| Submitter | Eric Dumazet |
|---|---|
| Date | Feb. 12, 2013, 3:15 a.m. |
| Message ID | <1360638903.20362.32.camel@edumazet-glaptop> |
| Download | mbox | patch |
| Permalink | /patch/219732/ |
| State | RFC |
| Delegated to: | David Miller |
| Headers | show |
Comments
2013/2/12 Eric Dumazet <eric.dumazet@gmail.com>: > On Mon, 2013-02-11 at 16:19 -0800, Eric Dumazet wrote: >> On Mon, 2013-02-11 at 21:25 +0200, Tommi Rantala wrote: >> > Hello, >> > >> > I am quite easily reproducing this lockup when fuzzing with Trinity as >> > the root user in a virtual machine. It seems to be busy-looping in the >> > do-while loop in __skb_recv_datagram(). >> > >> > [ 83.541011] INFO: rcu_sched detected stalls on CPUs/tasks: {} >> > (detected by 0, t=26002 jiffies, g=27673, c=27672, q=75) >> > [ 83.541011] INFO: Stall ended before state dump start >> > [ 108.067010] BUG: soft lockup - CPU#0 stuck for 22s! [trinity-child31:2847] >> > [ 108.067010] irq event stamp: 244034822 >> > [ 108.067010] hardirqs last enabled at (244034821): >> > [<ffffffff81ca2da5>] _raw_spin_unlock_irqrestore+0x55/0x70 >> > [ 108.067010] hardirqs last disabled at (244034822): >> > [<ffffffff81ca4fad>] apic_timer_interrupt+0x6d/0x80 >> > [ 108.067010] softirqs last enabled at (244030010): >> > [<ffffffff810a086a>] __do_softirq+0x1ca/0x240 >> > [ 108.067010] softirqs last disabled at (244030005): >> > [<ffffffff81ca56fc>] call_softirq+0x1c/0x30 >> > [ 108.067010] CPU 0 >> > [ 108.067010] Pid: 2847, comm: trinity-child31 Tainted: G W >> > 3.8.0-rc7+ #73 Bochs Bochs >> > [ 108.067010] RIP: 0010:[<ffffffff81ca2daa>] [<ffffffff81ca2daa>] >> > _raw_spin_unlock_irqrestore+0x5a/0x70 >> > [ 108.067010] RSP: 0018:ffff88002fb5db38 EFLAGS: 00000286 >> > [ 108.067010] RAX: ffff8800201ec520 RBX: ffffffff810d54fa RCX: 0000000000005220 >> > [ 108.067010] RDX: ffff8800201ec520 RSI: 0000000000000001 RDI: 0000000000000286 >> > [ 108.067010] RBP: ffff88002fb5db48 R08: 0000000000000068 R09: 0000000000000001 >> > [ 108.067010] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff810f5b9d >> > [ 108.067010] R13: ffff88002fb5daa8 R14: 00000019294ba499 R15: 0000000000000086 >> > [ 108.067010] FS: 00007f6aabc57700(0000) GS:ffff88003e000000(0000) >> > knlGS:0000000000000000 >> > [ 108.067010] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> > [ 108.067010] CR2: 0000000000000009 CR3: 000000002fb08000 CR4: 00000000000006f0 >> > [ 108.067010] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> > [ 108.067010] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 >> > [ 108.067010] Process trinity-child31 (pid: 2847, threadinfo >> > ffff88002fb5c000, task ffff8800201ec520) >> > [ 108.067010] Stack: >> > [ 108.067010] ffff88002fb5dc10 ffff88002fb5dc14 ffff88002fb5dbf8 >> > ffffffff818cc103 >> > [ 108.067010] ffff8800391a7d80 ffff8800201ec520 ffff88002fb5dbb8 >> > 7fffffffffffffff >> > [ 108.067010] ffff88002fb5dc54 40001202810d54fa ffff8800201ec520 >> > ffff8800277f87e8 >> > [ 108.067010] Call Trace: >> > [ 108.067010] [<ffffffff818cc103>] __skb_recv_datagram+0x1a3/0x3b0 >> > [ 108.067010] [<ffffffff818cbbe0>] ? >> > csum_partial_copy_fromiovecend+0x220/0x220 >> > [ 108.067010] [<ffffffff818cc33d>] skb_recv_datagram+0x2d/0x30 >> > [ 108.067010] [<ffffffff813029a0>] ? selinux_syslog+0x70/0x70 >> > [ 108.067010] [<ffffffff819ed43d>] rawv6_recvmsg+0xad/0x240 >> > [ 108.067010] [<ffffffff818c4b04>] sock_common_recvmsg+0x34/0x50 >> > [ 108.067010] [<ffffffff818bc8ec>] sock_recvmsg+0xbc/0xf0 >> > [ 108.067010] [<ffffffff81084adf>] ? kvm_clock_read+0x1f/0x30 >> > [ 108.067010] [<ffffffff810612d9>] ? sched_clock+0x9/0x10 >> > [ 108.067010] [<ffffffff818bf31e>] sys_recvfrom+0xde/0x150 >> > [ 108.067010] [<ffffffff810f5abd>] ? trace_hardirqs_on+0xd/0x10 >> > [ 108.067010] [<ffffffff81ca2deb>] ? _raw_spin_unlock_irq+0x2b/0x40 >> > [ 108.067010] [<ffffffff81ca4355>] ? sysret_check+0x22/0x5d >> > [ 108.067010] [<ffffffff810f5a15>] ? trace_hardirqs_on_caller+0x155/0x1f0 >> > [ 108.067010] [<ffffffff8135718e>] ? trace_hardirqs_on_thunk+0x3a/0x3f >> > [ 108.067010] [<ffffffff81ca4329>] system_call_fastpath+0x16/0x1b >> > [ 108.067010] Code: ff f6 c7 02 75 1b 48 89 df 57 9d 0f 1f 44 00 00 >> > e8 fc 2d 45 ff eb 19 66 2e 0f 1f 84 00 00 00 00 00 e8 0b 2d 45 ff 48 >> > 89 df 57 9d <0f> 1f 44 00 00 48 8b 5d f0 4c 8b 65 f8 c9 c3 0f 1f 80 00 >> > 00 00 >> > >> > Tommi >> >> Seems MSG_PEEK issue >> >> wait_for_packet() is unable to wait if one packet is in receive_queue. >> >> So yes, we basically loop forever. >> >> Bug added in commit 3f518bf745cbd6007d8069100fb9cb09e960c872 >> (datagram: Add offset argument to __skb_recv_datagram) >> >> CC Pavel Emelyanov >> > > If I am not mistaken, we can have skb with 0 bytes in them Thanks Eric, with the patch applied, I am no longer able to reproduce the bug with Trinity. Tommi > diff --git a/net/core/datagram.c b/net/core/datagram.c > index 0337e2b..368f9c3 100644 > --- a/net/core/datagram.c > +++ b/net/core/datagram.c > @@ -187,7 +187,7 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags, > skb_queue_walk(queue, skb) { > *peeked = skb->peeked; > if (flags & MSG_PEEK) { > - if (*off >= skb->len) { > + if (*off >= skb->len && skb->len) { > *off -= skb->len; > continue; > } > > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Patch
diff --git a/net/core/datagram.c b/net/core/datagram.c index 0337e2b..368f9c3 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -187,7 +187,7 @@ struct sk_buff *__skb_recv_datagram(struct sock *sk, unsigned int flags, skb_queue_walk(queue, skb) { *peeked = skb->peeked; if (flags & MSG_PEEK) { - if (*off >= skb->len) { + if (*off >= skb->len && skb->len) { *off -= skb->len; continue; }