From: syzbot <syzbot+138c9e58e3cb22eae3b4@syzkaller.appspotmail.com>
To: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
nathan@kernel.org, ndesaulniers@google.com,
syzkaller-bugs@googlegroups.com, tytso@mit.edu
Subject: Re: [syzbot] general protection fault in ext4_fill_super
Date: Sat, 05 Feb 2022 11:50:29 -0800 [thread overview]
Message-ID: <000000000000f517d505d74aad30@google.com> (raw)
In-Reply-To: <0000000000001e0ba105d5c2dede@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 0457e5153e0e Merge tag 'for-linus' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=146d12b4700000
kernel config: https://syzkaller.appspot.com/x/.config?x=cd57c0f940a9a1ec
dashboard link: https://syzkaller.appspot.com/bug?extid=138c9e58e3cb22eae3b4
compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17f7004fb00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=178cf108700000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+138c9e58e3cb22eae3b4@syzkaller.appspotmail.com
general protection fault, probably for non-canonical address 0xdffffc0000000012: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000090-0x0000000000000097]
CPU: 0 PID: 3603 Comm: syz-executor131 Not tainted 5.17.0-rc2-syzkaller-00316-g0457e5153e0e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:ext4_fill_super+0x247/0x770 fs/ext4/super.c:5550
Code: 3b 4c 89 6c 24 20 49 8d bd a8 06 00 00 be 2f 00 00 00 ba 21 00 00 00 e8 87 5a d9 01 4d 8d af 90 00 00 00 4d 89 ec 49 c1 ec 03 <41> 80 3c 2c 00 74 08 4c 89 ef e8 ca 7d 96 ff 49 c7 45 00 01 00 00
RSP: 0018:ffffc9000284fbe8 EFLAGS: 00010206
RAX: ffff8880217dc6ac RBX: ffff88801c4048f0 RCX: ffff88807d4b9d00
RDX: 0000000000000000 RSI: 000000000000002f RDI: 0000000000000035
RBP: dffffc0000000000 R08: ffffffff84142d6e R09: fffffbfff197f79f
R10: fffffbfff197f79f R11: 0000000000000000 R12: 0000000000000012
R13: 0000000000000090 R14: ffff888014784f00 R15: 0000000000000000
FS: 00005555563943c0(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000001c361000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
get_tree_bdev+0x406/0x630 fs/super.c:1292
vfs_get_tree+0x86/0x270 fs/super.c:1497
do_new_mount fs/namespace.c:2994 [inline]
path_mount+0x1986/0x2c30 fs/namespace.c:3324
do_mount fs/namespace.c:3337 [inline]
__do_sys_mount fs/namespace.c:3545 [inline]
__se_sys_mount+0x308/0x3c0 fs/namespace.c:3522
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fb3d4cbca49
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 15 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:00007ffc0c4f4df8 EFLAGS: 00000246
ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fb3d4cbca49
RDX: 0000000020000100 RSI: 00000000200000c0 RDI: 0000000020000080
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000003636
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc0c4f4e00
R13: 00007ffc0c4f4ea0 R14: 00007ffc0c4f4e60 R15: 0000000000000000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ext4_fill_super+0x247/0x770 fs/ext4/super.c:5550
Code: 3b 4c 89 6c 24 20 49 8d bd a8 06 00 00 be 2f 00 00 00 ba 21 00 00 00 e8 87 5a d9 01 4d 8d af 90 00 00 00 4d 89 ec 49 c1 ec 03 <41> 80 3c 2c 00 74 08 4c 89 ef e8 ca 7d 96 ff 49 c7 45 00 01 00 00
RSP: 0018:ffffc9000284fbe8 EFLAGS: 00010206
RAX: ffff8880217dc6ac RBX: ffff88801c4048f0 RCX: ffff88807d4b9d00
RDX: 0000000000000000 RSI: 000000000000002f RDI: 0000000000000035
----------------
Code disassembly (best guess):
0: 3b 4c 89 6c cmp 0x6c(%rcx,%rcx,4),%ecx
4: 24 20 and $0x20,%al
6: 49 8d bd a8 06 00 00 lea 0x6a8(%r13),%rdi
d: be 2f 00 00 00 mov $0x2f,%esi
12: ba 21 00 00 00 mov $0x21,%edx
17: e8 87 5a d9 01 callq 0x1d95aa3
1c: 4d 8d af 90 00 00 00 lea 0x90(%r15),%r13
23: 4d 89 ec mov %r13,%r12
26: 49 c1 ec 03 shr $0x3,%r12
* 2a: 41 80 3c 2c 00 cmpb $0x0,(%r12,%rbp,1) <-- trapping instruction
2f: 74 08 je 0x39
31: 4c 89 ef mov %r13,%rdi
34: e8 ca 7d 96 ff callq 0xff967e03
39: 49 rex.WB
3a: c7 .byte 0xc7
3b: 45 00 01 add %r8b,(%r9)
next prev parent reply other threads:[~2022-02-05 19:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-17 8:23 [syzbot] general protection fault in ext4_fill_super syzbot
2022-02-05 19:50 ` syzbot [this message]
2022-02-05 22:39 ` syzbot
2022-02-07 10:30 ` Lukas Czerner
2022-02-07 11:29 ` Dmitry Vyukov
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