[syzbot] [mm?] general protection fault in vsscanf (2)

syzbot
2024-12-16T03:40:24Z

Hello,

syzbot found the following issue on:

HEAD commit: f92f4749861b Merge tag 'clk-fixes-for-linus' of git://git...
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=116904f8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=99a5586995ec03b2
dashboard link: https://syzkaller.appspot.com/bug?extid=8a3da2f1bbf59227c289
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15758d44580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=156904f8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b85403132ddc/disk-f92f4749.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/20613d034287/vmlinux-f92f4749.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d1ea80bf7e4e/bzImage-f92f4749.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8a3da2f1bbf59227c289@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 5823 Comm: syz-executor234 Not tainted 6.13.0-rc2-syzkaller-00031-gf92f4749861b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:vsscanf+0x1a4/0x2a30 lib/vsprintf.c:3466
Code: db 74 5e e8 1e da 82 f6 49 8d 5d 01 48 89 e9 48 ba 00 00 00 00 00 fc ff df 48 c1 e9 03 48 89 5c 24 70 49 89 dc 41 0f b6 45 00 <0f> b6 14 11 48 89 e9 83 e1 07 38 ca 7f 08 84 d2 0f 85 1e 19 00 00
RSP: 0018:ffffc90003cc7668 EFLAGS: 00010246
RAX: 0000000000000030 RBX: ffffffff8b5c7801 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8b1663d2 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000030 R11: 00000000000a2001 R12: ffffffff8b5c7801
R13: ffffffff8b5c7800 R14: dffffc0000000000 R15: ffffc90003cc7eb0
FS: 0000555573fa8380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000080 CR3: 0000000073a06000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
sscanf+0xc8/0x100 lib/vsprintf.c:3722
split_huge_pages_write+0xa16/0x1f60 mm/huge_memory.c:4178
full_proxy_write+0xfb/0x1b0 fs/debugfs/file.c:356
vfs_write+0x24c/0x1150 fs/read_write.c:677
ksys_write+0x12b/0x250 fs/read_write.c:731
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9a505582e9
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdae2774c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffdae277698 RCX: 00007f9a505582e9
RDX: 0000000000000004 RSI: 0000000020000040 RDI: 0000000000000003
RBP: 00007f9a505cb610 R08: 0000000000000000 R09: 00007ffdae277698
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffdae277688 R14: 0000000000000001 R15: 0000000000000001
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:vsscanf+0x1a4/0x2a30 lib/vsprintf.c:3466
Code: db 74 5e e8 1e da 82 f6 49 8d 5d 01 48 89 e9 48 ba 00 00 00 00 00 fc ff df 48 c1 e9 03 48 89 5c 24 70 49 89 dc 41 0f b6 45 00 <0f> b6 14 11 48 89 e9 83 e1 07 38 ca 7f 08 84 d2 0f 85 1e 19 00 00
RSP: 0018:ffffc90003cc7668 EFLAGS: 00010246
RAX: 0000000000000030 RBX: ffffffff8b5c7801 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8b1663d2 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000030 R11: 00000000000a2001 R12: ffffffff8b5c7801
R13: ffffffff8b5c7800 R14: dffffc0000000000 R15: ffffc90003cc7eb0
FS: 0000555573fa8380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000080 CR3: 0000000073a06000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 74 5e je 0x60
2: e8 1e da 82 f6 call 0xf682da25
7: 49 8d 5d 01 lea 0x1(%r13),%rbx
b: 48 89 e9 mov %rbp,%rcx
e: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx
15: fc ff df
18: 48 c1 e9 03 shr $0x3,%rcx
1c: 48 89 5c 24 70 mov %rbx,0x70(%rsp)
21: 49 89 dc mov %rbx,%r12
24: 41 0f b6 45 00 movzbl 0x0(%r13),%eax
* 29: 0f b6 14 11 movzbl (%rcx,%rdx,1),%edx <-- trapping instruction
2d: 48 89 e9 mov %rbp,%rcx
30: 83 e1 07 and $0x7,%ecx
33: 38 ca cmp %cl,%dl
35: 7f 08 jg 0x3f
37: 84 d2 test %dl,%dl
39: 0f 85 1e 19 00 00 jne 0x195d

---
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