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  1. 09 Jun, 2017 14 commits
  3. 07 Jun, 2017 1 commit
  5. 03 Jun, 2017 14 commits
  7. 27 May, 2017 1 commit
  9. 25 May, 2017 3 commits
    • Nick Desaulniers's avatar
      sysfs: remove signedness from sysfs_get_dirent · 89cf2a20
      Nick Desaulniers authored 
      sysfs_get_dirent is usually invoked with a string literal, which
have the type char[].  While the toplevel Makefile
disables -Wpointer-sign, other Makefiles like

arch/x86/boot/compressed/Makefile

redefine KBUILD_CFLAGS. Fixes the warning:

In file included from arch/x86/boot/compressed/kaslr.c:17:
In file included from ./include/linux/module.h:17:
In file included from ./include/linux/kobject.h:21:
./include/linux/sysfs.h:517:37: warning: passing 'const unsigned char *'
to parameter of
      type 'const char *' converts between pointers to integer types
with different sign
      [-Wpointer-sign]
        return kernfs_find_and_get(parent, name);
                                           ^~~~
./include/linux/kernfs.h:462:57: note: passing argument to parameter
'name' here
kernfs_find_and_get(struct kernfs_node *kn, const char *name)
                                                        ^
Signed-off-by: default avatarNick Desaulniers <nick.desaulniers@gmail.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      89cf2a20
    • Peter Rajnoha's avatar
      kobject: support passing in variables for synthetic uevents · f36776fa
      Peter Rajnoha authored 
      This patch makes it possible to pass additional arguments in addition
to uevent action name when writing /sys/.../uevent attribute. These
additional arguments are then inserted into generated synthetic uevent
as additional environment variables.

Before, we were not able to pass any additional uevent environment
variables for synthetic uevents. This made it hard to identify such uevents
properly in userspace to make proper distinction between genuine uevents
originating from kernel and synthetic uevents triggered from userspace.
Also, it was not possible to pass any additional information which would
make it possible to optimize and change the way the synthetic uevents are
processed back in userspace based on the originating environment of the
triggering action in userspace. With the extra additional variables, we are
able to pass through this extra information needed and also it makes it
possible to synchronize with such synthetic uevents as they can be clearly
identified back in userspace.

The format for writing the uevent attribute is following:

    ACTION [UUID [KEY=VALUE ...]

There's no change in how "ACTION" is recognized - it stays the same
("add", "change", "remove"). The "ACTION" is the only argument required
to generate synthetic uevent, the rest of arguments, that this patch
adds support for, are optional.

The "UUID" is considered as transaction identifier so it's possible to
use the same UUID value for one or more synthetic uevents in which case
we logically group these uevents together for any userspace listeners.
The "UUID" is expected to be in "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
format where "x" is a hex digit. The value appears in uevent as
"SYNTH_UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" environment variable.

The "KEY=VALUE" pairs can contain alphanumeric characters only. It's
possible to define zero or more more pairs - each pair is then delimited
by a space character " ". Each pair appears in synthetic uevents as
"SYNTH_ARG_KEY=VALUE" environment variable. That means the KEY name gains
"SYNTH_ARG_" prefix to avoid possible collisions with existing variables.
To pass the "KEY=VALUE" pairs, it's also required to pass in the "UUID"
part for the synthetic uevent first.

If "UUID" is not passed in, the generated synthetic uevent gains
"SYNTH_UUID=0" environment variable automatically so it's possible to
identify this situation in userspace when reading generated uevent and so
we can still make a difference between genuine and synthetic uevents.
Signed-off-by: default avatarPeter Rajnoha <prajnoha@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f36776fa
    • Adrian Salido's avatar
      driver core: platform: fix race condition with driver_override · 62655397
      Adrian Salido authored 
      The driver_override implementation is susceptible to race condition when
different threads are reading vs storing a different driver override.
Add locking to avoid race condition.

Fixes: 3d713e0e ("driver core: platform: add device binding path 'driver_override'")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarAdrian Salido <salidoa@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      62655397
  11. 22 May, 2017 2 commits
    • Linus Torvalds's avatar
      Linux 4.12-rc2 · 08332893
      Linus Torvalds authored
      08332893
    • Linus Torvalds's avatar
      x86: fix 32-bit case of __get_user_asm_u64() · 33c9e972
      Linus Torvalds authored 
      The code to fetch a 64-bit value from user space was entirely buggered,
and has been since the code was merged in early 2016 in commit
b2f68038 ("x86/mm/32: Add support for 64-bit __get_user() on 32-bit
kernels").

Happily the buggered routine is almost certainly entirely unused, since
the normal way to access user space memory is just with the non-inlined
"get_user()", and the inlined version didn't even historically exist.

The normal "get_user()" case is handled by external hand-written asm in
arch/x86/lib/getuser.S that doesn't have either of these issues.

There were two independent bugs in __get_user_asm_u64():

 - it still did the STAC/CLAC user space access marking, even though
   that is now done by the wrapper macros, see commit 11f1a4b9
   ("x86: reorganize SMAP handling in user space accesses").

   This didn't result in a semantic error, it just means that the
   inlined optimized version was hugely less efficient than the
   allegedly slower standard version, since the CLAC/STAC overhead is
   quite high on modern Intel CPU's.

 - the double register %eax/%edx was marked as an output, but the %eax
   part of it was touched early in the asm, and could thus clobber other
   inputs to the asm that gcc didn't expect it to touch.

   In particular, that meant that the generated code could look like
   this:

        mov    (%eax),%eax
        mov    0x4(%eax),%edx

   where the load of %edx obviously was _supposed_ to be from the 32-bit
   word that followed the source of %eax, but because %eax was
   overwritten by the first instruction, the source of %edx was
   basically random garbage.

The fixes are trivial: remove the extraneous STAC/CLAC entries, and mark
the 64-bit output as early-clobber to let gcc know that no inputs should
alias with the output register.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@kernel.org   # v4.8+
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      33c9e972
  13. 21 May, 2017 5 commits
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