2022-08-30 15:46:14

by Nathan Chancellor

Subject: [PATCH] powerpc/papr_scm: Ensure rc is always initialized in papr_scm_pmu_register()

Clang warns:

arch/powerpc/platforms/pseries/papr_scm.c:492:6: warning: variable 'rc' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
if (!p->stat_buffer_len)
^~~~~~~~~~~~~~~~~~~
arch/powerpc/platforms/pseries/papr_scm.c:523:64: note: uninitialized use occurs here
dev_info(&p->pdev->dev, "nvdimm pmu didn't register rc=%d\n", rc);
^~
include/linux/dev_printk.h:150:67: note: expanded from macro 'dev_info'
dev_printk_index_wrap(_dev_info, KERN_INFO, dev, dev_fmt(fmt), ##__VA_ARGS__)
^~~~~~~~~~~
include/linux/dev_printk.h:110:23: note: expanded from macro 'dev_printk_index_wrap'
_p_func(dev, fmt, ##__VA_ARGS__); \
^~~~~~~~~~~
arch/powerpc/platforms/pseries/papr_scm.c:492:2: note: remove the 'if' if its condition is always false
if (!p->stat_buffer_len)
^~~~~~~~~~~~~~~~~~~~~~~~
arch/powerpc/platforms/pseries/papr_scm.c:484:8: note: initialize the variable 'rc' to silence this warning
int rc, nodeid;
^
= 0
1 warning generated.

The call to papr_scm_pmu_check_events() was eliminated but a return code
was not added to the if statement. Add the same return code from
papr_scm_pmu_check_events() for this condition so there is no more
warning.

Fixes: 9b1ac04698a4 ("powerpc/papr_scm: Fix nvdimm event mappings")
Link: https://github.com/ClangBuiltLinux/linux/issues/1701
Signed-off-by: Nathan Chancellor <[email protected]>
---
arch/powerpc/platforms/pseries/papr_scm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index 54740af21557..2f8385523a13 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -489,8 +489,10 @@ static void papr_scm_pmu_register(struct papr_scm_priv *p)
goto pmu_err_print;
}

- if (!p->stat_buffer_len)
+ if (!p->stat_buffer_len) {
+ rc = -ENOENT;
goto pmu_check_events_err;
+ }

nd_pmu->pmu.task_ctx_nr = perf_invalid_context;
nd_pmu->pmu.name = nvdimm_name(p->nvdimm);

base-commit: 91926d8b7e71aaf5f84f0cf208fc5a8b7a761050
--
2.37.2

2022-09-02 11:35:53

by Michael Ellerman

Subject: Re: [PATCH] powerpc/papr_scm: Ensure rc is always initialized in papr_scm_pmu_register()

On Tue, 30 Aug 2022 08:12:56 -0700, Nathan Chancellor wrote:
> Clang warns:
>
> arch/powerpc/platforms/pseries/papr_scm.c:492:6: warning: variable 'rc' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
> if (!p->stat_buffer_len)
> ^~~~~~~~~~~~~~~~~~~
> arch/powerpc/platforms/pseries/papr_scm.c:523:64: note: uninitialized use occurs here
> dev_info(&p->pdev->dev, "nvdimm pmu didn't register rc=%d\n", rc);
> ^~
> include/linux/dev_printk.h:150:67: note: expanded from macro 'dev_info'
> dev_printk_index_wrap(_dev_info, KERN_INFO, dev, dev_fmt(fmt), ##__VA_ARGS__)
> ^~~~~~~~~~~
> include/linux/dev_printk.h:110:23: note: expanded from macro 'dev_printk_index_wrap'
> _p_func(dev, fmt, ##__VA_ARGS__); \
> ^~~~~~~~~~~
> arch/powerpc/platforms/pseries/papr_scm.c:492:2: note: remove the 'if' if its condition is always false
> if (!p->stat_buffer_len)
> ^~~~~~~~~~~~~~~~~~~~~~~~
> arch/powerpc/platforms/pseries/papr_scm.c:484:8: note: initialize the variable 'rc' to silence this warning
> int rc, nodeid;
> ^
> = 0
> 1 warning generated.
>
> [...]

Applied to powerpc/fixes.

[1/1] powerpc/papr_scm: Ensure rc is always initialized in papr_scm_pmu_register()
https://git.kernel.org/powerpc/c/6cf07810e9ef8535d60160d13bf0fd05f2af38e7

cheers