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-rw-r--r--Documentation/sysctl/kernel.txt22
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index b3d8b492274..a028b92001e 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -22,6 +22,7 @@ show up in /proc/sys/kernel:
- callhome [ S390 only ]
- auto_msgmni
- core_pattern
+- core_pipe_limit
- core_uses_pid
- ctrl-alt-del
- dentry-state
@@ -135,6 +136,27 @@ core_pattern is used to specify a core dumpfile pattern name.
==============================================================
+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