Merge branch 'akpm' (patches from Andrew)

Unfortunately the memory available for ISA DMA is scarce so unless you

allocate the memory during boot-up it's a good idea to also pass

__GFP_REPEAT and __GFP_NOWARN to make the allocator try a bit harder.

__GFP_RETRY_MAYFAIL and __GFP_NOWARN to make the allocator try a bit harder.

(This scarcity also means that you should allocate the buffer as

early as possible and not release it until the driver is unloaded.)

	fail_futex=

	mmc_core.fail_request=<interval>,<probability>,<space>,<times>

o proc entries

- /proc/self/task/<current-tid>/fail-nth:

	Write to this file of integer N makes N-th call in the current task fail

	(N is 0-based). Read from this file returns a single char 'Y' or 'N'

	that says if the fault setup with a previous write to this file was

	injected or not, and disables the fault if it wasn't yet injected.

	Note that this file enables all types of faults (slab, futex, etc).

	This setting takes precedence over all other generic debugfs settings

	like probability, interval, times, etc. But per-capability settings

	(e.g. fail_futex/ignore-private) take precedence over it.

	This feature is intended for systematic testing of faults in a single

	system call. See an example below.

How to add new fault injection capability

-----------------------------------------

	# env FAILCMD_TYPE=fail_page_alloc \

		./tools/testing/fault-injection/failcmd.sh --times=100 \

                -- make -C tools/testing/selftests/ run_tests

Systematic faults using fail-nth

---------------------------------

The following code systematically faults 0-th, 1-st, 2-nd and so on

capabilities in the socketpair() system call.

#include <sys/types.h>

#include <sys/stat.h>

#include <sys/socket.h>

#include <sys/syscall.h>

#include <fcntl.h>

#include <unistd.h>

#include <string.h>

#include <stdlib.h>

#include <stdio.h>

#include <errno.h>

int main()

{

	int i, err, res, fail_nth, fds[2];

	char buf[128];

	system("echo N > /sys/kernel/debug/failslab/ignore-gfp-wait");

	sprintf(buf, "/proc/self/task/%ld/fail-nth", syscall(SYS_gettid));

	fail_nth = open(buf, O_RDWR);

	for (i = 0;; i++) {

		sprintf(buf, "%d", i);

		write(fail_nth, buf, strlen(buf));

		res = socketpair(AF_LOCAL, SOCK_STREAM, 0, fds);

		err = errno;

		read(fail_nth, buf, 1);

		if (res == 0) {

			close(fds[0]);

			close(fds[1]);

		}

		printf("%d-th fault %c: res=%d/%d\n", i, buf[0], res, err);

		if (buf[0] != 'Y')

			break;

	}

	return 0;

}

An example output:

0-th fault Y: res=-1/23

1-th fault Y: res=-1/23

2-th fault Y: res=-1/23

3-th fault Y: res=-1/12

4-th fault Y: res=-1/12

5-th fault Y: res=-1/23

6-th fault Y: res=-1/23

7-th fault Y: res=-1/23

8-th fault Y: res=-1/12

9-th fault Y: res=-1/12

10-th fault Y: res=-1/12

11-th fault Y: res=-1/12

12-th fault Y: res=-1/12

13-th fault Y: res=-1/12

14-th fault Y: res=-1/12

15-th fault Y: res=-1/12

16-th fault N: res=0/12

	pos:	0

	flags:	02

	mnt_id:	9

	tfd:        5 events:       1d data: ffffffffffffffff

	tfd:        5 events:       1d data: ffffffffffffffff pos:0 ino:61af sdev:7

	where 'tfd' is a target file descriptor number in decimal form,

	'events' is events mask being watched and the 'data' is data

	associated with a target [see epoll(7) for more details].

	The 'pos' is current offset of the target file in decimal form

	[see lseek(2)], 'ino' and 'sdev' are inode and device numbers

	where target file resides, all in hex format.

	Fsnotify files

	~~~~~~~~~~~~~~

	For inotify files the format is the following

2) Or use the system kernel binary itself as dump-capture kernel and there is

   no need to build a separate dump-capture kernel. This is possible

   only with the architectures which support a relocatable kernel. As

   of today, i386, x86_64, ppc64, ia64 and arm architectures support relocatable

   kernel.

   of today, i386, x86_64, ppc64, ia64, arm and arm64 architectures support

   relocatable kernel.

Building a relocatable kernel is advantageous from the point of view that

one does not have to build a second kernel for capturing the dump. But

For arm64:

	- Use vmlinux or Image

If you are using a uncompressed vmlinux image then use following command

If you are using an uncompressed vmlinux image then use following command

to load dump-capture kernel.

   kexec -p <dump-capture-kernel-vmlinux-image> \

   --dtb=<dtb-for-dump-capture-kernel> \

   --append="root=<root-dev> <arch-specific-options>"

If you are using an uncompressed Image, then use following command

to load dump-capture kernel.

   kexec -p <dump-capture-kernel-Image> \

   --initrd=<initrd-for-dump-capture-kernel> \

   --append="root=<root-dev> <arch-specific-options>"

Please note, that --args-linux does not need to be specified for ia64.

It is planned to make this a no-op on that architecture, but for now

config HAVE_NMI

	bool

config HAVE_NMI_WATCHDOG

	depends on HAVE_NMI

	bool

#

# An arch should select this if it provides all these things:

#

config GENERIC_IDLE_POLL_SETUP

       bool

config ARCH_HAS_FORTIFY_SOURCE

	bool

	help

	  An architecture should select this when it can successfully

	  build and run with CONFIG_FORTIFY_SOURCE.

# Select if arch has all set_memory_ro/rw/x/nx() functions in asm/cacheflush.h

config ARCH_HAS_SET_MEMORY

	bool

	  subsystem.  Also has support for calculating CPU cycle events

	  to determine how many clock cycles in a given period.

config HAVE_HARDLOCKUP_DETECTOR_PERF

	bool

	depends on HAVE_PERF_EVENTS_NMI

	help

	  The arch chooses to use the generic perf-NMI-based hardlockup

	  detector. Must define HAVE_PERF_EVENTS_NMI.

config HAVE_NMI_WATCHDOG

	depends on HAVE_NMI

	bool

	help

	  The arch provides a low level NMI watchdog. It provides

	  asm/nmi.h, and defines its own arch_touch_nmi_watchdog().

config HAVE_HARDLOCKUP_DETECTOR_ARCH

	bool

	select HAVE_NMI_WATCHDOG

	help

	  The arch chooses to provide its own hardlockup detector, which is

	  a superset of the HAVE_NMI_WATCHDOG. It also conforms to config

	  interfaces and parameters provided by hardlockup detector subsystem.

config HAVE_PERF_REGS

	bool

	help