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sched/core: Fix regression in cpuset_cpu_inactive() for suspend
Commit3c18d447b3
("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:3c18d447b3
("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>
This commit is contained in:
parent
0782e63bc6
commit
533445c6e5
1 changed files with 12 additions and 16 deletions
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@ -6999,27 +6999,23 @@ static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
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unsigned long flags;
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long cpu = (long)hcpu;
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struct dl_bw *dl_b;
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bool overflow;
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int cpus;
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switch (action & ~CPU_TASKS_FROZEN) {
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switch (action) {
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case CPU_DOWN_PREPARE:
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/* explicitly allow suspend */
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if (!(action & CPU_TASKS_FROZEN)) {
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bool overflow;
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int cpus;
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rcu_read_lock_sched();
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dl_b = dl_bw_of(cpu);
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rcu_read_lock_sched();
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dl_b = dl_bw_of(cpu);
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raw_spin_lock_irqsave(&dl_b->lock, flags);
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cpus = dl_bw_cpus(cpu);
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overflow = __dl_overflow(dl_b, cpus, 0, 0);
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raw_spin_unlock_irqrestore(&dl_b->lock, flags);
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raw_spin_lock_irqsave(&dl_b->lock, flags);
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cpus = dl_bw_cpus(cpu);
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overflow = __dl_overflow(dl_b, cpus, 0, 0);
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raw_spin_unlock_irqrestore(&dl_b->lock, flags);
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rcu_read_unlock_sched();
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rcu_read_unlock_sched();
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if (overflow)
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return notifier_from_errno(-EBUSY);
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}
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if (overflow)
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return notifier_from_errno(-EBUSY);
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cpuset_update_active_cpus(false);
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break;
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case CPU_DOWN_PREPARE_FROZEN:
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