Commit 4cc6028d authored by Jiri Kosina's avatar Jiri Kosina Committed by Ingo Molnar

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.
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 2d684cd6
......@@ -245,7 +245,7 @@ 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;
/*
......
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