Description
In the Linux kernel, the following vulnerability has been resolved: net: macb: Shuffle the tx ring before enabling tx Quanyang observed that when using an NFS rootfs on an AMD ZynqMp board, the rootfs may take an extended time to recover after a suspend. Upon investigation, it was determined that the issue originates from a problem in the macb driver. According to the Zynq UltraScale TRM [1], when transmit is disabled, the transmit buffer queue pointer resets to point to the address specified by the transmit buffer queue base address register. In the current implementation, the code merely resets `queue->tx_head` and `queue->tx_tail` to '0'. This approach presents several issues: - Packets already queued in the tx ring are silently lost, leading to memory leaks since the associated skbs cannot be released. - Concurrent write access to `queue->tx_head` and `queue->tx_tail` may occur from `macb_tx_poll()` or `macb_start_xmit()` when these values are reset to '0'. - The transmission may become stuck on a packet that has already been sent out, with its 'TX_USED' bit set, but has not yet been processed. However, due to the manipulation of 'queue->tx_head' and 'queue->tx_tail', `macb_tx_poll()` incorrectly assumes there are no packets to handle because `queue->tx_head == queue->tx_tail`. This issue is only resolved when a new packet is placed at this position. This is the root cause of the prolonged recovery time observed for the NFS root filesystem. To resolve this issue, shuffle the tx ring and tx skb array so that the first unsent packet is positioned at the start of the tx ring. Additionally, ensure that updates to `queue->tx_head` and `queue->tx_tail` are properly protected with the appropriate lock. [1] https://docs.amd.com/v/u/en-US/ug1085-zynq-ultrascale-trm
Product status
d89b8b17057e16fad4564c71160e68ca549c1b42 (git) before c6783bfa31a59f34fe4feb1bdbf67791ef3fb0b7
ec4445ae9e58aed88561d3d1dfa849b039c7782e (git) before 0a47c3889fcd843c72aa57fa8c4d06f5801fced4
6e704e89f16fd4a1145756210bc210f14f174f94 (git) before 88f974fe118cb4653f029929ecbca7cfe06132ae
316d9fe71fb18bc9b1dba464fdb68dd201315eba (git) before 58f5d34f88e8f00910b692537f7b2efdb8c3705d
b3a7aa33ca7d46be513fccf832d3540acfe587d0 (git) before 403182e0771b250cfde0fe7e1081d095ceaf8230
bf9cf80cab81e39701861a42877a28295ade266f (git) before 881a0263d502e1a93ebc13a78254e9ad19520232
6.1.165 (semver) before 6.1.167
6.6.128 (semver) before 6.6.130
6.12.75 (semver) before 6.12.78
6.18.16 (semver) before 6.18.20
6.19.6 (semver) before 6.19.9
References
git.kernel.org/...c/c6783bfa31a59f34fe4feb1bdbf67791ef3fb0b7
git.kernel.org/...c/0a47c3889fcd843c72aa57fa8c4d06f5801fced4
git.kernel.org/...c/88f974fe118cb4653f029929ecbca7cfe06132ae
git.kernel.org/...c/58f5d34f88e8f00910b692537f7b2efdb8c3705d
git.kernel.org/...c/403182e0771b250cfde0fe7e1081d095ceaf8230
git.kernel.org/...c/881a0263d502e1a93ebc13a78254e9ad19520232