5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiangshan Yi commit 1eeca1d5e0920fbdad6449768fd2d4364e714180 upstream. brcms_free_timer() calls brcms_del_timer() which uses the non-synchronous cancel_delayed_work() to cancel the timer's underlying delayed work. If the work callback (_brcms_timer) is already running, cancel_delayed_work() returns false without waiting, and brcms_free_timer() proceeds to kfree(t) while the callback still accesses t through container_of(). Add an explicit cancel_delayed_work_sync() after brcms_del_timer() to guarantee that any in-flight callback has completed before the timer structure is freed. Fixes: 5b435de0d786 ("net: wireless: add brcm80211 drivers") Cc: stable@vger.kernel.org Signed-off-by: Jiangshan Yi Acked-by: Arend van Spriel Link: https://patch.msgid.link/20260815121043.938414-1-yijiangshan@kylinos.cn Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireless/broadcom/brcm80211/brcmsmac/mac80211_if.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/net/wireless/broadcom/brcm80211/brcmsmac/mac80211_if.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmsmac/mac80211_if.c @@ -1567,6 +1567,10 @@ void brcms_free_timer(struct brcms_timer /* delete the timer in case it is active */ brcms_del_timer(t); + /* Ensure the callback has finished before freeing the timer + * structure, since brcms_del_timer() uses non-synchronous cancel. + */ + cancel_delayed_work_sync(&t->dly_wrk); if (wl->timers == t) { wl->timers = wl->timers->next;