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authorKees Cook <keescook@chromium.org>2022-05-18 00:44:20 +0300
committerKees Cook <keescook@chromium.org>2022-05-18 00:47:08 +0300
commitf260fd59e3f387432bda51072fff4494fba10b91 (patch)
tree9c1484cdb052b624f9ebb1efbf15a489eabb843a /drivers/misc/lkdtm
parent38c84c997d40f56273077af5f8ff3e6317d772b7 (diff)
downloadlinux-f260fd59e3f387432bda51072fff4494fba10b91.tar.xz
lkdtm/heap: Hide allocation size from -Warray-bounds
With the kmalloc() size annotations, GCC is smart enough to realize that LKDTM is intentionally writing past the end of the buffer. This is on purpose, of course, so hide the buffer from the optimizer. Silences: ../drivers/misc/lkdtm/heap.c: In function 'lkdtm_SLAB_LINEAR_OVERFLOW': ../drivers/misc/lkdtm/heap.c:59:13: warning: array subscript 256 is outside array bounds of 'void[1020]' [-Warray-bounds] 59 | data[1024 / sizeof(u32)] = 0x12345678; | ~~~~^~~~~~~~~~~~~~~~~~~~ In file included from ../drivers/misc/lkdtm/heap.c:7: In function 'kmalloc', inlined from 'lkdtm_SLAB_LINEAR_OVERFLOW' at ../drivers/misc/lkdtm/heap.c:54:14: ../include/linux/slab.h:581:24: note: at offset 1024 into object of size 1020 allocated by 'kmem_cache_alloc_trace' 581 | return kmem_cache_alloc_trace( | ^~~~~~~~~~~~~~~~~~~~~~~ 582 | kmalloc_caches[kmalloc_type(flags)][index], | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 583 | flags, size); | ~~~~~~~~~~~~ Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'drivers/misc/lkdtm')
-rw-r--r--drivers/misc/lkdtm/heap.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm/heap.c b/drivers/misc/lkdtm/heap.c
index 5d3b92cd23bd..62516078a619 100644
--- a/drivers/misc/lkdtm/heap.c
+++ b/drivers/misc/lkdtm/heap.c
@@ -56,6 +56,7 @@ static void lkdtm_SLAB_LINEAR_OVERFLOW(void)
return;
pr_info("Attempting slab linear overflow ...\n");
+ OPTIMIZER_HIDE_VAR(data);
data[1024 / sizeof(u32)] = 0x12345678;
kfree(data);
}