 0000000000040402 RSI: 00007fed770c7c00 RDI: ffffffffffffff9c
RBP: 00007fed770c7c00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007fed76416218 R14: 00007fed76416180 R15: 00007ffcc5dfe0c8
Allocated by task 1:
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:962 [inline]
kzalloc_noprof include/linux/slab.h:1204 [inline]
dvb_register_device+0x1d6/0x1e60 drivers/media/dvb-core/dvbdev.c:475
dvb_register_frontend+0x5a8/0x8a0 drivers/media/dvb-core/dvb_frontend.c:3051
vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline]
vidtv_bridge_probe+0x44b/0xa30 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
platform_probe+0x106/0x1d0 drivers/base/platform.c:1446
call_driver_probe drivers/base/dd.c:583 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:661
__driver_probe_device+0x1de/0x400 drivers/base/dd.c:803
driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:833
__driver_attach+0x217/0x5c0 drivers/base/dd.c:1227
bus_for_each_dev+0x13e/0x1d0 drivers/base/bus.c:383
bus_add_driver+0x305/0x5b0 drivers/base/bus.c:715
driver_register+0x1e2/0x360 drivers/base/driver.c:249
vidtv_bridge_init+0x38/0x70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598
do_one_initcall+0x11d/0x690 init/main.c:1378
do_initcall_level init/main.c:1440 [inline]
do_initcalls init/main.c:1456 [inline]
do_basic_setup init/main.c:1475 [inline]
kernel_init_freeable+0x6e5/0x790 init/main.c:1688
kernel_init+0x1f/0x1e0 init/main.c:1578
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 8786:
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:2670 [inline]
slab_free mm/slub.c:6082 [inline]
kfree+0x1aa/0x670 mm/slub.c:6399
dvb_free_device drivers/media/dvb-core/dvbdev.c:619 [inline]
kref_put include/linux/kref.h:65 [inline]
dvb_device_put.part.0+0x57/0x90 drivers/media/dvb-core/dvbdev.c:632
dvb_device_put drivers/media/dvb-core/dvbdev.c:631 [inline]
dvb_device_open+0x2ba/0x3b0 drivers/media/dvb-core/dvbdev.c:113
chrdev_open+0x234/0x6a0 fs/char_dev.c:411
do_dentry_open+0x6d8/0x1660 fs/open.c:949
vfs_open+0x82/0x3f0 fs/open.c:1081
do_open fs/namei.c:4671 [inline]
path_openat+0x208c/0x31a0 fs/namei.c:4830
do_file_open+0x20e/0x430 fs/namei.c:4859
do_sys_openat2+0x10d/0x1e0 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1383
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
The buggy address belongs to the object at ffff88802b978200
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 16 bytes inside of
freed 256-byte region [ffff88802b978200, ffff88802b978300)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2b978
head: order:1 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 ffff88813ff30b40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813ff30b40 dead000000000100 dead000000000122
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000001 ffffea0000ae5e01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000002
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 27637351492, free_ts 0
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1e1/0x250 mm/page_alloc.c:1884
prep_new_page mm/page_alloc.c:1892 [inline]
get_page_from_freelist+0x111d/0x3140 mm/page_alloc.c:3950
__alloc_frozen_pages_noprof+0x26c/0x2410 mm/page_alloc.c:5245
alloc_slab_page mm/slub.c:3238 [inline]
allocate_slab mm/slub.c:3411 [inline]
new_slab+0xa6/0x6e0 mm/slub.c:3469
refill_objects+0x26b/0x400 mm/slub.c:7091
refill_sheaf mm/slub.c:2787 [inline]
alloc_full_sheaf mm/slub.c:2808 [inline]
__pcs_replace_empty_main+0x19f/0x600 mm/slub.c:4546
alloc_from_pcs mm/slub.c:4639 [inline]
slab_alloc_node mm/slub.c:4773 [inline]
__kmalloc_cache_noprof+0x493/0x6f0 mm/slub.c:5292
kmalloc_noprof include/linux/slab.h:962 [inline]
kzalloc_noprof include/linux/slab.h:1204 [inline]
bus_add_driver+0x92/0x5b0 drivers/base/bus.c:699
driver_register+0x1e2/0x360 drivers/base/driver.c:249
usb_register_driver drivers/usb/core/driver.c:1078 [inline]
usb_register_driver+0x21c/0x3e0 drivers/usb/core/driver.c:1060
do_one_initcall+0x11d/0x690 init/main.c:1378
do_initcall_level init/main.c:1440 [inline]
do_initcalls init/main.c:1456 [inline]
do_basic_setup init/main.c:1475 [inline]
kernel_init_freeable+0x6e5/0x790 init/main.c:1688
kernel_init+0x1f/0x1e0 init/main.c:1578
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page_owner free stack trace missing
Memory state around the buggy address:
ffff88802b978100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88802b978180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802b978200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802b978280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802b978300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================