4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> [ Upstream commit 168f6b6ffbeec0b9333f3582e4cf637300858db5 ] del_timer_sync() is assumed to be pointless on uniprocessor systems and can be mapped to del_timer() because in theory del_timer() can never be invoked while the timer callback function is executed. This is not entirely true because del_timer() can be invoked from interrupt context and therefore hit in the middle of a running timer callback. Contrary to that del_timer_sync() is not allowed to be invoked from interrupt context unless the affected timer is marked with TIMER_IRQSAFE. del_timer_sync() has proper checks in place to detect such a situation. Give up on the UP optimization and make del_timer_sync() unconditionally available. Co-developed-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx> Reviewed-by: Jacob Keller <jacob.e.keller@xxxxxxxxx> Reviewed-by: Anna-Maria Behnsen <anna-maria@xxxxxxxxxxxxx> Link: https://lore.kernel.org/all/20220407161745.7d6754b3@xxxxxxxxxxxxxxxxxx Link: https://lore.kernel.org/all/20221110064101.429013735@xxxxxxxxxxx Link: https://lore.kernel.org/r/20221123201624.888306160@xxxxxxxxxxxxx Stable-dep-of: 0f7352557a35 ("wifi: brcmfmac: Fix use-after-free bug in brcmf_cfg80211_detach") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- include/linux/timer.h | 7 +------ kernel/time/timer.c | 2 -- 2 files changed, 1 insertion(+), 8 deletions(-) diff --git a/include/linux/timer.h b/include/linux/timer.h index 8e027cb10df01..a9c20a7ead305 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -171,12 +171,7 @@ extern int timer_reduce(struct timer_list *timer, unsigned long expires); extern void add_timer(struct timer_list *timer); extern int try_to_del_timer_sync(struct timer_list *timer); - -#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT) - extern int del_timer_sync(struct timer_list *timer); -#else -# define del_timer_sync(t) del_timer(t) -#endif +extern int del_timer_sync(struct timer_list *timer); #define del_singleshot_timer_sync(t) del_timer_sync(t) diff --git a/kernel/time/timer.c b/kernel/time/timer.c index f63efe259ae46..489bb01796de4 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1349,7 +1349,6 @@ static inline void timer_sync_wait_running(struct timer_base *base) { } static inline void del_timer_wait_running(struct timer_list *timer) { } #endif -#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT) /** * del_timer_sync - Deactivate a timer and wait for the handler to finish. * @timer: The timer to be deactivated @@ -1423,7 +1422,6 @@ int del_timer_sync(struct timer_list *timer) return ret; } EXPORT_SYMBOL(del_timer_sync); -#endif static void call_timer_fn(struct timer_list *timer, void (*fn)(struct timer_list *), -- 2.43.0
