From: Thomas Huth <thuth@linux.vnet.ibm.com>
To: netdev@vger.kernel.org
Cc: Vlad Yasevich <vyasevic@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>
Subject: macvtap bug: using smp_processor_id() in preemptible code
Date: Wed, 7 Aug 2013 16:43:19 +0200 [thread overview]
Message-ID: <20130807164319.20aa2333@thhw500> (raw)
Hi,
I am using macvtap (via KVM/virsh) on a s390 box. With the latest
kernel source from linux-next master branch, I suddenly get the
following error messages in the dmesg output:
BUG: using smp_processor_id() in preemptible [00000000] code: vhost-45891/45892
caller is macvtap_do_read+0x45c/0x600 [macvtap]
CPU: 1 PID: 45892 Comm: vhost-45891 Not tainted 3.11.0-bisecttest #13
000000010cab3a00 000000010cab3a10 0000000000000002 0000000000000000
000000010cab3aa0 000000010cab3a18 000000010cab3a18 00000000001127b4
0000000000000000 0000000000000001 0000000000000000 000000010000000b
0000000000000060 000003fe00000008 0000000000000000 000000010cab3a70
00000000006ea2f0 00000000001127b4 000000010cab3a00 000000010cab3a50
Call Trace:
([<00000000001126ee>] show_trace+0x126/0x144)
[<00000000001127d2>] show_stack+0xc6/0xd4
[<000000000068bcec>] dump_stack+0x74/0xd8
[<0000000000481066>] debug_smp_processor_id+0xf6/0x114
[<000003ff802e9a18>] macvtap_do_read+0x45c/0x600 [macvtap]
[<000003ff802e9c1c>] macvtap_recvmsg+0x60/0x88 [macvtap]
[<000003ff80318c5e>] handle_rx+0x5b2/0x800 [vhost_net]
[<000003ff8028f77c>] vhost_worker+0x15c/0x1c4 [vhost]
[<000000000015f3ac>] kthread+0xd8/0xe4
[<00000000006934a6>] kernel_thread_starter+0x6/0xc
[<00000000006934a0>] kernel_thread_starter+0x0/0xc
2 locks held by vhost-45891/45892:
#0: (&vq->mutex){+.+...}, at: [<000003ff80318718>] handle_rx+0x6c/0x800 [vhost_net]
#1: (rcu_read_lock){.+.+..}, at: [<000003ff802e98fe>] macvtap_do_read+0x342/0x600 [macvtap]
Apart from these "annoying" error messages (they are repeated
continually while the KVM guest is running / macvtap is in use),
everything still seems to work fine, though.
Since everything was still working fine in v3.10, I did some bisecting
and it seems like this commit introduced this problem:
commit: ac4e4af1e59e16a018527ffa58d9d3f30bb96ca9
Subject: macvtap: Consistently use rcu functions
I am not sure how to proceed here, this is my first bug report in this
area, so advice is welcome...
Regards,
Thomas Huth
next reply other threads:[~2013-08-07 14:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-07 14:43 Thomas Huth [this message]
2013-08-07 15:26 ` macvtap bug: using smp_processor_id() in preemptible code Eric Dumazet
2013-08-08 8:25 ` Thomas Huth
2013-08-08 13:21 ` Eric Dumazet
2013-08-08 13:56 ` Thomas Huth
2013-08-08 14:04 ` Eric Dumazet
2013-08-08 15:06 ` [PATCH] macvtap: fix two races Eric Dumazet
2013-08-09 17:16 ` Vlad Yasevich
2013-08-09 17:41 ` Eric Dumazet
2013-08-09 18:01 ` Vlad Yasevich
2013-08-12 4:50 ` David Miller
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