Rewrite existing cpu-notifier-error-inject module to use debugfs based new
framework.

This change removes cpu_up_prepare_error and cpu_down_prepare_error module
parameters which were used to specify error code to be injected.  We could
keep these module parameters for backward compatibility by module_param_cb
but it seems overkill for this module.

This provides the ability to inject artifical errors to CPU notifier chain
callbacks.  It is controlled through debugfs interface under
/sys/kernel/debug/notifier-error-inject/cpu

If the notifier call chain should be failed with some events notified,
write the error code to "actions/<notifier event>/error".

Example1: inject CPU offline error (-1 == -EPERM)

	# cd /sys/kernel/debug/notifier-error-inject/cpu
	# echo -1 > actions/CPU_DOWN_PREPARE/error
	# echo 0 > /sys/devices/system/cpu/cpu1/online
	bash: echo: write error: Operation not permitted

Example2: inject CPU online error (-2 == -ENOENT)

	# cd /sys/kernel/debug/notifier-error-inject/cpu
	# echo -2 > actions/CPU_UP_PREPARE/error
	# echo 1 > /sys/devices/system/cpu/cpu1/online
	bash: echo: write error: No such file or directory
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patchset provides kernel modules that can be used to test the error
handling of notifier call chain failures by injecting artifical errors to
the following notifier chain callbacks.

 * CPU notifier
 * PM notifier
 * memory hotplug notifier
 * powerpc pSeries reconfig notifier

Example: Inject CPU offline error (-1 == -EPERM)

  # cd /sys/kernel/debug/notifier-error-inject/cpu
  # echo -1 > actions/CPU_DOWN_PREPARE/error
  # echo 0 > /sys/devices/system/cpu/cpu1/online
  bash: echo: write error: Operation not permitted

The patchset also adds cpu and memory hotplug tests to
tools/testing/selftests These tests first do simple online and offline
test and then do fault injection tests if notifier error injection
module is available.

This patch:

The notifier error injection provides the ability to inject artifical
errors to specified notifier chain callbacks.  It is useful to test the
error handling of notifier call chain failures.

This adds common basic functions to define which type of events can be
fail and to initialize the debugfs interface to control what error code
should be returned and which event should be failed.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When we restore file descriptors we would like them to look exactly as
they were at dumping time.

With help of fcntl it's almost possible, the missing snippet is file
owners UIDs.

To be able to read their values the F_GETOWNER_UIDS is introduced.

This option is valid iif CONFIG_CHECKPOINT_RESTORE is turned on, otherwise
returning -EINVAL.
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When the requested range is outside of the root range the logic in
__reserve_region_with_split will cause an infinite recursion which will
overflow the stack as seen in the warning bellow.

This particular stack overflow was caused by requesting the
(100000000-107ffffff) range while the root range was (0-ffffffff).  In
this case __request_resource would return the whole root range as
conflict range (i.e.  0-ffffffff).  Then, the logic in
__reserve_region_with_split would continue the recursion requesting the
new range as (conflict->end+1, end) which incidentally in this case
equals the originally requested range.

This patch aborts looking for an usable range when the request does not
intersect with the root range.  When the request partially overlaps with
the root range, it ajust the request to fall in the root range and then
continues with the new request.

When the request is modified or aborted errors and a stack trace are
logged to allow catching the errors in the upper layers.

[    5.968374] WARNING: at kernel/sched.c:4129 sub_preempt_count+0x63/0x89()
[    5.975150] Modules linked in:
[    5.978184] Pid: 1, comm: swapper Not tainted 3.0.22-mid27-00004-gb72c817 #46
[    5.985324] Call Trace:
[    5.987759]  [<c1039dfc>] ? console_unlock+0x17b/0x18d
[    5.992891]  [<c1039620>] warn_slowpath_common+0x48/0x5d
[    5.998194]  [<c1031758>] ? sub_preempt_count+0x63/0x89
[    6.003412]  [<c1039644>] warn_slowpath_null+0xf/0x13
[    6.008453]  [<c1031758>] sub_preempt_count+0x63/0x89
[    6.013499]  [<c14d60c4>] _raw_spin_unlock+0x27/0x3f
[    6.018453]  [<c10c6349>] add_partial+0x36/0x3b
[    6.022973]  [<c10c7c0a>] deactivate_slab+0x96/0xb4
[    6.027842]  [<c14cf9d9>] __slab_alloc.isra.54.constprop.63+0x204/0x241
[    6.034456]  [<c103f78f>] ? kzalloc.constprop.5+0x29/0x38
[    6.039842]  [<c103f78f>] ? kzalloc.constprop.5+0x29/0x38
[    6.045232]  [<c10c7dc9>] kmem_cache_alloc_trace+0x51/0xb0
[    6.050710]  [<c103f78f>] ? kzalloc.constprop.5+0x29/0x38
[    6.056100]  [<c103f78f>] kzalloc.constprop.5+0x29/0x38
[    6.061320]  [<c17b45e9>] __reserve_region_with_split+0x1c/0xd1
[    6.067230]  [<c17b4693>] __reserve_region_with_split+0xc6/0xd1
...
[    7.179057]  [<c17b4693>] __reserve_region_with_split+0xc6/0xd1
[    7.184970]  [<c17b4779>] reserve_region_with_split+0x30/0x42
[    7.190709]  [<c17a8ebf>] e820_reserve_resources_late+0xd1/0xe9
[    7.196623]  [<c17c9526>] pcibios_resource_survey+0x23/0x2a
[    7.202184]  [<c17cad8a>] pcibios_init+0x23/0x35
[    7.206789]  [<c17ca574>] pci_subsys_init+0x3f/0x44
[    7.211659]  [<c1002088>] do_one_initcall+0x72/0x122
[    7.216615]  [<c17ca535>] ? pci_legacy_init+0x3d/0x3d
[    7.221659]  [<c17a27ff>] kernel_init+0xa6/0x118
[    7.226265]  [<c17a2759>] ? start_kernel+0x334/0x334
[    7.231223]  [<c14d7482>] kernel_thread_helper+0x6/0x10
Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com>
Signed-off-by: NRam Pai <linuxram@us.ibm.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Convert init_sync_kiocb() from a nasty macro into a nice C function.  The
struct assignment trick takes care of zeroing all unmentioned fields.
Shrinks fs/read_write.o's .text from 9857 bytes to 9714.

Also demacroize is_sync_kiocb() and aio_ring_avail().  The latter fixes an
arg-referenced-multiple-times hand grenade.

Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Acked-by: NJeff Moyer <jmoyer@redhat.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Support the caching of large files.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=31182Signed-off-by: NJustin Lecher <jlec@gentoo.org>
Signed-off-by: NSuresh Jayaraman <sjayaraman@suse.com>
Tested-by: NSuresh Jayaraman <sjayaraman@suse.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We should return PTR_ERR if the call to the device_create function fails.
Without this patch we instead return the value from a successful call to
cdev_add if the call to device_create fails.
Signed-off-by: NEmil Goode <emilgoode@gmail.com>
Acked-by: NDevendra Naga <devendra.aaru@gmail.com>
Cc: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Cc: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=44621

Reported-by: <rucsoftsec@gmail.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

register_sysctl_table() is a strange function, as it makes internal
allocations (a header) to register a sysctl_table.  This header is a
handle to the table that is created, and can be used to unregister the
table.  But if the table is permanent and never unregistered, the header
acts the same as a static variable.

Unfortunately, this allocation of memory that is never expected to be
freed fools kmemleak in thinking that we have leaked memory.  For those
sysctl tables that are never unregistered, and have no pointer referencing
them, kmemleak will think that these are memory leaks:

unreferenced object 0xffff880079fb9d40 (size 192):
  comm "swapper/0", pid 0, jiffies 4294667316 (age 12614.152s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8146b590>] kmemleak_alloc+0x73/0x98
    [<ffffffff8110a935>] kmemleak_alloc_recursive.constprop.42+0x16/0x18
    [<ffffffff8110b852>] __kmalloc+0x107/0x153
    [<ffffffff8116fa72>] kzalloc.constprop.8+0xe/0x10
    [<ffffffff811703c9>] __register_sysctl_paths+0xe1/0x160
    [<ffffffff81170463>] register_sysctl_paths+0x1b/0x1d
    [<ffffffff8117047d>] register_sysctl_table+0x18/0x1a
    [<ffffffff81afb0a1>] sysctl_init+0x10/0x14
    [<ffffffff81b05a6f>] proc_sys_init+0x2f/0x31
    [<ffffffff81b0584c>] proc_root_init+0xa5/0xa7
    [<ffffffff81ae5b7e>] start_kernel+0x3d0/0x40a
    [<ffffffff81ae52a7>] x86_64_start_reservations+0xae/0xb2
    [<ffffffff81ae53ad>] x86_64_start_kernel+0x102/0x111
    [<ffffffffffffffff>] 0xffffffffffffffff

The sysctl_base_table used by sysctl itself is one such instance that
registers the table to never be unregistered.

Use kmemleak_not_leak() to suppress the kmemleak false positive.
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Rather than #define the options manually in the architecture code, add
Kconfig options for them and select them there instead.  This also allows
us to select the compat IPC version parsing automatically for platforms
using the old compat IPC interface.
Reported-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The msgsnd and msgrcv system calls use size_t to represent the size of the
message being transferred.  POSIX states that values of msgsz greater than
SSIZE_MAX cause the result to be implementation-defined.  On Linux, this
equates to returning -EINVAL if (long) msgsz < 0.

For compat tasks where !CONFIG_ARCH_WANT_OLD_COMPAT_IPC and compat_size_t
is smaller than size_t, negative size values passed from userspace will be
interpreted as positive values by do_msg{rcv,snd} and will fail to exit
early with -EINVAL.

This patch changes the compat prototypes for msg{rcv,snd} so that the
message size is represented as a compat_ssize_t, which we cast to the
native ssize_t type for the core IPC code.

Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: NChris Metcalf <cmetcalf@tilera.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 48b25c43 ("ipc: provide generic compat versions of IPC
syscalls") added a new ARCH_WANT_OLD_COMPAT_IPC config option for
architectures to select if their compat target requires the old IPC
syscall interface.

For architectures (such as AArch64) that do not require the internal
calling conventions provided by this option, but have a compat target
where the C library passes the IPC_64 flag explicitly,
compat_ipc_parse_version no longer strips out the flag before calling
the native system call implementation, resulting in unknown SHM/IPC
commands and -EINVAL being returned to userspace.

This patch separates the selection of the internal calling conventions
for the IPC syscalls from the version parsing, allowing architectures to
select __ARCH_WANT_COMPAT_IPC_PARSE_VERSION if they want to use version
parsing whilst retaining the newer syscall calling conventions.
Acked-by: NChris Metcalf <cmetcalf@tilera.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the SHMLBA definition for a native task differs from the definition for
a compat task, the do_shmat() function would need to handle both.

This patch introduces COMPAT_SHMLBA, which is used by the compat shmat
syscall when calling the ipc code and allows architectures such as AArch64
(where the native SHMLBA is 64k but the compat (AArch32) definition is
16k) to provide the correct semantics for compat IPC system calls.

Cc: David S. Miller <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The last line of vmcoreinfo note does not end with \n.  Parsing all the
lines in note becomes easier if all lines end with \n instead of trying to
special case the last line.

I know at least one tool, vmcore-dmesg in kexec-tools tree which made the
assumption that all lines end with \n.  I think it is a good idea to fix
it.
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The function dup_task() may fail at the following function calls in the
following order.

0) alloc_task_struct_node()
1) alloc_thread_info_node()
2) arch_dup_task_struct()

Error by 0) is not a matter, it can just return.  But error by 1) requires
releasing task_struct allocated by 0) before it returns.  Likewise, error
by 2) requires releasing task_struct and thread_info allocated by 0) and
1).

The existing error handling calls free_task_struct() and
free_thread_info() which do not only release task_struct and thread_info,
but also call architecture specific arch_release_task_struct() and
arch_release_thread_info().

The problem is that task_struct and thread_info are not fully initialized
yet at this point, but arch_release_task_struct() and
arch_release_thread_info() are called with them.

For example, x86 defines its own arch_release_task_struct() that releases
a task_xstate.  If alloc_thread_info_node() fails in dup_task(),
arch_release_task_struct() is called with task_struct which is just
allocated and filled with garbage in this error handling.

This actually happened with tools/testing/fault-injection/failcmd.sh

	# env FAILCMD_TYPE=fail_page_alloc \
		./tools/testing/fault-injection/failcmd.sh --times=100 \
		--min-order=0 --ignore-gfp-wait=0 \
		-- make -C tools/testing/selftests/ run_tests

In order to fix this issue, make free_{task_struct,thread_info}() not to
call arch_release_{task_struct,thread_info}() and call
arch_release_{task_struct,thread_info}() implicitly where needed.

Default arch_release_task_struct() and arch_release_thread_info() are
defined as empty by default.  So this change only affects the
architectures which implement their own arch_release_task_struct() or
arch_release_thread_info() as listed below.

arch_release_task_struct(): x86, sh
arch_release_thread_info(): mn10300, tile
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Salman Qazi <sqazi@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

To make way for "fork: fix error handling in dup_task()", which fixes the
errors more completely.

Cc: Salman Qazi <sqazi@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current code can be replaced by vma_pages().  So use it to simplify
the code.

[akpm@linux-foundation.org: initialise `len' at its definition site]
Signed-off-by: NHuang Shijie <shijie8@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__mem_open() which is called by both /proc/<pid>/environ and
/proc/<pid>/mem ->open() handlers will allow the use of negative offsets.
/proc/<pid>/mem has negative offsets but not /proc/<pid>/environ.

Clean this by moving the 'force FMODE_UNSIGNED_OFFSET flag' to mem_open()
to allow negative offsets only on /proc/<pid>/mem.
Signed-off-by: NDjalal Harouni <tixxdz@opendz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Brad Spengler <spender@grsecurity.net>
Acked-by: NKees Cook <keescook@chromium.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently the following offset and environment address range check in
environ_read() of /proc/<pid>/environ is buggy:

  int this_len = mm->env_end - (mm->env_start + src);
  if (this_len <= 0)
    break;

Large or negative offsets on /proc/<pid>/environ converted to 'unsigned
long' may pass this check since '(mm->env_start + src)' can overflow and
'this_len' will be positive.

This can turn /proc/<pid>/environ to act like /proc/<pid>/mem since
(mm->env_start + src) will point and read from another VMA.

There are two fixes here plus some code cleaning:

1) Fix the overflow by checking if the offset that was converted to
   unsigned long will always point to the [mm->env_start, mm->env_end]
   address range.

2) Remove the truncation that was made to the result of the check,
   storing the result in 'int this_len' will alter its value and we can
   not depend on it.

For kernels that have commit b409e578 ("proc: clean up
/proc/<pid>/environ handling") which adds the appropriate ptrace check and
saves the 'mm' at ->open() time, this is not a security issue.

This patch is taken from the grsecurity patch since it was just made
available.
Signed-off-by: NDjalal Harouni <tixxdz@opendz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Brad Spengler <spender@grsecurity.net>
Acked-by: NKees Cook <keescook@chromium.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In commit 898b374a ("exec: replace call_usermodehelper_pipe with use
of umh init function and resolve limit"), the core limits recursive
check value was changed from 0 to 1, but the corresponding comments were
not updated.
Signed-off-by: NJovi Zhang <bookjovi@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The system deadlocks (at least since 2.6.10) when
call_usermodehelper(UMH_WAIT_EXEC) request triggers
call_usermodehelper(UMH_WAIT_PROC) request.

This is because "khelper thread is waiting for the worker thread at
wait_for_completion() in do_fork() since the worker thread was created
with CLONE_VFORK flag" and "the worker thread cannot call complete()
because do_execve() is blocked at UMH_WAIT_PROC request" and "the khelper
thread cannot start processing UMH_WAIT_PROC request because the khelper
thread is waiting for the worker thread at wait_for_completion() in
do_fork()".

The easiest example to observe this deadlock is to use a corrupted
/sbin/hotplug binary (like shown below).

  # : > /tmp/dummy
  # chmod 755 /tmp/dummy
  # echo /tmp/dummy > /proc/sys/kernel/hotplug
  # modprobe whatever

call_usermodehelper("/tmp/dummy", UMH_WAIT_EXEC) is called from
kobject_uevent_env() in lib/kobject_uevent.c upon loading/unloading a
module.  do_execve("/tmp/dummy") triggers a call to
request_module("binfmt-0000") from search_binary_handler() which in turn
calls call_usermodehelper(UMH_WAIT_PROC).

In order to avoid deadlock, as a for-now and easy-to-backport solution, do
not try to call wait_for_completion() in call_usermodehelper_exec() if the
worker thread was created by khelper thread with CLONE_VFORK flag.  Future
and fundamental solution might be replacing singleton khelper thread with
some workqueue so that recursive calls up to max_active dependency loop
can be handled without deadlock.

[akpm@linux-foundation.org: add comment to kmod_thread_locker]
Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This function's interface is, uh, subtle.  Attempt to apologise for it.

Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Nearly identical shortname parsing is performed in fat_search_long() and
__fat_readdir().  Extract this code into a function that may be called by
both.
Signed-off-by: NSteven J. Magnani <steve@digidescorp.com>
Acked-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Simplify code by providing accessor functions for the directory entry
start cluster fields.
Signed-off-by: NSteven J. Magnani <steve@digidescorp.com>
Acked-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use -ENOMEM return value instead of -EINVAL when kzalloc() fails.
Signed-off-by: NNamjae Jeon <linkinjeon@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add omitted comments for different structures in driver implementation.
Signed-off-by: NVyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add omitted comments for structures in nilfs2_fs.h.
Signed-off-by: NVyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

An fs-thaw ioctl causes deadlock with a chcp or mkcp -s command:

 chcp            D ffff88013870f3d0     0  1325   1324 0x00000004
 ...
 Call Trace:
   nilfs_transaction_begin+0x11c/0x1a0 [nilfs2]
   wake_up_bit+0x20/0x20
   copy_from_user+0x18/0x30 [nilfs2]
   nilfs_ioctl_change_cpmode+0x7d/0xcf [nilfs2]
   nilfs_ioctl+0x252/0x61a [nilfs2]
   do_page_fault+0x311/0x34c
   get_unmapped_area+0x132/0x14e
   do_vfs_ioctl+0x44b/0x490
   __set_task_blocked+0x5a/0x61
   vm_mmap_pgoff+0x76/0x87
   __set_current_blocked+0x30/0x4a
   sys_ioctl+0x4b/0x6f
   system_call_fastpath+0x16/0x1b
 thaw            D ffff88013870d890     0  1352   1351 0x00000004
 ...
 Call Trace:
   rwsem_down_failed_common+0xdb/0x10f
   call_rwsem_down_write_failed+0x13/0x20
   down_write+0x25/0x27
   thaw_super+0x13/0x9e
   do_vfs_ioctl+0x1f5/0x490
   vm_mmap_pgoff+0x76/0x87
   sys_ioctl+0x4b/0x6f
   filp_close+0x64/0x6c
   system_call_fastpath+0x16/0x1b

where the thaw ioctl deadlocked at thaw_super() when called while chcp was
waiting at nilfs_transaction_begin() called from
nilfs_ioctl_change_cpmode().  This deadlock is 100% reproducible.

This is because nilfs_ioctl_change_cpmode() first locks sb->s_umount in
read mode and then waits for unfreezing in nilfs_transaction_begin(),
whereas thaw_super() locks sb->s_umount in write mode.  The locking of
sb->s_umount here was intended to make snapshot mounts and the downgrade
of snapshots to checkpoints exclusive.

This fixes the deadlock issue by replacing the sb->s_umount usage in
nilfs_ioctl_change_cpmode() with a dedicated mutex which protects snapshot
mounts.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Tested-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The checkpoint deletion ioctl (rmcp ioctl) has potential for breaking
snapshot because it is not fully exclusive with checkpoint mode change
ioctl (chcp ioctl).

The rmcp ioctl first tests if the specified checkpoint is a snapshot or
not within nilfs_cpfile_delete_checkpoint function, and then calls
nilfs_cpfile_delete_checkpoints function to actually invalidate the
checkpoint only if it's not a snapshot.  However, the checkpoint can be
changed into a snapshot by the chcp ioctl between these two operations.
In that case, calling nilfs_cpfile_delete_checkpoints() wrongly
invalidates the snapshot, which leads to snapshot list corruption and
snapshot count mismatch.

This fixes the issue by changing nilfs_cpfile_delete_checkpoints() so
that it reconfirms the target checkpoints are snapshot or not.

This second check is exclusive with the chcp operation since it is
protected by an existing semaphore.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

->delete_inode(), ->write_super_lockfs(), ->unlockfs() are gone so remove
references to them in the NTFS code.  Noticed while cleaning up the
fsfreeze mess.
Signed-off-by: NFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add omitted comment for ns_mount_state field of the_nilfs structure.
Signed-off-by: NVyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

On minix2 and minix3 usually max_size is 7fffffff and the check in
question prohibits creation of last block spanning right before 7fffffff,
due to downward rounding during the division.  Fix it by using
multiplication instead.

[akpm@linux-foundation.org: fix up code layout, use local `sb']
Signed-off-by: NVladimir Serbinenko <phcoder@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Set the of_match_table for this driver so that devices can be described
in the device tree.
Signed-off-by: NNick Bowler <nbowler@elliptictech.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The owner member is supposed to be set to the module implementing the
device driver, i.e., THIS_MODULE.  This enables the appropriate module
link in sysfs.
Signed-off-by: NNick Bowler <nbowler@elliptictech.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Freeing will trigger when driver unloads, so using devm_kfree() is not
needed.
Signed-off-by: NDevendra Naga <devendra.aaru@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Ashish Jangam <ashish.jangam@kpitcummins.com>
Cc: David Dajun Chen <dchen@diasemi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This allows automatic driver loading for all supported device types.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fixes the following checkpatch warnings:

  WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
  WARNING: Use #include <linux/io.h> instead of <asm/io.h>
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When the driver detects that the clock time is invalid, it attempts to
write a sane time into the hardware.  We curently assume that everything
is OK if those writes succeeded.  But it is better to re-read the time
from the hardware to ensure that the new settings got there OK.

Cc: Devendra Naga <devendra.aaru@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: Andreas Dumberger <andreas.dumberger@tqs.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

r9701_get_datetime() calls rtc_valid_tm() and returns the value returned
by rtc_valid_tm(), which can be used in the `if', so calling
rtc_valid_tm() a second time is not required.
Signed-off-by: NDevendra Naga <devendra.aaru@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Anatolij Gustschin <agust@denx.de>
Cc: Andreas Dumberger <andreas.dumberger@tqs.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>