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authorVlad Yasevich <vyasevich@gmail.com>2015-11-09 09:14:17 -0500
committerDavid S. Miller <davem@davemloft.net>2015-11-09 12:04:44 -0500
commita499a2e9d9c03fd35bd9920b629e4d5b1d6cc1f0 (patch)
treeb314d3f9411eafd2eb8cff1ab1829c25e4619c9e /drivers/net/macvtap.c
parent4bed5395a521b475c2164510596d9af366a3d6dc (diff)
macvtap: Resolve possible __might_sleep warning in macvtap_do_read()
macvtap_do_read code calls macvtap_put_user while it might be set up to wait for the user. This results in the following warning: Jun 23 16:25:26 galen kernel: ------------[ cut here ]------------ Jun 23 16:25:26 galen kernel: WARNING: CPU: 0 PID: 30433 at kernel/sched/core.c: 7286 __might_sleep+0x7f/0x90() Jun 23 16:25:26 galen kernel: do not call blocking ops when !TASK_RUNNING; state =1 set at [<ffffffff810f1c1f>] prepare_to_wait+0x2f/0x90 Jun 23 16:25:26 galen kernel: CPU: 0 PID: 30433 Comm: cat Not tainted 4.1.0-rc6+ #11 Jun 23 16:25:26 galen kernel: Call Trace: Jun 23 16:25:26 galen kernel: [<ffffffff817f76ba>] dump_stack+0x4c/0x65 Jun 23 16:25:26 galen kernel: [<ffffffff810a07ca>] warn_slowpath_common+0x8a/0xc 0 Jun 23 16:25:26 galen kernel: [<ffffffff810a0846>] warn_slowpath_fmt+0x46/0x50 Jun 23 16:25:26 galen kernel: [<ffffffff810f1c1f>] ? prepare_to_wait+0x2f/0x90 Jun 23 16:25:26 galen kernel: [<ffffffff810f1c1f>] ? prepare_to_wait+0x2f/0x90 Jun 23 16:25:26 galen kernel: [<ffffffff810cdc1f>] __might_sleep+0x7f/0x90 Jun 23 16:25:26 galen kernel: [<ffffffff811f8e15>] might_fault+0x55/0xb0 Jun 23 16:25:26 galen kernel: [<ffffffff810fab9d>] ? trace_hardirqs_on_caller+0x fd/0x1c0 Jun 23 16:25:26 galen kernel: [<ffffffff813f639c>] copy_to_iter+0x7c/0x360 Jun 23 16:25:26 galen kernel: [<ffffffffa052da86>] macvtap_do_read+0x256/0x3d0 [macvtap] Jun 23 16:25:26 galen kernel: [<ffffffff810f20e0>] ? prepare_to_wait_event+0x110/0x110 Jun 23 16:25:26 galen kernel: [<ffffffffa052dcab>] macvtap_read_iter+0x2b/0x50 [macvtap] Jun 23 16:25:26 galen kernel: [<ffffffff81247f2e>] __vfs_read+0xae/0xe0 Jun 23 16:25:26 galen kernel: [<ffffffff81248526>] vfs_read+0x86/0x140 Jun 23 16:25:26 galen kernel: [<ffffffff812493b9>] SyS_read+0x49/0xb0 Jun 23 16:25:26 galen kernel: [<ffffffff8180182e>] system_call_fastpath+0x12/0x76 Jun 23 16:25:26 galen kernel: ---[ end trace 22e33f67e70c0c2a ]--- Make sure thet we call finish_wait() if we have the skb to process before trying to actually process it. Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/macvtap.c')
-rw-r--r--drivers/net/macvtap.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 197c93937c2d..54036ae0a388 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -935,6 +935,9 @@ static ssize_t macvtap_do_read(struct macvtap_queue *q,
/* Nothing to read, let's sleep */
schedule();
}
+ if (!noblock)
+ finish_wait(sk_sleep(&q->sk), &wait);
+
if (skb) {
ret = macvtap_put_user(q, skb, to);
if (unlikely(ret < 0))
@@ -942,8 +945,6 @@ static ssize_t macvtap_do_read(struct macvtap_queue *q,
else
consume_skb(skb);
}
- if (!noblock)
- finish_wait(sk_sleep(&q->sk), &wait);
return ret;
}