Hmm, libc5 is known to make broken assumptions about brk location, that's
why we introduced CONFIG_COMPAT_BRK, do you have that option turned on?
Indeed, this should take CONFIG_COMPAT_BRK into account. Does the patch
below fix it? (assuming that you have CONFIG_COMPAT_BRK=y):
From: Jiri Kosina <jkosina@suse.cz>
brk: check lower bound properly
The check in sys_brk() on minimum value the brk might have must take
CONFIG_COMPAT_BRK setting into account. When this option is turned on
(i.e. we support ancient legacy binaries, e.g. libc5-linked stuff), the
lower bound on brk value is mm->end_code, otherwise the brk start is
allowed to be arbitrarily shifted.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/mm/mmap.c b/mm/mmap.c
index fac6633..834118b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -245,10 +245,16 @@ asmlinkage unsigned long sys_brk(unsigned long brk)
unsigned long rlim, retval;
unsigned long newbrk, oldbrk;
struct mm_struct *mm = current->mm;
+ unsigned long min_brk;
down_write(&mm->mmap_sem);
- if (brk < mm->start_brk)
+#ifdef CONFIG_COMPAT_BRK
+ min_brk = mm->end_code;
+#else
+ min_brk = mm->start_brk;
+#endif
+ if (brk < min_brk)
goto out;
/*
--
