Граф коммитов

58 Коммитов

Автор SHA1 Сообщение Дата
Andy Shevchenko f39650de68 kernel.h: split out panic and oops helpers
kernel.h is being used as a dump for all kinds of stuff for a long time.
Here is the attempt to start cleaning it up by splitting out panic and
oops helpers.

There are several purposes of doing this:
- dropping dependency in bug.h
- dropping a loop by moving out panic_notifier.h
- unload kernel.h from something which has its own domain

At the same time convert users tree-wide to use new headers, although for
the time being include new header back to kernel.h to avoid twisted
indirected includes for existing users.

[akpm@linux-foundation.org: thread_info.h needs limits.h]
[andriy.shevchenko@linux.intel.com: ia64 fix]
  Link: https://lkml.kernel.org/r/20210520130557.55277-1-andriy.shevchenko@linux.intel.com

Link: https://lkml.kernel.org/r/20210511074137.33666-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Co-developed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Corey Minyard <cminyard@mvista.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Wei Liu <wei.liu@kernel.org>
Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Sebastian Reichel <sre@kernel.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-01 11:06:04 -07:00
Oleg Nesterov 5abbe51a52 kernel, fs: Introduce and use set_restart_fn() and arch_set_restart_data()
Preparation for fixing get_nr_restart_syscall() on X86 for COMPAT.

Add a new helper which sets restart_block->fn and calls a dummy
arch_set_restart_data() helper.

Fixes: 609c19a385 ("x86/ptrace: Stop setting TS_COMPAT in ptrace code")
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210201174641.GA17871@redhat.com
2021-03-16 22:13:10 +01:00
Gabriel Krisman Bertazi 6342adcaa6 entry: Ensure trap after single-step on system call return
Commit 2991552447 ("entry: Drop usage of TIF flags in the generic syscall
code") introduced a bug on architectures using the generic syscall entry
code, in which processes stopped by PTRACE_SYSCALL do not trap on syscall
return after receiving a TIF_SINGLESTEP.

The reason is that the meaning of TIF_SINGLESTEP flag is overloaded to
cause the trap after a system call is executed, but since the above commit,
the syscall call handler only checks for the SYSCALL_WORK flags on the exit
work.

Split the meaning of TIF_SINGLESTEP such that it only means single-step
mode, and create a new type of SYSCALL_WORK to request a trap immediately
after a syscall in single-step mode.  In the current implementation, the
SYSCALL_WORK flag shadows the TIF_SINGLESTEP flag for simplicity.

Update x86 to flip this bit when a tracer enables single stepping.

Fixes: 2991552447 ("entry: Drop usage of TIF flags in the generic syscall code")
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Kyle Huey <me@kylehuey.com>
Link: https://lore.kernel.org/r/87h7mtc9pr.fsf_-_@collabora.com
2021-02-06 00:21:42 +01:00
Gabriel Krisman Bertazi 1446e1df9e kernel: Implement selective syscall userspace redirection
Introduce a mechanism to quickly disable/enable syscall handling for a
specific process and redirect to userspace via SIGSYS.  This is useful
for processes with parts that require syscall redirection and parts that
don't, but who need to perform this boundary crossing really fast,
without paying the cost of a system call to reconfigure syscall handling
on each boundary transition.  This is particularly important for Windows
games running over Wine.

The proposed interface looks like this:

  prctl(PR_SET_SYSCALL_USER_DISPATCH, <op>, <off>, <length>, [selector])

The range [<offset>,<offset>+<length>) is a part of the process memory
map that is allowed to by-pass the redirection code and dispatch
syscalls directly, such that in fast paths a process doesn't need to
disable the trap nor the kernel has to check the selector.  This is
essential to return from SIGSYS to a blocked area without triggering
another SIGSYS from rt_sigreturn.

selector is an optional pointer to a char-sized userspace memory region
that has a key switch for the mechanism. This key switch is set to
either PR_SYS_DISPATCH_ON, PR_SYS_DISPATCH_OFF to enable and disable the
redirection without calling the kernel.

The feature is meant to be set per-thread and it is disabled on
fork/clone/execv.

Internally, this doesn't add overhead to the syscall hot path, and it
requires very little per-architecture support.  I avoided using seccomp,
even though it duplicates some functionality, due to previous feedback
that maybe it shouldn't mix with seccomp since it is not a security
mechanism.  And obviously, this should never be considered a security
mechanism, since any part of the program can by-pass it by using the
syscall dispatcher.

For the sysinfo benchmark, which measures the overhead added to
executing a native syscall that doesn't require interception, the
overhead using only the direct dispatcher region to issue syscalls is
pretty much irrelevant.  The overhead of using the selector goes around
40ns for a native (unredirected) syscall in my system, and it is (as
expected) dominated by the supervisor-mode user-address access.  In
fact, with SMAP off, the overhead is consistently less than 5ns on my
test box.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201127193238.821364-4-krisman@collabora.com
2020-12-02 15:07:56 +01:00
Gabriel Krisman Bertazi 5903f61e03 entry: Fix boot for !CONFIG_GENERIC_ENTRY
A copy-pasta mistake tries to set SYSCALL_WORK flags instead of TIF
flags for !CONFIG_GENERIC_ENTRY.  Also, add safeguards to catch this at
compilation time.

Fixes: 3136b93c3f ("entry: Expose helpers to migrate TIF to SYSCALL_WORK flags")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/87a6v8qd9p.fsf_-_@collabora.com
2020-11-25 02:20:09 +01:00
Gabriel Krisman Bertazi 785dc4eb7f audit: Migrate to use SYSCALL_WORK flag
On architectures using the generic syscall entry code the architecture
independent syscall work is moved to flags in thread_info::syscall_work.
This removes architecture dependencies and frees up TIF bits.

Define SYSCALL_WORK_SYSCALL_AUDIT, use it in the generic entry code and
convert the code which uses the TIF specific helper functions to use the
new *_syscall_work() helpers which either resolve to the new mode for users
of the generic entry code or to the TIF based functions for the other
architectures.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-9-krisman@collabora.com
2020-11-16 21:53:16 +01:00
Gabriel Krisman Bertazi 64eb35f701 ptrace: Migrate TIF_SYSCALL_EMU to use SYSCALL_WORK flag
On architectures using the generic syscall entry code the architecture
independent syscall work is moved to flags in thread_info::syscall_work.
This removes architecture dependencies and frees up TIF bits.

Define SYSCALL_WORK_SYSCALL_EMU, use it in the generic entry code and
convert the code which uses the TIF specific helper functions to use the
new *_syscall_work() helpers which either resolve to the new mode for users
of the generic entry code or to the TIF based functions for the other
architectures.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-8-krisman@collabora.com
2020-11-16 21:53:16 +01:00
Gabriel Krisman Bertazi 64c19ba29b ptrace: Migrate to use SYSCALL_TRACE flag
On architectures using the generic syscall entry code the architecture
independent syscall work is moved to flags in thread_info::syscall_work.
This removes architecture dependencies and frees up TIF bits.

Define SYSCALL_WORK_SYSCALL_TRACE, use it in the generic entry code and
convert the code which uses the TIF specific helper functions to use the
new *_syscall_work() helpers which either resolve to the new mode for users
of the generic entry code or to the TIF based functions for the other
architectures.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-7-krisman@collabora.com
2020-11-16 21:53:16 +01:00
Gabriel Krisman Bertazi 524666cb5d tracepoints: Migrate to use SYSCALL_WORK flag
On architectures using the generic syscall entry code the architecture
independent syscall work is moved to flags in thread_info::syscall_work.
This removes architecture dependencies and frees up TIF bits.

Define SYSCALL_WORK_SYSCALL_TRACEPOINT, use it in the generic entry code
and convert the code which uses the TIF specific helper functions to use
the new *_syscall_work() helpers which either resolve to the new mode for
users of the generic entry code or to the TIF based functions for the other
architectures.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-6-krisman@collabora.com
2020-11-16 21:53:15 +01:00
Gabriel Krisman Bertazi 23d67a5485 seccomp: Migrate to use SYSCALL_WORK flag
On architectures using the generic syscall entry code the architecture
independent syscall work is moved to flags in thread_info::syscall_work.
This removes architecture dependencies and frees up TIF bits.

Define SYSCALL_WORK_SECCOMP, use it in the generic entry code and convert
the code which uses the TIF specific helper functions to use the new
*_syscall_work() helpers which either resolve to the new mode for users of
the generic entry code or to the TIF based functions for the other
architectures.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-5-krisman@collabora.com
2020-11-16 21:53:15 +01:00
Gabriel Krisman Bertazi 3136b93c3f entry: Expose helpers to migrate TIF to SYSCALL_WORK flags
With the goal to split the syscall work related flags into a separate
field that is architecture independent, expose transitional helpers that
resolve to either the TIF flags or to the corresponding SYSCALL_WORK
flags.  This will allow architectures to migrate only when they port to
the generic syscall entry code.

Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20201116174206.2639648-3-krisman@collabora.com
2020-11-16 21:53:15 +01:00
Kees Cook 6d13de1489 uaccess: disallow > INT_MAX copy sizes
As we've done with VFS, string operations, etc, reject usercopy sizes
larger than INT_MAX, which would be nice to have for catching bugs
related to size calculation overflows[1].

This adds 10 bytes to x86_64 defconfig text and 1980 bytes to the data
section:

     text    data     bss     dec     hex filename
  19691167        5134320 1646664 26472151        193eed7 vmlinux.before
  19691177        5136300 1646664 26474141        193f69d vmlinux.after

[1] https://marc.info/?l=linux-s390&m=156631939010493&w=2

Link: http://lkml.kernel.org/r/201908251612.F9902D7A@keescook
Signed-off-by: Kees Cook <keescook@chromium.org>
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04 19:44:14 -08:00
Kees Cook 9dd819a151 uaccess: add missing __must_check attributes
The usercopy implementation comments describe that callers of the
copy_*_user() family of functions must always have their return values
checked.  This can be enforced at compile time with __must_check, so add
it where needed.

Link: http://lkml.kernel.org/r/201908251609.ADAD5CAAC1@keescook
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
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>
2019-09-25 17:51:40 -07:00
Dave Martin 93ee37c2a6 thread_info: Add update_thread_flag() helpers
There are a number of bits of code sprinkled around the kernel to
set a thread flag if a certain condition is true, and clear it
otherwise.

To help make those call sites terser and less cumbersome, this
patch adds a new family of thread flag manipulators

	update*_thread_flag([...,] flag, cond)

which do the equivalent of:

	if (cond)
		set*_thread_flag([...,] flag);
	else
		clear*_thread_flag([...,] flag);

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-05-25 12:27:53 +01:00
Kees Cook e01e80634e fork: unconditionally clear stack on fork
One of the classes of kernel stack content leaks[1] is exposing the
contents of prior heap or stack contents when a new process stack is
allocated.  Normally, those stacks are not zeroed, and the old contents
remain in place.  In the face of stack content exposure flaws, those
contents can leak to userspace.

Fixing this will make the kernel no longer vulnerable to these flaws, as
the stack will be wiped each time a stack is assigned to a new process.
There's not a meaningful change in runtime performance; it almost looks
like it provides a benefit.

Performing back-to-back kernel builds before:
	Run times: 157.86 157.09 158.90 160.94 160.80
	Mean: 159.12
	Std Dev: 1.54

and after:
	Run times: 159.31 157.34 156.71 158.15 160.81
	Mean: 158.46
	Std Dev: 1.46

Instead of making this a build or runtime config, Andy Lutomirski
recommended this just be enabled by default.

[1] A noisy search for many kinds of stack content leaks can be seen here:
https://cve.mitre.org/cgi-bin/cvekey.cgi?keyword=linux+kernel+stack+leak

I did some more with perf and cycle counts on running 100,000 execs of
/bin/true.

before:
Cycles: 218858861551 218853036130 214727610969 227656844122 224980542841
Mean:  221015379122.60
Std Dev: 4662486552.47

after:
Cycles: 213868945060 213119275204 211820169456 224426673259 225489986348
Mean:  217745009865.40
Std Dev: 5935559279.99

It continues to look like it's faster, though the deviation is rather
wide, but I'm not sure what I could do that would be less noisy.  I'm
open to ideas!

Link: http://lkml.kernel.org/r/20180221021659.GA37073@beast
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-20 17:18:35 -07:00
Levin, Alexander (Sasha Levin) 75f296d93b kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK
Convert all allocations that used a NOTRACK flag to stop using it.

Link: http://lkml.kernel.org/r/20171007030159.22241-3-alexander.levin@verizon.com
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tim Hansen <devtimhansen@gmail.com>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-15 18:21:04 -08:00
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00
Konstantin Khlebnikov ca18255185 kmemleak: clear stale pointers from task stacks
Kmemleak considers any pointers on task stacks as references.  This
patch clears newly allocated and reused vmap stacks.

Link: http://lkml.kernel.org/r/150728990124.744199.8403409836394318684.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-13 16:18:33 -07:00
Mark Rutland 48ac3c18cc fork: allow arch-override of VMAP stack alignment
In some cases, an architecture might wish its stacks to be aligned to a
boundary larger than THREAD_SIZE. For example, using an alignment of
double THREAD_SIZE can allow for stack overflows smaller than
THREAD_SIZE to be detected by checking a single bit of the stack
pointer.

This patch allows architectures to override the alignment of VMAP'd
stacks, by defining THREAD_ALIGN. Where not defined, this defaults to
THREAD_SIZE, as is the case today.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: linux-kernel@vger.kernel.org
2017-08-15 18:34:46 +01:00
Al Viro b0377fedb6 copy_{to,from}_user(): consolidate object size checks
... and move them into thread_info.h, next to check_object_size()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-29 22:21:21 -04:00
Linus Torvalds 5958cc49ed A couple hardened usercopy changes:
- drop now unneeded is_vmalloc_or_module() check; Laura Abbott
 - use enum instead of literals for stack frame API; Sahara
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Merge tag 'usercopy-v4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull hardened usercopy updates from Kees Cook:
 "A couple hardened usercopy changes:

   - drop now unneeded is_vmalloc_or_module() check (Laura Abbott)

   - use enum instead of literals for stack frame API (Sahara)"

* tag 'usercopy-v4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  mm/usercopy: Drop extra is_vmalloc_or_module() check
  usercopy: Move enum for arch_within_stack_frames()
2017-05-02 10:45:15 -07:00
Sahara 96dc4f9fb6 usercopy: Move enum for arch_within_stack_frames()
This patch moves the arch_within_stack_frames() return value enum up in
the header files so that per-architecture implementations can reuse the
same return values.

Signed-off-by: Sahara <keun-o.park@darkmatter.ae>
Signed-off-by: James Morse <james.morse@arm.com>
[kees: adjusted naming and commit log]
Signed-off-by: Kees Cook <keescook@chromium.org>
2017-04-04 14:30:29 -07:00
Kyle Huey e9ea1e7f53 x86/arch_prctl: Add ARCH_[GET|SET]_CPUID
Intel supports faulting on the CPUID instruction beginning with Ivy Bridge.
When enabled, the processor will fault on attempts to execute the CPUID
instruction with CPL>0. Exposing this feature to userspace will allow a
ptracer to trap and emulate the CPUID instruction.

When supported, this feature is controlled by toggling bit 0 of
MSR_MISC_FEATURES_ENABLES. It is documented in detail in Section 2.3.2 of
https://bugzilla.kernel.org/attachment.cgi?id=243991

Implement a new pair of arch_prctls, available on both x86-32 and x86-64.

ARCH_GET_CPUID: Returns the current CPUID state, either 0 if CPUID faulting
    is enabled (and thus the CPUID instruction is not available) or 1 if
    CPUID faulting is not enabled.

ARCH_SET_CPUID: Set the CPUID state to the second argument. If
    cpuid_enabled is 0 CPUID faulting will be activated, otherwise it will
    be deactivated. Returns ENODEV if CPUID faulting is not supported on
    this system.

The state of the CPUID faulting flag is propagated across forks, but reset
upon exec.

Signed-off-by: Kyle Huey <khuey@kylehuey.com>
Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com>
Cc: kvm@vger.kernel.org
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: linux-kselftest@vger.kernel.org
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Robert O'Callahan <robert@ocallahan.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: user-mode-linux-user@lists.sourceforge.net
Cc: David Matlack <dmatlack@google.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: linux-fsdevel@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: http://lkml.kernel.org/r/20170320081628.18952-9-khuey@kylehuey.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-20 16:10:34 +01:00
Mark Rutland dc3d2a679c thread_info: include <current.h> for THREAD_INFO_IN_TASK
When CONFIG_THREAD_INFO_IN_TASK is selected, the current_thread_info()
macro relies on current having been defined prior to its use. However,
not all users of current_thread_info() include <asm/current.h>, and thus
current is not guaranteed to be defined.

When CONFIG_THREAD_INFO_IN_TASK is not selected, it's possible that
get_current() / current are based upon current_thread_info(), and
<asm/current.h> includes <asm/thread_info.h>. Thus always including
<asm/current.h> would result in circular dependences on some platforms.

To ensure both cases work, this patch includes <asm/current.h>, but only
when CONFIG_THREAD_INFO_IN_TASK is selected.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-11-11 18:25:08 +00:00
Mark Rutland 53d74d056a thread_info: factor out restart_block
Since commit f56141e3e2 ("all arches, signal: move restart_block
to struct task_struct"), thread_info and restart_block have been
logically distinct, yet struct restart_block is still defined in
<linux/thread_info.h>.

At least one architecture (erroneously) uses restart_block as part of
its thread_info, and thus the definition of restart_block must come
before the include of <asm/thread_info>. Subsequent patches in this
series need to shuffle the order of includes and definitions in
<linux/thread_info.h>, and will make this ordering fragile.

This patch moves the definition of restart_block out to its own header.
This serves as generic cleanup, logically separating thread_info and
restart_block, and also makes it easier to avoid fragility.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-11-11 18:24:16 +00:00
Heiko Carstens c8061485a0 sched/core, x86: Make struct thread_info arch specific again
The following commit:

  c65eacbe29 ("sched/core: Allow putting thread_info into task_struct")

... made 'struct thread_info' a generic struct with only a
single ::flags member, if CONFIG_THREAD_INFO_IN_TASK_STRUCT=y is
selected.

This change however seems to be quite x86 centric, since at least the
generic preemption code (asm-generic/preempt.h) assumes that struct
thread_info also has a preempt_count member, which apparently was not
true for x86.

We could add a bit more #ifdefs to solve this problem too, but it seems
to be much simpler to make struct thread_info arch specific
again. This also makes the conversion to THREAD_INFO_IN_TASK_STRUCT a
bit easier for architectures that have a couple of arch specific stuff
in their thread_info definition.

The arch specific stuff _could_ be moved to thread_struct. However
keeping them in thread_info makes it easier: accessing thread_info
members is simple, since it is at the beginning of the task_struct,
while the thread_struct is at the end. At least on s390 the offsets
needed to access members of the thread_struct (with task_struct as
base) are too large for various asm instructions.  This is not a
problem when keeping these members within thread_info.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: keescook@chromium.org
Cc: linux-arch@vger.kernel.org
Link: http://lkml.kernel.org/r/1476901693-8492-2-git-send-email-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-20 13:27:47 +02:00
Mark Rutland 907241dccb thread_info: Use unsigned long for flags
The generic THREAD_INFO_IN_TASK definition of thread_info::flags is a
u32, matching x86 prior to the introduction of THREAD_INFO_IN_TASK.

However, common helpers like test_ti_thread_flag() implicitly assume
that thread_info::flags has at least the size and alignment of unsigned
long, and relying on padding and alignment provided by other elements of
task_struct is somewhat fragile. Additionally, some architectures use
more that 32 bits for thread_info::flags, and others may need to in
future.

With THREAD_INFO_IN_TASK, task struct follows thread_info with a long
field, and thus we no longer save any space as we did back in commit:

  affa219b60 ("x86: change thread_info's flag field back to 32 bits")

Given all this, it makes more sense for the generic thread_info::flags
to be an unsigned long.

In fact given <linux/thread_info.h> contains/uses the helpers mentioned
above, BE arches *must* use unsigned long (or something of the same size)
today, or they wouldn't work.

Make it so.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1474651447-30447-1-git-send-email-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-24 09:35:06 +02:00
Andy Lutomirski c65eacbe29 sched/core: Allow putting thread_info into task_struct
If an arch opts in by setting CONFIG_THREAD_INFO_IN_TASK_STRUCT,
then thread_info is defined as a single 'u32 flags' and is the first
entry of task_struct.  thread_info::task is removed (it serves no
purpose if thread_info is embedded in task_struct), and
thread_info::cpu gets its own slot in task_struct.

This is heavily based on a patch written by Linus.

Originally-from: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/a0898196f0476195ca02713691a5037a14f2aac5.1473801993.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-15 08:25:13 +02:00
Kees Cook a85d6b8242 usercopy: force check_object_size() inline
Just for good measure, make sure that check_object_size() is always
inlined too, as already done for copy_*_user() and __copy_*_user().

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
2016-09-07 11:33:26 -07:00
Kees Cook 81409e9e28 usercopy: fold builtin_const check into inline function
Instead of having each caller of check_object_size() need to remember to
check for a const size parameter, move the check into check_object_size()
itself. This actually matches the original implementation in PaX, though
this commit cleans up the now-redundant builtin_const() calls in the
various architectures.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-09-06 12:17:29 -07:00
Linus Torvalds 1eccfa090e Implements HARDENED_USERCOPY verification of copy_to_user/copy_from_user
bounds checking for most architectures on SLAB and SLUB.
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Merge tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull usercopy protection from Kees Cook:
 "Tbhis implements HARDENED_USERCOPY verification of copy_to_user and
  copy_from_user bounds checking for most architectures on SLAB and
  SLUB"

* tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  mm: SLUB hardened usercopy support
  mm: SLAB hardened usercopy support
  s390/uaccess: Enable hardened usercopy
  sparc/uaccess: Enable hardened usercopy
  powerpc/uaccess: Enable hardened usercopy
  ia64/uaccess: Enable hardened usercopy
  arm64/uaccess: Enable hardened usercopy
  ARM: uaccess: Enable hardened usercopy
  x86/uaccess: Enable hardened usercopy
  mm: Hardened usercopy
  mm: Implement stack frame object validation
  mm: Add is_migrate_cma_page
2016-08-08 14:48:14 -07:00
Andy Lutomirski 7e7814180b signal: consolidate {TS,TLF}_RESTORE_SIGMASK code
In general, there's no need for the "restore sigmask" flag to live in
ti->flags.  alpha, ia64, microblaze, powerpc, sh, sparc (64-bit only),
tile, and x86 use essentially identical alternative implementations,
placing the flag in ti->status.

Replace those optimized implementations with an equally good common
implementation that stores it in a bitfield in struct task_struct and
drop the custom implementations.

Additional architectures can opt in by removing their
TIF_RESTORE_SIGMASK defines.

Link: http://lkml.kernel.org/r/8a14321d64a28e40adfddc90e18a96c086a6d6f9.1468522723.git.luto@kernel.org
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>	[powerpc]
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02 19:35:23 -04:00
Kees Cook f5509cc18d mm: Hardened usercopy
This is the start of porting PAX_USERCOPY into the mainline kernel. This
is the first set of features, controlled by CONFIG_HARDENED_USERCOPY. The
work is based on code by PaX Team and Brad Spengler, and an earlier port
from Casey Schaufler. Additional non-slab page tests are from Rik van Riel.

This patch contains the logic for validating several conditions when
performing copy_to_user() and copy_from_user() on the kernel object
being copied to/from:
- address range doesn't wrap around
- address range isn't NULL or zero-allocated (with a non-zero copy size)
- if on the slab allocator:
  - object size must be less than or equal to copy size (when check is
    implemented in the allocator, which appear in subsequent patches)
- otherwise, object must not span page allocations (excepting Reserved
  and CMA ranges)
- if on the stack
  - object must not extend before/after the current process stack
  - object must be contained by a valid stack frame (when there is
    arch/build support for identifying stack frames)
- object must not overlap with kernel text

Signed-off-by: Kees Cook <keescook@chromium.org>
Tested-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
2016-07-26 14:41:47 -07:00
Kees Cook 0f60a8efe4 mm: Implement stack frame object validation
This creates per-architecture function arch_within_stack_frames() that
should validate if a given object is contained by a kernel stack frame.
Initial implementation is on x86.

This is based on code from PaX.

Signed-off-by: Kees Cook <keescook@chromium.org>
2016-07-26 14:41:47 -07:00
Vladimir Davydov 5d097056c9 kmemcg: account certain kmem allocations to memcg
Mark those kmem allocations that are known to be easily triggered from
userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
memcg.  For the list, see below:

 - threadinfo
 - task_struct
 - task_delay_info
 - pid
 - cred
 - mm_struct
 - vm_area_struct and vm_region (nommu)
 - anon_vma and anon_vma_chain
 - signal_struct
 - sighand_struct
 - fs_struct
 - files_struct
 - fdtable and fdtable->full_fds_bits
 - dentry and external_name
 - inode for all filesystems. This is the most tedious part, because
   most filesystems overwrite the alloc_inode method.

The list is far from complete, so feel free to add more objects.
Nevertheless, it should be close to "account everything" approach and
keep most workloads within bounds.  Malevolent users will be able to
breach the limit, but this was possible even with the former "account
everything" approach (simply because it did not account everything in
fact).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-14 16:00:49 -08:00
Vladimir Davydov 52383431b3 mm: get rid of __GFP_KMEMCG
Currently to allocate a page that should be charged to kmemcg (e.g.
threadinfo), we pass __GFP_KMEMCG flag to the page allocator.  The page
allocated is then to be freed by free_memcg_kmem_pages.  Apart from
looking asymmetrical, this also requires intrusion to the general
allocation path.  So let's introduce separate functions that will
alloc/free pages charged to kmemcg.

The new functions are called alloc_kmem_pages and free_kmem_pages.  They
should be used when the caller actually would like to use kmalloc, but
has to fall back to the page allocator for the allocation is large.
They only differ from alloc_pages and free_pages in that besides
allocating or freeing pages they also charge them to the kmem resource
counter of the current memory cgroup.

[sfr@canb.auug.org.au: export kmalloc_order() to modules]
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:53:56 -07:00
Peter Zijlstra 08f8aeb55d sched: Remove set_need_resched()
The last user is gone now, so we can safely remove this function.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <bitbucket@online.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-04-18 12:07:31 +02:00
Peter Zijlstra ea81174789 sched, idle: Fix the idle polling state logic
Mike reported that commit 7d1a9417 ("x86: Use generic idle loop")
regressed several workloads and caused excessive reschedule
interrupts.

The patch in question failed to notice that the x86 code had an
inverted sense of the polling state versus the new generic code (x86:
default polling, generic: default !polling).

Fix the two prominent x86 mwait based idle drivers and introduce a few
new generic polling helpers (fixing the wrong smp_mb__after_clear_bit
usage).

Also switch the idle routines to using tif_need_resched() which is an
immediate TIF_NEED_RESCHED test as opposed to need_resched which will
end up being slightly different.

Reported-by: Mike Galbraith <bitbucket@online.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: lenb@kernel.org
Cc: tglx@linutronix.de
Link: http://lkml.kernel.org/n/tip-nc03imb0etuefmzybzj7sprf@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-25 13:53:10 +02:00
Peter Zijlstra 3150398626 sched: Remove {set,clear}_need_resched
Preemption semantics are going to change which mandate a change.

All DRM usage sites are already broken and will not be affected (much)
by this change. DRM people are aware and will remove the last few
stragglers.

For now, leave an empty stub that generates a warning, once all users
are gone we can remove this.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: airlied@linux.ie
Cc: daniel.vetter@ffwll.ch
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/n/tip-qfc1el2zvhxiyut4ai99ij4n@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-09-25 13:53:09 +02:00
Glauber Costa 2ad306b17c fork: protect architectures where THREAD_SIZE >= PAGE_SIZE against fork bombs
Because those architectures will draw their stacks directly from the page
allocator, rather than the slab cache, we can directly pass __GFP_KMEMCG
flag, and issue the corresponding free_pages.

This code path is taken when the architecture doesn't define
CONFIG_ARCH_THREAD_INFO_ALLOCATOR (only ia64 seems to), and has
THREAD_SIZE >= PAGE_SIZE.  Luckily, most - if not all - of the remaining
architectures fall in this category.

This will guarantee that every stack page is accounted to the memcg the
process currently lives on, and will have the allocations to fail if they
go over limit.

For the time being, I am defining a new variant of THREADINFO_GFP, not to
mess with the other path.  Once the slab is also tracked by memcg, we can
get rid of that flag.

Tested to successfully protect against :(){ :|:& };:

Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Frederic Weisbecker <fweisbec@redhat.com>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 15:02:13 -08:00
Al Viro edd63a2763 set_restore_sigmask() is never called without SIGPENDING (and never should be)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 12:58:50 -04:00
Al Viro 4ebefe3ec7 new helpers: {clear,test,test_and_clear}_restore_sigmask()
helpers parallel to set_restore_sigmask(), used in the next commits

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 12:58:47 -04:00
Al Viro 754421c8ca HAVE_RESTORE_SIGMASK is defined on all architectures now
Everyone either defines it in arch thread_info.h or has TIF_RESTORE_SIGMASK
and picks default set_restore_sigmask() in linux/thread_info.h.  Kill the
ifdefs, slap #error in linux/thread_info.h to catch breakage when new ones
get merged.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-06-01 12:58:46 -04:00
Thomas Gleixner 2889f60814 fork: Move thread info gfp flags to header
These flags can be useful for extra allocations outside of the core
code.

Add __GFP_NOTRACK to them, so the archs which have kmemcheck do
not have to provide extra allocators just for that reason.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20120505150141.428211694@linutronix.de
2012-05-08 13:55:20 +02:00
Thomas Gleixner ab8177bc53 hrtimers: Avoid touching inactive timer bases
Instead of iterating over all possible timer bases avoid it by marking
the active bases in the cpu base.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
2011-05-23 13:59:54 +02:00
Thomas Gleixner d608c18203 thread_info: Remove legacy arg0-3 from restart_block
posix timers were the last users of the legacy arg0-3 members of
restart_block. Remove the cruft.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: John Stultz <johnstul@us.ibm.com>
Tested-by: Richard Cochran <richard.cochran@omicron.at>
LKML-Reference: <20110201134418.326209775@linutronix.de>
2011-02-02 15:28:13 +01:00
Namhyung Kim a3c74c5257 futex: Mark restart_block.futex.uaddr[2] __user
@uaddr and @uaddr2 fields in restart_block.futex are user
pointers. Add __user and remove unnecessary casts.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Darren Hart <dvhltc@us.ibm.com>
LKML-Reference: <1284468228-8723-2-git-send-email-namhyung@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-09-18 12:19:21 +02:00
Darren Hart 52400ba946 futex: add requeue_pi functionality
PI Futexes and their underlying rt_mutex cannot be left ownerless if
there are pending waiters as this will break the PI boosting logic, so
the standard requeue commands aren't sufficient.  The new commands
properly manage pi futex ownership by ensuring a futex with waiters
has an owner at all times.  This will allow glibc to properly handle
pi mutexes with pthread_condvars.

The approach taken here is to create two new futex op codes:

FUTEX_WAIT_REQUEUE_PI:
Tasks will use this op code to wait on a futex (such as a non-pi waitqueue)
and wake after they have been requeued to a pi futex.  Prior to returning to
userspace, they will acquire this pi futex (and the underlying rt_mutex).

futex_wait_requeue_pi() is the result of a high speed collision between
futex_wait() and futex_lock_pi() (with the first part of futex_lock_pi() being
done by futex_proxy_trylock_atomic() on behalf of the top_waiter).

FUTEX_REQUEUE_PI (and FUTEX_CMP_REQUEUE_PI):
This call must be used to wake tasks waiting with FUTEX_WAIT_REQUEUE_PI,
regardless of how many tasks the caller intends to wake or requeue.
pthread_cond_broadcast() should call this with nr_wake=1 and
nr_requeue=INT_MAX.  pthread_cond_signal() should call this with nr_wake=1 and
nr_requeue=0.  The reason being we need both callers to get the benefit of the
futex_proxy_trylock_atomic() routine.  futex_requeue() also enqueues the
top_waiter on the rt_mutex via rt_mutex_start_proxy_lock().

Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-04-06 11:14:03 +02:00
Thomas Gleixner be5dad20a5 select: add a poll specific struct to the restart_block union
with hrtimer poll/select, the signal restart data no longer is a single
long representing a jiffies count, but it becomes a second/nanosecond pair
that also needs to encode if there was a timeout at all or not.

This patch adds a struct to the restart_block union for this purpose

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
2008-09-05 21:35:01 -07:00
Roland McGrath f3de272b82 signals: use HAVE_SET_RESTORE_SIGMASK
Change all the #ifdef TIF_RESTORE_SIGMASK conditionals in non-arch code to
#ifdef HAVE_SET_RESTORE_SIGMASK.  If arch code defines it first, the generic
set_restore_sigmask() using TIF_RESTORE_SIGMASK is not defined.

Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:37 -07:00