From b9fa1fbf98178c8bbda23ff1d3ed0731bb3c0bd1 Mon Sep 17 00:00:00 2001
From: Rasesh Mody <rmody@brocade.com>
Date: Fri, 16 Sep 2011 15:06:48 +0000
Subject: bna: Eliminate Small Race Condition Window in RX Path
Change details:
- In a continuous sequence of ifconfig up/down operations, there is a small
window of race between bnad_set_rx_mode() and bnad_cleanup_rx() while the
former tries to access rx_info->rx & the latter sets it to NULL. This race
could lead to bna_rx_mode_set() being called with a NULL (rx_info->rx)
pointer and a crash.
- Hold bnad->bna_lock while setting / unsetting rx_info->rx in bnad_setup_rx()
& bnad_cleanup_rx(), thereby eliminating the race described above.
Signed-off-by: Gurunatha Karaje <gkaraje@brocade.com>
Signed-off-by: Rasesh Mody <rmody@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
drivers/net/ethernet/brocade/bna/bnad.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
(limited to 'drivers')
diff --git a/drivers/net/ethernet/brocade/bna/bnad.c b/drivers/net/ethernet/brocade/bna/bnad.c
index 33ab1f81c1c..abca1399fe5 100644
--- a/drivers/net/ethernet/brocade/bna/bnad.c
+++ b/drivers/net/ethernet/brocade/bna/bnad.c
@@ -1875,10 +1875,10 @@ bnad_cleanup_rx(struct bnad *bnad, u32 rx_id)
spin_lock_irqsave(&bnad->bna_lock, flags);
bna_rx_destroy(rx_info->rx);
- spin_unlock_irqrestore(&bnad->bna_lock, flags);
rx_info->rx = NULL;
rx_info->rx_id = 0;
+ spin_unlock_irqrestore(&bnad->bna_lock, flags);
bnad_rx_res_free(bnad, res_info);
}
@@ -1932,12 +1932,13 @@ bnad_setup_rx(struct bnad *bnad, u32 rx_id)
spin_lock_irqsave(&bnad->bna_lock, flags);
rx = bna_rx_create(&bnad->bna, bnad, rx_config, &rx_cbfn, res_info,
rx_info);
- spin_unlock_irqrestore(&bnad->bna_lock, flags);
if (!rx) {
err = -ENOMEM;
+ spin_unlock_irqrestore(&bnad->bna_lock, flags);
goto err_return;
}
rx_info->rx = rx;
+ spin_unlock_irqrestore(&bnad->bna_lock, flags);
/*
* Init NAPI, so that state is set to NAPI_STATE_SCHED,
--
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