[syzbot] [v9fs?] general protection fault in p9_client_walk
From: syzbot
Date: Mon Mar 10 2025 - 05:39:33 EST
Hello,
syzbot found the following issue on:
HEAD commit: bb2281fb05e5 Merge tag 'x86_microcode_for_v6.14_rc6' of gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=154078b7980000
kernel config: https://syzkaller.appspot.com/x/.config?x=bed8205d3b84ef81
dashboard link: https://syzkaller.appspot.com/bug?extid=5b667f9a1fee4ba3775a
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-bb2281fb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/2a0a6e98a402/vmlinux-bb2281fb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/55357371f99f/bzImage-bb2281fb.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5b667f9a1fee4ba3775a@xxxxxxxxxxxxxxxxxxxxxxxxx
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 2 UID: 0 PID: 21142 Comm: syz.4.3149 Not tainted 6.14.0-rc5-syzkaller-00023-gbb2281fb05e5 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:p9_client_walk+0x9a/0x530 net/9p/client.c:1165
Code: 28 00 00 00 48 89 84 24 88 00 00 00 31 c0 e8 dd 95 b2 f6 48 89 d8 31 f6 48 c1 e8 03 66 89 74 24 40 48 c7 44 24 50 00 00 00 00 <42> 80 3c 30 00 0f 85 3e 04 00 00 31 ff 89 ee 4c 8b 33 e8 af 90 b2
RSP: 0018:ffffc90006b77a90 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9002bc05000
RDX: 0000000000080000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000007 R09: fffffffffffff000
R10: 0000000000000000 R11: 0000000000000002 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000d6ef54
FS: 0000000000000000(0000) GS:ffff88802b600000(0063) knlGS:00000000f5106b40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000630b2000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
clone_fid fs/9p/fid.h:23 [inline]
v9fs_fid_xattr_set+0x119/0x2d0 fs/9p/xattr.c:121
v9fs_set_acl+0xe6/0x150 fs/9p/acl.c:276
v9fs_set_create_acl+0x4b/0x70 fs/9p/acl.c:306
v9fs_vfs_mkdir_dotl+0x517/0x6e0 fs/9p/vfs_inode_dotl.c:411
vfs_mkdir+0x57d/0x860 fs/namei.c:4313
do_mkdirat+0x301/0x3a0 fs/namei.c:4336
__do_sys_mkdirat fs/namei.c:4351 [inline]
__se_sys_mkdirat fs/namei.c:4349 [inline]
__ia32_sys_mkdirat+0x82/0xb0 fs/namei.c:4349
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:387
do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:412
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7fe0579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f510655c EFLAGS: 00000296 ORIG_RAX: 0000000000000128
RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 0000000080000140
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:p9_client_walk+0x9a/0x530 net/9p/client.c:1165
Code: 28 00 00 00 48 89 84 24 88 00 00 00 31 c0 e8 dd 95 b2 f6 48 89 d8 31 f6 48 c1 e8 03 66 89 74 24 40 48 c7 44 24 50 00 00 00 00 <42> 80 3c 30 00 0f 85 3e 04 00 00 31 ff 89 ee 4c 8b 33 e8 af 90 b2
RSP: 0018:ffffc90006b77a90 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9002bc05000
RDX: 0000000000080000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000007 R09: fffffffffffff000
R10: 0000000000000000 R11: 0000000000000002 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000d6ef54
FS: 0000000000000000(0000) GS:ffff88802b600000(0063) knlGS:00000000f5106b40
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000055eba214e600 CR3: 00000000630b2000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 28 00 sub %al,(%rax)
2: 00 00 add %al,(%rax)
4: 48 89 84 24 88 00 00 mov %rax,0x88(%rsp)
b: 00
c: 31 c0 xor %eax,%eax
e: e8 dd 95 b2 f6 call 0xf6b295f0
13: 48 89 d8 mov %rbx,%rax
16: 31 f6 xor %esi,%esi
18: 48 c1 e8 03 shr $0x3,%rax
1c: 66 89 74 24 40 mov %si,0x40(%rsp)
21: 48 c7 44 24 50 00 00 movq $0x0,0x50(%rsp)
28: 00 00
* 2a: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) <-- trapping instruction
2f: 0f 85 3e 04 00 00 jne 0x473
35: 31 ff xor %edi,%edi
37: 89 ee mov %ebp,%esi
39: 4c 8b 33 mov (%rbx),%r14
3c: e8 .byte 0xe8
3d: af scas %es:(%rdi),%eax
3e: 90 nop
3f: b2 .byte 0xb2
---
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