general protection fault in vsscanf

Status: upstream: reported C repro on 2026/08/18 10:26
Reported-by: syzbot+a514d4b7318a8f80f989@syzkaller.appspotmail.com
First crash: 2d07h, last: 3h19m
Similar bugs (11)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 general protection fault in vsscanf origin:lts-only 2 syz, C 6 16h55m 1d08h 0/3 upstream: reported C repro on 2026/08/18 22:35
linux-6.6 general protection fault in vsscanf 2 syz, C 7 20h13m 21h46m 0/2 upstream: reported C repro on 2026/08/19 08:56
android-5-15 general protection fault in vsscanf 2 syz, C 5 1d05h 1d08h 0/2 upstream: reported C repro on 2026/08/18 22:10
upstream general protection fault in vsscanf (2) mm 2 syz, C 11 606d 612d 28/29 fixed on 2025/05/06 15:33
upstream general protection fault in vsscanf v9fs 2 syz, C 7 2932d 2962d 8/29 fixed on 2018/09/03 14:47
android-49 general protection fault in vsscanf 2 syz, C 6 2912d 2685d 0/3 public: reported C repro on 2019/04/14 00:00
android-6-12 general protection fault in vsscanf 2 syz, C 9 18h38m 2d03h 0/1 premoderation: reported C repro on 2026/08/18 03:15
linux-6.1 BUG: unable to handle kernel paging request in vsscanf 8 syz, C 9 1d05h 1d15h 0/3 upstream: reported C repro on 2026/08/18 15:35
linux-4.19 BUG: unable to handle kernel paging request in vsscanf (2) 8 2 1770d 1872d 0/1 auto-closed as invalid on 2022/02/11 22:53
upstream KMSAN: uninit-value in vsscanf bluetooth 7 syz 9 1631d 1697d 0/29 auto-closed as invalid on 2022/09/27 18:52
linux-4.19 BUG: unable to handle kernel paging request in vsscanf (3) 8 1 1578d 1578d 0/1 auto-closed as invalid on 2022/08/22 19:56

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 305 Comm: syz-executor281 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:vsscanf+0x196/0x24b0 lib/vsprintf.c:3446
Code: 48 c7 c6 90 02 8e 87 e8 48 9e 7e fc 41 83 fe 25 74 4d 45 85 f6 0f 84 b6 21 00 00 48 ff c3 48 89 5c 24 78 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 4f 1b 00 00 41 0f b6 1f 45 0f b6 f6 44
RSP: 0018:ffffc90000e975e0 EFLAGS: 00010246

RAX: 0000000000000000 RBX: ffffffff85b0d901 RCX: 0000000000000001
RDX: ffffffff84f2cd48 RSI: ffffffff878e0290 RDI: 0000000000000030
RBP: ffffc90000e97710 R08: ffff8881103c0000 R09: 0000000000000002
R10: 0000000000000025 R11: 0000000000000000 R12: ffffffff85b0d900
R13: dffffc0000000000 R14: 0000000000000030 R15: 0000000000000000
FS:  00005555818ae3c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000040 CR3: 0000000122864000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 sscanf+0xdf/0x130 lib/vsprintf.c:3704
 split_huge_pages_write+0x37a/0x10d0 mm/huge_memory.c:3286
 full_proxy_write+0x121/0x1d0 fs/debugfs/file.c:244
 vfs_write+0x3fb/0xd00 fs/read_write.c:582
 ksys_write+0x14a/0x260 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x7b/0x90 fs/read_write.c:646
 x64_sys_call+0x27b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3fddebdc39
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcb50955c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0067756265642f2e RCX: 00007f3fddebdc39
RDX: 0000000000000015 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 00007ffcb50956f8
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcb50956e8
R13: 0000000000000002 R14: 00007f3fddf4eca0 R15: 0000000000000002
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:vsscanf+0x196/0x24b0 lib/vsprintf.c:3446
Code: 48 c7 c6 90 02 8e 87 e8 48 9e 7e fc 41 83 fe 25 74 4d 45 85 f6 0f 84 b6 21 00 00 48 ff c3 48 89 5c 24 78 4c 89 f8 48 c1 e8 03 <42> 0f b6 04 28 84 c0 0f 85 4f 1b 00 00 41 0f b6 1f 45 0f b6 f6 44
RSP: 0018:ffffc90000e975e0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffffffff85b0d901 RCX: 0000000000000001
RDX: ffffffff84f2cd48 RSI: ffffffff878e0290 RDI: 0000000000000030
RBP: ffffc90000e97710 R08: ffff8881103c0000 R09: 0000000000000002
R10: 0000000000000025 R11: 0000000000000000 R12: ffffffff85b0d900
R13: dffffc0000000000 R14: 0000000000000030 R15: 0000000000000000
FS:  00005555818ae3c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000040 CR3: 0000000122864000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	48 c7 c6 90 02 8e 87 	mov    $0xffffffff878e0290,%rsi
   7:	e8 48 9e 7e fc       	call   0xfc7e9e54
   c:	41 83 fe 25          	cmp    $0x25,%r14d
  10:	74 4d                	je     0x5f
  12:	45 85 f6             	test   %r14d,%r14d
  15:	0f 84 b6 21 00 00    	je     0x21d1
  1b:	48 ff c3             	inc    %rbx
  1e:	48 89 5c 24 78       	mov    %rbx,0x78(%rsp)
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 4f 1b 00 00    	jne    0x1b86
  37:	41 0f b6 1f          	movzbl (%r15),%ebx
  3b:	45 0f b6 f6          	movzbl %r14b,%r14d
  3f:	44                   	rex.R

Crashes (15):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/18 10:22 android14-6.1 92668decd5e0 1e72964b .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/20 03:23 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/20 00:56 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/20 00:55 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/19 07:00 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/19 07:00 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/19 01:18 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/19 01:18 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/18 21:43 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/18 21:42 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/18 20:40 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/18 10:07 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/18 10:04 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/18 10:04 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
2026/08/17 23:16 android14-6.1 92668decd5e0 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 general protection fault in vsscanf
* Struck through repros no longer work on HEAD.