kernel/linux.git/drivers/net/ethernet/stmicro, branch v7.0.10

net: stmmac: Prevent NULL deref when RX memory exhausted

2026-05-14T13:31:20+00:00

[ Upstream commit 0bb05e6adfa99a2ea1fee1125cc0953409f83ed8 ] The CPU receives frames from the MAC through conventional DMA: the CPU allocates buffers for the MAC, then the MAC fills them and returns ownership to the CPU. For each hardware RX queue, the CPU and MAC coordinate through a shared ring array of DMA descriptors: one descriptor per DMA buffer. Each descriptor includes the buffer's physical address and a status flag ("OWN") indicating which side owns the buffer: OWN=0 for CPU, OWN=1 for MAC. The CPU is only allowed to set the flag and the MAC is only allowed to clear it, and both must move through the ring in sequence: thus the ring is used for both "submissions" and "completions." In the stmmac driver, stmmac_rx() bookmarks its position in the ring with the `cur_rx` index. The main receive loop in that function checks for rx_descs[cur_rx].own=0, gives the corresponding buffer to the network stack (NULLing the pointer), and increments `cur_rx` modulo the ring size. After the loop exits, stmmac_rx_refill(), which bookmarks its position with `dirty_rx`, allocates fresh buffers and rearms the descriptors (setting OWN=1). If it fails any allocation, it simply stops early (leaving OWN=0) and will retry where it left off when next called. This means descriptors have a three-stage lifecycle (terms my own): - `empty` (OWN=1, buffer valid) - `full` (OWN=0, buffer valid and populated) - `dirty` (OWN=0, buffer NULL) But because stmmac_rx() only checks OWN, it confuses `full`/`dirty`. In the past (see 'Fixes:'), there was a bug where the loop could cycle `cur_rx` all the way back to the first descriptor it dirtied, resulting in a NULL dereference when mistaken for `full`. The aforementioned commit resolved that *specific* failure by capping the loop's iteration limit at `dma_rx_size - 1`, but this is only a partial fix: if the previous stmmac_rx_refill() didn't complete, then there are leftover `dirty` descriptors that the loop might encounter without needing to cycle fully around. The current code therefore panics (see 'Closes:') when stmmac_rx_refill() is memory-starved long enough for `cur_rx` to catch up to `dirty_rx`. Fix this by explicitly checking, before advancing `cur_rx`, if the next entry is dirty; exit the loop if so. This prevents processing of the final, used descriptor until stmmac_rx_refill() succeeds, but fully prevents the `cur_rx == dirty_rx` ambiguity as the previous bugfix intended: so remove the clamp as well. Since stmmac_rx_zc() is a copy-paste-and-tweak of stmmac_rx() and the code structure is identical, any fix to stmmac_rx() will also need a corresponding fix for stmmac_rx_zc(). Therefore, apply the same check there. In stmmac_rx() (not stmmac_rx_zc()), a related bug remains: after the MAC sets OWN=0 on the final descriptor, it will be unable to send any further DMA-complete IRQs until it's given more `empty` descriptors. Currently, the driver simply *hopes* that the next stmmac_rx_refill() succeeds, risking an indefinite stall of the receive process if not. But this is not a regression, so it can be addressed in a future change. Fixes: b6cb4541853c7 ("net: stmmac: avoid rx queue overrun") Closes: https://bugzilla.kernel.org/show_bug.cgi?id=221010 Cc: stable@vger.kernel.org Suggested-by: Russell King Signed-off-by: Sam Edwards Link: https://patch.msgid.link/20260422044503.5349-1-CFSworks@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

net: stmmac: rename STMMAC_GET_ENTRY() -> STMMAC_NEXT_ENTRY()

2026-05-14T13:31:20+00:00

[ Upstream commit 6b4286e0550814cdc4b897f881ec1fa8b0313227 ] STMMAC_GET_ENTRY() doesn't describe what this macro is doing - it is incrementing the provided index for the circular array of descriptors. Replace "GET" with "NEXT" as this better describes the action here. Signed-off-by: Russell King (Oracle) Link: https://patch.msgid.link/E1w2vba-0000000DbWo-1oL5@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski Stable-dep-of: 0bb05e6adfa9 ("net: stmmac: Prevent NULL deref when RX memory exhausted") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

net: stmmac: dwmac-motorcomm: fix eFUSE MAC address read failure

2026-04-08T01:21:00+00:00

This patch fixes an issue where reading the MAC address from the eFUSE fails due to a race condition. The root cause was identified by comparing the driver's behavior with a custom U-Boot port. In U-Boot, the MAC address was read successfully every time because the driver was loaded later in the boot process, giving the hardware ample time to initialize. In Linux, reading the eFUSE immediately returns all zeros, resulting in a fallback to a random MAC address. Hardware cold-boot testing revealed that the eFUSE controller requires a short settling time to load its internal data. Adding a 2000-5000us delay after the reset ensures the hardware is fully ready, allowing the native MAC address to be read consistently. Fixes: 02ff155ea281 ("net: stmmac: Add glue driver for Motorcomm YT6801 ethernet controller") Reported-by: Georg Gottleuber Closes: https://lore.kernel.org/24cfefff-1233-4745-8c47-812b502d5d19@tuxedocomputers.com Signed-off-by: Johan Alvarado Reviewed-by: Yao Zi Reviewed-by: Andrew Lunn Link: https://patch.msgid.link/fc5992a4-9532-49c3-8ec1-c2f8c5b84ca1@smtp-relay.sendinblue.com Signed-off-by: Jakub Kicinski

net: stmmac: Fix PTP ref clock for Tegra234

2026-04-03T23:02:21+00:00

Since commit 030ce919e114 ("net: stmmac: make sure that ptp_rate is not 0 before configuring timestamping") was added the following error is observed on Tegra234: ERR KERN tegra-mgbe 6800000.ethernet eth0: Invalid PTP clock rate WARNING KERN tegra-mgbe 6800000.ethernet eth0: PTP init failed It turns out that the Tegra234 device-tree binding defines the PTP ref clock name as 'ptp-ref' and not 'ptp_ref' and the above commit now exposes this and that the PTP clock is not configured correctly. In order to update device-tree to use the correct 'ptp_ref' name, update the Tegra MGBE driver to use 'ptp_ref' by default and fallback to using 'ptp-ref' if this clock name is present. Fixes: d8ca113724e7 ("net: stmmac: tegra: Add MGBE support") Signed-off-by: Jon Hunter Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260401102941.17466-2-jonathanh@nvidia.com Signed-off-by: Jakub Kicinski

net: stmmac: fix integer underflow in chain mode

2026-04-03T01:28:10+00:00

The jumbo_frm() chain-mode implementation unconditionally computes len = nopaged_len - bmax; where nopaged_len = skb_headlen(skb) (linear bytes only) and bmax is BUF_SIZE_8KiB or BUF_SIZE_2KiB. However, the caller stmmac_xmit() decides to invoke jumbo_frm() based on skb->len (total length including page fragments): is_jumbo = stmmac_is_jumbo_frm(priv, skb->len, enh_desc); When a packet has a small linear portion (nopaged_len <= bmax) but a large total length due to page fragments (skb->len > bmax), the subtraction wraps as an unsigned integer, producing a huge len value (~0xFFFFxxxx). This causes the while (len != 0) loop to execute hundreds of thousands of iterations, passing skb->data + bmax * i pointers far beyond the skb buffer to dma_map_single(). On IOMMU-less SoCs (the typical deployment for stmmac), this maps arbitrary kernel memory to the DMA engine, constituting a kernel memory disclosure and potential memory corruption from hardware. Fix this by introducing a buf_len local variable clamped to min(nopaged_len, bmax). Computing len = nopaged_len - buf_len is then always safe: it is zero when the linear portion fits within a single descriptor, causing the while (len != 0) loop to be skipped naturally, and the fragment loop in stmmac_xmit() handles page fragments afterward. Fixes: 286a83721720 ("stmmac: add CHAINED descriptor mode support (V4)") Cc: stable@vger.kernel.org Signed-off-by: Tyllis Xu Link: https://patch.msgid.link/20260401044708.1386919-1-LivelyCarpet87@gmail.com Signed-off-by: Jakub Kicinski

net: stmmac: skip VLAN restore when VLAN hash ops are missing

2026-04-01T02:45:26+00:00

stmmac_vlan_restore() unconditionally calls stmmac_vlan_update() when NETIF_F_VLAN_FEATURES is set. On platforms where priv->hw->vlan (or ->update_vlan_hash) is not provided, stmmac_update_vlan_hash() returns -EINVAL via stmmac_do_void_callback(), resulting in a spurious "Failed to restore VLANs" error even when no VLAN filtering is in use. Remove not needed comment. Remove not used return value from stmmac_vlan_restore(). Tested on Orange Pi Zero 3. Fixes: bd7ad51253a7 ("net: stmmac: Fix VLAN HW state restore") Signed-off-by: Michal Piekos Link: https://patch.msgid.link/20260328-vlan-restore-error-v4-1-f88624c530dc@mmpsystems.pl Signed-off-by: Jakub Kicinski

net: stmmac: Defer VLAN HW configuration when interface is down

2026-03-05T02:48:49+00:00

VLAN register accesses on the MAC side require the PHY RX clock to be active. When the network interface is down, the PHY is suspended and the RX clock is unavailable, causing VLAN operations to fail with timeouts. The VLAN core automatically removes VID 0 after the interface goes down and re-adds it when it comes back up, so these timeouts happen during normal interface down/up: # ip link set end1 down renesas-gbeth 15c40000.ethernet end1: Timeout accessing MAC_VLAN_Tag_Filter renesas-gbeth 15c40000.ethernet end1: failed to kill vid 0081/0 Adding VLANs while the interface is down also fails: # ip link add link end1 name end1.10 type vlan id 10 renesas-gbeth 15c40000.ethernet end1: Timeout accessing MAC_VLAN_Tag_Filter RTNETLINK answers: Device or resource busy To fix this, check if the interface is up before accessing VLAN registers. The software state is always kept up to date regardless of interface state. When the interface is brought up, stmmac_vlan_restore() is called to write the VLAN state to hardware. Fixes: ed64639bc1e0 ("net: stmmac: Add support for VLAN Rx filtering") Signed-off-by: Ovidiu Panait Link: https://patch.msgid.link/20260303145828.7845-5-ovidiu.panait.rb@renesas.com Signed-off-by: Jakub Kicinski

net: stmmac: Fix VLAN HW state restore

2026-03-05T02:48:49+00:00

When the network interface is opened or resumed, a DMA reset is performed, which resets all hardware state, including VLAN state. Currently, only the resume path is restoring the VLAN state via stmmac_restore_hw_vlan_rx_fltr(), but that is incomplete: the VLAN hash table and the VLAN_TAG control bits are not restored. Therefore, add stmmac_vlan_restore(), which restores the full VLAN state by updating both the HW filter entries and the hash table, and call it from both the open and resume paths. The VLAN restore is moved outside of phylink_rx_clk_stop_block/unblock in the resume path because receive clock stop is already disabled when stmmac supports VLAN. Also, remove the hash readback code in vlan_restore_hw_rx_fltr() that attempts to restore VTHM by reading VLAN_HASH_TABLE, as it always reads zero after DMA reset, making it dead code. Fixes: 3cd1cfcba26e ("net: stmmac: Implement VLAN Hash Filtering in XGMAC") Fixes: ed64639bc1e0 ("net: stmmac: Add support for VLAN Rx filtering") Signed-off-by: Ovidiu Panait Link: https://patch.msgid.link/20260303145828.7845-4-ovidiu.panait.rb@renesas.com Signed-off-by: Jakub Kicinski

net: stmmac: Improve double VLAN handling

2026-03-05T02:48:49+00:00

The double VLAN bits (EDVLP, ESVL, DOVLTC) are handled inconsistently between the two vlan_update_hash() implementations: - dwxgmac2_update_vlan_hash() explicitly clears the double VLAN bits when is_double is false, meaning that adding a 802.1Q VLAN will disable double VLAN mode: $ ip link add link eth0 name eth0.200 type vlan id 200 protocol 802.1ad $ ip link add link eth0 name eth0.100 type vlan id 100 # Double VLAN bits no longer set - vlan_update_hash() sets these bits and only clears them when the last VLAN has been removed, so double VLAN mode remains enabled even after all 802.1AD VLANs are removed. Address both issues by tracking the number of active 802.1AD VLANs in priv->num_double_vlans. Pass this count to stmmac_vlan_update() so both implementations correctly set the double VLAN bits when any 802.1AD VLAN is active, and clear them only when none remain. Also update vlan_update_hash() to explicitly clear the double VLAN bits when is_double is false, matching the dwxgmac2 behavior. Signed-off-by: Ovidiu Panait Link: https://patch.msgid.link/20260303145828.7845-3-ovidiu.panait.rb@renesas.com Signed-off-by: Jakub Kicinski

net: stmmac: Fix error handling in VLAN add and delete paths

2026-03-05T02:48:48+00:00

stmmac_vlan_rx_add_vid() updates active_vlans and the VLAN hash register before writing the HW filter entry. If the filter write fails, it leaves a stale VID in active_vlans and the hash register. stmmac_vlan_rx_kill_vid() has the reverse problem: it clears active_vlans before removing the HW filter. On failure, the VID is gone from active_vlans but still present in the HW filter table. To fix this, reorder the operations to update the hash table first, then attempt the HW filter operation. If the HW filter fails, roll back both the active_vlans bitmap and the hash table by calling stmmac_vlan_update() again. Fixes: ed64639bc1e0 ("net: stmmac: Add support for VLAN Rx filtering") Signed-off-by: Ovidiu Panait Link: https://patch.msgid.link/20260303145828.7845-2-ovidiu.panait.rb@renesas.com Signed-off-by: Jakub Kicinski