bnx2x: fix possible panic under memory stress

[ 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: Jiri Slaby <jslaby@suse.cz>

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index 0399458e6d44e05bc263c82534b8f01e7c5fd801..9846d3e712a125c5068b6be271a75c7b37a7c031 100644 (file)
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -755,7 +755,8 @@ static void bnx2x_tpa_stop(struct bnx2x *bp, struct bnx2x_fastpath *fp,
 
                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,