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Message-ID: <685e23ec.a00a0220.34b642.014d.GAE@google.com>
Date: Thu, 26 Jun 2025 21:54:04 -0700
From: syzbot <syzbot+9b9124ae9b12d5af5d95@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, lizhi.xu@...driver.com,
syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [kernel?] KMSAN: kernel-infoleak in vmci_host_unlocked_ioctl
(3)
Hello,
syzbot has tested the proposed patch but the reproducer is still triggering an issue:
BUG: unable to handle kernel NULL pointer dereference in ioctl
BUG: kernel NULL pointer dereference, address: 0000000000000320
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 8000000047e19067 P4D 8000000047e19067 PUD 0
Oops: Oops: 0000 [#1] SMP PTI
CPU: 1 UID: 0 PID: 6745 Comm: syz.0.16 Not tainted 6.16.0-rc3-syzkaller-g6f2a71a99ebd-dirty #0 PREEMPT(undef)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:vfs_ioctl fs/ioctl.c:51 [inline]
RIP: 0010:__do_sys_ioctl fs/ioctl.c:907 [inline]
RIP: 0010:__se_sys_ioctl+0x23f/0x400 fs/ioctl.c:893
Code: 83 20 03 00 00 00 00 00 00 49 83 fd 04 0f 83 b9 01 00 00 48 8b 7d c8 44 89 e6 48 8b 55 b0 4d 89 f3 2e e8 e0 4a 44 1d 49 89 c6 <44> 8b a3 20 03 00 00 8b 83 a8 0f 00 00 89 45 d4 c7 03 00 00 00 00
RSP: 0018:ffff88804a3dbe30 EFLAGS: 00010282
RAX: fffffffffffffff2 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 00000000219e67d0 RSI: 0000000000000001 RDI: ffff8880219e67d0
RBP: ffff88804a3dbe80 R08: ffffea000000000f R09: 0000000000000000
R10: ffff8880211e67d0 R11: ffffffff82831f32 R12: 00000000000007a0
R13: 0000000000000000 R14: fffffffffffffff2 R15: ffff888038101c01
FS: 00007f0f9a3e76c0(0000) GS:ffff8881aa97d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000320 CR3: 0000000047176000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
__x64_sys_ioctl+0x97/0xe0 fs/ioctl.c:893
x64_sys_call+0x1ebe/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0f9958e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f0f9a3e7038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f0f997b5fa0 RCX: 00007f0f9958e929
RDX: 0000200000000140 RSI: 00000000000007a0 RDI: 0000000000000004
RBP: 00007f0f99610b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f0f997b5fa0 R15: 00007ffe024bc598
</TASK>
Modules linked in:
CR2: 0000000000000320
---[ end trace 0000000000000000 ]---
RIP: 0010:vfs_ioctl fs/ioctl.c:51 [inline]
RIP: 0010:__do_sys_ioctl fs/ioctl.c:907 [inline]
RIP: 0010:__se_sys_ioctl+0x23f/0x400 fs/ioctl.c:893
Code: 83 20 03 00 00 00 00 00 00 49 83 fd 04 0f 83 b9 01 00 00 48 8b 7d c8 44 89 e6 48 8b 55 b0 4d 89 f3 2e e8 e0 4a 44 1d 49 89 c6 <44> 8b a3 20 03 00 00 8b 83 a8 0f 00 00 89 45 d4 c7 03 00 00 00 00
RSP: 0018:ffff88804a3dbe30 EFLAGS: 00010282
RAX: fffffffffffffff2 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 00000000219e67d0 RSI: 0000000000000001 RDI: ffff8880219e67d0
RBP: ffff88804a3dbe80 R08: ffffea000000000f R09: 0000000000000000
R10: ffff8880211e67d0 R11: ffffffff82831f32 R12: 00000000000007a0
R13: 0000000000000000 R14: fffffffffffffff2 R15: ffff888038101c01
FS: 00007f0f9a3e76c0(0000) GS:ffff8881aa97d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000320 CR3: 0000000047176000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
0: 83 20 03 andl $0x3,(%rax)
3: 00 00 add %al,(%rax)
5: 00 00 add %al,(%rax)
7: 00 00 add %al,(%rax)
9: 49 83 fd 04 cmp $0x4,%r13
d: 0f 83 b9 01 00 00 jae 0x1cc
13: 48 8b 7d c8 mov -0x38(%rbp),%rdi
17: 44 89 e6 mov %r12d,%esi
1a: 48 8b 55 b0 mov -0x50(%rbp),%rdx
1e: 4d 89 f3 mov %r14,%r11
21: 2e e8 e0 4a 44 1d cs call 0x1d444b07
27: 49 89 c6 mov %rax,%r14
* 2a: 44 8b a3 20 03 00 00 mov 0x320(%rbx),%r12d <-- trapping instruction
31: 8b 83 a8 0f 00 00 mov 0xfa8(%rbx),%eax
37: 89 45 d4 mov %eax,-0x2c(%rbp)
3a: c7 03 00 00 00 00 movl $0x0,(%rbx)
Tested on:
commit: 6f2a71a9 Merge tag 'bcachefs-2025-06-26' of git://evil..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1720608c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=595d344ff0b23ac5
dashboard link: https://syzkaller.appspot.com/bug?extid=9b9124ae9b12d5af5d95
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
patch: https://syzkaller.appspot.com/x/patch.diff?x=103ba08c580000
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