From afc2f576a7eeda68c731943a6deae3d5bce9f3df Mon Sep 17 00:00:00 2001 From: Thomas Richter Date: Wed, 11 Nov 2020 16:26:25 +0100 Subject: [PATCH] s390/cpum_sf.c: fix file permission for cpum_sfb_size commit 78d732e1f326f74f240d416af9484928303d9951 upstream. This file is installed by the s390 CPU Measurement sampling facility device driver to export supported minimum and maximum sample buffer sizes. This file is read by lscpumf tool to display the details of the device driver capabilities. The lscpumf tool might be invoked by a non-root user. In this case it does not print anything because the file contents can not be read. Fix this by allowing read access for all users. Reading the file contents is ok, changing the file contents is left to the root user only. For further reference and details see: [1] https://github.com/ibm-s390-tools/s390-tools/issues/97 Fixes: 69f239ed335a ("s390/cpum_sf: Dynamically extend the sampling buffer if overflows occur") Cc: # 3.14 Signed-off-by: Thomas Richter Acked-by: Sumanth Korikkar Signed-off-by: Heiko Carstens Signed-off-by: Greg Kroah-Hartman --- arch/s390/kernel/perf_cpum_sf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c index b652593d7d..984fea3605 100644 --- a/arch/s390/kernel/perf_cpum_sf.c +++ b/arch/s390/kernel/perf_cpum_sf.c @@ -1662,4 +1662,4 @@ static int __init init_cpum_sampling_pmu(void) return err; } arch_initcall(init_cpum_sampling_pmu); -core_param(cpum_sfb_size, CPUM_SF_MAX_SDB, sfb_size, 0640); +core_param(cpum_sfb_size, CPUM_SF_MAX_SDB, sfb_size, 0644);