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Message-ID: <20250109043057.2888953-1-kuba@kernel.org>
Date: Wed, 8 Jan 2025 20:30:57 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org,
edumazet@...gle.com,
pabeni@...hat.com,
andrew+netdev@...n.ch,
horms@...nel.org,
Jakub Kicinski <kuba@...nel.org>,
michael.chan@...adcom.com,
daniel@...earbox.net,
hawk@...nel.org,
john.fastabend@...il.com,
andrew.gospodarek@...adcom.com,
pavan.chebbi@...adcom.com
Subject: [PATCH net] eth: bnxt: always recalculate features after XDP clearing, fix null-deref
Recalculate features when XDP is detached.
Before:
# ip li set dev eth0 xdp obj xdp_dummy.bpf.o sec xdp
# ip li set dev eth0 xdp off
# ethtool -k eth0 | grep gro
rx-gro-hw: off [requested on]
After:
# ip li set dev eth0 xdp obj xdp_dummy.bpf.o sec xdp
# ip li set dev eth0 xdp off
# ethtool -k eth0 | grep gro
rx-gro-hw: on
The fact that HW-GRO doesn't get re-enabled automatically is just
a minor annoyance. The real issue is that the features will randomly
come back during another reconfiguration which just happens to invoke
netdev_update_features(). The driver doesn't handle reconfiguring
two things at a time very robustly.
Starting with commit 98ba1d931f61 ("bnxt_en: Fix RSS logic in
__bnxt_reserve_rings()") we only reconfigure the RSS hash table
if the "effective" number of Rx rings has changed. If HW-GRO is
enabled "effective" number of rings is 2x what user sees.
So if we are in the bad state, with HW-GRO re-enablement "pending"
after XDP off, and we lower the rings by / 2 - the HW-GRO rings
doing 2x and the ethtool -L doing / 2 may cancel each other out,
and the:
if (old_rx_rings != bp->hw_resc.resv_rx_rings &&
condition in __bnxt_reserve_rings() will be false.
The RSS map won't get updated, and we'll crash with:
BUG: kernel NULL pointer dereference, address: 0000000000000168
RIP: 0010:__bnxt_hwrm_vnic_set_rss+0x13a/0x1a0
bnxt_hwrm_vnic_rss_cfg_p5+0x47/0x180
__bnxt_setup_vnic_p5+0x58/0x110
bnxt_init_nic+0xb72/0xf50
__bnxt_open_nic+0x40d/0xab0
bnxt_open_nic+0x2b/0x60
ethtool_set_channels+0x18c/0x1d0
As we try to access a freed ring.
The issue is present since XDP support was added, really, but
prior to commit 98ba1d931f61 ("bnxt_en: Fix RSS logic in
__bnxt_reserve_rings()") it wasn't causing major issues.
Fixes: 1054aee82321 ("bnxt_en: Use NETIF_F_GRO_HW.")
Fixes: 98ba1d931f61 ("bnxt_en: Fix RSS logic in __bnxt_reserve_rings()")
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
---
CC: michael.chan@...adcom.com
CC: daniel@...earbox.net
CC: hawk@...nel.org
CC: john.fastabend@...il.com
CC: andrew.gospodarek@...adcom.com
CC: pavan.chebbi@...adcom.com
---
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 25 +++++++++++++++----
drivers/net/ethernet/broadcom/bnxt/bnxt.h | 2 +-
drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c | 7 ------
3 files changed, 21 insertions(+), 13 deletions(-)
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index aeaa74f03046..b6f844cac80e 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -4708,7 +4708,7 @@ void bnxt_set_ring_params(struct bnxt *bp)
/* Changing allocation mode of RX rings.
* TODO: Update when extending xdp_rxq_info to support allocation modes.
*/
-int bnxt_set_rx_skb_mode(struct bnxt *bp, bool page_mode)
+static void __bnxt_set_rx_skb_mode(struct bnxt *bp, bool page_mode)
{
struct net_device *dev = bp->dev;
@@ -4729,15 +4729,30 @@ int bnxt_set_rx_skb_mode(struct bnxt *bp, bool page_mode)
bp->rx_skb_func = bnxt_rx_page_skb;
}
bp->rx_dir = DMA_BIDIRECTIONAL;
- /* Disable LRO or GRO_HW */
- netdev_update_features(dev);
} else {
dev->max_mtu = bp->max_mtu;
bp->flags &= ~BNXT_FLAG_RX_PAGE_MODE;
bp->rx_dir = DMA_FROM_DEVICE;
bp->rx_skb_func = bnxt_rx_skb;
}
- return 0;
+}
+
+void bnxt_set_rx_skb_mode(struct bnxt *bp, bool page_mode)
+{
+ __bnxt_set_rx_skb_mode(bp, page_mode);
+
+ if (!page_mode) {
+ int rx, tx;
+
+ bnxt_get_max_rings(bp, &rx, &tx, true);
+ if (rx > 1) {
+ bp->flags &= ~BNXT_FLAG_NO_AGG_RINGS;
+ bp->dev->hw_features |= NETIF_F_LRO;
+ }
+ }
+
+ /* Update LRO and GRO_HW availability */
+ netdev_update_features(bp->dev);
}
static void bnxt_free_vnic_attributes(struct bnxt *bp)
@@ -16214,7 +16229,7 @@ static int bnxt_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
if (bp->max_fltr < BNXT_MAX_FLTR)
bp->max_fltr = BNXT_MAX_FLTR;
bnxt_init_l2_fltr_tbl(bp);
- bnxt_set_rx_skb_mode(bp, false);
+ __bnxt_set_rx_skb_mode(bp, false);
bnxt_set_tpa_flags(bp);
bnxt_set_ring_params(bp);
bnxt_rdma_aux_device_init(bp);
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.h b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
index 7df7a2233307..f11ed59203d9 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.h
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.h
@@ -2846,7 +2846,7 @@ u32 bnxt_fw_health_readl(struct bnxt *bp, int reg_idx);
bool bnxt_bs_trace_avail(struct bnxt *bp, u16 type);
void bnxt_set_tpa_flags(struct bnxt *bp);
void bnxt_set_ring_params(struct bnxt *);
-int bnxt_set_rx_skb_mode(struct bnxt *bp, bool page_mode);
+void bnxt_set_rx_skb_mode(struct bnxt *bp, bool page_mode);
void bnxt_insert_usr_fltr(struct bnxt *bp, struct bnxt_filter_base *fltr);
void bnxt_del_one_usr_fltr(struct bnxt *bp, struct bnxt_filter_base *fltr);
int bnxt_hwrm_func_drv_rgtr(struct bnxt *bp, unsigned long *bmap,
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
index f88b641533fc..dc51dce209d5 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_xdp.c
@@ -422,15 +422,8 @@ static int bnxt_xdp_set(struct bnxt *bp, struct bpf_prog *prog)
bnxt_set_rx_skb_mode(bp, true);
xdp_features_set_redirect_target(dev, true);
} else {
- int rx, tx;
-
xdp_features_clear_redirect_target(dev);
bnxt_set_rx_skb_mode(bp, false);
- bnxt_get_max_rings(bp, &rx, &tx, true);
- if (rx > 1) {
- bp->flags &= ~BNXT_FLAG_NO_AGG_RINGS;
- bp->dev->hw_features |= NETIF_F_LRO;
- }
}
bp->tx_nr_rings_xdp = tx_xdp;
bp->tx_nr_rings = bp->tx_nr_rings_per_tc * tc + tx_xdp;
--
2.47.1
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