6.6-stable review patch. If anyone has any objections, please let me know.
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From: Nathan Chancellor nathan@kernel.org
Upstream commit ce971233242b ("s390/cpum_cf: Deny all sampling events by counter PMU"), backported to 6.6 as commit d660c8d8142e ("s390/cpum_cf: Deny all sampling events by counter PMU"), implicitly depends on the unconditional initialization of err to -ENOENT added by upstream commit aa1ac98268cd ("s390/cpumf: Fix double free on error in cpumf_pmu_event_init()"). The latter change is missing from 6.6, resulting in an instance of -Wuninitialized, which is fairly obvious from looking at the actual diff.
arch/s390/kernel/perf_cpum_cf.c:858:10: warning: variable 'err' is uninitialized when used here [-Wuninitialized] 858 | return err; | ^~~
Commit aa1ac98268cd ("s390/cpumf: Fix double free on error in cpumf_pmu_event_init()") depends on commit c70ca298036c ("perf/core: Simplify the perf_event_alloc() error path"), which is a part of a much larger series unsuitable for stable.
Extract the unconditional initialization of err to -ENOENT from commit aa1ac98268cd ("s390/cpumf: Fix double free on error in cpumf_pmu_event_init()") and apply it to 6.6 as a standalone change to resolve the warning.
Fixes: d660c8d8142e ("s390/cpum_cf: Deny all sampling events by counter PMU") Signed-off-by: Nathan Chancellor nathan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/s390/kernel/perf_cpum_cf.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
--- a/arch/s390/kernel/perf_cpum_cf.c +++ b/arch/s390/kernel/perf_cpum_cf.c @@ -852,7 +852,7 @@ static int cpumf_pmu_event_type(struct p static int cpumf_pmu_event_init(struct perf_event *event) { unsigned int type = event->attr.type; - int err; + int err = -ENOENT;
if (is_sampling_event(event)) /* No sampling support */ return err; @@ -861,8 +861,6 @@ static int cpumf_pmu_event_init(struct p else if (event->pmu->type == type) /* Registered as unknown PMU */ err = __hw_perf_event_init(event, cpumf_pmu_event_type(event)); - else - return -ENOENT;
if (unlikely(err) && event->destroy) event->destroy(event);