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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Mitch Williams <mitch.a.williams@intel.com>,
	Andrew Bowers <andrewx.bowers@intel.com>,
	Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
	Sasha Levin <sashal@kernel.org>,
	intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org,
	bpf@vger.kernel.org
Subject: [PATCH AUTOSEL 5.5 278/542] ice: add extra check for null Rx descriptor
Date: Fri, 14 Feb 2020 10:44:30 -0500
Message-ID: <20200214154854.6746-278-sashal@kernel.org> (raw)
In-Reply-To: <20200214154854.6746-1-sashal@kernel.org>

From: Mitch Williams <mitch.a.williams@intel.com>

[ Upstream commit 1f45ebe0d8fbe6178670b663005f38ef8535db5d ]

In the case where the hardware gives us a null Rx descriptor, it is
theoretically possible that we could call one of our skb-construction
functions with no data pointer, which would cause a panic.

In real life, this will never happen - we only get null RX
descriptors as the final descriptor in a chain of otherwise-valid
descriptors. When this happens, the skb will be extant and we'll just
call ice_add_rx_frag(), which can deal with empty data buffers.

Unfortunately, Coverity does not have intimate knowledge of our
hardware, so we must add a check here.

Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/ice/ice_txrx.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
index 2c212f64d99f2..8b2b9e254d28d 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
@@ -1071,13 +1071,16 @@ static int ice_clean_rx_irq(struct ice_ring *rx_ring, int budget)
 		ice_put_rx_buf(rx_ring, rx_buf);
 		continue;
 construct_skb:
-		if (skb)
+		if (skb) {
 			ice_add_rx_frag(rx_ring, rx_buf, skb, size);
-		else if (ice_ring_uses_build_skb(rx_ring))
-			skb = ice_build_skb(rx_ring, rx_buf, &xdp);
-		else
+		} else if (likely(xdp.data)) {
+			if (ice_ring_uses_build_skb(rx_ring))
+				skb = ice_build_skb(rx_ring, rx_buf, &xdp);
+			else
+				skb = ice_construct_skb(rx_ring, rx_buf, &xdp);
+		} else {
 			skb = ice_construct_skb(rx_ring, rx_buf, &xdp);
-
+		}
 		/* exit if we failed to retrieve a buffer */
 		if (!skb) {
 			rx_ring->rx_stats.alloc_buf_failed++;
-- 
2.20.1


  parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200214154854.6746-1-sashal@kernel.org>
2020-02-14 15:42 ` [PATCH AUTOSEL 5.5 133/542] bpftool: Don't crash on missing xlated program instructions Sasha Levin
2020-02-14 15:42 ` [PATCH AUTOSEL 5.5 134/542] bpf, sockhash: Synchronize_rcu before free'ing map Sasha Levin
2020-02-14 15:42 ` [PATCH AUTOSEL 5.5 135/542] bpf, sockmap: Check update requirements after locking Sasha Levin
2020-02-14 15:42 ` [PATCH AUTOSEL 5.5 136/542] bpf: Improve bucket_log calculation logic Sasha Levin
2020-02-14 15:42 ` [PATCH AUTOSEL 5.5 137/542] bpf, sockmap: Don't sleep while holding RCU lock on tear-down Sasha Levin
2020-02-14 15:43 ` [PATCH AUTOSEL 5.5 212/542] samples/bpf: Set -fno-stack-protector when building BPF programs Sasha Levin
2020-02-14 15:44 ` [PATCH AUTOSEL 5.5 263/542] bpf: Print error message for bpftool cgroup show Sasha Levin
2020-02-14 15:44 ` Sasha Levin [this message]
2020-02-14 15:44 ` [PATCH AUTOSEL 5.5 286/542] tools lib api fs: Fix gcc9 stringop-truncation compilation error Sasha Levin
2020-02-14 15:45 ` [PATCH AUTOSEL 5.5 352/542] bpf: Return -EBADRQC for invalid map type in __bpf_tx_xdp_map Sasha Levin
2020-02-14 15:47 ` [PATCH AUTOSEL 5.5 438/542] bpf, btf: Always output invariant hit in pahole DWARF to BTF transform Sasha Levin
2020-02-14 15:47 ` [PATCH AUTOSEL 5.5 461/542] selftests: bpf: Reset global state between reuseport test runs Sasha Levin
2020-02-14 15:47 ` [PATCH AUTOSEL 5.5 482/542] bpf: map_seq_next should always increase position index Sasha Levin
2020-02-14 15:48 ` [PATCH AUTOSEL 5.5 502/542] powerpc: Do not consider weak unresolved symbol relocations as bad Sasha Levin
2020-02-14 15:48 ` [PATCH AUTOSEL 5.5 535/542] i40e: Relax i40e_xsk_wakeup's return value when PF is busy Sasha Levin

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