| From f8b7530aa0a1def79c93101216b5b17cf408a70a Mon Sep 17 00:00:00 2001 |
| From: Neeraj Upadhyay <neeraju@codeaurora.org> |
| Date: Wed, 5 Sep 2018 11:22:07 +0530 |
| Subject: cpu/hotplug: Adjust misplaced smb() in cpuhp_thread_fun() |
| |
| From: Neeraj Upadhyay <neeraju@codeaurora.org> |
| |
| commit f8b7530aa0a1def79c93101216b5b17cf408a70a upstream. |
| |
| The smp_mb() in cpuhp_thread_fun() is misplaced. It needs to be after the |
| load of st->should_run to prevent reordering of the later load/stores |
| w.r.t. the load of st->should_run. |
| |
| Fixes: 4dddfb5faa61 ("smp/hotplug: Rewrite AP state machine core") |
| Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org> |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Acked-by: Peter Zijlstra (Intel) <peterz@infraded.org> |
| Cc: josh@joshtriplett.org |
| Cc: peterz@infradead.org |
| Cc: jiangshanlai@gmail.com |
| Cc: dzickus@redhat.com |
| Cc: brendan.jackman@arm.com |
| Cc: malat@debian.org |
| Cc: mojha@codeaurora.org |
| Cc: sramana@codeaurora.org |
| Cc: linux-arm-msm@vger.kernel.org |
| Cc: stable@vger.kernel.org |
| Link: https://lkml.kernel.org/r/1536126727-11629-1-git-send-email-neeraju@codeaurora.org |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| kernel/cpu.c | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| --- a/kernel/cpu.c |
| +++ b/kernel/cpu.c |
| @@ -612,15 +612,15 @@ static void cpuhp_thread_fun(unsigned in |
| bool bringup = st->bringup; |
| enum cpuhp_state state; |
| |
| + if (WARN_ON_ONCE(!st->should_run)) |
| + return; |
| + |
| /* |
| * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
| * that if we see ->should_run we also see the rest of the state. |
| */ |
| smp_mb(); |
| |
| - if (WARN_ON_ONCE(!st->should_run)) |
| - return; |
| - |
| cpuhp_lock_acquire(bringup); |
| |
| if (st->single) { |