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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-01-18 13:00:59 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-01-18 13:00:59 -0800 |
| commit | 7ff15cd0458c288afa954de843bb1903c723e5b3 (patch) | |
| tree | ba2cd2cee87452b4d337b8a529b7f8d18b23ad0f | |
| parent | 9e79c5233290884d54addb601afc7ece2f70c79e (diff) | |
| parent | de95a991bb72e009f47e0c4bbc90fc5f594588d5 (diff) | |
| download | linux-7ff15cd0458c288afa954de843bb1903c723e5b3.tar.bz2 | |
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Ingo Molnar:
"Three fixes: fix link failure on Alpha, fix a Sparse warning and
annotate/robustify a lockless access in the NOHZ code"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
tick/sched: Annotate lockless access to last_jiffies_update
lib/vdso: Make __cvdso_clock_getres() static
time/posix-stubs: Provide compat itimer supoprt for alpha
| -rw-r--r-- | kernel/time/posix-stubs.c | 3 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 14 | ||||
| -rw-r--r-- | lib/vdso/gettimeofday.c | 1 |
3 files changed, 13 insertions, 5 deletions
diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c index 67df65f887ac..20c65a7d4e3a 100644 --- a/kernel/time/posix-stubs.c +++ b/kernel/time/posix-stubs.c @@ -151,6 +151,9 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags, #ifdef CONFIG_COMPAT COMPAT_SYS_NI(timer_create); +#endif + +#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA) COMPAT_SYS_NI(getitimer); COMPAT_SYS_NI(setitimer); #endif diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 8b192e67aabc..a792d21cac64 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -58,8 +58,9 @@ static void tick_do_update_jiffies64(ktime_t now) /* * Do a quick check without holding jiffies_lock: + * The READ_ONCE() pairs with two updates done later in this function. */ - delta = ktime_sub(now, last_jiffies_update); + delta = ktime_sub(now, READ_ONCE(last_jiffies_update)); if (delta < tick_period) return; @@ -70,8 +71,9 @@ static void tick_do_update_jiffies64(ktime_t now) if (delta >= tick_period) { delta = ktime_sub(delta, tick_period); - last_jiffies_update = ktime_add(last_jiffies_update, - tick_period); + /* Pairs with the lockless read in this function. */ + WRITE_ONCE(last_jiffies_update, + ktime_add(last_jiffies_update, tick_period)); /* Slow path for long timeouts */ if (unlikely(delta >= tick_period)) { @@ -79,8 +81,10 @@ static void tick_do_update_jiffies64(ktime_t now) ticks = ktime_divns(delta, incr); - last_jiffies_update = ktime_add_ns(last_jiffies_update, - incr * ticks); + /* Pairs with the lockless read in this function. */ + WRITE_ONCE(last_jiffies_update, + ktime_add_ns(last_jiffies_update, + incr * ticks)); } do_timer(++ticks); diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index 9ecfd3b547ba..42bd8ab955fa 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -221,6 +221,7 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) return 0; } +static __maybe_unused int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res) { int ret = __cvdso_clock_getres_common(clock, res); |