From: Jiri Kosina <[EMAIL PROTECTED]> brk: check the lower bound properly
There is a check in sys_brk(), that tries to make sure that we do not underflow the area that is dedicated to brk heap. The check is however wrong, as it assumes that brk area starts immediately after the end of the code (+bss), which is wrong for example in environments with randomized brk start. The proper way is to check whether the address is not below the start_brk address. Cc: Ingo Molnar <[EMAIL PROTECTED]> Cc: Arjan van de Ven <[EMAIL PROTECTED]> Acked-by: Hugh Dickins <[EMAIL PROTECTED]> Acked-by: Pavel Machek <[EMAIL PROTECTED]> Signed-off-by: Jiri Kosina <[EMAIL PROTECTED]> diff --git a/mm/mmap.c b/mm/mmap.c index 8295577..1c3b48f 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -241,7 +241,7 @@ asmlinkage unsigned long sys_brk(unsigned long brk) down_write(&mm->mmap_sem); - if (brk < mm->end_code) + if (brk < mm->start_brk) goto out; /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/