mlxsw: spectrum_acl_tcam: Fix incorrect list API usage

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: mlxsw: spectrum_acl_tcam: Fix incorrect list API usage Both the function that migrates all the chunks within a region and the function that migrates all the entries within a chunk call list_first_entry() on the respective lists without checking that the lists are not empty. This is incorrect usage of the API, which leads to the following warning [1]. Fix by returning if the lists are empty as there is nothing to migrate in this case. [1] WARNING: CPU: 0 PID: 6437 at drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c:1266 mlxsw_sp_acl_tcam_vchunk_migrate_all+0x1f1/0> Modules linked in: CPU: 0 PID: 6437 Comm: kworker/0:37 Not tainted 6.9.0-rc3-custom-00883-g94a65f079ef6 #39 Hardware name: Mellanox Technologies Ltd. MSN3700/VMOD0005, BIOS 5.11 01/06/2019 Workqueue: mlxsw_core mlxsw_sp_acl_tcam_vregion_rehash_work RIP: 0010:mlxsw_sp_acl_tcam_vchunk_migrate_all+0x1f1/0x2c0 [...] Call Trace: <TASK> mlxsw_sp_acl_tcam_vregion_rehash_work+0x6c/0x4a0 process_one_work+0x151/0x370 worker_thread+0x2cb/0x3e0 kthread+0xd0/0x100 ret_from_fork+0x34/0x50 ret_from_fork_asm+0x1a/0x30 </TASK>

References

• https://git.kernel.org/stable/c/0b2c13b670b168e324e1cf109e67056a20fd610a
• https://git.kernel.org/stable/c/09846c2309b150b8ce4e0ce96f058197598fc530
• https://git.kernel.org/stable/c/64435b64e43d8ee60faa46c0cd04e323e8b2a7b0
• https://git.kernel.org/stable/c/4526a56e02da3725db979358964df9cd9c567154
• https://git.kernel.org/stable/c/ab4ecfb627338e440ae11def004c524a00d93e40
• https://git.kernel.org/stable/c/af8b593c3dd9df82cb199be65863af004b09fd97
• https://git.kernel.org/stable/c/b377add0f0117409c418ddd6504bd682ebe0bf79