From: Rasesh Mody Date: Fri, 16 Sep 2011 15:06:48 +0000 (+0000) Subject: bna: Eliminate Small Race Condition Window in RX Path X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=b9fa1fbf98178c8bbda23ff1d3ed0731bb3c0bd1;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git 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 Signed-off-by: Rasesh Mody Signed-off-by: David S. Miller --- diff --git a/drivers/net/ethernet/brocade/bna/bnad.c b/drivers/net/ethernet/brocade/bna/bnad.c index 33ab1f81c1c2..abca1399fe51 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,