Joel Fernandes created a nice patch that cleaned up the duplicate hooks used
by lockdep and irqsoff latency tracer. It made both use tracepoints. But it
caused lockdep to trigger several false positives. We have not figured out
why yet, but removing lockdep from using the trace event hooks and just call
its helper functions directly (like it use to), makes the problem go away.
This is a partial revert of the clean up patch c3bc8fd637 ("tracing:
Centralize preemptirq tracepoints and unify their usage") that adds direct
calls for lockdep, but also keeps most of the clean up done to get rid of
the horrible preprocessor if statements.
Link: http://lkml.kernel.org/r/20180806155058.5ee875f4@gandalf.local.home
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Fixes: c3bc8fd637 ("tracing: Centralize preemptirq tracepoints and unify their usage")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This patch detaches the preemptirq tracepoints from the tracers and
keeps it separate.
Advantages:
* Lockdep and irqsoff event can now run in parallel since they no longer
have their own calls.
* This unifies the usecase of adding hooks to an irqsoff and irqson
event, and a preemptoff and preempton event.
3 users of the events exist:
- Lockdep
- irqsoff and preemptoff tracers
- irqs and preempt trace events
The unification cleans up several ifdefs and makes the code in preempt
tracer and irqsoff tracers simpler. It gets rid of all the horrific
ifdeferry around PROVE_LOCKING and makes configuration of the different
users of the tracepoints more easy and understandable. It also gets rid
of the time_* function calls from the lockdep hooks used to call into
the preemptirq tracer which is not needed anymore. The negative delta in
lines of code in this patch is quite large too.
In the patch we introduce a new CONFIG option PREEMPTIRQ_TRACEPOINTS
as a single point for registering probes onto the tracepoints. With
this,
the web of config options for preempt/irq toggle tracepoints and its
users becomes:
PREEMPT_TRACER PREEMPTIRQ_EVENTS IRQSOFF_TRACER PROVE_LOCKING
| | \ | |
\ (selects) / \ \ (selects) /
TRACE_PREEMPT_TOGGLE ----> TRACE_IRQFLAGS
\ /
\ (depends on) /
PREEMPTIRQ_TRACEPOINTS
Other than the performance tests mentioned in the previous patch, I also
ran the locking API test suite. I verified that all tests cases are
passing.
I also injected issues by not registering lockdep probes onto the
tracepoints and I see failures to confirm that the probes are indeed
working.
This series + lockdep probes not registered (just to inject errors):
[ 0.000000] hard-irqs-on + irq-safe-A/21: ok | ok | ok |
[ 0.000000] soft-irqs-on + irq-safe-A/21: ok | ok | ok |
[ 0.000000] sirq-safe-A => hirqs-on/12:FAILED|FAILED| ok |
[ 0.000000] sirq-safe-A => hirqs-on/21:FAILED|FAILED| ok |
[ 0.000000] hard-safe-A + irqs-on/12:FAILED|FAILED| ok |
[ 0.000000] soft-safe-A + irqs-on/12:FAILED|FAILED| ok |
[ 0.000000] hard-safe-A + irqs-on/21:FAILED|FAILED| ok |
[ 0.000000] soft-safe-A + irqs-on/21:FAILED|FAILED| ok |
[ 0.000000] hard-safe-A + unsafe-B #1/123: ok | ok | ok |
[ 0.000000] soft-safe-A + unsafe-B #1/123: ok | ok | ok |
With this series + lockdep probes registered, all locking tests pass:
[ 0.000000] hard-irqs-on + irq-safe-A/21: ok | ok | ok |
[ 0.000000] soft-irqs-on + irq-safe-A/21: ok | ok | ok |
[ 0.000000] sirq-safe-A => hirqs-on/12: ok | ok | ok |
[ 0.000000] sirq-safe-A => hirqs-on/21: ok | ok | ok |
[ 0.000000] hard-safe-A + irqs-on/12: ok | ok | ok |
[ 0.000000] soft-safe-A + irqs-on/12: ok | ok | ok |
[ 0.000000] hard-safe-A + irqs-on/21: ok | ok | ok |
[ 0.000000] soft-safe-A + irqs-on/21: ok | ok | ok |
[ 0.000000] hard-safe-A + unsafe-B #1/123: ok | ok | ok |
[ 0.000000] soft-safe-A + unsafe-B #1/123: ok | ok | ok |
Link: http://lkml.kernel.org/r/20180730222423.196630-4-joel@joelfernandes.org
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Merge tag 'init_task-20180117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull init_task initializer cleanups from David Howells:
"It doesn't seem useful to have the init_task in a header file rather
than in a normal source file. We could consolidate init_task handling
instead and expand out various macros.
Here's a series of patches that consolidate init_task handling:
(1) Make THREAD_SIZE available to vmlinux.lds for cris, hexagon and
openrisc.
(2) Alter the INIT_TASK_DATA linker script macro to set
init_thread_union and init_stack rather than defining these in C.
Insert init_task and init_thread_into into the init_stack area in
the linker script as appropriate to the configuration, with
different section markers so that they end up correctly ordered.
We can then get merge ia64's init_task.c into the main one.
We then have a bunch of single-use INIT_*() macros that seem only
to be macros because they used to be used per-arch. We can then
expand these in place of the user and get rid of a few lines and
a lot of backslashes.
(3) Expand INIT_TASK() in place.
(4) Expand in place various small INIT_*() macros that are defined
conditionally. Expand them and surround them by #if[n]def/#endif
in the .c file as it takes fewer lines.
(5) Expand INIT_SIGNALS() and INIT_SIGHAND() in place.
(6) Expand INIT_STRUCT_PID in place.
These macros can then be discarded"
* tag 'init_task-20180117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
Expand INIT_STRUCT_PID and remove
Expand the INIT_SIGNALS and INIT_SIGHAND macros and remove
Expand various INIT_* macros and remove
Expand INIT_TASK() in init/init_task.c and remove
Construct init thread stack in the linker script rather than by union
openrisc: Make THREAD_SIZE available to vmlinux.lds
hexagon: Make THREAD_SIZE available to vmlinux.lds
cris: Make THREAD_SIZE available to vmlinux.lds
Expand various INIT_* macros into the single places they're used in
init/init_task.c and remove them.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Tested-by: Will Deacon <will.deacon@arm.com> (arm64)
Tested-by: Palmer Dabbelt <palmer@sifive.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
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>
Where XHLOCK_{SOFT,HARD} are save/restore points in the xhlocks[] to
ensure the temporal IRQ events don't interact with task state, the
XHLOCK_PROC is a fundament different beast that just happens to share
the interface.
The purpose of XHLOCK_PROC is to annotate independent execution inside
one task. For example workqueues, each work should appear to run in its
own 'pristine' 'task'.
Remove XHLOCK_PROC in favour of its own interface to avoid confusion.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: david@fromorbit.com
Cc: johannes@sipsolutions.net
Cc: kernel-team@lge.com
Cc: oleg@redhat.com
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/20170829085939.ggmb6xiohw67micb@hirez.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The new completion/crossrelease annotations interact unfavourable with
the extant flush_work()/flush_workqueue() annotations.
The problem is that when a single work class does:
wait_for_completion(&C)
and
complete(&C)
in different executions, we'll build dependencies like:
lock_map_acquire(W)
complete_acquire(C)
and
lock_map_acquire(W)
complete_release(C)
which results in the dependency chain: W->C->W, which lockdep thinks
spells deadlock, even though there is no deadlock potential since
works are ran concurrently.
One possibility would be to change the work 'lock' to recursive-read,
but that would mean hitting a lockdep limitation on recursive locks.
Also, unconditinoally switching to recursive-read here would fail to
detect the actual deadlock on single-threaded workqueues, which do
have a problem with this.
For now, forcefully disregard these locks for crossrelease.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: byungchul.park@lge.com
Cc: david@fromorbit.com
Cc: johannes@sipsolutions.net
Cc: oleg@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Lockdep is a runtime locking correctness validator that detects and
reports a deadlock or its possibility by checking dependencies between
locks. It's useful since it does not report just an actual deadlock but
also the possibility of a deadlock that has not actually happened yet.
That enables problems to be fixed before they affect real systems.
However, this facility is only applicable to typical locks, such as
spinlocks and mutexes, which are normally released within the context in
which they were acquired. However, synchronization primitives like page
locks or completions, which are allowed to be released in any context,
also create dependencies and can cause a deadlock.
So lockdep should track these locks to do a better job. The 'crossrelease'
implementation makes these primitives also be tracked.
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: boqun.feng@gmail.com
Cc: kernel-team@lge.com
Cc: kirill@shutemov.name
Cc: npiggin@gmail.com
Cc: walken@google.com
Cc: willy@infradead.org
Link: http://lkml.kernel.org/r/1502089981-21272-6-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The conditional in local_irq_restore() otherwise can cause code
bloat (the if and else blocks may get translated into separate
code paths despite the generated code being identical, dependent
on compiler internal heuristics). Note that this adjustment gets
the code in sync with the comment preceding it (which was
slightly wrong from at least from 2.6.37 onwards).
The code bloat was observed in reality with an experimental x86
patch.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/54BE5F8E02000078000570A7@mail.emea.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fix the IRQ flag handling naming. In linux/irqflags.h under one configuration,
it maps:
local_irq_enable() -> raw_local_irq_enable()
local_irq_disable() -> raw_local_irq_disable()
local_irq_save() -> raw_local_irq_save()
...
and under the other configuration, it maps:
raw_local_irq_enable() -> local_irq_enable()
raw_local_irq_disable() -> local_irq_disable()
raw_local_irq_save() -> local_irq_save()
...
This is quite confusing. There should be one set of names expected of the
arch, and this should be wrapped to give another set of names that are expected
by users of this facility.
Change this to have the arch provide:
flags = arch_local_save_flags()
flags = arch_local_irq_save()
arch_local_irq_restore(flags)
arch_local_irq_disable()
arch_local_irq_enable()
arch_irqs_disabled_flags(flags)
arch_irqs_disabled()
arch_safe_halt()
Then linux/irqflags.h wraps these to provide:
raw_local_save_flags(flags)
raw_local_irq_save(flags)
raw_local_irq_restore(flags)
raw_local_irq_disable()
raw_local_irq_enable()
raw_irqs_disabled_flags(flags)
raw_irqs_disabled()
raw_safe_halt()
with type checking on the flags 'arguments', and then wraps those to provide:
local_save_flags(flags)
local_irq_save(flags)
local_irq_restore(flags)
local_irq_disable()
local_irq_enable()
irqs_disabled_flags(flags)
irqs_disabled()
safe_halt()
with tracing included if enabled.
The arch functions can now all be inline functions rather than some of them
having to be macros.
Signed-off-by: David Howells <dhowells@redhat.com> [X86, FRV, MN10300]
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> [Tile]
Signed-off-by: Michal Simek <monstr@monstr.eu> [Microblaze]
Tested-by: Catalin Marinas <catalin.marinas@arm.com> [ARM]
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> [AVR]
Acked-by: Tony Luck <tony.luck@intel.com> [IA-64]
Acked-by: Hirokazu Takata <takata@linux-m32r.org> [M32R]
Acked-by: Greg Ungerer <gerg@uclinux.org> [M68K/M68KNOMMU]
Acked-by: Ralf Baechle <ralf@linux-mips.org> [MIPS]
Acked-by: Kyle McMartin <kyle@mcmartin.ca> [PA-RISC]
Acked-by: Paul Mackerras <paulus@samba.org> [PowerPC]
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [S390]
Acked-by: Chen Liqin <liqin.chen@sunplusct.com> [Score]
Acked-by: Matt Fleming <matt@console-pimps.org> [SH]
Acked-by: David S. Miller <davem@davemloft.net> [Sparc]
Acked-by: Chris Zankel <chris@zankel.net> [Xtensa]
Reviewed-by: Richard Henderson <rth@twiddle.net> [Alpha]
Reviewed-by: Yoshinori Sato <ysato@users.sourceforge.jp> [H8300]
Cc: starvik@axis.com [CRIS]
Cc: jesper.nilsson@axis.com [CRIS]
Cc: linux-cris-kernel@axis.com
The comment suggests this #endif is CONFIG_X86 but it's really
CONFIG_TRACE_IRQFLAGS_SUPPORT
Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: michael@ellerman.id.au
LKML-Reference: <18191.1256182768@neuling.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
The naming clashes with upcoming softirq tracepoints, so rename the
APIs to lockdep_*().
Requested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There haave been several areas in the kernel where an int has been used for
flags in local_irq_save() and friends instead of a long. This can cause some
hard to debug problems on some architectures.
This patch adds a typecheck inside the irqsave and restore functions to flag
these cases.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: build fix]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add preempt off timings. A lot of kernel core code is taken from the RT patch
latency trace that was written by Ingo Molnar.
This adds "preemptoff" and "preemptirqsoff" to /debugfs/tracing/available_tracers
Now instead of just tracing irqs off, preemption off can be selected
to be recorded.
When this is selected, it shares the same files as irqs off timings.
One can either trace preemption off, irqs off, or one or the other off.
By echoing "preemptoff" into /debugfs/tracing/current_tracer, recording
of preempt off only is performed. "irqsoff" will only record the time
irqs are disabled, but "preemptirqsoff" will take the total time irqs
or preemption are disabled. Runtime switching of these options is now
supported by simpling echoing in the appropriate trace name into
/debugfs/tracing/current_tracer.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
irqs_disabled() uses flags internally, use _flags to avoid shadowing
code calling into this macro.
Introduced between 2.6.25-rc3 and -rc4
Fixes the sparse warning:
arch/x86/mm/pageattr.c:383:21: warning: symbol 'flags' shadows an earlier one
arch/x86/mm/pageattr.c:369:16: originally declared here
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Accurate hard-IRQ-flags and softirq-flags state tracing.
This allows us to attach extra functionality to IRQ flags on/off
events (such as trace-on/off).
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Steven Rostedt (VMware)