syzbot

 sign-in | mailing list | source | docs | 🏰
🐞 Open [1272]
≡ Subsystems
🐞 Fixed [7236]
🐞 Invalid [19149]
⬇ Missing Backports [222]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
Total Repo Heatmap Subsystems Heatmap
✨ AI
💬 Send us feedback

WARNING: refcount bug in dvb_device_get

Status: moderation: reported on 2026/07/16 20:30
Subsystems: media
[Documentation on labels]
Reported-by: syzbot+df25983d45d7c6891ca9@syzkaller.appspotmail.com
First crash: 7d14h, last: 7d14h
▶ ▼ ✨ AI Jobs (3)
ID Workflow Result Correct Bug Created Started Finished Revision Error
4e5ddb8c-425d-4931-b52f-b3a982f4c0a5 assessment-security 💥 WARNING: refcount bug in dvb_device_get 2026/07/19 00:02 2026/07/19 00:02 2026/07/19 00:22 72524a6625c995608a7d179201dff2195b8d1f66 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=arm64" "CROSS_COMPILE=aarch64-linux-gnu-" "CC=ccache clang" "LD=ld.lld" "O=/app/work...
truncated to first 200 bytes; open job for full error
c7ab9d9c-4b68-424f-9744-1735d7e09bb9 assessment-security 💥 WARNING: refcount bug in dvb_device_get 2026/07/16 00:56 2026/07/16 00:56 2026/07/16 01:08 10d97020b199b1f285ec4bc6c5f7092b5af41892 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=arm64" "CROSS_COMPILE=aarch64-linux-gnu-" "CC=ccache clang" "LD=ld.lld" "O=/app/work...
truncated to first 200 bytes; open job for full error
4e147df3-2836-4221-b300-ce6ac775847f assessment-security 💥 WARNING: refcount bug in dvb_device_get 2026/07/14 00:21 2026/07/14 00:21 2026/07/14 00:43 2130f682322a1c2ef698e3c27a2b97e89e96142f 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=arm64" "CROSS_COMPILE=aarch64-linux-gnu-" "CC=ccache clang" "LD=ld.lld" "O=/app/work...
truncated to first 200 bytes; open job for full error

Sample crash report:
------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25, CPU#0: syz.6.545/8047
Modules linked in:
CPU: 0 UID: 0 PID: 8047 Comm: syz.6.545 Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/02/2026
pstate: 63400005 (nZCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25
lr : refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25
sp : ffff800099927640
x29: ffff800099927640 x28: dfff800000000000 x27: 1fffe00019353751
x26: dfff800000000000 x25: ffff700013324edc x24: dfff800000000000
x23: ffff80008742cca8 x22: ffff0000d9e83a10 x21: ffff0000cbbc9e00
x20: ffff0000cbbc9e10 x19: ffff80008a116000 x18: 1fffe00035bce428
x17: 0000000000000003 x16: ffff800088ac7000 x15: ffff800088b7cfa0
x14: ffff0001ade7214c x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000003 x9 : 2b8a9c5458a86c00
x8 : 2b8a9c5458a86c00 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000008 x3 : ffff8000803b7a0c
x2 : 0000000000000001 x1 : ffff000105b99d40 x0 : 0000000000000001
Call trace:
 refcount_warn_saturate+0x134/0x1f8 lib/refcount.c:25 (P)
 __refcount_add include/linux/refcount.h:-1 [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+0x9c/0xc0 drivers/media/dvb-core/dvbdev.c:621
 dvb_device_open+0x100/0x254 drivers/media/dvb-core/dvbdev.c:106
 chrdev_open+0x398/0x3e8 fs/char_dev.c:411
 do_dentry_open+0x5c4/0xfc0 fs/open.c:947
 vfs_open+0x44/0x2dc fs/open.c:1052
 do_open fs/namei.c:4700 [inline]
 path_openat+0x21fc/0x2a60 fs/namei.c:4859
 do_file_open+0x1c8/0x2e8 fs/namei.c:4888
 do_sys_openat2+0x114/0x1e8 fs/open.c:1368
 do_sys_open+0xb0/0xe0 fs/open.c:1374
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __arm64_sys_openat+0xa0/0xbc fs/open.c:1385
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594
irq event stamp: 140
hardirqs last  enabled at (139): [<ffff8000803b79bc>] raw_spin_rq_unlock_irq kernel/sched/sched.h:1673 [inline]
hardirqs last  enabled at (139): [<ffff8000803b79bc>] finish_lock_switch kernel/sched/core.c:5241 [inline]
hardirqs last  enabled at (139): [<ffff8000803b79bc>] finish_task_switch+0x234/0x858 kernel/sched/core.c:5359
hardirqs last disabled at (140): [<ffff8000868bf3a0>] el1_brk64+0x20/0x54 arch/arm64/kernel/entry-common.c:425
softirqs last  enabled at (108): [<ffff800080139980>] local_bh_enable include/linux/bottom_half.h:33 [inline]
softirqs last  enabled at (108): [<ffff800080139980>] put_cpu_fpsimd_context arch/arm64/kernel/fpsimd.c:251 [inline]
softirqs last  enabled at (108): [<ffff800080139980>] do_sve_acc+0x32c/0x4b8 arch/arm64/kernel/fpsimd.c:1349
softirqs last disabled at (106): [<ffff800080139760>] local_bh_disable include/linux/bottom_half.h:20 [inline]
softirqs last disabled at (106): [<ffff800080139760>] get_cpu_fpsimd_context arch/arm64/kernel/fpsimd.c:234 [inline]
softirqs last disabled at (106): [<ffff800080139760>] do_sve_acc+0x10c/0x4b8 arch/arm64/kernel/fpsimd.c:1325
---[ end trace 0000000000000000 ]---
Internal error: SP/PC alignment exception: 000000008a000000 [#1]  SMP
Modules linked in:
CPU: 0 UID: 0 PID: 8047 Comm: syz.6.545 Tainted: G        W    L      syzkaller #0 PREEMPT 
Tainted: [W]=WARN, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/02/2026
pstate: 83400805 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=-c)
pc : 0x1
lr : vfs_ioctl fs/ioctl.c:51 [inline]
lr : __do_sys_ioctl fs/ioctl.c:597 [inline]
lr : __se_sys_ioctl fs/ioctl.c:583 [inline]
lr : __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583
sp : ffff800099927d30
x29: ffff800099927d30 x28: ffff000105b99d40 x27: 0000000000000003
x26: 1fffe00020b733a8 x25: dfff800000000000 x24: 00000000fffffdfd
x23: 0000000000000001 x22: 0000000020000000 x21: 0000000080106f53
x20: ffff0000c9a9ba40 x19: ffff0000c9a9ba41 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
x14: 00000000ffff8000 x13: 0000000000000005 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000080000 x9 : 000000000000091d
x8 : ffff800099f99000 x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000040 x4 : 0000000000000000 x3 : ffff800080ce6e14
x2 : 0000000020000000 x1 : 0000000080106f53 x0 : ffff0000c9a9ba40
Call trace:
 0x1 (P)
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:736
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:755
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:594
---[ end trace 0000000000000000 ]---

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/07/12 20:22 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci a52d6c7160f7 d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING: refcount bug in dvb_device_get
* Struck through repros no longer work on HEAD.