From: Muhammad Hammad Ijaz Date: Mon, 16 Mar 2026 19:31:01 +0000 (-0700) Subject: net: mvpp2: guard flow control update with global_tx_fc in buffer switching X-Git-Tag: v7.0-rc5~31^2~6 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=8a63baadf08453f66eb582fdb6dd234f72024723;p=thirdparty%2Flinux.git net: mvpp2: guard flow control update with global_tx_fc in buffer switching mvpp2_bm_switch_buffers() unconditionally calls mvpp2_bm_pool_update_priv_fc() when switching between per-cpu and shared buffer pool modes. This function programs CM3 flow control registers via mvpp2_cm3_read()/mvpp2_cm3_write(), which dereference priv->cm3_base without any NULL check. When the CM3 SRAM resource is not present in the device tree (the third reg entry added by commit 60523583b07c ("dts: marvell: add CM3 SRAM memory to cp11x ethernet device tree")), priv->cm3_base remains NULL and priv->global_tx_fc is false. Any operation that triggers mvpp2_bm_switch_buffers(), for example an MTU change that crosses the jumbo frame threshold, will crash: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Mem abort info: ESR = 0x0000000096000006 EC = 0x25: DABT (current EL), IL = 32 bits pc : readl+0x0/0x18 lr : mvpp2_cm3_read.isra.0+0x14/0x20 Call trace: readl+0x0/0x18 mvpp2_bm_pool_update_fc+0x40/0x12c mvpp2_bm_pool_update_priv_fc+0x94/0xd8 mvpp2_bm_switch_buffers.isra.0+0x80/0x1c0 mvpp2_change_mtu+0x140/0x380 __dev_set_mtu+0x1c/0x38 dev_set_mtu_ext+0x78/0x118 dev_set_mtu+0x48/0xa8 dev_ifsioc+0x21c/0x43c dev_ioctl+0x2d8/0x42c sock_ioctl+0x314/0x378 Every other flow control call site in the driver already guards hardware access with either priv->global_tx_fc or port->tx_fc. mvpp2_bm_switch_buffers() is the only place that omits this check. Add the missing priv->global_tx_fc guard to both the disable and re-enable calls in mvpp2_bm_switch_buffers(), consistent with the rest of the driver. Fixes: 3a616b92a9d1 ("net: mvpp2: Add TX flow control support for jumbo frames") Signed-off-by: Muhammad Hammad Ijaz Reviewed-by: Gunnar Kudrjavets Link: https://patch.msgid.link/20260316193157.65748-1-mhijaz@amazon.com Signed-off-by: Paolo Abeni --- diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c index d1b8650cb4b4..f442b874bb59 100644 --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c @@ -5016,7 +5016,7 @@ static int mvpp2_bm_switch_buffers(struct mvpp2 *priv, bool percpu) if (priv->percpu_pools) numbufs = port->nrxqs * 2; - if (change_percpu) + if (change_percpu && priv->global_tx_fc) mvpp2_bm_pool_update_priv_fc(priv, false); for (i = 0; i < numbufs; i++) @@ -5041,7 +5041,7 @@ static int mvpp2_bm_switch_buffers(struct mvpp2 *priv, bool percpu) mvpp2_open(port->dev); } - if (change_percpu) + if (change_percpu && priv->global_tx_fc) mvpp2_bm_pool_update_priv_fc(priv, true); return 0;