diff options
| author | Alexey Kardashevskiy <aik@ozlabs.ru> | 2020-06-02 05:56:12 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-08-27 10:41:44 +0300 |
| commit | b460b512417ae9c8b51a3bdcc09020cd6c60ff69 (patch) | |
| tree | 00437f714f58621dd249d2dc50b49b197a1f3c00 /arch | |
| parent | b91eb5182405b01a8aeb42e9b5207831767e97ee (diff) | |
| download | linux-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.c | 19 |
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) { |