[PATCH 3.10 23/56] bnx2x: fix possible panic under memory stress

Greg Kroah-Hartman
2014-07-26T19:02:16Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 07b0f00964def8af9321cfd6c4a7e84f6362f728 ]

While it is legal to kfree(NULL), it is not wise to use :
put_page(virt_to_head_page(NULL))

BUG: unable to handle kernel paging request at ffffeba400000000
IP: [<ffffffffc01f5928>] virt_to_head_page+0x36/0x44 [bnx2x]

Reported-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Ariel Elior <ariel.elior@qlogic.com>
Fixes: d46d132cc021 ("bnx2x: use netdev_alloc_frag()")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -745,7 +745,8 @@ static void bnx2x_tpa_stop(struct bnx2x

return;
}
- bnx2x_frag_free(fp, new_data);
+ if (new_data)
+ bnx2x_frag_free(fp, new_data);
drop:
/* drop the packet and keep the buffer in the bin */
DP(NETIF_MSG_RX_STATUS,