Commit:     1ec7fd50ba4f845d1cf6b67acabd774577ef13b6
Parent:     6697c05296fab4d113c7144459b72b6172b485a5
Author:     Jiri Kosina <[EMAIL PROTECTED]>
AuthorDate: Sat Feb 9 23:24:08 2008 +0100
Committer:  Thomas Gleixner <[EMAIL PROTECTED]>
CommitDate: Sat Feb 9 23:24:08 2008 +0100

    brk: document randomize_va_space and CONFIG_COMPAT_BRK (was Re:
    Document randomize_va_space and CONFIG_COMPAT_BRK.
    Signed-off-by: Jiri Kosina <[EMAIL PROTECTED]>
    Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
    Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
 Documentation/sysctl/kernel.txt |   29 +++++++++++++++++++++++++++++
 1 files changed, 29 insertions(+), 0 deletions(-)

diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 8984a53..dc8801d 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -41,6 +41,7 @@ show up in /proc/sys/kernel:
 - pid_max
 - powersave-nap               [ PPC only ]
 - printk
+- randomize_va_space
 - real-root-dev               ==> Documentation/initrd.txt
 - reboot-cmd                  [ SPARC only ]
 - rtsig-max
@@ -280,6 +281,34 @@ send before ratelimiting kicks in.
+This option can be used to select the type of process address
+space randomization that is used in the system, for architectures
+that support this feature.
+0 - Turn the process address space randomization off by default.
+1 - Make the addresses of mmap base, stack and VDSO page randomized.
+    This, among other things, implies that shared libraries will be
+    loaded to random addresses. Also for PIE-linked binaries, the location
+    of code start is randomized.
+    With heap randomization, the situation is a little bit more
+    complicated.
+    There a few legacy applications out there (such as some ancient
+    versions of from 1996) that assume that brk area starts
+    just after the end of the code+bss. These applications break when
+    start of the brk area is randomized. There are however no known
+    non-legacy applications that would be broken this way, so for most
+    systems it is safe to choose full randomization. However there is
+    a CONFIG_COMPAT_BRK option for systems with ancient and/or broken
+    binaries, that makes heap non-randomized, but keeps all other
+    parts of process address space randomized if randomize_va_space
+    sysctl is turned on.
 reboot-cmd: (Sparc only)
 ??? This seems to be a way to give an argument to the Sparc
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