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authorOmar Sandoval <osandov@osandov.com>2015-05-04 03:09:36 -0700
committerIngo Molnar <mingo@kernel.org>2015-05-08 11:53:56 +0200
commit533445c6e53368569e50ab3fb712230c03d523f3 (patch)
tree5cc6ee0434c62215bb4c3e9be9acbbf05fb6adda /kernel
parentsched: Handle priority boosted tasks proper in setscheduler() (diff)
downloadlinux-dev-533445c6e53368569e50ab3fb712230c03d523f3.tar.xz
linux-dev-533445c6e53368569e50ab3fb712230c03d523f3.zip
sched/core: Fix regression in cpuset_cpu_inactive() for suspend
Commit 3c18d447b3b3 ("sched/core: Check for available DL bandwidth in cpuset_cpu_inactive()"), a SCHED_DEADLINE bugfix, had a logic error that caused a regression in setting a CPU inactive during suspend. I ran into this when a program was failing pthread_setaffinity_np() with EINVAL after a suspend+wake up. A simple reproducer: $ ./a.out sched_setaffinity: Success $ systemctl suspend $ ./a.out sched_setaffinity: Invalid argument ... where ./a.out is: #define _GNU_SOURCE #include <errno.h> #include <sched.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> int main(void) { long num_cores; cpu_set_t cpu_set; int ret; num_cores = sysconf(_SC_NPROCESSORS_ONLN); CPU_ZERO(&cpu_set); CPU_SET(num_cores - 1, &cpu_set); errno = 0; ret = sched_setaffinity(getpid(), sizeof(cpu_set), &cpu_set); perror("sched_setaffinity"); return ret ? EXIT_FAILURE : EXIT_SUCCESS; } The mistake is that suspend is handled in the action == CPU_DOWN_PREPARE_FROZEN case of the switch statement in cpuset_cpu_inactive(). However, the commit in question masked out CPU_TASKS_FROZEN from the action, making this case dead. The fix is straightforward. Signed-off-by: Omar Sandoval <osandov@osandov.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 3c18d447b3b3 ("sched/core: Check for available DL bandwidth in cpuset_cpu_inactive()") Link: http://lkml.kernel.org/r/1cb5ecb3d6543c38cce5790387f336f54ec8e2bc.1430733960.git.osandov@osandov.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/core.c28
1 files changed, 12 insertions, 16 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 34db9bf892a3..57bd333bc4ab 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6999,27 +6999,23 @@ static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
unsigned long flags;
long cpu = (long)hcpu;
struct dl_bw *dl_b;
+ bool overflow;
+ int cpus;
- switch (action & ~CPU_TASKS_FROZEN) {
+ switch (action) {
case CPU_DOWN_PREPARE:
- /* explicitly allow suspend */
- if (!(action & CPU_TASKS_FROZEN)) {
- bool overflow;
- int cpus;
-
- rcu_read_lock_sched();
- dl_b = dl_bw_of(cpu);
+ rcu_read_lock_sched();
+ dl_b = dl_bw_of(cpu);
- raw_spin_lock_irqsave(&dl_b->lock, flags);
- cpus = dl_bw_cpus(cpu);
- overflow = __dl_overflow(dl_b, cpus, 0, 0);
- raw_spin_unlock_irqrestore(&dl_b->lock, flags);
+ raw_spin_lock_irqsave(&dl_b->lock, flags);
+ cpus = dl_bw_cpus(cpu);
+ overflow = __dl_overflow(dl_b, cpus, 0, 0);
+ raw_spin_unlock_irqrestore(&dl_b->lock, flags);
- rcu_read_unlock_sched();
+ rcu_read_unlock_sched();
- if (overflow)
- return notifier_from_errno(-EBUSY);
- }
+ if (overflow)
+ return notifier_from_errno(-EBUSY);
cpuset_update_active_cpus(false);
break;
case CPU_DOWN_PREPARE_FROZEN: