[PATCH 3.12 40/94] bnx2x: fix possible panic under memory stress

From: Jiri Slaby
Date: Wed Jul 30 2014 - 08:28:58 EST

From: Eric Dumazet <edumazet@xxxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.


[ Upstream commit 07b0f00964def8af9321cfd6c4a7e84f6362f728 ]

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

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

Reported-by: Michel Lespinasse <walken@xxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Ariel Elior <ariel.elior@xxxxxxxxxx>
Fixes: d46d132cc021 ("bnx2x: use netdev_alloc_frag()")
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index 0399458e6d44..9846d3e712a1 100644
--- 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,

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

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