s390/cpum_cf: Fix uninitialized warning after backport of ce971233242b

Upstream commit ce971233242b ("s390/cpum_cf: Deny all sampling events by
counter PMU"), backported to 6.6 as commit d660c8d814 ("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: d660c8d814 ("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>
This commit is contained in:
Nathan Chancellor
2025-09-22 14:15:50 -07:00
committed by Greg Kroah-Hartman
parent 09e3bda3a7
commit 53888cd32a

View File

@@ -852,7 +852,7 @@ static int cpumf_pmu_event_type(struct perf_event *event)
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 perf_event *event)
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);