> KOSAKI Motohiro wrote: > > > fs/binfmt_elf.c: > > > 77 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE) > > Can do_brk() return BAD_ADDR() _and_ !IS_ERR_VALUE() value? when? > > For example, arch/mips/include/asm/processor.h has below definitions > which is smaller than INT_MAX > > 47 #ifdef CONFIG_32BIT > (...snipped...) > 52 #define TASK_SIZE 0x7fff8000UL > (...snipped...) > 63 #endif > 64 > 65 #ifdef CONFIG_64BIT > (...snipped...) > 74 #define TASK_SIZE 0x10000000000UL > (...snipped...) > 91 #endif > > Also, several architectures define TASK_SIZE as > > #define TASK_SIZE PAGE_OFFSET > > and PAGE_OFFSET could be 0 if CONFIG_KERNEL_RAM_BASE_ADDRESS is not defined. > > include/asm-generic/page.h > 68 #ifdef CONFIG_KERNEL_RAM_BASE_ADDRESS > 69 #define PAGE_OFFSET (CONFIG_KERNEL_RAM_BASE_ADDRESS) > 70 #else > 71 #define PAGE_OFFSET (0) > 72 #endif > > If TASK_SIZE == 0, BAD_ADDR(x) is always true and !IS_ERR_VALUE(x) can be true. > Although I don't know which combination makes such environment, > I think "BAD_ADDR() _and_ !IS_ERR_VALUE()" can happen. I think you should read do_brk() itself. the spec is success case: return addr argument error case: return error code When does it return invalid address? -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
