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authorPrarit Bhargava <prarit@redhat.com>2019-06-10 13:15:44 -0400
committerThomas Gleixner <tglx@linutronix.de>2019-06-12 10:31:50 +0200
commitc7563e62a6d720aa3b068e26ddffab5f0df29263 (patch)
tree79924a1f6a54b6d5f8038413b6392048065244f3 /arch/x86
parent87d3aa28f345bea77c396855fa5d5fec4c24461f (diff)
x86/resctrl: Prevent NULL pointer dereference when local MBM is disabled
Booting with kernel parameter "rdt=cmt,mbmtotal,memlocal,l3cat,mba" and executing "mount -t resctrl resctrl -o mba_MBps /sys/fs/resctrl" results in a NULL pointer dereference on systems which do not have local MBM support enabled.. BUG: kernel NULL pointer dereference, address: 0000000000000020 PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 722 Comm: kworker/0:3 Not tainted 5.2.0-0.rc3.git0.1.el7_UNSUPPORTED.x86_64 #2 Workqueue: events mbm_handle_overflow RIP: 0010:mbm_handle_overflow+0x150/0x2b0 Only enter the bandwith update loop if the system has local MBM enabled. Fixes: de73f38f7680 ("x86/intel_rdt/mba_sc: Feedback loop to dynamically update mem bandwidth") Signed-off-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Reinette Chatre <reinette.chatre@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190610171544.13474-1-prarit@redhat.com
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/cpu/resctrl/monitor.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 1573a0a6b525..ff6e8e561405 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -368,6 +368,9 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm)
struct list_head *head;
struct rdtgroup *entry;
+ if (!is_mbm_local_enabled())
+ return;
+
r_mba = &rdt_resources_all[RDT_RESOURCE_MBA];
closid = rgrp->closid;
rmid = rgrp->mon.rmid;