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Commit e7a7912a authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm 

Pull ARM fix from Russell King:
 "Last ARM fix for 4.14.

  This plugs a hole in dump_instr(), which, with certain conditions
  satisfied, can dump instructions from kernel space"

* 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 8720/1: ensure dump_instr() checks addr_limit
parents 3fefc318 b9dd05c7

arch/arm/kernel/traps.c

+18 −10
Original line number Diff line number Diff line
@@ -154,30 +154,26 @@ static void dump_mem(const char *lvl, const char *str, unsigned long bottom, 
	set_fs(fs);

}



static void dump_instr(const char *lvl, struct pt_regs *regs)

static void __dump_instr(const char *lvl, struct pt_regs *regs)

{

	unsigned long addr = instruction_pointer(regs);

	const int thumb = thumb_mode(regs);

	const int width = thumb ? 4 : 8;

	mm_segment_t fs;

	char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;

	int i;



	/*

	 * We need to switch to kernel mode so that we can use __get_user

	 * to safely read from kernel space.  Note that we now dump the

	 * code first, just in case the backtrace kills us.

	 * Note that we now dump the code first, just in case the backtrace

	 * kills us.

	 */

	fs = get_fs();

	set_fs(KERNEL_DS);



	for (i = -4; i < 1 + !!thumb; i++) {

		unsigned int val, bad;



		if (thumb)

			bad = __get_user(val, &((u16 *)addr)[i]);

			bad = get_user(val, &((u16 *)addr)[i]);

		else

			bad = __get_user(val, &((u32 *)addr)[i]);

			bad = get_user(val, &((u32 *)addr)[i]);



		if (!bad)

			p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
@@ -188,8 +184,20 @@ static void dump_instr(const char *lvl, struct pt_regs *regs) 
		}

	}

	printk("%sCode: %s\n", lvl, str);

}



static void dump_instr(const char *lvl, struct pt_regs *regs)

{

	mm_segment_t fs;



	if (!user_mode(regs)) {

		fs = get_fs();

		set_fs(KERNEL_DS);

		__dump_instr(lvl, regs);

		set_fs(fs);

	} else {

		__dump_instr(lvl, regs);

	}

}



#ifdef CONFIG_ARM_UNWIND