gfs2: Fix possible data races in gfs2_show_options()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix possible data races in gfs2_show_options() Some fields such as gt_logd_secs of the struct gfs2_tune are accessed without holding the lock gt_spin in gfs2_show_options(): val = sdp->sd_tune.gt_logd_secs; if (val != 30) seq_printf(s, ",commit=%d", val); And thus can cause data races when gfs2_show_options() and other functions such as gfs2_reconfigure() are concurrently executed: spin_lock(&gt->gt_spin); gt->gt_logd_secs = newargs->ar_commit; To fix these possible data races, the lock sdp->sd_tune.gt_spin is acquired before accessing the fields of gfs2_tune and released after these accesses. Further changes by Andreas: - Don't hold the spin lock over the seq_printf operations.

References

• https://git.kernel.org/stable/c/7e5bbeb7eb813bb2568e1d5d02587df943272e57
• https://git.kernel.org/stable/c/235a5ae73cea29109a3e06f100493f17857e6a93
• https://git.kernel.org/stable/c/b4a7ab57effbed42624842f2ab2a49b177c21a47
• https://git.kernel.org/stable/c/7c5b2649f6a37d45bfb7abf34c9b71d08677139f
• https://git.kernel.org/stable/c/85e888150075cb221270b64bf772341fc6bd11d9
• https://git.kernel.org/stable/c/a4f71523ed2123d63b431cc0cea4e9f363a0f054
• https://git.kernel.org/stable/c/42077d4de49e4d9c773c97c42d5383b4899a8f9d
• https://git.kernel.org/stable/c/6fa0a72cbbe45db4ed967a51f9e6f4e3afe61d20