From: Prarit Bhargava <prarit@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Prarit Bhargava <prarit@redhat.com>,
Fenghua Yu <fenghua.yu@intel.com>,
Reinette Chatre <reinette.chatre@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org
Subject: [PATCH] x86/resctrl: Fix panic on systems that do not enable local MBM
Date: Mon, 10 Jun 2019 13:15:44 -0400 [thread overview]
Message-ID: <20190610171544.13474-1-prarit@redhat.com> (raw)
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 panic on systems without local MBM support enabled in
firmware.
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
Hardware name: Dell Inc. PowerEdge R740/0923K0, BIOS 2.1.8 04/30/2019
Workqueue: events mbm_handle_overflow
RIP: 0010:mbm_handle_overflow+0x150/0x2b0
Only call the bandwith update loop if the system has local MBM enabled.
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
---
arch/x86/kernel/cpu/resctrl/monitor.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 7ee93125a211..397206f23d14 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -360,6 +360,9 @@ 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;
--
2.21.0
next reply other threads:[~2019-06-10 17:15 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-10 17:15 Prarit Bhargava [this message]
2019-06-12 12:26 ` [tip:x86/urgent] x86/resctrl: Prevent NULL pointer dereference when local MBM is disabled tip-bot for Prarit Bhargava
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