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authorBabu Moger <babu.moger@amd.com>2021-08-20 16:52:42 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-09-15 09:47:40 +0200
commit0323ab5b254e05a5f84051afb61ad7e646d840f3 (patch)
treec0ad947eeaae22f2a773d45fd832493ff395548d /arch/x86/kernel
parent51f4575ca182071218cc709c13827d96c52a2d8f (diff)
x86/resctrl: Fix a maybe-uninitialized build warning treated as error
commit 527f721478bce3f49b513a733bacd19d6f34b08c upstream. The recent commit 064855a69003 ("x86/resctrl: Fix default monitoring groups reporting") caused a RHEL build failure with an uninitialized variable warning treated as an error because it removed the default case snippet. The RHEL Makefile uses '-Werror=maybe-uninitialized' to force possibly uninitialized variable warnings to be treated as errors. This is also reported by smatch via the 0day robot. The error from the RHEL build is: arch/x86/kernel/cpu/resctrl/monitor.c: In function ‘__mon_event_count’: arch/x86/kernel/cpu/resctrl/monitor.c:261:12: error: ‘m’ may be used uninitialized in this function [-Werror=maybe-uninitialized] m->chunks += chunks; ^~ The upstream Makefile does not build using '-Werror=maybe-uninitialized'. So, the problem is not seen there. Fix the problem by putting back the default case snippet. [ bp: note that there's nothing wrong with the code and other compilers do not trigger this warning - this is being done just so the RHEL compiler is happy. ] Fixes: 064855a69003 ("x86/resctrl: Fix default monitoring groups reporting") Reported-by: Terry Bowman <Terry.Bowman@amd.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Babu Moger <babu.moger@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/162949631908.23903.17090272726012848523.stgit@bmoger-ubuntu Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r--arch/x86/kernel/cpu/resctrl/monitor.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 21eb593e0313..008bcb15fe96 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -242,6 +242,12 @@ static u64 __mon_event_count(u32 rmid, struct rmid_read *rr)
case QOS_L3_MBM_LOCAL_EVENT_ID:
m = &rr->d->mbm_local[rmid];
break;
+ default:
+ /*
+ * Code would never reach here because an invalid
+ * event id would fail the __rmid_read.
+ */
+ return RMID_VAL_ERROR;
}
if (rr->first) {