Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
Date:   Wed, 19 Oct 2022 23:16:48 -0700
Message-ID: <0000000000002feb6605eb71458e@google.com>
Subject: [syzbot] general protection fault in _parse_integer_fixup_radix
From:   syzbot <syzbot+db1d2ea936378be0e4ea@syzkaller.appspotmail.com>
To:     akpm@linux-foundation.org, hughd@google.com,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        syzkaller-bugs@googlegroups.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hello,

syzbot found the following issue on:

HEAD commit:    a72b55bc981b Add linux-next specific files for 20221019
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1728c644880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=200524babbc01b2a
dashboard link: https://syzkaller.appspot.com/bug?extid=db1d2ea936378be0e4ea
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=12afb08c880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11001c72880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/fa24fb5893fd/disk-a72b55bc.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cf1b7e7b579c/vmlinux-a72b55bc.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+db1d2ea936378be0e4ea@syzkaller.appspotmail.com

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: 3606 Comm: syz-executor141 Not tainted 6.1.0-rc1-next-20221019-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
RIP: 0010:_parse_integer_fixup_radix+0x60/0x290 lib/kstrtox.c:29
Code: 02 00 00 41 8b 2c 24 31 ff 89 ee e8 4a ae 76 fd 85 ed 75 62 e8 71 b1 76 fd 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 04 02 48 89 da 83 e2 07 38 d0 7f 08 84 c0 0f 85 e2 01 00 00
RSP: 0018:ffffc90003d3fa40 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8405d49f RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 000000000008c001 R12: ffffc90003d3fa90
R13: ffffc90003d3fbd8 R14: 000000007fffffff R15: ffff8880798524d0
FS:  000055555732c300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 000000007b427000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 simple_strntoull+0x88/0x160 lib/vsprintf.c:68
 memparse+0x72/0x180 lib/cmdline.c:154
 shmem_parse_one+0x6a3/0xa60 mm/shmem.c:3478
 vfs_parse_fs_param fs/fs_context.c:148 [inline]
 vfs_parse_fs_param+0x1f9/0x3c0 fs/fs_context.c:129
 vfs_parse_fs_string+0xdb/0x170 fs/fs_context.c:191
 shmem_parse_options+0x15f/0x240 mm/shmem.c:3570
 do_new_mount fs/namespace.c:3036 [inline]
 path_mount+0x12de/0x1e20 fs/namespace.c:3370
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount fs/namespace.c:3568 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f012fe73e09
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffed54dd188 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007f012fe73e09
RDX: 0000000020000040 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 00007f012fe37d20 R08: 0000000020000180 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f012fe37db0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:_parse_integer_fixup_radix+0x60/0x290 lib/kstrtox.c:29
Code: 02 00 00 41 8b 2c 24 31 ff 89 ee e8 4a ae 76 fd 85 ed 75 62 e8 71 b1 76 fd 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 04 02 48 89 da 83 e2 07 38 d0 7f 08 84 c0 0f 85 e2 01 00 00
RSP: 0018:ffffc90003d3fa40 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8405d49f RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 000000000008c001 R12: ffffc90003d3fa90
R13: ffffc90003d3fbd8 R14: 000000007fffffff R15: ffff8880798524d0
FS:  000055555732c300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 000000007b427000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	02 00                	add    (%rax),%al
   2:	00 41 8b             	add    %al,-0x75(%rcx)
   5:	2c 24                	sub    $0x24,%al
   7:	31 ff                	xor    %edi,%edi
   9:	89 ee                	mov    %ebp,%esi
   b:	e8 4a ae 76 fd       	callq  0xfd76ae5a
  10:	85 ed                	test   %ebp,%ebp
  12:	75 62                	jne    0x76
  14:	e8 71 b1 76 fd       	callq  0xfd76b18a
  19:	48 89 da             	mov    %rbx,%rdx
  1c:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  23:	fc ff df
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	0f b6 04 02          	movzbl (%rdx,%rax,1),%eax <-- trapping instruction
  2e:	48 89 da             	mov    %rbx,%rdx
  31:	83 e2 07             	and    $0x7,%edx
  34:	38 d0                	cmp    %dl,%al
  36:	7f 08                	jg     0x40
  38:	84 c0                	test   %al,%al
  3a:	0f 85 e2 01 00 00    	jne    0x222


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches