WARNING in __dynamic_dev_dbg

Status: upstream: reported C repro on 2026/10/03 22:53
Reported-by: syzbot+58bd3643f21b1a39a676@syzkaller.appspotmail.com
First crash: 7d11h, last: 6d21h
▶ ▼ 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 112 18h54m 53d 0/29 upstream: reported C repro on 2026/08/19 05:33
linux-5.15 WARNING in __dynamic_dev_dbg -1 syz, C 6 7d03h 21d 0/3 upstream: reported C repro on 2026/09/20 04:56

Sample crash report:
------------[ cut here ]------------
field width 536871040 too large
WARNING: CPU: 0 PID: 4510 at lib/vsprintf.c:2693 set_field_width lib/vsprintf.c:2693 [inline]
WARNING: CPU: 0 PID: 4510 at lib/vsprintf.c:2693 vsnprintf+0x126c/0x18d8 lib/vsprintf.c:2774
Modules linked in:
CPU: 0 PID: 4510 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/14/2026
pstate: 624000c5 (nZCv daIF +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : set_field_width lib/vsprintf.c:2693 [inline]
pc : vsnprintf+0x126c/0x18d8 lib/vsprintf.c:2774
lr : set_field_width lib/vsprintf.c:2693 [inline]
lr : vsnprintf+0x126c/0x18d8 lib/vsprintf.c:2774
sp : ffff8000216b6be0
x29: ffff8000216b6c20 x28: ffff0a00ffffff01 x27: 0000000020000080
x26: 0000000000000080 x25: ffff800013270b62 x24: 0000000000008000
x23: ffff8000216b6fba x22: ffff0a0000000001 x21: ffff8000216b6ca0
x20: ffff8000216b6f6b x19: dfff800000000000 x18: 0000000000000000
x17: 0000000000000000 x16: ffff800011bc8ec8 x15: 0000000000000000
x14: 0000000000000001 x13: 1fffe00033e62da3 x12: 0000000000000000
x11: ff00800008195f68 x10: 0000000000000000 x9 : 6938d2934e9bbd00
x8 : 6938d2934e9bbd00 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000216b6678 x4 : ffff8000154b4f40 x3 : ffff800008542f08
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000000
Call trace:
 set_field_width lib/vsprintf.c:2693 [inline]
 vsnprintf+0x126c/0x18d8 lib/vsprintf.c:2774
 va_format lib/vsprintf.c:1685 [inline]
 pointer+0x7ac/0xdd8 lib/vsprintf.c:2436
 vsnprintf+0xcc0/0x18d8 lib/vsprintf.c:2809
 vprintk_store+0x36c/0xb60 kernel/printk/printk.c:2187
 vprintk_emit+0x118/0x2f0 kernel/printk/printk.c:2284
 dev_vprintk_emit+0x2dc/0x39c drivers/base/core.c:4948
 dev_printk_emit+0xe0/0x130 drivers/base/core.c:4959
 __dynamic_dev_dbg+0x1b4/0x250 lib/dynamic_debug.c:900
 dtv_property_process_get+0x2b0c/0x2c70 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+0x1c20/0x34f8 drivers/media/dvb-core/dvb_frontend.c:2097
 dvb_usercopy+0x248/0x45c drivers/media/dvb-core/dvbdev.c:1007
 dvb_frontend_ioctl+0x68/0x8c drivers/media/dvb-core/dvb_frontend.c:2111
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 48914
hardirqs last  enabled at (48913): [<ffff800011cb031c>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
hardirqs last  enabled at (48913): [<ffff800011cb031c>] _raw_spin_unlock_irqrestore+0x48/0xac kernel/locking/spinlock.c:194
hardirqs last disabled at (48914): [<ffff800008312e40>] vprintk_store+0x168/0xb60 kernel/printk/printk.c:2167
softirqs last  enabled at (48846): [<ffff800008031254>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (48844): [<ffff800008031220>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/04 13:01 linux-6.1.y a500ba24937a 57bbd979 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __dynamic_dev_dbg
2026/10/04 10:55 linux-6.1.y a500ba24937a 57bbd979 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __dynamic_dev_dbg
2026/10/04 08:37 linux-6.1.y a500ba24937a 57bbd979 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __dynamic_dev_dbg
2026/10/04 06:55 linux-6.1.y a500ba24937a 57bbd979 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __dynamic_dev_dbg
2026/10/04 04:55 linux-6.1.y a500ba24937a 57bbd979 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __dynamic_dev_dbg
2026/10/04 02:59 linux-6.1.y a500ba24937a 57bbd979 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __dynamic_dev_dbg
2026/10/04 00:54 linux-6.1.y a500ba24937a 57bbd979 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __dynamic_dev_dbg
2026/10/04 10:42 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __dynamic_dev_dbg
2026/10/03 22:52 linux-6.1.y a500ba24937a 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in __dynamic_dev_dbg
* Struck through repros no longer work on HEAD.