This is a note to let you know that I've just added the patch titled s390/cpum_sf.c: fix file permission for cpum_sfb_size to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: s390-cpum_sf.c-fix-file-permission-for-cpum_sfb_size.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 78d732e1f326f74f240d416af9484928303d9951 Mon Sep 17 00:00:00 2001 From: Thomas Richter <tmricht@xxxxxxxxxxxxx> Date: Wed, 11 Nov 2020 16:26:25 +0100 Subject: s390/cpum_sf.c: fix file permission for cpum_sfb_size From: Thomas Richter <tmricht@xxxxxxxxxxxxx> 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: <stable@xxxxxxxxxxxxxxx> # 3.14 Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx> Acked-by: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx> Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/s390/kernel/perf_cpum_sf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/s390/kernel/perf_cpum_sf.c +++ b/arch/s390/kernel/perf_cpum_sf.c @@ -2217,4 +2217,4 @@ out: } 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); Patches currently in stable-queue which might be from tmricht@xxxxxxxxxxxxx are queue-5.4/s390-cpum_sf.c-fix-file-permission-for-cpum_sfb_size.patch