kernel/linux.git/net/ethtool, branch v6.18.34

ethtool: fix ethnl_bitmap32_not_zero() bit interval semantics

2026-06-01T15:50:59+00:00

[ Upstream commit 3d042592ebd4c7e44974d556de0b727cb7db4dab ] ethnl_bitmap32_not_zero() should return true if some bit in [start, end) is set: - Fix inverted memchr_inv() sense: return true when the scan finds a non-zero byte, not when the middle words are all zero. - Return false for an empty interval (end <= start). - When end is 32-bit aligned, indices in [start, end) do not include any bits from map[end_word]; return false after earlier checks found no non-zero data. Fixes: 10b518d4e6dd ("ethtool: netlink bitset handling") Signed-off-by: Chenguang Zhao Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: ethtool: phy: avoid NULL deref when PHY driver is unbound

2026-06-01T15:50:43+00:00

[ Upstream commit e3adf69f8eb121a9128c2b0029efd050d3649153 ] phydev->drv can become NULL while the phy_device is still attached to its net_device, namely after the PHY driver is unbound via sysfs: echo > /sys/bus/mdio_bus/drivers//unbind phy_remove() clears phydev->drv but doesn't call phy_detach(), so the phy_device stays in the link topology xarray and ethnl_req_get_phydev() still hands it back. ETHTOOL_MSG_PHY_GET then oopses on: rep_data->drvname = kstrdup(phydev->drv->name, GFP_KERNEL); drvname is already treated as optional by phy_reply_size(), phy_fill_reply() and phy_cleanup_data(), so just skip the allocation when there is no driver bound. Fixes: 9dd2ad5e92b9 ("net: ethtool: phy: Convert the PHY_GET command to generic phy dump") Cc: stable@vger.kernel.org # 6.13.x Signed-off-by: David Carlier Reviewed-by: Maxime Chevallier Tested-by: Maxime Chevallier Link: https://patch.msgid.link/20260509215046.107157-1-devnexen@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

net: ethtool: fix NULL pointer dereference in phy_reply_size

2026-06-01T15:50:43+00:00

[ Upstream commit 4908f1395fb1b832ceec11584af649874a2732ea ] In phy_prepare_data(), several strings such as 'name', 'drvname', 'upstream_sfp_name', and 'downstream_sfp_name' are allocated using kstrdup(). However, these allocations were not checked for failure. If kstrdup() fails for 'name', it returns NULL while the function continues. This leads to a kernel NULL pointer dereference and panic later in phy_reply_size() when it unconditionally calls strlen() on the NULL pointer. While other strings like 'upstream_sfp_name' might be checked before access in certain code paths, failing to handle these allocations consistently can lead to incomplete data reporting or hidden bugs. Fix this by adding proper NULL checks for all kstrdup() calls in phy_prepare_data() and implement a centralized error handling path using goto labels to ensure all previously allocated resources are freed on failure. Fixes: 9dd2ad5e92b9 ("net: ethtool: phy: Convert the PHY_GET command to generic phy dump") Signed-off-by: Quan Sun <2022090917019@std.uestc.edu.cn> Reviewed-by: Maxime Chevallier Link: https://patch.msgid.link/20260507131738.1173835-1-2022090917019@std.uestc.edu.cn Signed-off-by: Jakub Kicinski Stable-dep-of: e3adf69f8eb1 ("net: ethtool: phy: avoid NULL deref when PHY driver is unbound") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

net: rss: fix reporting RXH_XFRM_NO_CHANGE as input_xfrm for contexts

2026-02-11T12:41:57+00:00

[ Upstream commit 1c172febdf065375359b2b95156e476bfee30b60 ] Initializing input_xfrm to RXH_XFRM_NO_CHANGE in RSS contexts is problematic. I think I did this to make it clear that the context does not have its own settings applied. But unlike ETH_RSS_HASH_NO_CHANGE which is zero, RXH_XFRM_NO_CHANGE is 0xff. We need to be careful when reading the value back, and remember to treat 0xff as 0. Remove the initialization and switch to storing 0. This lets us also remove the workaround in ethnl_rss_set(). Get side does not need any adjustments and context get no longer reports: RSS input transformation: symmetric-xor: on symmetric-or-xor: on Unknown bits in RSS input transformation: 0xfc for NICs which don't support input_xfrm. Remove the init of hfunc to ETH_RSS_HASH_NO_CHANGE while at it. As already mentioned this is a noop since ETH_RSS_HASH_NO_CHANGE is 0 and struct is zalloc'd. But as this fix exemplifies storing NO_CHANGE as state is fragile. This issue is implicitly caught by running our selftests because YNL in selftests errors out on unknown bits. Fixes: d3e2c7bab124 ("ethtool: rss: support setting input-xfrm via Netlink") Link: https://patch.msgid.link/20260130190311.811129-1-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

ethtool: Avoid overflowing userspace buffer on stats query

2026-01-02T11:56:48+00:00

[ Upstream commit 7b07be1ff1cb6c49869910518650e8d0abc7d25f ] The ethtool -S command operates across three ioctl calls: ETHTOOL_GSSET_INFO for the size, ETHTOOL_GSTRINGS for the names, and ETHTOOL_GSTATS for the values. If the number of stats changes between these calls (e.g., due to device reconfiguration), userspace's buffer allocation will be incorrect, potentially leading to buffer overflow. Drivers are generally expected to maintain stable stat counts, but some drivers (e.g., mlx5, bnx2x, bna, ksz884x) use dynamic counters, making this scenario possible. Some drivers try to handle this internally: - bnad_get_ethtool_stats() returns early in case stats.n_stats is not equal to the driver's stats count. - micrel/ksz884x also makes sure not to write anything beyond stats.n_stats and overflow the buffer. However, both use stats.n_stats which is already assigned with the value returned from get_sset_count(), hence won't solve the issue described here. Change ethtool_get_strings(), ethtool_get_stats(), ethtool_get_phy_stats() to not return anything in case of a mismatch between userspace's size and get_sset_size(), to prevent buffer overflow. The returned n_stats value will be equal to zero, to reflect that nothing has been returned. This could result in one of two cases when using upstream ethtool, depending on when the size change is detected: 1. When detected in ethtool_get_strings(): # ethtool -S eth2 no stats available 2. When detected in get stats, all stats will be reported as zero. Both cases are presumably transient, and a subsequent ethtool call should succeed. Other than the overflow avoidance, these two cases are very evident (no output/cleared stats), which is arguably better than presenting incorrect/shifted stats. I also considered returning an error instead of a "silent" response, but that seems more destructive towards userspace apps. Notes: - This patch does not claim to fix the inherent race, it only makes sure that we do not overflow the userspace buffer, and makes for a more predictable behavior. - RTNL lock is held during each ioctl, the race window exists between the separate ioctl calls when the lock is released. - Userspace ethtool always fills stats.n_stats, but it is likely that these stats ioctls are implemented in other userspace applications which might not fill it. The added code checks that it's not zero, to prevent any regressions. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reviewed-by: Dragos Tatulea Reviewed-by: Tariq Toukan Signed-off-by: Gal Pressman Link: https://patch.msgid.link/20251208121901.3203692-1-gal@nvidia.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

Revert "Documentation: net: add flow control guide and document ethtool API"

2025-10-01T07:48:21+00:00

This reverts commit 7bd80ed89d72285515db673803b021469ba71ee8. I should not have merged it to begin with due to pending review and changes to be addressed. Link: https://patch.msgid.link/c6f3af12df9b7998920a02027fc8893ce82afc4c.1759239721.git.pabeni@redhat.com Signed-off-by: Paolo Abeni

Documentation: net: add flow control guide and document ethtool API

2025-09-30T07:48:31+00:00

Introduce a new document, flow_control.rst, to provide a comprehensive guide on Ethernet Flow Control in Linux. The guide explains how flow control works, how autonegotiation resolves pause capabilities, and how to configure it using ethtool and Netlink. In parallel, document the pause and pause-stat attributes in the ethtool.yaml netlink spec. This enables the ynl tool to generate kernel-doc comments for the corresponding enums in the UAPI header, making the C interface self-documenting. Finally, replace the legacy flow control section in phy.rst with a reference to the new document and add pointers in the relevant C source files. Signed-off-by: Oleksij Rempel Link: https://patch.msgid.link/20250924120241.724850-1-o.rempel@pengutronix.de Signed-off-by: Paolo Abeni

net: ethtool: remove duplicated mm.o from Makefile

2025-09-29T19:09:24+00:00

Fixes: 2b30f8291a30 ("net: ethtool: add support for MAC Merge layer") Signed-off-by: Markus Heidelberg Reviewed-by: Vladimir Oltean Link: https://patch.msgid.link/20250926131323.222192-1-m.heidelberg@cab.de Signed-off-by: Jakub Kicinski

ethtool: add FEC bins histogram report

2025-09-26T23:49:18+00:00

IEEE 802.3ck-2022 defines counters for FEC bins and 802.3df-2024 clarifies it a bit further. Implement reporting interface through as addition to FEC stats available in ethtool. Drivers can leave bin counter uninitialized if per-lane values are provided. In this case the core will recalculate summ for the bin. Signed-off-by: Vadim Fedorenko Reviewed-by: Aleksandr Loktionov Link: https://patch.msgid.link/20250924124037.1508846-2-vadim.fedorenko@linux.dev Signed-off-by: Jakub Kicinski

net: ethtool: tsconfig: set command must provide a reply

2025-09-24T00:13:05+00:00

Timestamping configuration through ethtool has inconsistent behavior of skipping the reply for set command if configuration was not changed. Fix it be providing reply in any case. Fixes: 6e9e2eed4f39d ("net: ethtool: Add support for tsconfig command to get/set hwtstamp config") Signed-off-by: Vadim Fedorenko Reviewed-by: Kory Maincent Link: https://patch.msgid.link/20250922231924.2769571-1-vadfed@meta.com Signed-off-by: Jakub Kicinski