There is a race condition between nilfs_dirty_inode() and
nilfs_set_file_dirty().

When a file is opened, nilfs_dirty_inode() is called to update the
access timestamp in the inode.  It calls __nilfs_mark_inode_dirty() in a
separate transaction.  __nilfs_mark_inode_dirty() caches the ifile
buffer_head in the i_bh field of the inode info structure and marks it
as dirty.

After some data was written to the file in another transaction, the
function nilfs_set_file_dirty() is called, which adds the inode to the
ns_dirty_files list.

Then the segment construction calls nilfs_segctor_collect_dirty_files(),
which goes through the ns_dirty_files list and checks the i_bh field.
If there is a cached buffer_head in i_bh it is not marked as dirty
again.

Since nilfs_dirty_inode() and nilfs_set_file_dirty() use separate
transactions, it is possible that a segment construction that writes out
the ifile occurs in-between the two.  If this happens the inode is not
on the ns_dirty_files list, but its ifile block is still marked as dirty
and written out.

In the next segment construction, the data for the file is written out
and nilfs_bmap_propagate() updates the b-tree.  Eventually the bmap root
is written into the i_bh block, which is not dirty, because it was
written out in another segment construction.

As a result the bmap update can be lost, which leads to file system
corruption.  Either the virtual block address points to an unallocated
DAT block, or the DAT entry will be reused for something different.

The error can remain undetected for a long time.  A typical error
message would be one of the "bad btree" errors or a warning that a DAT
entry could not be found.

This bug can be reproduced reliably by a simple benchmark that creates
and overwrites millions of 4k files.

Link: http://lkml.kernel.org/r/1509367935-3086-2-git-send-email-konishi.ryusuke@lab.ntt.co.jpSigned-off-by: NAndreas Rohner <andreas.rohner@gmx.net>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: NAndreas Rohner <andreas.rohner@gmx.net>
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>

In preparation for unconditionally passing the struct timer_list pointer
to all timer callbacks, switch to using the new timer_setup() and
from_timer() to pass the timer pointer explicitly.  This requires adding
a pointer to hold the timer's target task, as the lifetime of sc_task
doesn't appear to match the timer's task.

Link: http://lkml.kernel.org/r/20171016235900.GA102729@beastSigned-off-by: NKees Cook <keescook@chromium.org>
Acked-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>

Mikulas noticed in the existing do_proc_douintvec_minmax_conv() and
do_proc_dopipe_max_size_conv() introduced in this patchset, that they
inconsistently handle overflow and min/max range inputs:

For example:

  0 ... param->min - 1 ---> ERANGE
  param->min ... param->max ---> the value is accepted
  param->max + 1 ... 0x100000000L + param->min - 1 ---> ERANGE
  0x100000000L + param->min ... 0x100000000L + param->max ---> EINVAL
  0x100000000L + param->max + 1, 0x200000000L + param->min - 1 ---> ERANGE
  0x200000000L + param->min ... 0x200000000L + param->max ---> EINVAL
  0x200000000L + param->max + 1, 0x300000000L + param->min - 1 ---> ERANGE

In do_proc_do*() routines which store values into unsigned int variables
(4 bytes wide for 64-bit builds), first validate that the input unsigned
long value (8 bytes wide for 64-bit builds) will fit inside the smaller
unsigned int variable.  Then check that the unsigned int value falls
inside the specified parameter min, max range.  Otherwise the unsigned
long -> unsigned int conversion drops leading bits from the input value,
leading to the inconsistent pattern Mikulas documented above.

Link: http://lkml.kernel.org/r/1507658689-11669-5-git-send-email-joe.lawrence@redhat.comSigned-off-by: NJoe Lawrence <joe.lawrence@redhat.com>
Reported-by: NMikulas Patocka <mpatocka@redhat.com>
Reviewed-by: NMikulas Patocka <mpatocka@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

pipe_max_size is assigned directly via procfs sysctl:

  static struct ctl_table fs_table[] = {
          ...
          {
                  .procname       = "pipe-max-size",
                  .data           = &pipe_max_size,
                  .maxlen         = sizeof(int),
                  .mode           = 0644,
                  .proc_handler   = &pipe_proc_fn,
                  .extra1         = &pipe_min_size,
          },
          ...

  int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf,
                   size_t *lenp, loff_t *ppos)
  {
          ...
          ret = proc_dointvec_minmax(table, write, buf, lenp, ppos)
          ...

and then later rounded in-place a few statements later:

          ...
          pipe_max_size = round_pipe_size(pipe_max_size);
          ...

This leaves a window of time between initial assignment and rounding
that may be visible to other threads.  (For example, one thread sets a
non-rounded value to pipe_max_size while another reads its value.)

Similar reads of pipe_max_size are potentially racy:

  pipe.c :: alloc_pipe_info()
  pipe.c :: pipe_set_size()

Add a new proc_dopipe_max_size() that consolidates reading the new value
from the user buffer, verifying bounds, and calling round_pipe_size()
with a single assignment to pipe_max_size.

Link: http://lkml.kernel.org/r/1507658689-11669-4-git-send-email-joe.lawrence@redhat.comSigned-off-by: NJoe Lawrence <joe.lawrence@redhat.com>
Reported-by: NMikulas Patocka <mpatocka@redhat.com>
Reviewed-by: NMikulas Patocka <mpatocka@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

round_pipe_size() contains a right-bit-shift expression which may
overflow, which would cause undefined results in a subsequent
roundup_pow_of_two() call.

  static inline unsigned int round_pipe_size(unsigned int size)
  {
          unsigned long nr_pages;

          nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
          return roundup_pow_of_two(nr_pages) << PAGE_SHIFT;
  }

PAGE_SIZE is defined as (1UL << PAGE_SHIFT), so:
  - 4 bytes wide on 32-bit (0 to 0xffffffff)
  - 8 bytes wide on 64-bit (0 to 0xffffffffffffffff)

That means that 32-bit round_pipe_size(), nr_pages may overflow to 0:

  size=0x00000000    nr_pages=0x0
  size=0x00000001    nr_pages=0x1
  size=0xfffff000    nr_pages=0xfffff
  size=0xfffff001    nr_pages=0x0         << !
  size=0xffffffff    nr_pages=0x0         << !

This is bad because roundup_pow_of_two(n) is undefined when n == 0!

64-bit is not a problem as the unsigned int size is 4 bytes wide
(similar to 32-bit) and the larger, 8 byte wide unsigned long, is
sufficient to handle the largest value of the bit shift expression:

  size=0xffffffff    nr_pages=100000

Modify round_pipe_size() to return 0 if n == 0 and updates its callers to
handle accordingly.

Link: http://lkml.kernel.org/r/1507658689-11669-3-git-send-email-joe.lawrence@redhat.comSigned-off-by: NJoe Lawrence <joe.lawrence@redhat.com>
Reported-by: NMikulas Patocka <mpatocka@redhat.com>
Reviewed-by: NMikulas Patocka <mpatocka@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "A few round_pipe_size() and pipe-max-size fixups", v3.

While backporting Michael's "pipe: fix limit handling" patchset to a
distro-kernel, Mikulas noticed that current upstream pipe limit handling
contains a few problems:

  1 - procfs signed wrap: echo'ing a large number into
      /proc/sys/fs/pipe-max-size and then cat'ing it back out shows a
      negative value.

  2 - round_pipe_size() nr_pages overflow on 32bit:  this would
      subsequently try roundup_pow_of_two(0), which is undefined.

  3 - visible non-rounded pipe-max-size value: there is no mutual
      exclusion or protection between the time pipe_max_size is assigned
      a raw value from proc_dointvec_minmax() and when it is rounded.

  4 - unsigned long -> unsigned int conversion makes for potential odd
      return errors from do_proc_douintvec_minmax_conv() and
      do_proc_dopipe_max_size_conv().

This version underwent the same testing as v1:
https://marc.info/?l=linux-kernel&m=150643571406022&w=2

This patch (of 4):

pipe_max_size is defined as an unsigned int:

  unsigned int pipe_max_size = 1048576;

but its procfs/sysctl representation is an integer:

  static struct ctl_table fs_table[] = {
          ...
          {
                  .procname       = "pipe-max-size",
                  .data           = &pipe_max_size,
                  .maxlen         = sizeof(int),
                  .mode           = 0644,
                  .proc_handler   = &pipe_proc_fn,
                  .extra1         = &pipe_min_size,
          },
          ...

that is signed:

  int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf,
                   size_t *lenp, loff_t *ppos)
  {
          ...
          ret = proc_dointvec_minmax(table, write, buf, lenp, ppos)

This leads to signed results via procfs for large values of pipe_max_size:

  % echo 2147483647 >/proc/sys/fs/pipe-max-size
  % cat /proc/sys/fs/pipe-max-size
  -2147483648

Use unsigned operations on this variable to avoid such negative values.

Link: http://lkml.kernel.org/r/1507658689-11669-2-git-send-email-joe.lawrence@redhat.comSigned-off-by: NJoe Lawrence <joe.lawrence@redhat.com>
Reported-by: NMikulas Patocka <mpatocka@redhat.com>
Reviewed-by: NMikulas Patocka <mpatocka@redhat.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently if the autofs kernel module gets an error when writing to the
pipe which links to the daemon, then it marks the whole moutpoint as
catatonic, and it will stop working.

It is possible that the error is transient.  This can happen if the
daemon is slow and more than 16 requests queue up.  If a subsequent
process tries to queue a request, and is then signalled, the write to
the pipe will return -ERESTARTSYS and autofs will take that as total
failure.

So change the code to assess -ERESTARTSYS and -ENOMEM as transient
failures which only abort the current request, not the whole mountpoint.

It isn't a crash or a data corruption, but having autofs mountpoints
suddenly stop working is rather inconvenient.

Ian said:

: And given the problems with a half dozen (or so) user space applications
: consuming large amounts of CPU under heavy mount and umount activity this
: could happen more easily than we expect.

Link: http://lkml.kernel.org/r/87y3norvgp.fsf@notabene.neil.brown.nameSigned-off-by: NNeilBrown <neilb@suse.com>
Acked-by: NIan Kent <raven@themaw.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

init/version.c has nothing to do with modules, so remove the
<linux/modude.h>.

Instead, include <linux/export.h> for EXPORT_SYMBOL_GPL.

This cuts off a lot of unnecessary header parsing.

Link: http://lkml.kernel.org/r/1505920984-8523-1-git-send-email-yamada.masahiro@socionext.comSigned-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The use of ep_call_nested() in ep_eventpoll_poll(), which is the .poll
routine for an epoll fd, is used to prevent excessively deep epoll
nesting, and to prevent circular paths.

However, we are already preventing these conditions during
EPOLL_CTL_ADD.  In terms of too deep epoll chains, we do in fact allow
deep nesting of the epoll fds themselves (deeper than EP_MAX_NESTS),
however we don't allow more than EP_MAX_NESTS when an epoll file
descriptor is actually connected to a wakeup source.  Thus, we do not
require the use of ep_call_nested(), since ep_eventpoll_poll(), which is
called via ep_scan_ready_list() only continues nesting if there are
events available.

Since ep_call_nested() is implemented using a global lock, applications
that make use of nested epoll can see large performance improvements
with this change.

Davidlohr said:

: Improvements are quite obscene actually, such as for the following
: epoll_wait() benchmark with 2 level nesting on a 80 core IvyBridge:
:
: ncpus  vanilla     dirty     delta
: 1      2447092     3028315   +23.75%
: 4      231265      2986954   +1191.57%
: 8      121631      2898796   +2283.27%
: 16     59749       2902056   +4757.07%
: 32     26837	     2326314   +8568.30%
: 64     12926       1341281   +10276.61%
:
: (http://linux-scalability.org/epoll/epoll-test.c)

Link: http://lkml.kernel.org/r/1509430214-5599-1-git-send-email-jbaron@akamai.comSigned-off-by: NJason Baron <jbaron@akamai.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Salman Qazi <sqazi@google.com>
Cc: Hou Tao <houtao1@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ep_poll_safewake() is used to wakeup potentially nested epoll file
descriptors.  The function uses ep_call_nested() to prevent entering the
same wake up queue more than once, and to prevent excessively deep
wakeup paths (deeper than EP_MAX_NESTS).  However, this is not necessary
since we are already preventing these conditions during EPOLL_CTL_ADD.
This saves extra function calls, and avoids taking a global lock during
the ep_call_nested() calls.

I have, however, left ep_call_nested() for the CONFIG_DEBUG_LOCK_ALLOC
case, since ep_call_nested() keeps track of the nesting level, and this
is required by the call to spin_lock_irqsave_nested().  It would be nice
to remove the ep_call_nested() calls for the CONFIG_DEBUG_LOCK_ALLOC
case as well, however its not clear how to simply pass the nesting level
through multiple wake_up() levels without more surgery.  In any case, I
don't think CONFIG_DEBUG_LOCK_ALLOC is generally used for production.
This patch, also apparently fixes a workload at Google that Salman Qazi
reported by completely removing the poll_safewake_ncalls->lock from
wakeup paths.

Link: http://lkml.kernel.org/r/1507920533-8812-1-git-send-email-jbaron@akamai.comSigned-off-by: NJason Baron <jbaron@akamai.com>
Acked-by: NDavidlohr Bueso <dbueso@suse.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Salman Qazi <sqazi@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A userspace application can directly trigger the allocations from
eventpoll_epi and eventpoll_pwq slabs.  A buggy or malicious application
can consume a significant amount of system memory by triggering such
allocations.  Indeed we have seen in production where a buggy
application was leaking the epoll references and causing a burst of
eventpoll_epi and eventpoll_pwq slab allocations.  This patch opt-in the
charging of eventpoll_epi and eventpoll_pwq slabs.

There is a per-user limit (~4% of total memory if no highmem) on these
caches.  I think it is too generous particularly in the scenario where
jobs of multiple users are running on the system and the administrator
is reducing cost by overcomitting the memory.  This is unaccounted
kernel memory and will not be considered by the oom-killer.  I think by
accounting it to kmemcg, for systems with kmem accounting enabled, we
can provide better isolation between jobs of different users.

Link: http://lkml.kernel.org/r/20171003021519.23907-1-shakeelb@google.comSigned-off-by: NShakeel Butt <shakeelb@google.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

checkpatch.pl does not check missing blank line before module_*_driver.
I want it to behave likewise for builtin_*_driver.

Link: http://lkml.kernel.org/r/1505700081-12854-1-git-send-email-yamada.masahiro@socionext.comSigned-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Lines that end in an open bracket or open parenthesis are generally hard
to follow.  Lines following those ending with open parenthesis are also
rarely aligned to that open parenthesis.

Suggest not ending lines with '[' or '('

Link: http://lkml.kernel.org/r/8fd0b2b4a7482064254e37931eb9302a81d5aa2f.1508340786.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Suggested-by: NVivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

So the line length check can be bypassed by its callers.

Link: http://lkml.kernel.org/r/7de542c08a6e79f2ebe7c1416c9f403c23fdcc09.1508282823.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Reported-by: NSong Liu <songliubraving@fb.com>
Tested-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Some of the definitions are very long and can't be split into multiple
lines because ctags is limited.

Exempt these lines from the line length checks.

See commit 25528213 ("tags: Fix DEFINE_PER_CPU expansions") for more
details.

Link: http://lkml.kernel.org/r/1508170320.6530.15.camel@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Acked-by: NMark Rutland <mark.rutland@arm.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There was code in checkpatch that allowed continuation printks to be
used without KERN_CONT.  Remove the continuation check and always
require a KERN_<LEVEL>.

Link: http://lkml.kernel.org/r/61980ef41d5b9b6543da1c49055042e0ab74d308.1507047008.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

void foo(int a)
	switch (a) {
	case 'h':
		fun1();
		exit(1);
	default:
}

creates a warning "Possible switch case/default not preceded by break or
fallthrough comment".

exit( should be treated like return.

Link: http://lkml.kernel.org/r/20170910154618.25819-1-xypron.glpk@gmx.deSigned-off-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>
Acked-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Current unnamed function definition argument does not include function
pointer cases and it reports something like:

  WARNING: function definition argument 'void' should also have an identifier name
  +unsigned int (*dummy)(void);

Support function pointers for unnamed function arguments

Link: http://lkml.kernel.org/r/1505389925-31087-1-git-send-email-miles.chen@mediatek.comSigned-off-by: NMiles Chen <miles.chen@mediatek.com>
Acked-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

find_bit functions are widely used in the kernel, including hot paths.
This module tests performance of those functions in 2 typical scenarios:
randomly filled bitmap with relatively equal distribution of set and
cleared bits, and sparse bitmap which has 1 set bit for 500 cleared
bits.

On ThunderX machine:

	 Start testing find_bit() with random-filled bitmap
	find_next_bit:          240043 cycles,  164062 iterations
	find_next_zero_bit:     312848 cycles,  163619 iterations
	find_last_bit:          193748 cycles,  164062 iterations
	find_first_bit:      177720874 cycles,  164062 iterations

	 Start testing find_bit() with sparse bitmap
	find_next_bit:            3633 cycles,     656 iterations
	find_next_zero_bit:     620399 cycles,  327025 iterations
	find_last_bit:            3038 cycles,     656 iterations
	find_first_bit:         691407 cycles,     656 iterations

[arnd@arndb.de: use correct format string for find-bit tests]
  Link: http://lkml.kernel.org/r/20171113135605.3166307-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20171109140714.13168-1-ynorov@caviumnetworks.comSigned-off-by: NYury Norov <ynorov@caviumnetworks.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NClement Courbet <courbet@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fengguang reported soft lockups while running the rbtree and interval
tree test modules.  The logic for these tests all occur in init phase,
and we currently are pounding with the default values for number of
nodes and number of iterations of each test.  Reduce the latter by two
orders of magnitude.  This does not influence the value of the tests in
that one thousand times by default is enough to get the picture.

Link: http://lkml.kernel.org/r/20171109161715.xai2dtwqw2frhkcm@linux-n805Signed-off-by: NDavidlohr Bueso <dbueso@suse.de>
Reported-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The uniform structure filter_arg sets its union based on the difference
of enum filter_arg_type, However, some functions use implicit type
conversion obviously.

warning: implicit conversion from enumeration type 'enum filter_exp_type'
	 to different enumeration type 'enum filter_op_type'

warning: implicit conversion from enumeration type 'enum filter_cmp_type'
	 to different enumeration type 'enum filter_exp_type'

Link: http://lkml.kernel.org/r/1509938415-113825-1-git-send-email-cj.chengjian@huawei.comSigned-off-by: NCheng Jian <cj.chengjian@huawei.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Xie XiuQi <xiexiuqi@huawei.com>
Cc: Li Bin <huawei.libin@huawei.com>
Cc: Steven Rostedt (Red Hat) <rostedt@goodmis.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Don't leak idle function address in NMI backtrace.

Link: http://lkml.kernel.org/r/20171106165648.GA95243@sofiaSigned-off-by: NLiu Changcheng <changcheng.liu@intel.com>
Reviewed-by: NPetr Mladek <pmladek@suse.com>
Reviewed-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the amount of resources allocated to a gen_pool exceeds 2^32 then the
avail atomic overflows and this causes problems when clients try and
borrow resources from the pool.  This is only expected to be an issue on
64 bit systems.

Add the <linux/atomic.h> header to pull in atomic_long* operations.  So
that 32 bit systems continue to use atomic32_t but 64 bit systems can
use atomic64_t.

Link: http://lkml.kernel.org/r/1509033843-25667-1-git-send-email-sbates@raithlin.comSigned-off-by: NStephen Bates <sbates@raithlin.com>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: NDaniel Mentz <danielmentz@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Our current int_sqrt() is not rough nor any approximation; it calculates
the exact value of: floor(sqrt()).  Document this.

Link: http://lkml.kernel.org/r/20171020164645.001652117@infradead.orgSigned-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Anshul Garg <aksgarg1989@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Joe Perches <joe@perches.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Michael Davidson <md@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The initial value (@m) compute is:

	m = 1UL << (BITS_PER_LONG - 2);
	while (m > x)
		m >>= 2;

Which is a linear search for the highest even bit smaller or equal to @x
We can implement this using a binary search using __fls() (or better when
its hardware implemented).

	m = 1UL << (__fls(x) & ~1UL);

Especially for small values of @x; which are the more common arguments
when doing a CDF on idle times; the linear search is near to worst case,
while the binary search of __fls() is a constant 6 (or 5 on 32bit)
branches.

      cycles:                 branches:              branch-misses:

PRE:

hot:   43.633557 +- 0.034373  45.333132 +- 0.002277  0.023529 +- 0.000681
cold: 207.438411 +- 0.125840  45.333132 +- 0.002277  6.976486 +- 0.004219

SOFTWARE FLS:

hot:   29.576176 +- 0.028850  26.666730 +- 0.004511  0.019463 +- 0.000663
cold: 165.947136 +- 0.188406  26.666746 +- 0.004511  6.133897 +- 0.004386

HARDWARE FLS:

hot:   24.720922 +- 0.025161  20.666784 +- 0.004509  0.020836 +- 0.000677
cold: 132.777197 +- 0.127471  20.666776 +- 0.004509  5.080285 +- 0.003874

Averages computed over all values <128k using a LFSR to generate order.
Cold numbers have a LFSR based branch trace buffer 'confuser' ran between
each int_sqrt() invocation.

Link: http://lkml.kernel.org/r/20171020164644.936577234@infradead.orgSigned-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Suggested-by: NJoe Perches <joe@perches.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Anshul Garg <aksgarg1989@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Michael Davidson <md@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current int_sqrt() computation is sub-optimal for the case of small
@x.  Which is the interesting case when we're going to do cumulative
distribution functions on idle times, which we assume to be a random
variable, where the target residency of the deepest idle state gives an
upper bound on the variable (5e6ns on recent Intel chips).

In the case of small @x, the compute loop:

	while (m != 0) {
		b = y + m;
		y >>= 1;

		if (x >= b) {
			x -= b;
			y += m;
		}
		m >>= 2;
	}

can be reduced to:

	while (m > x)
		m >>= 2;

Because y==0, b==m and until x>=m y will remain 0.

And while this is computationally equivalent, it runs much faster
because there's less code, in particular less branches.

      cycles:                 branches:              branch-misses:

OLD:

hot:   45.109444 +- 0.044117  44.333392 +- 0.002254  0.018723 +- 0.000593
cold: 187.737379 +- 0.156678  44.333407 +- 0.002254  6.272844 +- 0.004305

PRE:

hot:   67.937492 +- 0.064124  66.999535 +- 0.000488  0.066720 +- 0.001113
cold: 232.004379 +- 0.332811  66.999527 +- 0.000488  6.914634 +- 0.006568

POST:

hot:   43.633557 +- 0.034373  45.333132 +- 0.002277  0.023529 +- 0.000681
cold: 207.438411 +- 0.125840  45.333132 +- 0.002277  6.976486 +- 0.004219

Averages computed over all values <128k using a LFSR to generate order.
Cold numbers have a LFSR based branch trace buffer 'confuser' ran between
each int_sqrt() invocation.

Link: http://lkml.kernel.org/r/20171020164644.876503355@infradead.org
Fixes: 30493cc9 ("lib/int_sqrt.c: optimize square root algorithm")
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Suggested-by: NAnshul Garg <aksgarg1989@gmail.com>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Joe Perches <joe@perches.com>
Cc: David Miller <davem@davemloft.net>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Michael Davidson <md@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Omit extra messages for a memory allocation failure in these functions.

This issue was detected by using the Coccinelle software.

Link: http://lkml.kernel.org/r/410a4c5a-4ee0-6fcc-969c-103d8e496b78@users.sourceforge.netSigned-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Extract the string test code into its own source file, to allow
compiling it either to a loadable module, or built into the kernel.

Fixes: 03270c13 ("lib/string.c: add testcases for memset16/32/64")
Link: http://lkml.kernel.org/r/1505397744-3387-1-git-send-email-geert@linux-m68k.orgSigned-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This include was added by commit 187f1882 ("BUG: headers with
BUG/BUG_ON etc. need linux/bug.h") because BUG_ON() was used in this
header at that time.

Some time later, commit 6d75f366 ("lib: radix-tree: check accounting
of existing slot replacement users") removed the use of BUG_ON() from
this header.

Since then, there is no reason to include <linux/bug.h>.

Link: http://lkml.kernel.org/r/1505660151-4383-1-git-send-email-yamada.masahiro@socionext.comSigned-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Chris Mi <chrism@mellanox.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since commit bc6245e5 ("bug: split BUILD_BUG stuff out into
<linux/build_bug.h>"), #include <linux/build_bug.h> is better to pull
minimal headers needed for BUILG_BUG() family.

Link: http://lkml.kernel.org/r/1505700775-19826-1-git-send-email-yamada.masahiro@socionext.comSigned-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Cc: Dinan Gunawardena <dinan.gunawardena@netronome.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add tests for duplicate section headers, missing section content, link and
scm reachability.

Miscellanea:

o Add --self-test=<foo> options
  (a comma separated list of any of sections, patterns, links or scm)
  where the default without options is all tests
o Rename check_maintainers_patterns to self_test
o Rename self_test_pattern_info to self_test_info

[tom.saeger@oracle.com: improvements]
Link: http://lkml.kernel.org/r/13e3986c374902fcf08ae947e36c5c608bbe3b79.1510075301.git.joe@perches.comSigned-off-by: NJoe Perches <joe@perches.com>
Reviewed-by: NTom Saeger <tom.saeger@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add "--self-test" option to get_maintainer.pl to show potential
issues in MAINTAINERS file(s) content.

Pattern check warnings are shown for "F" and "X" patterns found in
MAINTAINERS file(s) which do not match any files known by git.

Link: http://lkml.kernel.org/r/64994f911b3510d0f4c8ac2e113501dfcec1f3c9.1509559540.git.tom.saeger@oracle.comSigned-off-by: NTom Saeger <tom.saeger@oracle.com>
Acked-by: NJoe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix minor typo.

Fix missing words in explaining parsing of last line number.

Link: http://lkml.kernel.org/r/ebb7ff42-4945-103f-d5b4-f07a6f3343a7@infradead.orgSigned-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Jason Baron <jbaron@akamai.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

line-range is supposed to treat "1-" as "1-endoffile", so
handle the special case by setting last_lineno to UINT_MAX.

Fixes this error:

  dynamic_debug:ddebug_parse_query: last-line:0 < 1st-line:1
  dynamic_debug:ddebug_exec_query: query parse failed

Link: http://lkml.kernel.org/r/10a6a101-e2be-209f-1f41-54637824788e@infradead.orgSigned-off-by: NRandy Dunlap <rdunlap@infradead.org>
Acked-by: NJason Baron <jbaron@akamai.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If 'write' is 0, we can avoid a call to spin_lock/spin_unlock.

Link: http://lkml.kernel.org/r/20171020193331.7233-1-christophe.jaillet@wanadoo.frSigned-off-by: NChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The GCC randomize layout plugin can randomize the member offsets of
sensitive kernel data structures.  To use this feature, certain
annotations and members are added to the structures which affect the
member offsets even if this plugin is not used.

All of these structures are completely randomized, except for task_struct
which leaves out some of its members.  All the other members are wrapped
within an anonymous struct with the __randomize_layout attribute.  This is
done using the randomized_struct_fields_start and
randomized_struct_fields_end defines.

When the plugin is disabled, the behaviour of this attribute can vary
based on the GCC version.  For GCC 5.1+, this attribute maps to
__designated_init otherwise it is just an empty define but the anonymous
structure is still present.  For other compilers, both
randomized_struct_fields_start and randomized_struct_fields_end default
to empty defines meaning the anonymous structure is not introduced at
all.

So, if a module compiled with Clang, such as a BPF program, needs to
access task_struct fields such as pid and comm, the offsets of these
members as recognized by Clang are different from those recognized by
modules compiled with GCC.  If GCC 4.6+ is used to build the kernel,
this can be solved by introducing appropriate defines for Clang so that
the anonymous structure is seen when determining the offsets for the
members.

Link: http://lkml.kernel.org/r/20171109064645.25581-1-sandipan@linux.vnet.ibm.comSigned-off-by: NSandipan Das <sandipan@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Alexei Starovoitov <ast@fb.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Prior to v4.11, x86 used warn_slowpath_fmt() for handling WARN()s.
After WARN() was moved to using UD0 on x86, the warning text started
appearing _before_ the "cut here" line.  This appears to have been a
long-standing bug on architectures that used __WARN_TAINT, but it didn't
get fixed.

v4.11 and earlier on x86:

  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 2956 at drivers/misc/lkdtm_bugs.c:65 lkdtm_WARNING+0x21/0x30
  This is a warning message
  Modules linked in:

v4.12 and later on x86:

  This is a warning message
  ------------[ cut here ]------------
  WARNING: CPU: 1 PID: 2982 at drivers/misc/lkdtm_bugs.c:68 lkdtm_WARNING+0x15/0x20
  Modules linked in:

With this fix:

  ------------[ cut here ]------------
  This is a warning message
  WARNING: CPU: 3 PID: 3009 at drivers/misc/lkdtm_bugs.c:67 lkdtm_WARNING+0x15/0x20

Since the __FILE__ reporting happens as part of the UD0 handler, it
isn't trivial to move the message to after the WARNING line, but at
least we can fix the position of the "cut here" line so all the various
logging tools will start including the actual runtime warning message
again, when they follow the instruction and "cut here".

Link: http://lkml.kernel.org/r/1510100869-73751-4-git-send-email-keescook@chromium.org
Fixes: 9a93848f ("x86/debug: Implement __WARN() using UD0")
Signed-off-by: NKees Cook <keescook@chromium.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The "cut here" string is used in a few paths.  Define it in a single
place.

Link: http://lkml.kernel.org/r/1510100869-73751-3-git-send-email-keescook@chromium.orgSigned-off-by: NKees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In order to test the ordering of WARN format strings, actually include
one in LKDTM.

Link: http://lkml.kernel.org/r/1510100869-73751-2-git-send-email-keescook@chromium.orgSigned-off-by: NKees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When we pass the result of a multiplication as the timeout or the delay,
we can get a warning from gcc-7:

  drivers/mmc/host/bcm2835.c:596:149: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]
  drivers/mfd/arizona-core.c:247:195: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]
  drivers/gpu/drm/sun4i/sun4i_hdmi_i2c.c:49:27: error: '*' in boolean context, suggest '&&' instead [-Werror=int-in-bool-context]

The warning is a bit questionable inside of a macro, but this is
intentional on the side of the gcc developers.  It is also an indication
of another problem: we evaluate the timeout and sleep arguments multiple
times, which can have undesired side-effects when those are complex
expressions.

This changes the two iopoll variants to use local variables for storing
copies of the timeouts.  This adds some more type safety, and avoids
both the double-evaluation and the gcc warning.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81484
Link: http://lkml.kernel.org/r/20170726133756.2161367-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20171102114048.1526955-1-arnd@arndb.deSigned-off-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>