| Message ID | 20200907110540.21349-1-vaibhav@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 0460534b532e5518c657c7d6492b9337d975eaa3 |
| Headers | show |
| Series | [v2] powerpc/papr_scm: Limit the readability of 'perf_stats' sysfs attribute | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (35f066fda170dde0a31f1447547a5d30b83c3920) |
| snowpatch_ozlabs/build-ppc64le | warning | Upstream build failed, couldn't test patch |
| snowpatch_ozlabs/build-ppc64be | warning | Upstream build failed, couldn't test patch |
| snowpatch_ozlabs/build-ppc64e | warning | Upstream build failed, couldn't test patch |
| snowpatch_ozlabs/build-pmac32 | warning | Upstream build failed, couldn't test patch |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 8 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch fixes a commit that hasn't been released yet |
On Mon, Sep 07, 2020 at 04:35:40PM +0530, Vaibhav Jain wrote: > The newly introduced 'perf_stats' attribute uses the default access > mode of 0444 letting non-root users access performance stats of an > nvdimm and potentially force the kernel into issuing large number of > expensive HCALLs. Since the information exposed by this attribute > cannot be cached hence its better to ward of access to this attribute ^^^ off? > from users who don't need to access these performance statistics. > > Hence this patch updates access mode of 'perf_stats' attribute to > be only readable by root users. Generally it is bad form to say "this patch". See 4c here: -- https://www.ozlabs.org/~akpm/stuff/tpp.txt But I'm not picky... :-D With the s/of/off/ change: Reviewed-by: Ira Weiny <ira.weiny@intel.com> > > Fixes: 2d02bf835e573 ('powerpc/papr_scm: Fetch nvdimm performance stats from PHYP') > Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com> > --- > Change-log: > > v2: > * Instead of checking for perfmon_capable() inside show_perf_stats() > set the attribute as DEVICE_ATTR_ADMIN_RO [ Aneesh ] > * Update patch description > --- > arch/powerpc/platforms/pseries/papr_scm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c > index f439f0dfea7d1..a88a707a608aa 100644 > --- a/arch/powerpc/platforms/pseries/papr_scm.c > +++ b/arch/powerpc/platforms/pseries/papr_scm.c > @@ -822,7 +822,7 @@ static ssize_t perf_stats_show(struct device *dev, > kfree(stats); > return rc ? rc : seq_buf_used(&s); > } > -DEVICE_ATTR_RO(perf_stats); > +DEVICE_ATTR_ADMIN_RO(perf_stats); > > static ssize_t flags_show(struct device *dev, > struct device_attribute *attr, char *buf) > -- > 2.26.2 >
On Mon, 7 Sep 2020 16:35:40 +0530, Vaibhav Jain wrote: > The newly introduced 'perf_stats' attribute uses the default access > mode of 0444 letting non-root users access performance stats of an > nvdimm and potentially force the kernel into issuing large number of > expensive HCALLs. Since the information exposed by this attribute > cannot be cached hence its better to ward of access to this attribute > from users who don't need to access these performance statistics. > > [...] Applied to powerpc/fixes. [1/1] powerpc/papr_scm: Limit the readability of 'perf_stats' sysfs attribute https://git.kernel.org/powerpc/c/0460534b532e5518c657c7d6492b9337d975eaa3 cheers
diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index f439f0dfea7d1..a88a707a608aa 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -822,7 +822,7 @@ static ssize_t perf_stats_show(struct device *dev, kfree(stats); return rc ? rc : seq_buf_used(&s); } -DEVICE_ATTR_RO(perf_stats); +DEVICE_ATTR_ADMIN_RO(perf_stats); static ssize_t flags_show(struct device *dev, struct device_attribute *attr, char *buf)
The newly introduced 'perf_stats' attribute uses the default access mode of 0444 letting non-root users access performance stats of an nvdimm and potentially force the kernel into issuing large number of expensive HCALLs. Since the information exposed by this attribute cannot be cached hence its better to ward of access to this attribute from users who don't need to access these performance statistics. Hence this patch updates access mode of 'perf_stats' attribute to be only readable by root users. Fixes: 2d02bf835e573 ('powerpc/papr_scm: Fetch nvdimm performance stats from PHYP') Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com> --- Change-log: v2: * Instead of checking for perfmon_capable() inside show_perf_stats() set the attribute as DEVICE_ATTR_ADMIN_RO [ Aneesh ] * Update patch description --- arch/powerpc/platforms/pseries/papr_scm.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)