Merge tag 'perf-urgent-2021-06-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

torvalds · torvalds · commit df5011000496 · 2021-06-24T08:55:12.000-07:00
Pull x86 perf fix from Ingo Molnar:
 "An LBR buffer fix for code that probably only worked accidentally"

* tag 'perf-urgent-2021-06-24' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel/lbr: Zero the xstate buffer on allocation
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
@@ -731,7 +731,8 @@ void reserve_lbr_buffers(void)
 		if (!kmem_cache || cpuc->lbr_xsave)
 			continue;
 
-		cpuc->lbr_xsave = kmem_cache_alloc_node(kmem_cache, GFP_KERNEL,
+		cpuc->lbr_xsave = kmem_cache_alloc_node(kmem_cache,
+							GFP_KERNEL | __GFP_ZERO,
 							cpu_to_node(cpu));
 	}
 }

Original file line number	Diff line number	Diff line change
`@@ -731,7 +731,8 @@ void reserve_lbr_buffers(void)`
`731`	`731`	`if (!kmem_cache \|\| cpuc->lbr_xsave)`
`732`	`732`	`continue;`
`733`	`733`
`734`		`- cpuc->lbr_xsave = kmem_cache_alloc_node(kmem_cache, GFP_KERNEL,`
	`734`	`+ cpuc->lbr_xsave = kmem_cache_alloc_node(kmem_cache,`
	`735`	`+ GFP_KERNEL \| __GFP_ZERO,`
`735`	`736`	`cpu_to_node(cpu));`
`736`	`737`	`}`
`737`	`738`	`}`