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Patch "x86/intel_rdt: Fix locking in rdtgroup_schemata_write()" has been added to the 4.10-stable tree

PATCH [email protected] 1 participant 1 message Apr 18, 2017

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This is a note to let you know that I've just added the patch titled

x86/intel_rdt: Fix locking in rdtgroup_schemata_write()

to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
x86-intel_rdt-fix-locking-in-rdtgroup_schemata_write.patch
and it can be found in the queue-4.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 7f00f388712b29005782bad7e4b25942620f3b9c Mon Sep 17 00:00:00 2001

From: Jiri Olsa <[email protected]>
Date: Tue, 11 Apr 2017 09:14:46 +0200
Subject: x86/intel_rdt: Fix locking in rdtgroup_schemata_write()

From: Jiri Olsa <[email protected]>

commit 7f00f388712b29005782bad7e4b25942620f3b9c upstream.

The schemata lock is released before freeing the resource's temporary tmp_cbms allocation. That's racy versus another write which allocates and uses new temporary storage, resulting in memory leaks, freeing in use memory, double a free or any combination of those.

Move the unlock after the release code.

Fixes 60ec2440c63d ("x86/intel_rdt: Add schemata file")
Cc Fenghua Yu <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Peter Zijlstra <[email protected]>
Cc Mike Galbraith <[email protected]>
Cc Shaohua Li <[email protected]>
---
 arch/x86/kernel/cpu/intel_rdt_schemata.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
arch/x86/kernel/cpu/intel_rdt_schemata.c +1 -1
@@ -200,11 +200,11 @@ ssize_t rdtgroup_schemata_write(struct k
 	}
 
 out:
-	rdtgroup_kn_unlock(of->kn);
 	for_each_enabled_rdt_resource(r) {
 		kfree(r->tmp_cbms);
 		r->tmp_cbms = NULL;
 	}
+	rdtgroup_kn_unlock(of->kn);
 	return ret ?: nbytes;
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.10/x86-intel_rdt-fix-locking-in-rdtgroup_schemata_write.patch