2 files changed, 9 insertions, 3 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e2202e93b148..21a99474df93 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -784,8 +784,12 @@ and is between 256 and 4096 characters. It is defined in the file
                         as early as possible in order to facilitate early
                         boot debugging.
 
-        ftrace_dump_on_oops
+        ftrace_dump_on_oops[=orig_cpu]
                         [FTRACE] will dump the trace buffers on oops.
+                        If no parameter is passed, ftrace will dump
+                        buffers of all CPUs, but if you pass orig_cpu, it will
+                        dump only the buffer of the CPU that triggered the
+                        oops.
 
         ftrace_filter=[function-list]
                         [FTRACE] Limit the functions traced by the function
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index 03485bfbd797..52011815c905 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -1337,12 +1337,14 @@ ftrace_dump_on_oops must be set. To set ftrace_dump_on_oops, one
 can either use the sysctl function or set it via the proc system
 interface.
 
-  sysctl kernel.ftrace_dump_on_oops=1
+  sysctl kernel.ftrace_dump_on_oops=n
 
 or
 
-  echo 1 > /proc/sys/kernel/ftrace_dump_on_oops
+  echo n > /proc/sys/kernel/ftrace_dump_on_oops
 
+If n = 1, ftrace will dump buffers of all CPUs, if n = 2 ftrace will
+only dump the buffer of the CPU that triggered the oops.
 
 Here's an example of such a dump after a null pointer
 dereference in a kernel module: