[Devel] [PATCH RHEL7 COMMIT] mm, kasan: don't call kasan_krealloc() from ksize().

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-693.1.1.vz7.37.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.1.1.vz7.37.4
------>
commit 9c3bc8b43df21819ed4d6acafb4408b0e93f49ef
Author: Alexander Potapenko <glider at google.com>
Date:   Fri Sep 15 17:18:10 2017 +0300

    mm, kasan: don't call kasan_krealloc() from ksize().
    
    Instead of calling kasan_krealloc(), which replaces the memory
    allocation stack ID (if stack depot is used), just unpoison the whole
    memory chunk.
    
    Signed-off-by: Alexander Potapenko <glider at google.com>
    Acked-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
    Cc: Andrey Konovalov <adech.fo at gmail.com>
    Cc: Dmitry Vyukov <dvyukov at google.com>
    Cc: Christoph Lameter <cl at linux.com>
    Cc: Konstantin Serebryany <kcc at google.com>
    Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
    Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
    
    https://jira.sw.ru/browse/PSBM-69081
    (cherry picked from commit 4ebb31a42ffa03912447fe1aabbdb28242f909ba)
    Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
---
 mm/slab.c | 2 +-
 mm/slub.c | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index ba35acc..7f5b2a3 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -4590,7 +4590,7 @@ size_t ksize(const void *objp)
 	/* We assume that ksize callers could use the whole allocated area,
 	 * so we need to unpoison this area.
 	 */
-	kasan_krealloc(objp, size, GFP_NOWAIT);
+	kasan_unpoison_shadow(objp, size);
 
 	return size;
 }
diff --git a/mm/slub.c b/mm/slub.c
index e32920f..2a97b19 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3591,8 +3591,9 @@ size_t ksize(const void *object)
 {
 	size_t size = __ksize(object);
 	/* We assume that ksize callers could use whole allocated area,
-	   so we need unpoison this area. */
-	kasan_krealloc(object, size, GFP_NOWAIT);
+	 * so we need to unpoison this area.
+	 */
+	kasan_unpoison_shadow(object, size);
 	return size;
 }
 EXPORT_SYMBOL(ksize);