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| author | Eric Dumazet <edumazet@google.com> | 2013-08-08 08:06:14 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-08-11 21:48:58 -0700 |
| commit | 29d7919692e591c2f0e1f743a7f6c613c1266ece (patch) | |
| tree | f07046c3a4dd67f60becda844e1ab99174c38c86 | |
| parent | e5ac5da8072104bed1749ffe64f2517f40416117 (diff) | |
| download | linux-29d7919692e591c2f0e1f743a7f6c613c1266ece.tar.gz | |
macvtap: fix two races
Since commit ac4e4af1e59e1 ("macvtap: Consistently use rcu functions"),
Thomas gets two different warnings :
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
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
And
BUG: using smp_processor_id() in preemptible [00000000] code: vhost-45897/45898
caller is macvlan_start_xmit+0x10a/0x1b4 [macvlan]
CPU: 1 PID: 45898 Comm: vhost-45897 Not tainted 3.11.0-bisecttest #16
Call Trace:
([<00000000001126ee>] show_trace+0x126/0x144)
[<00000000001127d2>] show_stack+0xc6/0xd4
[<000000000068bdb8>] dump_stack+0x74/0xd4
[<0000000000481132>] debug_smp_processor_id+0xf6/0x114
[<000003ff802b72ca>] macvlan_start_xmit+0x10a/0x1b4 [macvlan]
[<000003ff802ea69a>] macvtap_get_user+0x982/0xbc4 [macvtap]
[<000003ff802ea92a>] macvtap_sendmsg+0x4e/0x60 [macvtap]
[<000003ff8031947c>] handle_tx+0x494/0x5ec [vhost_net]
[<000003ff8028f77c>] vhost_worker+0x15c/0x1c4 [vhost]
[<000000000015f3ac>] kthread+0xd8/0xe4
[<000000000069356e>] kernel_thread_starter+0x6/0xc
[<0000000000693568>] kernel_thread_starter+0x0/0xc
2 locks held by vhost-45897/45898:
#0: (&vq->mutex){+.+.+.}, at: [<000003ff8031903c>] handle_tx+0x54/0x5ec [vhost_net]
#1: (rcu_read_lock){.+.+..}, at: [<000003ff802ea53c>] macvtap_get_user+0x824/0xbc4 [macvtap]
In the first case, macvtap_put_user() calls macvlan_count_rx()
in a preempt-able context, and this is not allowed.
In the second case, macvtap_get_user() calls
macvlan_start_xmit() with BH enabled, and this is not allowed.
Reported-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Bisected-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Cc: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/macvtap.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index a98fb0ed6aef..b51db2abfe44 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -818,10 +818,13 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; } - if (vlan) + if (vlan) { + local_bh_disable(); macvlan_start_xmit(skb, vlan->dev); - else + local_bh_enable(); + } else { kfree_skb(skb); + } rcu_read_unlock(); return total_len; @@ -912,8 +915,11 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q, done: rcu_read_lock(); vlan = rcu_dereference(q->vlan); - if (vlan) + if (vlan) { + preempt_disable(); macvlan_count_rx(vlan, copied - vnet_hdr_len, ret == 0, 0); + preempt_enable(); + } rcu_read_unlock(); return ret ? ret : copied; |