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Commit ff0c7014 authored by Vinayak Menon's avatar Vinayak Menon Committed by Patrick Daly
Browse files

mm: usercopy: skip stack page span check 



Kernel stack pages can span multiple pages and GFP_COMP is not
set for stack pages. Fix the false "spans multiple pages" error.

Change-Id: I2ba414be466b7c90fb4a3542237da809175e0590
Signed-off-by: default avatarVinayak Menon <vinmenon@codeaurora.org>
[swatsrid@codeaurora.org: Fix trivial merge conflicts]
Signed-off-by: default avatarSwathi Sridhar <swatsrid@codeaurora.org>
parent 72c6f5f1

mm/usercopy.c

+6 −0
Original line number Diff line number Diff line
@@ -167,6 +167,8 @@ static inline void check_page_span(const void *ptr, unsigned long n, 
	const void *end = ptr + n - 1;

	struct page *endpage;

	bool is_reserved, is_cma;

	const void * const stack = task_stack_page(current);

	const void * const stackend = stack + THREAD_SIZE;



	/*

	 * Sometimes the kernel data regions are not marked Reserved (see
@@ -191,6 +193,10 @@ static inline void check_page_span(const void *ptr, unsigned long n, 
	    end <= (const void *)__bss_stop)

		return;



	/* Allow stack region to span multiple pages */

	if (ptr >= stack && end <= stackend)

		return;



	/* Is the object wholly within one base page? */

	if (likely(((unsigned long)ptr & (unsigned long)PAGE_MASK) ==

		   ((unsigned long)end & (unsigned long)PAGE_MASK)))