[PATCH] vmxnet3: fix lock imbalance in vmxnet3_tq_xmit()

From: Arnd Bergmann
Date: Mon Mar 14 2016 - 10:55:18 EST


A recent bug fix rearranged the code in vmxnet3_tq_xmit() in a
way that left the error handling for oversized headers unlock
a lock that had not been taken yet. Gcc warns about the incorrect
use of the 'flags' variable because of that:

drivers/net/vmxnet3/vmxnet3_drv.c: In function 'vmxnet3_tq_xmit.constprop':
include/linux/spinlock.h:246:3: error: 'flags' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This changes the error handling path to 'goto' the end of the function
beyond the lock/unlock pair.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Fixes: cec05562fb1d ("vmxnet3: avoid calling pskb_may_pull with interrupts disabled")
---
drivers/net/vmxnet3/vmxnet3_drv.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index fc895d0e85d9..b2348f67b00a 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -1022,14 +1022,16 @@ vmxnet3_tq_xmit(struct sk_buff *skb, struct vmxnet3_tx_queue *tq,
if (ctx.mss) {
if (unlikely(ctx.eth_ip_hdr_size + ctx.l4_hdr_size >
VMXNET3_MAX_TX_BUF_SIZE)) {
- goto hdr_too_big;
+ tq->stats.drop_oversized_hdr++;
+ goto drop_pkt;
}
} else {
if (skb->ip_summed == CHECKSUM_PARTIAL) {
if (unlikely(ctx.eth_ip_hdr_size +
skb->csum_offset >
VMXNET3_MAX_CSUM_OFFSET)) {
- goto hdr_too_big;
+ tq->stats.drop_oversized_hdr++;
+ goto drop_pkt;
}
}
}
@@ -1123,8 +1125,6 @@ vmxnet3_tq_xmit(struct sk_buff *skb, struct vmxnet3_tx_queue *tq,

return NETDEV_TX_OK;

-hdr_too_big:
- tq->stats.drop_oversized_hdr++;
unlock_drop_pkt:
spin_unlock_irqrestore(&tq->tx_lock, flags);
drop_pkt:
--
2.7.0