WARNING in __dynamic_dev_dbg

Status: upstream: reported C repro on 2026/09/20 04:56
Reported-by: syzbot+d03ba43ddf655f5e4e60@syzkaller.appspotmail.com
First crash: 17d, last: 3d15h
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in __dynamic_dev_dbg prio:low kernel -1 C 104 1h35m 49d 0/29 upstream: reported C repro on 2026/08/19 05:33
linux-6.1 WARNING in __dynamic_dev_dbg -1 syz, C 9 3d09h 3d23h 0/3 upstream: reported C repro on 2026/10/03 22:53

Sample crash report:
hfsplus: invalid length 1033 has been corrected to 255
hfsplus: invalid length 1033 has been corrected to 255
------------[ cut here ]------------
field width 936623576 too large
WARNING: CPU: 1 PID: 4325 at lib/vsprintf.c:2699 set_field_width lib/vsprintf.c:2699 [inline]
WARNING: CPU: 1 PID: 4325 at lib/vsprintf.c:2699 vsnprintf+0x1548/0x1c20 lib/vsprintf.c:2780
Modules linked in:
CPU: 1 PID: 4325 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:set_field_width lib/vsprintf.c:2699 [inline]
RIP: 0010:vsnprintf+0x1548/0x1c20 lib/vsprintf.c:2780
Code: 44 89 fe e8 0a 31 aa 05 0f 0b e9 be f7 ff ff e8 ce fb 6c fd c6 05 22 4c 6b 09 01 48 c7 c7 e0 6d 7d 8a 44 89 fe e8 e8 30 aa 05 <0f> 0b e9 59 fa ff ff 89 e9 80 e1 07 38 c1 0f 8c 8e fd ff ff 48 89
RSP: 0018:ffffc900031ceef0 EFLAGS: 00010046
RAX: d446bb05f837a300 RBX: ffff0a0000000001 RCX: ffff888025b5bb80
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffffff8ae28022 R08: ffff8880b912795b R09: 1ffff11017224f2b
R10: dffffc0000000000 R11: ffffed1017224f2c R12: 00ffffffffd3bdd8
R13: ffffc900031cf2d5 R14: 00000000d3bdd800 R15: 0000000037d3bdd8
FS:  0000555593b82500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31824008 CR3: 000000007bceb000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 va_format lib/vsprintf.c:1713 [inline]
 pointer+0x7b2/0xc60 lib/vsprintf.c:2448
 vsnprintf+0xd7c/0x1c20 lib/vsprintf.c:2815
 vprintk_store+0x378/0x11b0 kernel/printk/printk.c:2164
 vprintk_emit+0x85/0x150 kernel/printk/printk.c:2258
 dev_vprintk_emit+0x2c2/0x360 drivers/base/core.c:4665
 dev_printk_emit+0xeb/0x140 drivers/base/core.c:4676
 __dynamic_dev_dbg+0x200/0x2b0 lib/dynamic_debug.c:644
 dtv_property_process_get+0x3eca/0x4090 drivers/media/dvb-core/dvb_frontend.c:1592
 dvb_get_property drivers/media/dvb-core/dvb_frontend.c:2390 [inline]
 dvb_frontend_handle_ioctl drivers/media/dvb-core/dvb_frontend.c:2471 [inline]
 dvb_frontend_do_ioctl+0x227d/0x3b90 drivers/media/dvb-core/dvb_frontend.c:2097
 dvb_usercopy+0x191/0x2b0 drivers/media/dvb-core/dvbdev.c:1017
 dvb_frontend_ioctl+0x58/0x70 drivers/media/dvb-core/dvb_frontend.c:2111
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 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: 0033:0x7f277fe96159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd6185e508 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f278011dfa0 RCX: 00007f277fe96159
RDX: 0000200000000400 RSI: 0000000080106f53 RDI: 0000000000000004
RBP: 00007f277ff2d06b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f278011dfac R14: 00007f278011dfa0 R15: 00007f278011dfa0
 </TASK>

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/20 20:37 linux-5.15.y 0248c33e835e 853b104b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan WARNING in __dynamic_dev_dbg
2026/09/20 17:10 linux-5.15.y 0248c33e835e 853b104b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan WARNING in __dynamic_dev_dbg
2026/09/20 12:33 linux-5.15.y 0248c33e835e 853b104b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan WARNING in __dynamic_dev_dbg
2026/09/20 08:56 linux-5.15.y 0248c33e835e 853b104b .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan WARNING in __dynamic_dev_dbg
2026/10/04 06:53 linux-5.15.y a051a4bf909f 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in __dynamic_dev_dbg
2026/09/20 04:55 linux-5.15.y 0248c33e835e 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in __dynamic_dev_dbg
* Struck through repros no longer work on HEAD.