- callhome [ S390 only ]
- auto_msgmni
- core_pattern
+- core_pipe_limit
- core_uses_pid
- ctrl-alt-del
- dentry-state
==============================================================
+core_pipe_limit:
+
+This sysctl is only applicable when core_pattern is configured to pipe core
+files to user space helper a (when the first character of core_pattern is a '|',
+see above). When collecting cores via a pipe to an application, it is
+occasionally usefull for the collecting application to gather data about the
+crashing process from its /proc/pid directory. In order to do this safely, the
+kernel must wait for the collecting process to exit, so as not to remove the
+crashing processes proc files prematurely. This in turn creates the possibility
+that a misbehaving userspace collecting process can block the reaping of a
+crashed process simply by never exiting. This sysctl defends against that. It
+defines how many concurrent crashing processes may be piped to user space
+applications in parallel. If this value is exceeded, then those crashing
+processes above that value are noted via the kernel log and their cores are
+skipped. 0 is a special value, indicating that unlimited processes may be
+captured in parallel, but that no waiting will take place (i.e. the collecting
+process is not guaranteed access to /proc/<crahing pid>/). This value defaults
+to 0.
+
+==============================================================
+
core_uses_pid:
The default coredump filename is "core". By setting
==============================================================
+printk_delay:
+
+Delay each printk message in printk_delay milliseconds
+
+Value from 0 - 10000 is allowed.
+
+==============================================================
+
randomize-va-space:
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.
+0 - Turn the process address space randomization off. This is the
+ default for architectures that do not support this feature anyways,
+ and kernels that are booted with the "norandmaps" parameter.
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.
+ loaded to random addresses. Also for PIE-linked binaries, the
+ location of code start is randomized. This is the default if the
+ CONFIG_COMPAT_BRK option is enabled.
- With heap randomization, the situation is a little bit more
- complicated.
- There a few legacy applications out there (such as some ancient
+2 - Additionally enable heap randomization. This is the default if
+ CONFIG_COMPAT_BRK is disabled.
+
+ There are a few legacy applications out there (such as some ancient
versions of libc.so.5 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
+ 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.
+ systems it is safe to choose full randomization.
+
+ Systems with ancient and/or broken binaries should be configured
+ with CONFIG_COMPAT_BRK enabled, which excludes the heap from process
+ address space randomization.
==============================================================
git.openpandora.org / pandora-kernel.git / blobdiff