syzbot

 sign-in | mailing list | source | docs
🐞 Open [462]
🐞 Fixed [23]
🐞 Invalid [247]
⬇ Missing Backports [16]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

KFENCE: use-after-free read in dvb_device_open

Status: upstream: reported C repro on 2026/02/08 23:24
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+681e0dd2b4b3e48496c3@syzkaller.appspotmail.com
First crash: 104d, last: 3h15m
▶ ▼ Bug presence (1)
Date Name Commit Repro Result
2026/03/02 upstream (ToT) 11439c4635ed C [report] KASAN: slab-use-after-free Read in dvb_device_open
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: use-after-free Read in dvb_device_open origin:upstream 19 C 500 6h52m 106d 0/3 upstream: reported C repro on 2026/02/07 10:59
upstream KASAN: slab-use-after-free Read in dvb_device_open prio:normal media 22 C error 8370 2h00m 519d 0/29 upstream: reported C repro on 2024/12/21 08:54
linux-5.15 KASAN: use-after-free Read in dvb_device_open origin:lts-only 19 C error 173 8h58m 105d 0/3 upstream: reported C repro on 2026/02/08 16:16

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in dvb_device_open+0xca/0x370 drivers/media/dvb-core/dvbdev.c:99
Read of size 8 at addr ffff888026a5a618 by task syz.0.19/5930

CPU: 0 PID: 5930 Comm: syz.0.19 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x18c/0x250 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 dvb_device_open+0xca/0x370 drivers/media/dvb-core/dvbdev.c:99
 chrdev_open+0x5cc/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x8c6/0x1500 fs/open.c:929
 do_open fs/namei.c:3640 [inline]
 path_openat+0x27f1/0x3230 fs/namei.c:3797
 do_filp_open+0x1f5/0x430 fs/namei.c:3824
 do_sys_openat2+0x134/0x1d0 fs/open.c:1421
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_openat fs/open.c:1452 [inline]
 __se_sys_openat fs/open.c:1447 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9a7f35cfce
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:00007f9a801ddb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f9a801de6c0 RCX: 00007f9a7f35cfce
RDX: 0000000000000e82 RSI: 00007f9a801ddc00 RDI: ffffffffffffff9c
RBP: 00007f9a801ddc00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f9a7f616128 R14: 00007f9a7f616090 R15: 00007ffc514e2ce8
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 ____kasan_kmalloc mm/kasan/common.c:375 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:384
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 dvb_register_device+0x2fd/0x2210 drivers/media/dvb-core/dvbdev.c:475
 dvb_register_frontend+0x649/0x930 drivers/media/dvb-core/dvb_frontend.c:3056
 vidtv_bridge_dvb_init drivers/media/test-drivers/vidtv/vidtv_bridge.c:436 [inline]
 vidtv_bridge_probe+0x9ab/0xf80 drivers/media/test-drivers/vidtv/vidtv_bridge.c:508
 platform_probe+0x13b/0x1c0 drivers/base/platform.c:1404
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x25b/0xb20 drivers/base/dd.c:658
 __driver_probe_device+0x18c/0x330 drivers/base/dd.c:800
 driver_probe_device+0x4f/0x420 drivers/base/dd.c:830
 __driver_attach+0x44e/0x6e0 drivers/base/dd.c:1216
 bus_for_each_dev+0x235/0x2b0 drivers/base/bus.c:370
 bus_add_driver+0x340/0x630 drivers/base/bus.c:675
 driver_register+0x23a/0x310 drivers/base/driver.c:246
 vidtv_bridge_init+0x3d/0x70 drivers/media/test-drivers/vidtv/vidtv_bridge.c:598
 do_one_initcall+0x242/0x790 init/main.c:1250
 do_initcall_level+0x137/0x1f0 init/main.c:1312
 do_initcalls+0x69/0xd0 init/main.c:1328
 kernel_init_freeable+0x3ed/0x580 init/main.c:1565
 kernel_init+0x1d/0x1c0 init/main.c:1455
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293

Freed by task 5926:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1a0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 __kmem_cache_free+0xba/0x1e0 mm/slub.c:3843
 dvb_free_device drivers/media/dvb-core/dvbdev.c:619 [inline]
 kref_put include/linux/kref.h:65 [inline]
 dvb_device_put drivers/media/dvb-core/dvbdev.c:632 [inline]
 dvb_device_open+0x2ee/0x370 drivers/media/dvb-core/dvbdev.c:113
 chrdev_open+0x5cc/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x8c6/0x1500 fs/open.c:929
 do_open fs/namei.c:3640 [inline]
 path_openat+0x27f1/0x3230 fs/namei.c:3797
 do_filp_open+0x1f5/0x430 fs/namei.c:3824
 do_sys_openat2+0x134/0x1d0 fs/open.c:1421
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_openat fs/open.c:1452 [inline]
 __se_sys_openat fs/open.c:1447 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff888026a5a600
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 24 bytes inside of
 freed 256-byte region [ffff888026a5a600, ffff888026a5a700)

The buggy address belongs to the physical page:
page:ffffea00009a9680 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x26a5a
head:ffffea00009a9680 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888017c41b40 dead000000000122 0000000000000000
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 15537607941, free_ts 0
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1c1/0x200 mm/page_alloc.c:1581
 prep_new_page mm/page_alloc.c:1588 [inline]
 get_page_from_freelist+0x1951/0x19e0 mm/page_alloc.c:3220
 __alloc_pages+0x1f0/0x460 mm/page_alloc.c:4486
 alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2120
 alloc_slab_page+0x5d/0x160 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2d0 mm/slub.c:2081
 ___slab_alloc+0xc5d/0x12f0 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 __kmem_cache_alloc_node+0x19e/0x250 mm/slub.c:3534
 kmalloc_trace+0x2a/0xe0 mm/slab_common.c:1098
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 bus_add_driver+0x162/0x630 drivers/base/bus.c:659
 driver_register+0x23a/0x310 drivers/base/driver.c:246
 do_one_initcall+0x242/0x790 init/main.c:1250
 do_initcall_level+0x137/0x1f0 init/main.c:1312
 do_initcalls+0x69/0xd0 init/main.c:1328
 kernel_init_freeable+0x3ed/0x580 init/main.c:1565
 kernel_init+0x1d/0x1c0 init/main.c:1455
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888026a5a500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888026a5a580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888026a5a600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888026a5a680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888026a5a700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (188):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/04 06:38 linux-6.6.y 7a137e9bfa0e 4180d919 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/04 05:38 linux-6.6.y 7a137e9bfa0e 4180d919 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/02 03:21 linux-6.6.y 7a137e9bfa0e 43249bac .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/02 03:33 linux-6.6.y 7a137e9bfa0e 43249bac .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/02/09 02:31 linux-6.6.y c56aaf1a85ae 4c131dc4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/02/09 01:03 linux-6.6.y c56aaf1a85ae 4c131dc4 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/04/15 16:28 linux-6.6.y 8cee53b8eaeb c441f497 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KFENCE: use-after-free read in dvb_device_open
2026/03/06 20:27 linux-6.6.y 4fc00fe35d46 41d8037d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KFENCE: use-after-free read in dvb_device_open
2026/03/05 09:26 linux-6.6.y 682d8e2f892b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KFENCE: use-after-free read in dvb_device_open
2026/02/08 23:24 linux-6.6.y c56aaf1a85ae 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KFENCE: use-after-free read in dvb_device_open
2026/05/24 13:20 linux-6.6.y 0a40c6fbd105 c69befb3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/22 11:21 linux-6.6.y eac8889a3a1c 70ae9b03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/22 11:01 linux-6.6.y eac8889a3a1c 70ae9b03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/22 04:28 linux-6.6.y eac8889a3a1c 70ae9b03 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/20 19:47 linux-6.6.y eac8889a3a1c 62fb93a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/17 07:11 linux-6.6.y 4d922539ad7d de5aae85 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/16 16:33 linux-6.6.y 4d922539ad7d a15a64a6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in dvb_device_open
2026/05/16 05:15 linux-6.6.y 4d922539ad7d 81fb92f3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/16 04:14 linux-6.6.y 4d922539ad7d 81fb92f3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/13 00:58 linux-6.6.y 3b9f64db0496 a0949470 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/11 15:18 linux-6.6.y 3b9f64db0496 845acb1c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/10 05:18 linux-6.6.y 3b9f64db0496 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/09 21:26 linux-6.6.y 3b9f64db0496 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/09 13:32 linux-6.6.y 3b9f64db0496 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/05/09 08:52 linux-6.6.y 3b9f64db0496 29233ece .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/04/25 09:44 linux-6.6.y 9760bf04666d 9c2d0995 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/04/21 01:24 linux-6.6.y 9760bf04666d e65da4ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/04/12 17:16 linux-6.6.y 8cee53b8eaeb 38c8e246 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/04/04 01:51 linux-6.6.y c09fbcd31ae6 4440e7c2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/04/02 06:07 linux-6.6.y c09fbcd31ae6 0cb124d5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/27 08:18 linux-6.6.y c09fbcd31ae6 766b6434 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/27 08:12 linux-6.6.y c09fbcd31ae6 766b6434 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/18 21:36 linux-6.6.y 4fc00fe35d46 0199f9a1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/17 18:29 linux-6.6.y 4fc00fe35d46 c01bca74 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/17 18:29 linux-6.6.y 4fc00fe35d46 c01bca74 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/10 20:57 linux-6.6.y 4fc00fe35d46 4683d576 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/08 14:27 linux-6.6.y 4fc00fe35d46 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/08 04:08 linux-6.6.y 4fc00fe35d46 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/08 00:37 linux-6.6.y 4fc00fe35d46 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/08 00:30 linux-6.6.y 4fc00fe35d46 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/07 15:57 linux-6.6.y 4fc00fe35d46 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/07 08:43 linux-6.6.y 4fc00fe35d46 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/05 20:38 linux-6.6.y 4fc00fe35d46 d20b04c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/05 09:45 linux-6.6.y 682d8e2f892b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/05 09:30 linux-6.6.y 682d8e2f892b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/05 09:28 linux-6.6.y 682d8e2f892b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/05 09:26 linux-6.6.y 682d8e2f892b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/05 09:24 linux-6.6.y 682d8e2f892b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/05 09:23 linux-6.6.y 682d8e2f892b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/05 09:21 linux-6.6.y 682d8e2f892b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/05 09:18 linux-6.6.y 682d8e2f892b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
2026/03/05 09:18 linux-6.6.y 682d8e2f892b a9fe5c9e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in dvb_device_open
* Struck through repros no longer work on HEAD.