From 5bb9efe33ea4001a17ab98186a40a134a3061d67 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 13 May 2009 08:12:51 +0200 Subject: [PATCH] perf_counter: fix print debug irq disable inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. bash/15802 [HC0[0]:SC0[0]:HE1:SE1] takes: (sysrq_key_table_lock){?.....}, Don't unconditionally enable interrupts in the perf_counter_print_debug() path. [ Impact: fix potential deadlock pointed out by lockdep ] LKML-Reference: Reported-by: Ingo Molnar Signed-off-by: Peter Zijlstra --- arch/x86/kernel/cpu/perf_counter.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index da27419923a8..f7772ff7936e 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -621,12 +621,13 @@ void perf_counter_print_debug(void) { u64 ctrl, status, overflow, pmc_ctrl, pmc_count, prev_left, fixed; struct cpu_hw_counters *cpuc; + unsigned long flags; int cpu, idx; if (!x86_pmu.num_counters) return; - local_irq_disable(); + local_irq_save(flags); cpu = smp_processor_id(); cpuc = &per_cpu(cpu_hw_counters, cpu); @@ -664,7 +665,7 @@ void perf_counter_print_debug(void) pr_info("CPU#%d: fixed-PMC%d count: %016llx\n", cpu, idx, pmc_count); } - local_irq_enable(); + local_irq_restore(flags); } static void x86_pmu_disable(struct perf_counter *counter) -- 2.20.1