Messages in this thread | | | Date | Mon, 17 Jan 2022 08:35:57 +0100 | Subject | Re: [syzbot] general protection fault in nfc_alloc_send_skb | From | Krzysztof Kozlowski <> |
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On 17/01/2022 02:11, Hillf Danton wrote: > On Sun, 16 Jan 2022 17:56:51 +0100 Krzysztof Kozlowski wrote: >> On 16/01/2022 12:42, Hillf Danton wrote: >>> On Wed, 05 Jan 2022 06:25:31 -0800 >>>> Hello, >>>> >>>> syzbot found the following issue on: >>>> >>>> HEAD commit: eec4df26e24e Merge tag 's390-5.16-6' of git://git.kernel.o.. >>>> git tree: upstream >>>> console output: https://syzkaller.appspot.com/x/log.txt?x=149771a5b00000 >>>> kernel config: https://syzkaller.appspot.com/x/.config?x=dc943eeb68074e3 >>>> dashboard link: https://syzkaller.appspot.com/bug?extid=7f23bcddf626e0593a39 >>>> 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=133e5e2bb00000 >>>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=152e6571b00000 >>>> >>>> The issue was bisected to: >>>> >>>> commit c33b1cc62ac05c1dbb1cdafe2eb66da01c76ca8d >>>> Author: Xiaoming Ni <nixiaoming@huawei.com> >>>> Date: Thu Mar 25 03:51:10 2021 +0000 >>>> >>>> nfc: fix refcount leak in llcp_sock_bind() >>>> >>>> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=16b92ba3b00000 >>>> final oops: https://syzkaller.appspot.com/x/report.txt?x=15b92ba3b00000 >>>> console output: https://syzkaller.appspot.com/x/log.txt?x=11b92ba3b00000 >>>> >>>> IMPORTANT: if you fix the issue, please add the following tag to the commit: >>>> Reported-by: syzbot+7f23bcddf626e0593a39@syzkaller.appspotmail.com >>>> Fixes: c33b1cc62ac0 ("nfc: fix refcount leak in llcp_sock_bind()") >>>> >>>> general protection fault, probably for non-canonical address 0xdffffc00000000c2: 0000 [#1] PREEMPT SMP KASAN >>>> KASAN: null-ptr-deref in range [0x0000000000000610-0x0000000000000617] >>>> CPU: 1 PID: 7219 Comm: syz-executor408 Not tainted 5.16.0-rc7-syzkaller #0 >>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 >>>> RIP: 0010:nfc_alloc_send_skb+0x3a/0x190 net/nfc/core.c:722 >>>> Code: 54 41 89 d4 55 53 48 89 fb 48 8d ab 10 06 00 00 48 83 ec 08 e8 47 53 92 f8 48 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 14 01 00 00 48 8d bb 14 06 00 >>>> RSP: 0018:ffffc9000ca97888 EFLAGS: 00010202 >>>> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 >>>> RDX: 00000000000000c2 RSI: ffffffff88e474b9 RDI: 0000000000000000 >>>> RBP: 0000000000000610 R08: ffffc9000ca97938 R09: 0000000000000880 >>>> R10: ffffffff88e6031d R11: 000000000000087f R12: 0000000000000000 >>>> R13: 0000000000000082 R14: ffff88807ca8b000 R15: ffffc9000ca97938 >>>> FS: 00007f6b81ae2700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 >>>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>> CR2: 00007fff1b2fd960 CR3: 000000007ca3a000 CR4: 00000000003506e0 >>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>>> Call Trace: >>>> <TASK> >>>> nfc_llcp_send_ui_frame+0x2c0/0x430 net/nfc/llcp_commands.c:759 >>>> llcp_sock_sendmsg+0x2b9/0x3a0 net/nfc/llcp_sock.c:803 >>>> sock_sendmsg_nosec net/socket.c:704 [inline] >>>> sock_sendmsg+0xcf/0x120 net/socket.c:724 >>>> ____sys_sendmsg+0x331/0x810 net/socket.c:2409 >>>> ___sys_sendmsg+0xf3/0x170 net/socket.c:2463 >>>> __sys_sendmmsg+0x195/0x470 net/socket.c:2549 >>>> __do_sys_sendmmsg net/socket.c:2578 [inline] >>>> __se_sys_sendmmsg net/socket.c:2575 [inline] >>>> __x64_sys_sendmmsg+0x99/0x100 net/socket.c:2575 >>>> 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+0x44/0xae >>>> RIP: 0033:0x7f6b81b51f89 >>>> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 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 b8 ff ff ff f7 d8 64 89 01 48 >>>> RSP: 002b:00007f6b81ae22f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 >>>> RAX: ffffffffffffffda RBX: 0000000000000033 RCX: 00007f6b81b51f89 >>>> RDX: 0000000000000006 RSI: 0000000020004540 RDI: 0000000000000003 >>>> RBP: 00007f6b81bdb3f8 R08: 0000000000000000 R09: 0000000000000000 >>>> R10: 0000000000000040 R11: 0000000000000246 R12: 00007f6b81bdb3f0 >>>> R13: 93cb663f6753dadd R14: 4b973dfbaeacdab3 R15: f981dd66eb1318f7 >>>> </TASK> >>>> Modules linked in: >>>> ---[ end trace 570920f865b173be ]--- >>>> RIP: 0010:nfc_alloc_send_skb+0x3a/0x190 net/nfc/core.c:722 >>>> Code: 54 41 89 d4 55 53 48 89 fb 48 8d ab 10 06 00 00 48 83 ec 08 e8 47 53 92 f8 48 89 ea 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 14 01 00 00 48 8d bb 14 06 00 >>>> RSP: 0018:ffffc9000ca97888 EFLAGS: 00010202 >>>> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 >>>> RDX: 00000000000000c2 RSI: ffffffff88e474b9 RDI: 0000000000000000 >>>> RBP: 0000000000000610 R08: ffffc9000ca97938 R09: 0000000000000880 >>>> R10: ffffffff88e6031d R11: 000000000000087f R12: 0000000000000000 >>>> R13: 0000000000000082 R14: ffff88807ca8b000 R15: ffffc9000ca97938 >>>> FS: 00007f6b81ae2700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 >>>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>> CR2: 00007fff1b2fd960 CR3: 000000007ca3a000 CR4: 00000000003506e0 >>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>>> ---------------- >>>> Code disassembly (best guess): >>>> 0: 54 push %rsp >>>> 1: 41 89 d4 mov %edx,%r12d >>>> 4: 55 push %rbp >>>> 5: 53 push %rbx >>>> 6: 48 89 fb mov %rdi,%rbx >>>> 9: 48 8d ab 10 06 00 00 lea 0x610(%rbx),%rbp >>>> 10: 48 83 ec 08 sub $0x8,%rsp >>>> 14: e8 47 53 92 f8 callq 0xf8925360 >>>> 19: 48 89 ea mov %rbp,%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: 84 c0 test %al,%al >>>> 30: 74 08 je 0x3a >>>> 32: 3c 03 cmp $0x3,%al >>>> 34: 0f 8e 14 01 00 00 jle 0x14e >>>> 3a: 48 rex.W >>>> 3b: 8d .byte 0x8d >>>> 3c: bb .byte 0xbb >>>> 3d: 14 06 adc $0x6,%al >>>> >>>> >>>> --- >>>> 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. >>>> For information about bisection process see: https://goo.gl/tpsmEJ#bisection >>>> syzbot can test patches for this issue, for details see: >>>> https://goo.gl/tpsmEJ#testing-patches >>> >>> Before sending frame out, check llcp dev bond to llcp sock and bail out in >>> case of invalid device. >>> >>> #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >>> >>> --- a/net/nfc/llcp_sock.c >>> +++ b/net/nfc/llcp_sock.c >>> @@ -798,6 +798,10 @@ static int llcp_sock_sendmsg(struct sock >>> return -EINVAL; >>> } >>> >>> + if (llcp_sock->dev == NULL) { >>> + release_sock(sk); >>> + return -EBADFD; >>> + } >>> release_sock(sk); >>> >> >> The patch looks the same as mine, except the test for ->dev is slightly >> later. Why sending the same set? > > Why did you use the words like looks and except here in addition to same? > I feel free to fix the syzbot report, clear?
It's just confusing to hear that a patch is not working while sending almost the same one a moment later with Cc to all...
> Did you post your patch with Hillf on the Cc list? > >> My patch was already tested: > > Fine, feel free to show us the tag below you had received. > > Reported-and-tested-by: syzbot+7f23bcddf626e0593a39@syzkaller.appspotmail.com
I got email confirmation from syzbot later, so I mentioned this in a reply to my patch.
Best regards, Krzysztof
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