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Commit e2124bb8 authored by Andi Kleen's avatar Andi Kleen Committed by Andi Kleen
Browse files

[PATCH] unwinder: Use probe_kernel_address instead of __get_user in kernel/unwind.c 



This avoids trouble with the page fault handler if the fault
happens inside an interrupt context.

Suggested by Linus

Cc: jbeulich@novell.com
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
parent f3d73707

kernel/unwind.c

+8 −6
Original line number Original line Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/bootmem.h>

#include <linux/bootmem.h>

#include <linux/sort.h>

#include <linux/sort.h>

#include <linux/stop_machine.h>

#include <linux/stop_machine.h>

#include <linux/uaccess.h>

#include <asm/sections.h>

#include <asm/sections.h>

#include <asm/uaccess.h>

#include <asm/uaccess.h>

#include <asm/unaligned.h>

#include <asm/unaligned.h>
@@ -550,7 +551,7 @@ static unsigned long read_pointer(const u8 **pLoc, 
		return 0;

		return 0;

	}

	}

	if ((ptrType & DW_EH_PE_indirect)

	if ((ptrType & DW_EH_PE_indirect)

	    && __get_user(value, (unsigned long *)value))

	    && probe_kernel_address((unsigned long *)value, value))

		return 0;

		return 0;

	*pLoc = ptr.p8;

	*pLoc = ptr.p8;
@@ -982,18 +983,19 @@ int unwind(struct unwind_frame_info *frame) 
		        & (sizeof(unsigned long) - 1))) {

		        & (sizeof(unsigned long) - 1))) {

			unsigned long link;

			unsigned long link;





			if (!__get_user(link,

			if (!probe_kernel_address(

			                (unsigned long *)(UNW_FP(frame)

			                (unsigned long *)(UNW_FP(frame)

			                                  + FRAME_LINK_OFFSET))

			                                  + FRAME_LINK_OFFSET),

						  link)

# if FRAME_RETADDR_OFFSET < 0

# if FRAME_RETADDR_OFFSET < 0

			   && link > bottom && link < UNW_FP(frame)

			   && link > bottom && link < UNW_FP(frame)

# else

# else

			   && link > UNW_FP(frame) && link < bottom

			   && link > UNW_FP(frame) && link < bottom

# endif

# endif

			   && !(link & (sizeof(link) - 1))

			   && !(link & (sizeof(link) - 1))

			   && !__get_user(UNW_PC(frame),

			   && !probe_kernel_address(

			                  (unsigned long *)(UNW_FP(frame)

			                  (unsigned long *)(UNW_FP(frame)

			                                    + FRAME_RETADDR_OFFSET))) {

			                                    + FRAME_RETADDR_OFFSET), UNW_PC(frame))) {

				UNW_SP(frame) = UNW_FP(frame) + FRAME_RETADDR_OFFSET

				UNW_SP(frame) = UNW_FP(frame) + FRAME_RETADDR_OFFSET

# if FRAME_RETADDR_OFFSET < 0

# if FRAME_RETADDR_OFFSET < 0

					-

					-
@@ -1104,7 +1106,7 @@ int unwind(struct unwind_frame_info *frame) 
					return -EIO;

					return -EIO;

				switch(reg_info[i].width) {

				switch(reg_info[i].width) {

#define CASE(n)     case sizeof(u##n): \

#define CASE(n)     case sizeof(u##n): \

					__get_user(FRAME_REG(i, u##n), (u##n *)addr); \

					probe_kernel_address((u##n *)addr, FRAME_REG(i, u##n)); \

					break

					break

				CASES;

				CASES;

#undef CASE

#undef CASE