diff options
authorDavid S. Miller <davem@davemloft.net>2014-08-11 15:38:46 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-10-30 09:40:19 -0700
commite7f7dcadf97accf7a3f0fca58c8d3b4ffb563808 (patch)
parent4eed408a0ba807eacbab3c93c7096cf4ff002b9a (diff)
sparc64: Fix pcr_ops initialization and usage bugs.
[ Upstream commit 8bccf5b313180faefce38e0d1140f76e0f327d28 ] Christopher reports that perf_event_print_debug() can crash in uniprocessor builds. The crash is due to pcr_ops being NULL. This happens because pcr_arch_init() is only invoked by smp_cpus_done() which only executes in SMP builds. init_hw_perf_events() is closely intertwined with pcr_ops being setup properly, therefore: 1) Call pcr_arch_init() early on from init_hw_perf_events(), instead of from smp_cpus_done(). 2) Do not hook up a PMU type if pcr_ops is NULL after pcr_arch_init(). 3) Move init_hw_perf_events to a later initcall so that it we will be sure to invoke pcr_arch_init() after all cpus are brought up. Finally, guard the one naked sequence of pcr_ops dereferences in __global_pmu_self() with an appropriate NULL check. Reported-by: Christopher Alexander Tobias Schulze <cat.schulze@alice-dsl.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
3 files changed, 8 insertions, 3 deletions
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index 8efd33753ad3..d35c490a91cb 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -1671,9 +1671,12 @@ static bool __init supported_pmu(void)
static int __init init_hw_perf_events(void)
+ int err;
pr_info("Performance events: ");
- if (!supported_pmu()) {
+ err = pcr_arch_init();
+ if (err || !supported_pmu()) {
pr_cont("No support for PMU type '%s'\n", sparc_pmu_type);
return 0;
@@ -1685,7 +1688,7 @@ static int __init init_hw_perf_events(void)
return 0;
void perf_callchain_kernel(struct perf_callchain_entry *entry,
struct pt_regs *regs)
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index 027e09986194..0be7bf978cb1 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -312,6 +312,9 @@ static void __global_pmu_self(int this_cpu)
struct global_pmu_snapshot *pp;
int i, num;
+ if (!pcr_ops)
+ return;
pp = &global_cpu_snapshot[this_cpu].pmu;
num = 1;
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index 41aa2478f3ca..f7ba87543e5f 100644
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -1383,7 +1383,6 @@ void __cpu_die(unsigned int cpu)
void __init smp_cpus_done(unsigned int max_cpus)
- pcr_arch_init();
void smp_send_reschedule(int cpu)