diff options
author | Romain Perier <romain.perier@gmail.com> | 2019-08-27 17:07:45 +0200 |
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committer | Romain Perier <romain.perier@opensource.viveris.fr> | 2019-08-27 17:08:08 +0200 |
commit | 23d5ad8d5f3c53402d4deff0405b99764d6d6f26 (patch) | |
tree | 0ff5e42af6e127a5f14fb0c4d068ae03c8ba2ba4 /debian/patches-rt/0001-hrtimer-Use-READ_ONCE-to-access-timer-base-in-hrimer.patch | |
parent | 1aed09ad6e2763da9fabb4f9d1e37a22a9c3bb4a (diff) | |
download | linux-debian-23d5ad8d5f3c53402d4deff0405b99764d6d6f26.tar.gz |
[rt] Update to 5.2.10-rt5
Diffstat (limited to 'debian/patches-rt/0001-hrtimer-Use-READ_ONCE-to-access-timer-base-in-hrimer.patch')
-rw-r--r-- | debian/patches-rt/0001-hrtimer-Use-READ_ONCE-to-access-timer-base-in-hrimer.patch | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/debian/patches-rt/0001-hrtimer-Use-READ_ONCE-to-access-timer-base-in-hrimer.patch b/debian/patches-rt/0001-hrtimer-Use-READ_ONCE-to-access-timer-base-in-hrimer.patch new file mode 100644 index 000000000..d4fe9b0a8 --- /dev/null +++ b/debian/patches-rt/0001-hrtimer-Use-READ_ONCE-to-access-timer-base-in-hrimer.patch @@ -0,0 +1,33 @@ +From: Julien Grall <julien.grall@arm.com> +Date: Wed, 21 Aug 2019 10:24:07 +0100 +Subject: [PATCH 1/3] hrtimer: Use READ_ONCE to access timer->base in + hrimer_grab_expiry_lock() +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.2/older/patches-5.2.10-rt5.tar.xz + +The update to timer->base is protected by the base->cpu_base->lock(). +However, hrtimer_grab_expirty_lock() does not access it with the lock. + +So it would theorically be possible to have timer->base changed under +our feet. We need to prevent the compiler to refetch timer->base so the +check and the access is performed on the same base. + +Other access of timer->base are either done with a lock or protected +with READ_ONCE(). So use READ_ONCE() in hrtimer_grab_expirty_lock(). + +Signed-off-by: Julien Grall <julien.grall@arm.com> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + kernel/time/hrtimer.c | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +--- a/kernel/time/hrtimer.c ++++ b/kernel/time/hrtimer.c +@@ -932,7 +932,7 @@ EXPORT_SYMBOL_GPL(hrtimer_forward); + + void hrtimer_grab_expiry_lock(const struct hrtimer *timer) + { +- struct hrtimer_clock_base *base = timer->base; ++ struct hrtimer_clock_base *base = READ_ONCE(timer->base); + + if (base && base->cpu_base) { + spin_lock(&base->cpu_base->softirq_expiry_lock); |