The memset/memcpy functions are by default instrumented by KASAN, which
complains about user memory access when using a poking page in
userspace.
Using a userspace address is expected though, so don't instrument with
KASAN for this function.
Signed-off-by: Benjamin Gray <bg...@linux.ibm.com>
---
I tried to replace the memsetN calls with __memsetN, but we appear to
disable the non-instrumented variants of these when KASAN is enabled.
Christophe might you know more here?
The cost of just suppressing reports for this section shouldn't be too
relevant; KASAN detects the access, but exits before it starts preparing
the report itself. So it's just like any other KASAN instrumented
function for the most part.
---
arch/powerpc/lib/code-patching.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index c6ab46156cda..24989594578a 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -3,6 +3,7 @@
* Copyright 2008 Michael Ellerman, IBM Corporation.
*/
+#include <linux/kasan.h>
#include <linux/kprobes.h>
#include <linux/mmu_context.h>
#include <linux/random.h>
@@ -377,6 +378,7 @@ static int __patch_instructions(u32 *patch_addr, u32 *code,
size_t len, bool rep
unsigned long start = (unsigned long)patch_addr;
/* Repeat instruction */
+ kasan_disable_current();
if (repeat_instr) {
ppc_inst_t instr = ppc_inst_read(code);
@@ -392,6 +394,7 @@ static int __patch_instructions(u32 *patch_addr, u32 *code,
size_t len, bool rep
} else {
memcpy(patch_addr, code, len);
}
+ kasan_enable_current();
smp_wmb(); /* smp write barrier */
flush_icache_range(start, start + len);
--
2.43.0
