From: Vaibhav Jain <vaibhav@linux.ibm.com> To: Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@lists.ozlabs.org, linux-nvdimm@lists.01.org Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com> Subject: Re: [PATCH v2] powerpc/papr_scm: Fix warning triggered by perf_stats_show() Date: Tue, 15 Sep 2020 21:33:34 +0530 [thread overview] Message-ID: <87mu1rdo2x.fsf@vajain21.in.ibm.com> (raw) In-Reply-To: <87imcfp9a7.fsf@mpe.ellerman.id.au> Michael Ellerman <mpe@ellerman.id.au> writes: > Vaibhav Jain <vaibhav@linux.ibm.com> writes: >> A warning is reported by the kernel in case perf_stats_show() returns >> an error code. The warning is of the form below: >> >> papr_scm ibm,persistent-memory:ibm,pmemory@44100001: >> Failed to query performance stats, Err:-10 >> dev_attr_show: perf_stats_show+0x0/0x1c0 [papr_scm] returned bad count >> fill_read_buffer: dev_attr_show+0x0/0xb0 returned bad count >> >> On investigation it looks like that the compiler is silently truncating the >> return value of drc_pmem_query_stats() from 'long' to 'int', since the >> variable used to store the return code 'rc' is an 'int'. This >> truncated value is then returned back as a 'ssize_t' back from >> perf_stats_show() to 'dev_attr_show()' which thinks of it as a large >> unsigned number and triggers this warning.. >> >> To fix this we update the type of variable 'rc' from 'int' to >> 'ssize_t' that prevents the compiler from truncating the return value >> of drc_pmem_query_stats() and returning correct signed value back from >> perf_stats_show(). >> >> Fixes: 2d02bf835e573 ('powerpc/papr_scm: Fetch nvdimm performance >> stats from PHYP') > > Please don't word wrap the Fixes tag it breaks b4. > > I've fixed it up this time. Thanks Mpe > > cheers -- Cheers ~ Vaibhav _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org
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From: Vaibhav Jain <vaibhav@linux.ibm.com> To: Michael Ellerman <mpe@ellerman.id.au>, linuxppc-dev@lists.ozlabs.org, linux-nvdimm@lists.01.org Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>, Santosh Sivaraj <santosh@fossix.org>, Oliver O'Halloran <oohall@gmail.com>, Dan Williams <dan.j.williams@intel.com>, Ira Weiny <ira.weiny@intel.com> Subject: Re: [PATCH v2] powerpc/papr_scm: Fix warning triggered by perf_stats_show() Date: Tue, 15 Sep 2020 21:33:34 +0530 [thread overview] Message-ID: <87mu1rdo2x.fsf@vajain21.in.ibm.com> (raw) In-Reply-To: <87imcfp9a7.fsf@mpe.ellerman.id.au> Michael Ellerman <mpe@ellerman.id.au> writes: > Vaibhav Jain <vaibhav@linux.ibm.com> writes: >> A warning is reported by the kernel in case perf_stats_show() returns >> an error code. The warning is of the form below: >> >> papr_scm ibm,persistent-memory:ibm,pmemory@44100001: >> Failed to query performance stats, Err:-10 >> dev_attr_show: perf_stats_show+0x0/0x1c0 [papr_scm] returned bad count >> fill_read_buffer: dev_attr_show+0x0/0xb0 returned bad count >> >> On investigation it looks like that the compiler is silently truncating the >> return value of drc_pmem_query_stats() from 'long' to 'int', since the >> variable used to store the return code 'rc' is an 'int'. This >> truncated value is then returned back as a 'ssize_t' back from >> perf_stats_show() to 'dev_attr_show()' which thinks of it as a large >> unsigned number and triggers this warning.. >> >> To fix this we update the type of variable 'rc' from 'int' to >> 'ssize_t' that prevents the compiler from truncating the return value >> of drc_pmem_query_stats() and returning correct signed value back from >> perf_stats_show(). >> >> Fixes: 2d02bf835e573 ('powerpc/papr_scm: Fetch nvdimm performance >> stats from PHYP') > > Please don't word wrap the Fixes tag it breaks b4. > > I've fixed it up this time. Thanks Mpe > > cheers -- Cheers ~ Vaibhav
next prev parent reply other threads:[~2020-09-15 16:03 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-09-12 8:14 [PATCH v2] powerpc/papr_scm: Fix warning triggered by perf_stats_show() Vaibhav Jain 2020-09-12 8:14 ` Vaibhav Jain 2020-09-14 16:56 ` Ira Weiny 2020-09-14 16:56 ` Ira Weiny 2020-09-15 11:30 ` Michael Ellerman 2020-09-15 11:30 ` Michael Ellerman 2020-09-15 16:03 ` Vaibhav Jain [this message] 2020-09-15 16:03 ` Vaibhav Jain 2020-09-17 11:27 ` Michael Ellerman 2020-09-17 11:27 ` Michael Ellerman
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