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
Signed-off-by: Don Mullis
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds