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x86/intel_rdt: Prevent pseudo-locking from using stale pointers

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When the last CPU in an rdt_domain goes offline, its rdt_domain struct gets
freed. Current pseudo-locking code is unaware of this scenario and tries to
dereference the freed structure in a few places.

Add checks to prevent pseudo-locking code from doing this.

While further work is needed to seamlessly restore resource groups (not
just pseudo-locking) to their configuration when the domain is brought back
online, the immediate issue of invalid pointers is addressed here.

Fixes: f4e80d67a5 ("x86/intel_rdt: Resctrl files reflect pseudo-locked information")
Fixes: 443810fe61 ("x86/intel_rdt: Create debugfs files for pseudo-locking testing")
Fixes: 746e08590b ("x86/intel_rdt: Create character device exposing pseudo-locked region")
Fixes: 33dc3e410a ("x86/intel_rdt: Make CPU information accessible for pseudo-locked regions")
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: gavin.hindman@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/231f742dbb7b00a31cc104416860e27dba6b072d.1539384145.git.reinette.chatre@intel.com
This commit is contained in:
Jithu Joseph
2018-10-12 15:51:01 -07:00
committed by Thomas Gleixner
parent 2a7adf6ce6
commit b61b8bba18
4 changed files with 55 additions and 12 deletions
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7
arch/x86/kernel/cpu/intel_rdt.c
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@@ -608,6 +608,13 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
cancel_delayed_work(&d->cqm_limbo);
}
/*
* rdt_domain "d" is going to be freed below, so clear
* its pointer from pseudo_lock_region struct.
*/
if (d->plr)
d->plr->d = NULL;
kfree(d->ctrl_val);
kfree(d->mbps_val);
bitmap_free(d->rmid_busy_llc);