Hello,
syzbot found the following issue on:
HEAD commit: fff5a5e7f528 Merge tag 'for-linus' of git://git.armlinux.o..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1136e97ac80000
kernel config: https://syzkaller.appspot.com/x/.config?x=aaa4b45720ca0519
dashboard link: https://syzkaller.appspot.com/bug?extid=befff0a9536049e7902e
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=14365781c80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12eebc66c80000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/997791f5f9e1/disk-fff5a5e7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0b0155b5eac1/vmlinux-fff5a5e7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8d98dd2ba6b6/bzImage-fff5a5e7.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 8759 Comm: syz-executor379 Not tainted 6.3.0-rc3-syzkaller-00026-gfff5a5e7f528 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
RIP: 0010:virtio_transport_purge_skbs+0x139/0x4c0 net/vmw_vsock/virtio_transport_common.c:1370
Code: 00 00 00 00 fc ff df 48 89 c2 48 89 44 24 28 48 c1 ea 03 48 8d 04 1a 48 89 44 24 10 eb 29 e8 ee 27 a3 f7 48 89 e8 48 c1 e8 03 <80> 3c 18 00 0f 85 a6 02 00 00 49 39 ec 48 8b 55 00 49 89 ef 0f 84
RSP: 0018:ffffc90006427b48 EFLAGS: 00010256
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff8880211157c0 RSI: ffffffff89dfbd12 RDI: ffff88802c11a018
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000003
R10: fffff52000c84f5b R11: 0000000000000000 R12: ffffffff92179188
R13: ffffc90006427ba0 R14: ffff88801e0f1100 R15: ffff88802c11a000
FS: 00007f01fdd51700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f01fdd30718 CR3: 000000002a3f9000 CR4: 0000000000350ef0
Call Trace:
<TASK>
vsock_loopback_cancel_pkt+0x1c/0x20 net/vmw_vsock/vsock_loopback.c:48
vsock_transport_cancel_pkt net/vmw_vsock/af_vsock.c:1284 [inline]
vsock_connect+0x852/0xcc0 net/vmw_vsock/af_vsock.c:1426
__sys_connect_file+0x153/0x1a0 net/socket.c:2001
__sys_connect+0x165/0x1a0 net/socket.c:2018
__do_sys_connect net/socket.c:2028 [inline]
__se_sys_connect net/socket.c:2025 [inline]
__x64_sys_connect+0x73/0xb0 net/socket.c:2025
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f01fdda0159
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 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:00007f01fdd51308 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f01fde28428 RCX: 00007f01fdda0159
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f01fde28420 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f01fddf606c
R13: 0000000000000000 R14: 00007f01fdd51400 R15: 0000000000022000
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:virtio_transport_purge_skbs+0x139/0x4c0 net/vmw_vsock/virtio_transport_common.c:1370
Code: 00 00 00 00 fc ff df 48 89 c2 48 89 44 24 28 48 c1 ea 03 48 8d 04 1a 48 89 44 24 10 eb 29 e8 ee 27 a3 f7 48 89 e8 48 c1 e8 03 <80> 3c 18 00 0f 85 a6 02 00 00 49 39 ec 48 8b 55 00 49 89 ef 0f 84
RSP: 0018:ffffc90006427b48 EFLAGS: 00010256
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff8880211157c0 RSI: ffffffff89dfbd12 RDI: ffff88802c11a018
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000003
R10: fffff52000c84f5b R11: 0000000000000000 R12: ffffffff92179188
R13: ffffc90006427ba0 R14: ffff88801e0f1100 R15: ffff88802c11a000
FS: 00007f01fdd51700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f01fdd30718 CR3: 000000002a3f9000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess), 6 bytes skipped:
0: df 48 89 fisttps -0x77(%rax)
3: c2 48 89 retq $0x8948
6: 44 24 28 rex.R and $0x28,%al
9: 48 c1 ea 03 shr $0x3,%rdx
d: 48 8d 04 1a lea (%rdx,%rbx,1),%rax
11: 48 89 44 24 10 mov %rax,0x10(%rsp)
16: eb 29 jmp 0x41
18: e8 ee 27 a3 f7 callq 0xf7a3280b
1d: 48 89 e8 mov %rbp,%rax
20: 48 c1 e8 03 shr $0x3,%rax
* 24: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction
28: 0f 85 a6 02 00 00 jne 0x2d4
2e: 49 39 ec cmp %rbp,%r12
31: 48 8b 55 00 mov 0x0(%rbp),%rdx
35: 49 89 ef mov %rbp,%r15
38: 0f .byte 0xf
39: 84 .byte 0x84
---
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 [email protected].
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
Hi Bobby,
can you take a look at this report?
It seems related to the changes we made to support skbuff.
Thanks,
Stefano
On Fri, Mar 24, 2023 at 1:52 AM syzbot
<[email protected]> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: fff5a5e7f528 Merge tag 'for-linus' of git://git.armlinux.o..
> git tree: upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1136e97ac80000
> kernel config: https://syzkaller.appspot.com/x/.config?x=aaa4b45720ca0519
> dashboard link: https://syzkaller.appspot.com/bug?extid=befff0a9536049e7902e
> 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=14365781c80000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12eebc66c80000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/997791f5f9e1/disk-fff5a5e7.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/0b0155b5eac1/vmlinux-fff5a5e7.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/8d98dd2ba6b6/bzImage-fff5a5e7.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>
> general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> CPU: 0 PID: 8759 Comm: syz-executor379 Not tainted 6.3.0-rc3-syzkaller-00026-gfff5a5e7f528 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
> RIP: 0010:virtio_transport_purge_skbs+0x139/0x4c0 net/vmw_vsock/virtio_transport_common.c:1370
> Code: 00 00 00 00 fc ff df 48 89 c2 48 89 44 24 28 48 c1 ea 03 48 8d 04 1a 48 89 44 24 10 eb 29 e8 ee 27 a3 f7 48 89 e8 48 c1 e8 03 <80> 3c 18 00 0f 85 a6 02 00 00 49 39 ec 48 8b 55 00 49 89 ef 0f 84
> RSP: 0018:ffffc90006427b48 EFLAGS: 00010256
> RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
> RDX: ffff8880211157c0 RSI: ffffffff89dfbd12 RDI: ffff88802c11a018
> RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000003
> R10: fffff52000c84f5b R11: 0000000000000000 R12: ffffffff92179188
> R13: ffffc90006427ba0 R14: ffff88801e0f1100 R15: ffff88802c11a000
> FS: 00007f01fdd51700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f01fdd30718 CR3: 000000002a3f9000 CR4: 0000000000350ef0
> Call Trace:
> <TASK>
> vsock_loopback_cancel_pkt+0x1c/0x20 net/vmw_vsock/vsock_loopback.c:48
> vsock_transport_cancel_pkt net/vmw_vsock/af_vsock.c:1284 [inline]
> vsock_connect+0x852/0xcc0 net/vmw_vsock/af_vsock.c:1426
> __sys_connect_file+0x153/0x1a0 net/socket.c:2001
> __sys_connect+0x165/0x1a0 net/socket.c:2018
> __do_sys_connect net/socket.c:2028 [inline]
> __se_sys_connect net/socket.c:2025 [inline]
> __x64_sys_connect+0x73/0xb0 net/socket.c:2025
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7f01fdda0159
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 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:00007f01fdd51308 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
> RAX: ffffffffffffffda RBX: 00007f01fde28428 RCX: 00007f01fdda0159
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
> RBP: 00007f01fde28420 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007f01fddf606c
> R13: 0000000000000000 R14: 00007f01fdd51400 R15: 0000000000022000
> </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:virtio_transport_purge_skbs+0x139/0x4c0 net/vmw_vsock/virtio_transport_common.c:1370
> Code: 00 00 00 00 fc ff df 48 89 c2 48 89 44 24 28 48 c1 ea 03 48 8d 04 1a 48 89 44 24 10 eb 29 e8 ee 27 a3 f7 48 89 e8 48 c1 e8 03 <80> 3c 18 00 0f 85 a6 02 00 00 49 39 ec 48 8b 55 00 49 89 ef 0f 84
> RSP: 0018:ffffc90006427b48 EFLAGS: 00010256
> RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
> RDX: ffff8880211157c0 RSI: ffffffff89dfbd12 RDI: ffff88802c11a018
> RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000003
> R10: fffff52000c84f5b R11: 0000000000000000 R12: ffffffff92179188
> R13: ffffc90006427ba0 R14: ffff88801e0f1100 R15: ffff88802c11a000
> FS: 00007f01fdd51700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f01fdd30718 CR3: 000000002a3f9000 CR4: 0000000000350ef0
> ----------------
> Code disassembly (best guess), 6 bytes skipped:
> 0: df 48 89 fisttps -0x77(%rax)
> 3: c2 48 89 retq $0x8948
> 6: 44 24 28 rex.R and $0x28,%al
> 9: 48 c1 ea 03 shr $0x3,%rdx
> d: 48 8d 04 1a lea (%rdx,%rbx,1),%rax
> 11: 48 89 44 24 10 mov %rax,0x10(%rsp)
> 16: eb 29 jmp 0x41
> 18: e8 ee 27 a3 f7 callq 0xf7a3280b
> 1d: 48 89 e8 mov %rbp,%rax
> 20: 48 c1 e8 03 shr $0x3,%rax
> * 24: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction
> 28: 0f 85 a6 02 00 00 jne 0x2d4
> 2e: 49 39 ec cmp %rbp,%r12
> 31: 48 8b 55 00 mov 0x0(%rbp),%rdx
> 35: 49 89 ef mov %rbp,%r15
> 38: 0f .byte 0xf
> 39: 84 .byte 0x84
>
>
> ---
> 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 [email protected].
>
> 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
>
Hello,
syzbot has tested the proposed patch and the reproducer did not trigger any issue:
Reported-and-tested-by: [email protected]
Tested on:
commit: fff5a5e7 Merge tag 'for-linus' of git://git.armlinux.o..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=10b96eeec80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ea09b0836073ee4
dashboard link: https://syzkaller.appspot.com/bug?extid=befff0a9536049e7902e
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=15ad956ec80000
Note: testing is done by a robot and is best-effort only.
On Fri, Mar 24, 2023 at 9:31 AM Stefano Garzarella <[email protected]> wrote:
>
> Hi Bobby,
> can you take a look at this report?
>
> It seems related to the changes we made to support skbuff.
Could it be a problem of concurrent access to pkt_queue ?
IIUC we should hold pkt_queue.lock when we call skb_queue_splice_init()
and remove pkt_list_lock. (or hold pkt_list_lock when calling
virtio_transport_purge_skbs, but pkt_list_lock seems useless now that
we use skbuff)
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fff5a5e7f528
--- a/net/vmw_vsock/vsock_loopback.c
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -15,7 +15,6 @@
struct vsock_loopback {
struct workqueue_struct *workqueue;
- spinlock_t pkt_list_lock; /* protects pkt_list */
struct sk_buff_head pkt_queue;
struct work_struct pkt_work;
};
@@ -32,9 +31,7 @@ static int vsock_loopback_send_pkt(struct sk_buff *skb)
struct vsock_loopback *vsock = &the_vsock_loopback;
int len = skb->len;
- spin_lock_bh(&vsock->pkt_list_lock);
skb_queue_tail(&vsock->pkt_queue, skb);
- spin_unlock_bh(&vsock->pkt_list_lock);
queue_work(vsock->workqueue, &vsock->pkt_work);
@@ -113,9 +110,9 @@ static void vsock_loopback_work(struct work_struct *work)
skb_queue_head_init(&pkts);
- spin_lock_bh(&vsock->pkt_list_lock);
+ spin_lock_bh(&vsock->pkt_queue.lock);
skb_queue_splice_init(&vsock->pkt_queue, &pkts);
- spin_unlock_bh(&vsock->pkt_list_lock);
+ spin_unlock_bh(&vsock->pkt_queue.lock);
while ((skb = __skb_dequeue(&pkts))) {
virtio_transport_deliver_tap_pkt(skb);
@@ -132,7 +129,6 @@ static int __init vsock_loopback_init(void)
if (!vsock->workqueue)
return -ENOMEM;
- spin_lock_init(&vsock->pkt_list_lock);
skb_queue_head_init(&vsock->pkt_queue);
INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
>
> Thanks,
> Stefano
>
> On Fri, Mar 24, 2023 at 1:52 AM syzbot
> <[email protected]> wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit: fff5a5e7f528 Merge tag 'for-linus' of git://git.armlinux.o..
> > git tree: upstream
> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1136e97ac80000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=aaa4b45720ca0519
> > dashboard link: https://syzkaller.appspot.com/bug?extid=befff0a9536049e7902e
> > 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=14365781c80000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12eebc66c80000
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/997791f5f9e1/disk-fff5a5e7.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/0b0155b5eac1/vmlinux-fff5a5e7.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/8d98dd2ba6b6/bzImage-fff5a5e7.xz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: [email protected]
> >
> > general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
> > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> > CPU: 0 PID: 8759 Comm: syz-executor379 Not tainted 6.3.0-rc3-syzkaller-00026-gfff5a5e7f528 #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
> > RIP: 0010:virtio_transport_purge_skbs+0x139/0x4c0 net/vmw_vsock/virtio_transport_common.c:1370
> > Code: 00 00 00 00 fc ff df 48 89 c2 48 89 44 24 28 48 c1 ea 03 48 8d 04 1a 48 89 44 24 10 eb 29 e8 ee 27 a3 f7 48 89 e8 48 c1 e8 03 <80> 3c 18 00 0f 85 a6 02 00 00 49 39 ec 48 8b 55 00 49 89 ef 0f 84
> > RSP: 0018:ffffc90006427b48 EFLAGS: 00010256
> > RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
> > RDX: ffff8880211157c0 RSI: ffffffff89dfbd12 RDI: ffff88802c11a018
> > RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000003
> > R10: fffff52000c84f5b R11: 0000000000000000 R12: ffffffff92179188
> > R13: ffffc90006427ba0 R14: ffff88801e0f1100 R15: ffff88802c11a000
> > FS: 00007f01fdd51700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f01fdd30718 CR3: 000000002a3f9000 CR4: 0000000000350ef0
> > Call Trace:
> > <TASK>
> > vsock_loopback_cancel_pkt+0x1c/0x20 net/vmw_vsock/vsock_loopback.c:48
> > vsock_transport_cancel_pkt net/vmw_vsock/af_vsock.c:1284 [inline]
> > vsock_connect+0x852/0xcc0 net/vmw_vsock/af_vsock.c:1426
> > __sys_connect_file+0x153/0x1a0 net/socket.c:2001
> > __sys_connect+0x165/0x1a0 net/socket.c:2018
> > __do_sys_connect net/socket.c:2028 [inline]
> > __se_sys_connect net/socket.c:2025 [inline]
> > __x64_sys_connect+0x73/0xb0 net/socket.c:2025
> > do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> > do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
> > entry_SYSCALL_64_after_hwframe+0x63/0xcd
> > RIP: 0033:0x7f01fdda0159
> > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 41 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:00007f01fdd51308 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
> > RAX: ffffffffffffffda RBX: 00007f01fde28428 RCX: 00007f01fdda0159
> > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
> > RBP: 00007f01fde28420 R08: 0000000000000000 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000246 R12: 00007f01fddf606c
> > R13: 0000000000000000 R14: 00007f01fdd51400 R15: 0000000000022000
> > </TASK>
> > Modules linked in:
> > ---[ end trace 0000000000000000 ]---
> > RIP: 0010:virtio_transport_purge_skbs+0x139/0x4c0 net/vmw_vsock/virtio_transport_common.c:1370
> > Code: 00 00 00 00 fc ff df 48 89 c2 48 89 44 24 28 48 c1 ea 03 48 8d 04 1a 48 89 44 24 10 eb 29 e8 ee 27 a3 f7 48 89 e8 48 c1 e8 03 <80> 3c 18 00 0f 85 a6 02 00 00 49 39 ec 48 8b 55 00 49 89 ef 0f 84
> > RSP: 0018:ffffc90006427b48 EFLAGS: 00010256
> > RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
> > RDX: ffff8880211157c0 RSI: ffffffff89dfbd12 RDI: ffff88802c11a018
> > RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000003
> > R10: fffff52000c84f5b R11: 0000000000000000 R12: ffffffff92179188
> > R13: ffffc90006427ba0 R14: ffff88801e0f1100 R15: ffff88802c11a000
> > FS: 00007f01fdd51700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > CR2: 00007f01fdd30718 CR3: 000000002a3f9000 CR4: 0000000000350ef0
> > ----------------
> > Code disassembly (best guess), 6 bytes skipped:
> > 0: df 48 89 fisttps -0x77(%rax)
> > 3: c2 48 89 retq $0x8948
> > 6: 44 24 28 rex.R and $0x28,%al
> > 9: 48 c1 ea 03 shr $0x3,%rdx
> > d: 48 8d 04 1a lea (%rdx,%rbx,1),%rax
> > 11: 48 89 44 24 10 mov %rax,0x10(%rsp)
> > 16: eb 29 jmp 0x41
> > 18: e8 ee 27 a3 f7 callq 0xf7a3280b
> > 1d: 48 89 e8 mov %rbp,%rax
> > 20: 48 c1 e8 03 shr $0x3,%rax
> > * 24: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) <-- trapping instruction
> > 28: 0f 85 a6 02 00 00 jne 0x2d4
> > 2e: 49 39 ec cmp %rbp,%r12
> > 31: 48 8b 55 00 mov 0x0(%rbp),%rdx
> > 35: 49 89 ef mov %rbp,%r15
> > 38: 0f .byte 0xf
> > 39: 84 .byte 0x84
> >
> >
> > ---
> > 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 [email protected].
> >
> > 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
> >
On Fri, Mar 24, 2023 at 9:55 AM Stefano Garzarella <[email protected]> wrote:
>
> On Fri, Mar 24, 2023 at 9:31 AM Stefano Garzarella <[email protected]> wrote:
> >
> > Hi Bobby,
> > can you take a look at this report?
> >
> > It seems related to the changes we made to support skbuff.
>
> Could it be a problem of concurrent access to pkt_queue ?
>
> IIUC we should hold pkt_queue.lock when we call skb_queue_splice_init()
> and remove pkt_list_lock. (or hold pkt_list_lock when calling
> virtio_transport_purge_skbs, but pkt_list_lock seems useless now that
> we use skbuff)
>
In the previous patch was missing a hunk, new one attached:
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fff5a5e7f528
--- a/net/vmw_vsock/vsock_loopback.c
+++ b/net/vmw_vsock/vsock_loopback.c
@@ -15,7 +15,6 @@
struct vsock_loopback {
struct workqueue_struct *workqueue;
- spinlock_t pkt_list_lock; /* protects pkt_list */
struct sk_buff_head pkt_queue;
struct work_struct pkt_work;
};
@@ -32,9 +31,7 @@ static int vsock_loopback_send_pkt(struct sk_buff *skb)
struct vsock_loopback *vsock = &the_vsock_loopback;
int len = skb->len;
- spin_lock_bh(&vsock->pkt_list_lock);
skb_queue_tail(&vsock->pkt_queue, skb);
- spin_unlock_bh(&vsock->pkt_list_lock);
queue_work(vsock->workqueue, &vsock->pkt_work);
@@ -113,9 +110,9 @@ static void vsock_loopback_work(struct work_struct *work)
skb_queue_head_init(&pkts);
- spin_lock_bh(&vsock->pkt_list_lock);
+ spin_lock_bh(&vsock->pkt_queue.lock);
skb_queue_splice_init(&vsock->pkt_queue, &pkts);
- spin_unlock_bh(&vsock->pkt_list_lock);
+ spin_unlock_bh(&vsock->pkt_queue.lock);
while ((skb = __skb_dequeue(&pkts))) {
virtio_transport_deliver_tap_pkt(skb);
@@ -132,7 +129,6 @@ static int __init vsock_loopback_init(void)
if (!vsock->workqueue)
return -ENOMEM;
- spin_lock_init(&vsock->pkt_list_lock);
skb_queue_head_init(&vsock->pkt_queue);
INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
@@ -156,9 +152,7 @@ static void __exit vsock_loopback_exit(void)
flush_work(&vsock->pkt_work);
- spin_lock_bh(&vsock->pkt_list_lock);
virtio_vsock_skb_queue_purge(&vsock->pkt_queue);
- spin_unlock_bh(&vsock->pkt_list_lock);
destroy_workqueue(vsock->workqueue);
}
On 24.03.2023 12:06, Stefano Garzarella wrote:
> On Fri, Mar 24, 2023 at 9:55 AM Stefano Garzarella <[email protected]> wrote:
>>
>> On Fri, Mar 24, 2023 at 9:31 AM Stefano Garzarella <[email protected]> wrote:
>>>
>>> Hi Bobby,
>>> can you take a look at this report?
>>>
>>> It seems related to the changes we made to support skbuff.
>>
>> Could it be a problem of concurrent access to pkt_queue ?
>>
>> IIUC we should hold pkt_queue.lock when we call skb_queue_splice_init()
>> and remove pkt_list_lock. (or hold pkt_list_lock when calling
>> virtio_transport_purge_skbs, but pkt_list_lock seems useless now that
>> we use skbuff)
>>
>
> In the previous patch was missing a hunk, new one attached:
>
> #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fff5a5e7f528
>
> --- a/net/vmw_vsock/vsock_loopback.c
> +++ b/net/vmw_vsock/vsock_loopback.c
> @@ -15,7 +15,6 @@
> struct vsock_loopback {
> struct workqueue_struct *workqueue;
>
> - spinlock_t pkt_list_lock; /* protects pkt_list */
> struct sk_buff_head pkt_queue;
> struct work_struct pkt_work;
> };
> @@ -32,9 +31,7 @@ static int vsock_loopback_send_pkt(struct sk_buff *skb)
> struct vsock_loopback *vsock = &the_vsock_loopback;
> int len = skb->len;
>
> - spin_lock_bh(&vsock->pkt_list_lock);
> skb_queue_tail(&vsock->pkt_queue, skb);
Hello Stefano and Bobby,
Small remark, may be here we can use virtio_vsock_skb_queue_tail() instead of skb_queue_tail().
skb_queue_tail() disables irqs during spinlock access, while virtio_vsock_skb_queue_tail()
uses spin_lock_bh(). vhost and virtio transports use virtio_vsock_skb_queue_tail().
Thanks, Arseniy
> - spin_unlock_bh(&vsock->pkt_list_lock);
>
> queue_work(vsock->workqueue, &vsock->pkt_work);
>
> @@ -113,9 +110,9 @@ static void vsock_loopback_work(struct work_struct *work)
>
> skb_queue_head_init(&pkts);
>
> - spin_lock_bh(&vsock->pkt_list_lock);
> + spin_lock_bh(&vsock->pkt_queue.lock);
> skb_queue_splice_init(&vsock->pkt_queue, &pkts);
> - spin_unlock_bh(&vsock->pkt_list_lock);
> + spin_unlock_bh(&vsock->pkt_queue.lock);
>
> while ((skb = __skb_dequeue(&pkts))) {
> virtio_transport_deliver_tap_pkt(skb);
> @@ -132,7 +129,6 @@ static int __init vsock_loopback_init(void)
> if (!vsock->workqueue)
> return -ENOMEM;
>
> - spin_lock_init(&vsock->pkt_list_lock);
> skb_queue_head_init(&vsock->pkt_queue);
> INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
>
> @@ -156,9 +152,7 @@ static void __exit vsock_loopback_exit(void)
>
> flush_work(&vsock->pkt_work);
>
> - spin_lock_bh(&vsock->pkt_list_lock);
> virtio_vsock_skb_queue_purge(&vsock->pkt_queue);
> - spin_unlock_bh(&vsock->pkt_list_lock);
>
> destroy_workqueue(vsock->workqueue);
> }
>
Hello,
syzbot tried to test the proposed patch but the build/boot failed:
net/vmw_vsock/vsock_loopback.c:155:21: error: 'struct vsock_loopback' has no member named 'pkt_list_lock'
net/vmw_vsock/vsock_loopback.c:157:23: error: 'struct vsock_loopback' has no member named 'pkt_list_lock'
Tested on:
commit: fff5a5e7 Merge tag 'for-linus' of git://git.armlinux.o..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
dashboard link: https://syzkaller.appspot.com/bug?extid=befff0a9536049e7902e
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
patch: https://syzkaller.appspot.com/x/patch.diff?x=15ed6191c80000
Hello,
syzbot tried to test the proposed patch but the build/boot failed:
failed to apply patch:
checking file net/vmw_vsock/vsock_loopback.c
patch: **** unexpected end of file in patch
Tested on:
commit: fff5a5e7 Merge tag 'for-linus' of git://git.armlinux.o..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
dashboard link: https://syzkaller.appspot.com/bug?extid=befff0a9536049e7902e
compiler:
patch: https://syzkaller.appspot.com/x/patch.diff?x=16b4bba1c80000
On Fri, Mar 24, 2023 at 10:10 AM Arseniy Krasnov
<[email protected]> wrote:
> On 24.03.2023 12:06, Stefano Garzarella wrote:
> > On Fri, Mar 24, 2023 at 9:55 AM Stefano Garzarella <[email protected]> wrote:
> >>
> >> On Fri, Mar 24, 2023 at 9:31 AM Stefano Garzarella <[email protected]> wrote:
> >>>
> >>> Hi Bobby,
> >>> can you take a look at this report?
> >>>
> >>> It seems related to the changes we made to support skbuff.
> >>
> >> Could it be a problem of concurrent access to pkt_queue ?
> >>
> >> IIUC we should hold pkt_queue.lock when we call skb_queue_splice_init()
> >> and remove pkt_list_lock. (or hold pkt_list_lock when calling
> >> virtio_transport_purge_skbs, but pkt_list_lock seems useless now that
> >> we use skbuff)
> >>
> >
> > In the previous patch was missing a hunk, new one attached:
> >
> > #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fff5a5e7f528
> >
> > --- a/net/vmw_vsock/vsock_loopback.c
> > +++ b/net/vmw_vsock/vsock_loopback.c
> > @@ -15,7 +15,6 @@
> > struct vsock_loopback {
> > struct workqueue_struct *workqueue;
> >
> > - spinlock_t pkt_list_lock; /* protects pkt_list */
> > struct sk_buff_head pkt_queue;
> > struct work_struct pkt_work;
> > };
> > @@ -32,9 +31,7 @@ static int vsock_loopback_send_pkt(struct sk_buff *skb)
> > struct vsock_loopback *vsock = &the_vsock_loopback;
> > int len = skb->len;
> >
> > - spin_lock_bh(&vsock->pkt_list_lock);
> > skb_queue_tail(&vsock->pkt_queue, skb);
> Hello Stefano and Bobby,
>
> Small remark, may be here we can use virtio_vsock_skb_queue_tail() instead of skb_queue_tail().
> skb_queue_tail() disables irqs during spinlock access, while virtio_vsock_skb_queue_tail()
> uses spin_lock_bh(). vhost and virtio transports use virtio_vsock_skb_queue_tail().
>
Yep, but this shouldn't be related.
I would make this change in a separate patch. ;-)
Thanks,
Stefano
On Fri, Mar 24, 2023 at 10:06 AM Stefano Garzarella <[email protected]> wrote:
>
> On Fri, Mar 24, 2023 at 9:55 AM Stefano Garzarella <[email protected]> wrote:
> >
> > On Fri, Mar 24, 2023 at 9:31 AM Stefano Garzarella <[email protected]> wrote:
> > >
> > > Hi Bobby,
> > > can you take a look at this report?
> > >
> > > It seems related to the changes we made to support skbuff.
> >
> > Could it be a problem of concurrent access to pkt_queue ?
> >
> > IIUC we should hold pkt_queue.lock when we call skb_queue_splice_init()
> > and remove pkt_list_lock. (or hold pkt_list_lock when calling
> > virtio_transport_purge_skbs, but pkt_list_lock seems useless now that
> > we use skbuff)
> >
>
Patch posted here:
https://lore.kernel.org/netdev/[email protected]/
syzbot has bisected this issue to:
commit 71dc9ec9ac7d3eee785cdc986c3daeb821381e20
Author: Bobby Eshleman <[email protected]>
Date: Fri Jan 13 22:21:37 2023 +0000
virtio/vsock: replace virtio_vsock_pkt with sk_buff
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12661f29c80000
start commit: fff5a5e7f528 Merge tag 'for-linus' of git://git.armlinux.o..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=11661f29c80000
console output: https://syzkaller.appspot.com/x/log.txt?x=16661f29c80000
kernel config: https://syzkaller.appspot.com/x/.config?x=aaa4b45720ca0519
dashboard link: https://syzkaller.appspot.com/bug?extid=befff0a9536049e7902e
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14365781c80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12eebc66c80000
Reported-by: [email protected]
Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection