Vaibhav Jain <vaib...@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. cheers