[PATCH] fault injection: documentation and scripts

This patch set provides some fault-injection capabilities.

- kmalloc() failures

- alloc_pages() failures

- disk IO errors

We can see what really happens if those failures happen.

In order to enable these fault-injection capabilities:

1. Enable relevant config options (CONFIG_FAILSLAB, CONFIG_PAGE_ALLOC,
   CONFIG_MAKE_REQUEST) and if you want to configure them via debugfs,
   enable CONFIG_FAULT_INJECTION_DEBUG_FS.

2. Build and boot with this kernel

3. Configure fault-injection capabilities behavior by boot option or debugfs

   - Boot option

     failslab=
     fail_page_alloc=
     fail_make_request=

   - Debugfs

     /debug/failslab/*
     /debug/fail_page_alloc/*
     /debug/fail_make_request/*

   Please refer to the Documentation/fault-injection/fault-injection.txt
   for details.

4. See what really happens.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Don Mullis <dwm@meer.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index b79bcdf16319..d8323b8893c3 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -548,6 +548,13 @@ and is between 256 and 4096 characters. It is defined in the file
 	eurwdt=		[HW,WDT] Eurotech CPU-1220/1410 onboard watchdog.
 			Format: <io>[,<irq>]
 
+	failslab=
+	fail_page_alloc=
+	fail_make_request=[KNL]
+			General fault injection mechanism.
+			Format: <interval>,<probability>,<space>,<times>
+			See also /Documentation/fault-injection/.
+
 	fd_mcs=		[HW,SCSI]
 			See header of drivers/scsi/fd_mcs.c.