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| author | Heiko Carstens <hca@linux.ibm.com> | 2021-02-17 07:19:09 +0100 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2021-02-24 00:31:22 +0100 |
| commit | f213e5502d2e68f141a4e3faadffd03000224192 (patch) | |
| tree | 793cc80cab0f72c41585ceaee890088e053cbfb9 /arch | |
| parent | 62c8dca9e194326802b43c60763f856d782b225c (diff) | |
| download | linux-stable-f213e5502d2e68f141a4e3faadffd03000224192.tar.gz linux-stable-f213e5502d2e68f141a4e3faadffd03000224192.tar.bz2 linux-stable-f213e5502d2e68f141a4e3faadffd03000224192.zip | |
s390/smp: smp_emergency_stop() - move cpumask away from stack
Make "cpumask_t cpumask" a static variable to avoid a potential large
stack frame. Also protect against potential concurrent callers by
introducing a local lock.
Note: smp_emergency_stop() gets only called with irqs and machine
checks disabled, therefore a cpu local deadlock is not possible. For
concurrent callers the first cpu which enters the critical section
wins and will stop all other cpus.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/kernel/smp.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 3d838b7bbb3b..7f30d954519b 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -434,10 +434,12 @@ void notrace smp_yield_cpu(int cpu) */ void notrace smp_emergency_stop(void) { - cpumask_t cpumask; + static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED; + static cpumask_t cpumask; u64 end; int cpu; + arch_spin_lock(&lock); cpumask_copy(&cpumask, cpu_online_mask); cpumask_clear_cpu(smp_processor_id(), &cpumask); @@ -458,6 +460,7 @@ void notrace smp_emergency_stop(void) break; cpu_relax(); } + arch_spin_unlock(&lock); } NOKPROBE_SYMBOL(smp_emergency_stop); |