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| author | Prarit Bhargava <prarit@redhat.com> | 2019-06-10 13:15:44 -0400 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-06-12 10:31:50 +0200 |
| commit | c7563e62a6d720aa3b068e26ddffab5f0df29263 (patch) | |
| tree | 79924a1f6a54b6d5f8038413b6392048065244f3 /arch | |
| parent | 87d3aa28f345bea77c396855fa5d5fec4c24461f (diff) | |
| download | lwn-c7563e62a6d720aa3b068e26ddffab5f0df29263.tar.gz lwn-c7563e62a6d720aa3b068e26ddffab5f0df29263.zip | |
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')
| -rw-r--r-- | arch/x86/kernel/cpu/resctrl/monitor.c | 3 |
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; |