lib/lcm.c: ensure correct result whenever it fits

Ensure that lcm(a,b) returns the mathematically correct result, provided
it fits in an unsigned long.  The current version returns garbage if a*b
overflows, even if the final result would fit.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib/lcm.c: lcm(n,0)=lcm(0,n) is 0, not n

Return the mathematically correct answer when an argument is 0.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: add an error test for no space before comma

Using code like:

    int foo , bar;

is not preferred to:

    int foo, bar;

so emit an error on this style.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: add error on use of attribute((weak)) or __weak declarations

Using weak declarations can have unintended link defects.  The __weak on
the declaration causes non-weak definitions to become weak.

Emit an error on its use.

Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: improve test for no space after cast

sizeof(foo) is not a cast, allow a space after it.

Signed-off-by: Joe Perches <joe@perches.com>
Tested-by: Kalle Valo <kvalo@qca.qualcomm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: improve warning message for "needless if" case

Add an 'and' to the sentence so that it looks better:

  WARNING: debugfs_remove(NULL) is safe and this check is probably not required

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: fix use via symlink, make missing spelling file non-fatal

Commit 66b47b4a9dad ("checkpatch: look for common misspellings") made it
difficult to use checkpatch via a symlink.

Fix that and make a missing spelling.txt file non-fatal.  Emit a warning
when the spelling.txt file can not be opened.

Reference: http://xkcd.com/1172/

Signed-off-by: Joe Perches <joe@perches.com>
Reported-by: Jani Nikula <jani.nikula@intel.com>
Tested-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: try to avoid mask and shift errors

Shift has a higher precedence that mask so warn when a mask then shift
operation is done without parentheses around the mask.

This test works well for a right shift, but the left shift is pretty
commonly done correctly so only warn on the right shift.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: reduce MAINTAINERS update message frequency

When files are being added/moved/deleted and a patch contains an update to
the MAINTAINERS file, assume it's to update the MAINTAINERS file correctly
and do not emit the "does MAINTAINERS need updating?" message.

Reported by many people.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: Add --strict test for function pointer calling style

Peter Hurley wrote:

The use of older function ptr calling style, (*fn)(), makes static
analysis more error-prone; replace with modern fn() style.

So make checkpatch emit a --strict test for that condition.

Update the unnecessary parentheses test for dereferencing
objects at the same time and create a $fix mechanism too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: allow certain SI units with three characters

Checkpatch flags CamelCase identifiers in strict mode, but it has a
feature to ignore parts with only two characters to allow for SI units
like mV or uA.  Unfortunately, not all SI units fit in two characters, and
not all are lower case followed by upper case.

This patch adds hardcoded detection for frequency and 1024-based size
units (Hz/KHz/MHz/GHz/THz and KiB/MiB/GiB/TiB), since allowing any three
character combinations might be too lenient.  The list can later be
expanded as needed.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Acked-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: add --strict preference for #defines using BIT(foo)

Using BIT(foo) and BIT_ULL(bar) is more common now.  Suggest using these
macros over #defines with 1<<value.

Add a --fix option too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: David Miller <davem@davemloft.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: add test for consecutive string fragments

Emit a warning when single line string coalescing occurs.

Code that uses compiler string concatenation on a single line like:

    printk("foo" "bar");

is generally better to read concatenated like:

    printk("foobar");

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: add --strict "pointer comparison to NULL" test

It seems there are more and more uses of "if (!ptr)" in preference to "if
(ptr == NULL)" so add a --strict test to emit a message when using the
latter form.

This also finds (ptr != NULL).

Fix it too if desired.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
checkpatch: add ability to --fix (coalesce) string fragments on multiple lines

Add --fix option to coalesce string fragments.

This does not coalesce string fragments that have newline terminations or
are otherwise exempted.

Other miscellanea:

o move all the string tests together.
o fix get_quoted_string function for tab characters
o fix concatination typo

Signed-off-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
binfmt_misc: add comments & debug logs

When trying to develop a custom format handler, the errors returned all
effectively get bucketed as EINVAL with no kernel messages.  The other
errors (ENOMEM/EFAULT) are internal/obvious and basic.  Thus any time a
bad handler is rejected, the developer has to walk the dense code and
try to guess where it went wrong.  Needing to dive into kernel code is
itself a fairly high barrier for a lot of people.

To improve this situation, let's deploy extensive pr_debug markers at
logical parse points, and add comments to the dense parsing logic.  It
let's you see exactly where the parsing aborts, the string the kernel
received (useful when dealing with shell code), how it translated the
buffers to binary data, and how it will apply the mask at runtime.

Some example output:
  $ echo ':qemu-foo:M::\x7fELF\xAD\xAD\x01\x00:\xff\xff\xff\xff\xff\x00\xff\x00:/usr/bin/qemu-foo:POC' > register
  $ dmesg
  binfmt_misc: register: received 92 bytes
  binfmt_misc: register: delim: 0x3a {:}
  binfmt_misc: register: name: {qemu-foo}
  binfmt_misc: register: type: M (magic)
  binfmt_misc: register: offset: 0x0
  binfmt_misc: register: magic[raw]: 5c 78 37 66 45 4c 46 5c 78 41 44 5c 78 41 44 5c  \x7fELF\xAD\xAD\
  binfmt_misc: register: magic[raw]: 78 30 31 5c 78 30 30 00                          x01\x00.
  binfmt_misc: register:  mask[raw]: 5c 78 66 66 5c 78 66 66 5c 78 66 66 5c 78 66 66  \xff\xff\xff\xff
  binfmt_misc: register:  mask[raw]: 5c 78 66 66 5c 78 30 30 5c 78 66 66 5c 78 30 30  \xff\x00\xff\x00
  binfmt_misc: register:  mask[raw]: 00                                               .
  binfmt_misc: register: magic/mask length: 8
  binfmt_misc: register: magic[decoded]: 7f 45 4c 46 ad ad 01 00                          .ELF....
  binfmt_misc: register:  mask[decoded]: ff ff ff ff ff 00 ff 00                          ........
  binfmt_misc: register:  magic[masked]: 7f 45 4c 46 ad 00 01 00                          .ELF....
  binfmt_misc: register: interpreter: {/usr/bin/qemu-foo}
  binfmt_misc: register: flag: P (preserve argv0)
  binfmt_misc: register: flag: O (open binary)
  binfmt_misc: register: flag: C (preserve creds)

The [raw] lines show us exactly what was received from userspace.  The
lines after that show us how the kernel has decoded things.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
binfmt_misc: clean up code style a bit

Clean up various coding style issues that checkpatch complains about.
No functional changes here.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/binfmt_misc.c: use GFP_KERNEL instead of GFP_USER

GFP_USER means "honour cpuset nodes-allowed beancounting".  These are
regular old kernel objects and there seems no reason to give them this
treatment.

Acked-by: Mike Frysinger <vapier@gentoo.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/binfmt_elf.c: fix internal inconsistency relating to vma dump size

vma_dump_size() has been used several times on actual dumper and it is
supposed to return the same value for the same vma.  But vma_dump_size()
could return different values for same vma.

The known problem case is concurrent shared memory removal.  If a vma is
used for a shared memory and that shared memory is removed between
writing program header and dumping vma memory, this will result in a
dump file which is internally consistent.

To fix the problem, we set baseline to get dump size and store the size
into vma_filesz and always use the same vma dump size which is stored in
vma_filsz.  The consistnecy with reality is not actually guranteed, but
it's tolerable since that is fully consistent with base line.

Signed-off-by: Jungseung Lee <js07.lee@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
init: allow CONFIG_INIT_FALLBACK=n to disable defaults if init= fails

If a user puts init=/whatever on the command line and /whatever can't be
run, then the kernel will try a few default options before giving up.  If
init=/whatever came from a bootloader prompt, then this is unexpected but
probably harmless.  On the other hand, if it comes from a script (e.g.  a
tool like virtme or perhaps a future kselftest script), then the fallbacks
are likely to exist, but they'll do the wrong thing.  For example, they
might unexpectedly invoke systemd.

This adds a config option CONFIG_INIT_FALLBACK.  If unset, then a failure
to run the specified init= process be fatal.

The tentative plan is to remove CONFIG_INIT_FALLBACK for 3.20.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Rob Landley <rob@landley.net>
Cc: Chuck Ebbert <cebbert.lkml@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shuah Khan <shuah.kh@samsung.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>