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authorAlexey Kardashevskiy <aik@ozlabs.ru>2020-06-02 05:56:12 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2020-08-27 10:41:44 +0300
commitb460b512417ae9c8b51a3bdcc09020cd6c60ff69 (patch)
tree00437f714f58621dd249d2dc50b49b197a1f3c00 /arch
parentb91eb5182405b01a8aeb42e9b5207831767e97ee (diff)
downloadlinux-b460b512417ae9c8b51a3bdcc09020cd6c60ff69.tar.xz
powerpc/perf: Fix crashes with generic_compat_pmu & BHRB
The bhrb_filter_map ("The Branch History Rolling Buffer") callback is only defined in raw CPUs' power_pmu structs. The "architected" CPUs use generic_compat_pmu, which does not have this callback, and crashes occur if a user tries to enable branch stack for an event. This add a NULL pointer check for bhrb_filter_map() which behaves as if the callback returned an error. This does not add the same check for config_bhrb() as the only caller checks for cpuhw->bhrb_users which remains zero if bhrb_filter_map==0. Fixes: be80e758d0c2 ("powerpc/perf: Add generic compat mode pmu driver") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Reviewed-by: Madhavan Srinivasan <maddy@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200602025612.62707-1-aik@ozlabs.ru
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/perf/core-book3s.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 93d20e1ed845..08643cba1494 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -1557,9 +1557,16 @@ nocheck:
ret = 0;
out:
if (has_branch_stack(event)) {
- power_pmu_bhrb_enable(event);
- cpuhw->bhrb_filter = ppmu->bhrb_filter_map(
- event->attr.branch_sample_type);
+ u64 bhrb_filter = -1;
+
+ if (ppmu->bhrb_filter_map)
+ bhrb_filter = ppmu->bhrb_filter_map(
+ event->attr.branch_sample_type);
+
+ if (bhrb_filter != -1) {
+ cpuhw->bhrb_filter = bhrb_filter;
+ power_pmu_bhrb_enable(event);
+ }
}
perf_pmu_enable(event->pmu);
@@ -1881,7 +1888,6 @@ static int power_pmu_event_init(struct perf_event *event)
int n;
int err;
struct cpu_hw_events *cpuhw;
- u64 bhrb_filter;
if (!ppmu)
return -ENOENT;
@@ -1987,7 +1993,10 @@ static int power_pmu_event_init(struct perf_event *event)
err = power_check_constraints(cpuhw, events, cflags, n + 1);
if (has_branch_stack(event)) {
- bhrb_filter = ppmu->bhrb_filter_map(
+ u64 bhrb_filter = -1;
+
+ if (ppmu->bhrb_filter_map)
+ bhrb_filter = ppmu->bhrb_filter_map(
event->attr.branch_sample_type);
if (bhrb_filter == -1) {