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[PATCH 4.10 24/69] x86/intel_rdt: Fix locking in rdtgroup_schemata_write()

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4.10-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jiri Olsa <jolsa@kernel.org>

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")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Shaohua Li <shli@fb.com>
Link: http://lkml.kernel.org/r/20170411071446.15241-1-jolsa@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/kernel/cpu/intel_rdt_schemata.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/cpu/intel_rdt_schemata.c
+++ b/arch/x86/kernel/cpu/intel_rdt_schemata.c
@@ -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;
 }
 

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[PATCH 4.10 24/69] x86/intel_rdt: Fix locking in rdtgroup_schemata_write() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-04-19 16:40 +0200

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