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authorJiri Kosina <jkosina@suse.cz>2008-06-06 18:43:23 +0000
committerChris Wright <chrisw@sous-sol.org>2008-06-09 11:27:05 -0700
commit921b0dbeeecd12729b49c0e9db1b70f5da1b20d3 (patch)
tree8a7432d0bafe3ab2069012bf316a2d580b39ad4e
parent3dac273cad59097a8ab335958a7c5904f0a99d65 (diff)
downloadlinux-linaro-stable-921b0dbeeecd12729b49c0e9db1b70f5da1b20d3.tar.gz
brk: make sys_brk() honor COMPAT_BRK when computing lower bound
upstream commit: a5b4592cf77b973c29e7c9695873a26052b58951 Fix a regression introduced by commit 4cc6028d4040f95cdb590a87db478b42b8be0508 Author: Jiri Kosina <jkosina@suse.cz> Date: Wed Feb 6 22:39:44 2008 +0100 brk: check the 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> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
-rw-r--r--mm/mmap.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index a32d28ce31cd..96bdd73db08b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -242,10 +242,16 @@ 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;
/*