net: libwx: fix concurrent bitmap overwrite in PTP setup

In wx_ptp_set_timestamp_mode(), the driver copies the global `wx->flags`
bitmap to a local variable, modifies the PTP-related bits, and then writes
the entire bitmap back using memcpy().

This Read-Copy-Update pattern is unsafe and introduces a critical race
condition. Other asynchronous contexts (such as Tx timeout routines or
GPIO IRQ handlers) update individual bits in `wx->flags` concurrently
using atomic bitops like set_bit() or clear_bit(). The memcpy() write-back
can silently overwrite and drop these concurrent changes, potentially
causing the driver to miss critical module reset or PCIe recovery requests.

Fix this by removing the local bitmap copy. Instead, evaluate the intended
PTP flag states locally and apply them directly to `wx->flags` using
atomic set_bit() and clear_bit() operations only after the hardware is
successfully configured.

Fixes: 06e75161b9d4 ("net: wangxun: Add support for PTP clock")
Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/6C7EC12D69217315+20260818074721.45536-1-jiawenwu@trustnetic.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

0 files changed, 0 insertions, 0 deletions