From: Andrey Ryabinin a.ryabinin@samsung.com
Commit 537094b64b229bf3ad146042f83e74cf6abe59df upstream.
According to arm procedure call standart r2 register is call-cloberred. So after the result of x expression was put into r2 any following function call in p may overwrite r2. To fix this, the result of p expression must be saved to the temporary variable before the assigment x expression to __r2.
Signed-off-by: Andrey Ryabinin a.ryabinin@samsung.com Reviewed-by: Nicolas Pitre nico@linaro.org Cc: stable@vger.kernel.org Signed-off-by: Russell King rmk+kernel@arm.linux.org.uk Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm/include/asm/uaccess.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -251,7 +251,7 @@ extern int __put_user_8(void *, unsigned ({ \ unsigned long __limit = current_thread_info()->addr_limit - 1; \ const typeof(*(p)) __user *__tmp_p = (p); \ - register typeof(*(p)) __r2 asm("r2") = (x); \ + register const typeof(*(p)) __r2 asm("r2") = (x); \ register const typeof(*(p)) __user *__p asm("r0") = __tmp_p; \ register unsigned long __l asm("r1") = __limit; \ register int __e asm("r0"); \