From: Rasmus Villemoes <[email protected]> v4.19.115-rt50-rc1 stable review patch. If anyone has any objections, please let me know.
----------- Commit hrtimer: Add a missing bracket and hide `migration_base' on !SMP which is 47b6de0b7f22 in 5.2-rt and 40aae5708e7a in 4.19-rt, inadvertently changed the logic from base != &migration_base to base == &migration_base. On !CONFIG_SMP, the effect was to effectively always elide this lock/unlock pair (since is_migration_base() is unconditionally false), which for me consistently causes lockups during reboot, and reportedly also often causes a hang during boot. Adding this logical negation (or, what is effectively the same thing on !CONFIG_SMP, reverting the above commit as well as "hrtimer: Prevent using hrtimer_grab_expiry_lock() on migration_base") fixes that lockup. Fixes: 40aae5708e7a (hrtimer: Add a missing bracket and hide `migration_base' on !SMP) # 4.19-rt Fixes: 47b6de0b7f22 (hrtimer: Add a missing bracket and hide `migration_base' on !SMP) # 5.2-rt Signed-off-by: Rasmus Villemoes <[email protected]> Reviewed-by: Steven Rostedt (VMware) <[email protected]> Signed-off-by: Tom Zanussi <[email protected]> --- kernel/time/hrtimer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index e54a95de8b79..c3966c090246 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -953,7 +953,7 @@ void hrtimer_grab_expiry_lock(const struct hrtimer *timer) { struct hrtimer_clock_base *base = READ_ONCE(timer->base); - if (timer->is_soft && is_migration_base(base)) { + if (timer->is_soft && !is_migration_base(base)) { spin_lock(&base->cpu_base->softirq_expiry_lock); spin_unlock(&base->cpu_base->softirq_expiry_lock); } -- 2.17.1
