arch_uprobe_exception_notify() may receive register state without
valid KMSAN metadata, which will lead to false positives.
Explicitly unpoison args and args->regs to avoid this.
Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx>
To: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Cc: linux-mm@xxxxxxxxx
---
This patch was split from "kmsan: disable instrumentation of certain
functions"
v4:
- split this patch away
Change-Id: I466ef628b00362ab5eb1852c76baa8cdb06736d9
---
arch/x86/kernel/uprobes.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 15e5aad8ac2c..bc156b016dc5 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -8,6 +8,7 @@
* Jim Keniston
*/
#include <linux/kernel.h>
+#include <linux/kmsan-checks.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/uprobes.h>
@@ -997,9 +998,13 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data)
{
struct die_args *args = data;
- struct pt_regs *regs = args->regs;
+ struct pt_regs *regs;
int ret = NOTIFY_DONE;
+ kmsan_unpoison_shadow(args, sizeof(*args));
+ regs = args->regs;
+ if (regs)
+ kmsan_unpoison_shadow(regs, sizeof(*regs));
/* We are only interested in userspace traps */
if (regs && !user_mode(regs))
return NOTIFY_DONE;
--
2.24.1.735.g03f4e72817-goog
