diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-04-12 08:06:55 -0700 |
|---|---|---|
| committer | Luis Henriques <luis.henriques@canonical.com> | 2016-03-30 12:02:54 +0100 |
| commit | 477a64e62f2816229d755553dd575a6e05539817 (patch) | |
| tree | 25f1ec33e452051667ef977f76ee715fc57197d4 /include/linux/cpu.h | |
| parent | eb99153be3ae70672c8074dc89ac8c01828840fc (diff) | |
cpu: Defer smpboot kthread unparking until CPU known to scheduler
commit 00df35f991914db6b8bde8cf09808e19a9cffc3d upstream.
Currently, smpboot_unpark_threads() is invoked before the incoming CPU
has been added to the scheduler's runqueue structures. This might
potentially cause the unparked kthread to run on the wrong CPU, since the
correct CPU isn't fully set up yet.
That causes a sporadic, hard to debug boot crash triggering on some
systems, reported by Borislav Petkov, and bisected down to:
2a442c9c6453 ("x86: Use common outgoing-CPU-notification code")
This patch places smpboot_unpark_threads() in a CPU hotplug
notifier with priority set so that these kthreads are unparked just after
the CPU has been added to the runqueues.
Reported-and-tested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Owen Hofmann <osh@google.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Diffstat (limited to 'include/linux/cpu.h')
| -rw-r--r-- | include/linux/cpu.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 95978ad7fcdd..cd895a5e4d59 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -69,6 +69,7 @@ enum { /* migration should happen before other stuff but after perf */ CPU_PRI_PERF = 20, CPU_PRI_MIGRATION = 10, + CPU_PRI_SMPBOOT = 9, /* bring up workqueues before normal notifiers and down after */ CPU_PRI_WORKQUEUE_UP = 5, CPU_PRI_WORKQUEUE_DOWN = -5, @@ -157,6 +158,7 @@ static inline void __unregister_cpu_notifier(struct notifier_block *nb) } #endif +void smpboot_thread_init(void); int cpu_up(unsigned int cpu); void notify_cpu_starting(unsigned int cpu); extern void cpu_maps_update_begin(void); |