[syzbot] general protection fault in s_show

syzbot
2023-01-18T13:43:57Z

Hello,

syzbot found the following issue on:

HEAD commit: 9ce08dd7ea24 Add linux-next specific files for 20230117
git tree: linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=118b99ca480000
kernel config: https://syzkaller.appspot.com/x/.config?x=35b17571659142bd
dashboard link: https://syzkaller.appspot.com/bug?extid=a0258de3c9175e61a024
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16e960de480000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13c99296480000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5dc082154a67/disk-9ce08dd7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c4232ae45260/vmlinux-9ce08dd7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bb484ac2d045/bzImage-9ce08dd7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a0258de3c9175e61a024@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
CPU: 1 PID: 5094 Comm: syz-executor205 Not tainted 6.2.0-rc4-next-20230117-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
RIP: 0010:s_show+0x6d/0xa90 mm/vmalloc.c:4243
Code: 74 24 08 49 8b 5e 10 48 85 db 0f 84 1b 05 00 00 e8 48 98 bf ff 48 8d 7b 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 35 09 00 00 48 8d 7b 08 4c 8b 43 10 48 b8 00 00
RSP: 0018:ffffc90003d1f9d8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff81c23c18 RDI: 0000000000000010
RBP: ffff888021a736f0 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000007c07 R14: ffff888028ca8980 R15: ffffffff8a589ba0
FS: 0000555555e67300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f609a0d8130 CR3: 000000007779b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
traverse.part.0+0xcf/0x5f0 fs/seq_file.c:111
traverse fs/seq_file.c:101 [inline]
seq_read_iter+0x913/0x1280 fs/seq_file.c:195
proc_reg_read_iter+0x1ff/0x2d0 fs/proc/inode.c:305
call_read_iter include/linux/fs.h:1846 [inline]
do_iter_readv_writev+0x2e0/0x3b0 fs/read_write.c:733
do_iter_read+0x2f2/0x750 fs/read_write.c:796
vfs_readv+0xe5/0x150 fs/read_write.c:916
do_preadv fs/read_write.c:1008 [inline]
__do_sys_preadv fs/read_write.c:1058 [inline]
__se_sys_preadv fs/read_write.c:1053 [inline]
__x64_sys_preadv+0x22f/0x310 fs/read_write.c:1053
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f609a067e19
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe66bc5d68 EFLAGS: 00000246 ORIG_RAX: 0000000000000127
RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007f609a067e19
RDX: 0000000000000001 RSI: 00000000200020c0 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
R10: 00000000ffff7fff R11: 0000000000000246 R12: 000000000000f33b
R13: 00007ffe66bc5d7c R14: 00007ffe66bc5d90 R15: 00007ffe66bc5d80
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:s_show+0x6d/0xa90 mm/vmalloc.c:4243
Code: 74 24 08 49 8b 5e 10 48 85 db 0f 84 1b 05 00 00 e8 48 98 bf ff 48 8d 7b 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 35 09 00 00 48 8d 7b 08 4c 8b 43 10 48 b8 00 00
RSP: 0018:ffffc90003d1f9d8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000002 RSI: ffffffff81c23c18 RDI: 0000000000000010
RBP: ffff888021a736f0 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000007c07 R14: ffff888028ca8980 R15: ffffffff8a589ba0
FS: 0000555555e67300(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f609a0d8130 CR3: 000000007779b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
0: 24 08 and $0x8,%al
2: 49 8b 5e 10 mov 0x10(%r14),%rbx
6: 48 85 db test %rbx,%rbx
9: 0f 84 1b 05 00 00 je 0x52a
f: e8 48 98 bf ff callq 0xffbf985c
14: 48 8d 7b 10 lea 0x10(%rbx),%rdi
18: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
1f: fc ff df
22: 48 89 fa mov %rdi,%rdx
25: 48 c1 ea 03 shr $0x3,%rdx
* 29: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2d: 0f 85 35 09 00 00 jne 0x968
33: 48 8d 7b 08 lea 0x8(%rbx),%rdi
37: 4c 8b 43 10 mov 0x10(%rbx),%r8
3b: 48 rex.W
3c: b8 .byte 0xb8

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