syzbot


WARNING: refcount bug in dvb_device_open

Status: upstream: reported on 2026/02/09 03:53
Reported-by: syzbot+51a2e1546f1a0739057c@syzkaller.appspotmail.com
First crash: 17d, last: 17d
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING: refcount bug in dvb_device_open (2) media 13 1 118d 114d 0/29 auto-obsoleted due to no activity on 2026/01/28 21:06
upstream WARNING: refcount bug in dvb_device_open media 13 1 320d 315d 0/29 auto-obsoleted due to no activity on 2025/07/21 00:17
upstream WARNING: refcount bug in dvb_device_open (3) media 13 3 3d05h 8d18h 0/29 upstream: reported on 2026/02/17 16:08

Sample crash report:
------------[ cut here ]------------
refcount_t: saturated; leaking memory.
WARNING: CPU: 1 PID: 5103 at lib/refcount.c:22 refcount_warn_saturate+0x153/0x1a0 lib/refcount.c:22
Modules linked in:
CPU: 1 PID: 5103 Comm: syz.4.235 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:refcount_warn_saturate+0x153/0x1a0 lib/refcount.c:22
Code: 09 01 48 c7 c7 00 b8 79 8a e8 69 68 cd 05 0f 0b eb 8c e8 d0 5f 95 fd c6 05 ca 72 92 09 01 48 c7 c7 00 b8 79 8a e8 4d 68 cd 05 <0f> 0b e9 6d ff ff ff e8 b1 5f 95 fd c6 05 af 72 92 09 01 48 c7 c7
RSP: 0018:ffffc9000375f798 EFLAGS: 00010246
RAX: 25aa356a47451100 RBX: 0000000000000001 RCX: 0000000000080000
RDX: ffffc9000e7fa000 RSI: 0000000000004a72 RDI: 0000000000004a73
RBP: 00000000ffffffff R08: ffff8880b9133d7f R09: 1ffff110172267af
R10: dffffc0000000000 R11: ffffed10172267b0 R12: ffff88802910aa18
R13: ffffffff9632be78 R14: 0000000000000001 R15: ffff88802910aa00
FS:  00007f0e5578d6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000404030 CR3: 000000005785b000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __refcount_add include/linux/refcount.h:-1 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 kref_get include/linux/kref.h:45 [inline]
 dvb_device_get drivers/media/dvb-core/dvbdev.c:641 [inline]
 dvb_device_open+0x330/0x370 drivers/media/dvb-core/dvbdev.c:116
 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: 0033:0x7f0e574f278e
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:00007f0e5578cb28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f0e5578d6c0 RCX: 00007f0e574f278e
RDX: 0000000000000000 RSI: 00007f0e5578cc00 RDI: ffffffffffffff9c
RBP: 00007f0e5578cc00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: cccccccccccccccd
R13: 00007f0e577ad038 R14: 00007f0e577acfa0 R15: 00007ffc395664c8
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/09 03:52 linux-5.15.y 7b232985052f 4c131dc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING: refcount bug in dvb_device_open
* Struck through repros no longer work on HEAD.