From: Christoph Hellwig

Sent: 18 February 2022 06:29

...

quoted

diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index 15b058eefc4e..ee117fcf46ed 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c

@@ -90,7 +90,7 @@ copy_stack_frame(const struct stack_frame_user __user *fp,
 {
 	int ret;

-	if (__range_not_ok(fp, sizeof(*frame), TASK_SIZE))
+	if (!__access_ok(fp, sizeof(*frame)))
 		return 0;

Just switch the __get_user calls below to get_user instead.

Is this worth doing at all?
How much userspace code is actually compiled with stack frames?

Won't work well for a 32bit process on a 64bit kernel either.

	David

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