Commit Graph

61 Commits

Author SHA1 Message Date
Paul E. McKenney ab1b7880de rcutorture: Make stutter_wait() caller restore priority
Currently, stutter_wait() will happily spin waiting for the stutter
interval to end even if the caller is running at a real-time priority
level.  This could starve normal-priority tasks for no good reason.  This
commit therefore drops the calling task's priority to SCHED_OTHER MAX_NICE
if stutter_wait() needs to wait.  But when it waits, stutter_wait()
returns true, which allows the caller to restore the priority if needed.
Callers that were already running at SCHED_OTHER MAX_NICE obviously
do not need any changes, but this commit also restores priority for
higher-priority callers.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-11-06 17:13:54 -08:00
Paul E. McKenney fda5ba9ed2 torture: Make torture_stutter() use hrtimer
The torture_stutter() function uses schedule_timeout_interruptible()
to time the stutter duration, but this can miss race conditions due to
its being time-synchronized with everything else that is based on the
timer wheels.  This commit therefore converts torture_stutter() to use
the high-resolution timers via schedule_hrtimeout(), and also to fuzz
the stutter interval.  While in the area, this commit also limits the
spin-loop portion of the stutter_wait() function's wait loop to two
jiffies, down from about one second.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-11-06 17:13:49 -08:00
Paul E. McKenney 19012b786e torture: Periodically pause in stutter_wait()
Running locktorture scenario LOCK05 results in hangs:

tools/testing/selftests/rcutorture/bin/kvm.sh --allcpus --torture lock --duration 3 --configs LOCK05

The lock_torture_writer() kthreads set themselves to MAX_NICE while
running SCHED_OTHER.  Other locktorture kthreads run at default niceness,
also SCHED_OTHER.  This results in these other locktorture kthreads
indefinitely preempting the lock_torture_writer() kthreads.  Note that
the cond_resched() in the stutter_wait() function's loop is ineffective
because this scenario is built with CONFIG_PREEMPT=y.

It is not clear that such indefinite preemption is supposed to happen, but
in the meantime this commit prevents kthreads running in stutter_wait()
from being completely CPU-bound, thus allowing the other threads to get
some CPU in a timely fashion.  This commit also uses hrtimers to provide
very short sleeps to avoid degrading the sudden-on testing that stutter
is supposed to provide.

Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-11-06 17:13:48 -08:00
Paul E. McKenney 2102ad290a torture: Dump ftrace at shutdown only if requested
If there is a large number of torture tests running concurrently,
all of which are dumping large ftrace buffers at shutdown time, the
resulting dumping can take a very long time, particularly on systems
with rotating-rust storage.  This commit therefore adds a default-off
torture.ftrace_dump_at_shutdown module parameter that enables
shutdown-time ftrace-buffer dumping.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-06-29 12:01:45 -07:00
Linus Torvalds 992a1a3b45 CPU (hotplug) updates:
- Support for locked CSD objects in smp_call_function_single_async()
     which allows to simplify callsites in the scheduler core and MIPS
 
   - Treewide consolidation of CPU hotplug functions which ensures the
     consistency between the sysfs interface and kernel state. The low level
     functions cpu_up/down() are now confined to the core code and not
     longer accessible from random code.
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Merge tag 'smp-core-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core SMP updates from Thomas Gleixner:
 "CPU (hotplug) updates:

   - Support for locked CSD objects in smp_call_function_single_async()
     which allows to simplify callsites in the scheduler core and MIPS

   - Treewide consolidation of CPU hotplug functions which ensures the
     consistency between the sysfs interface and kernel state. The low
     level functions cpu_up/down() are now confined to the core code and
     not longer accessible from random code"

* tag 'smp-core-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
  cpu/hotplug: Ignore pm_wakeup_pending() for disable_nonboot_cpus()
  cpu/hotplug: Hide cpu_up/down()
  cpu/hotplug: Move bringup of secondary CPUs out of smp_init()
  torture: Replace cpu_up/down() with add/remove_cpu()
  firmware: psci: Replace cpu_up/down() with add/remove_cpu()
  xen/cpuhotplug: Replace cpu_up/down() with device_online/offline()
  parisc: Replace cpu_up/down() with add/remove_cpu()
  sparc: Replace cpu_up/down() with add/remove_cpu()
  powerpc: Replace cpu_up/down() with add/remove_cpu()
  x86/smp: Replace cpu_up/down() with add/remove_cpu()
  arm64: hibernate: Use bringup_hibernate_cpu()
  cpu/hotplug: Provide bringup_hibernate_cpu()
  arm64: Use reboot_cpu instead of hardconding it to 0
  arm64: Don't use disable_nonboot_cpus()
  ARM: Use reboot_cpu instead of hardcoding it to 0
  ARM: Don't use disable_nonboot_cpus()
  ia64: Replace cpu_down() with smp_shutdown_nonboot_cpus()
  cpu/hotplug: Create a new function to shutdown nonboot cpus
  cpu/hotplug: Add new {add,remove}_cpu() functions
  sched/core: Remove rq.hrtick_csd_pending
  ...
2020-03-30 18:06:39 -07:00
Qais Yousef 457bc8ed3e torture: Replace cpu_up/down() with add/remove_cpu()
The core device API performs extra housekeeping bits that are missing
from directly calling cpu_up/down().

See commit a6717c01dd ("powerpc/rtas: use device model APIs and
serialization during LPM") for an example description of what might go
wrong.

This also prepares to make cpu_up/down() a private interface of the CPU
subsystem.

Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: "Paul E. McKenney" <paulmck@kernel.org>
Link: https://lkml.kernel.org/r/20200323135110.30522-16-qais.yousef@arm.com
2020-03-25 12:59:37 +01:00
Paul E. McKenney 8171d3e0da torture: Allow disabling of boottime CPU-hotplug torture operations
In theory, RCU-hotplug operations are supposed to work as soon as there
is more than one CPU online.  However, in practice, in normal production
there is no way to make them happen until userspace is up and running.
Besides which, on smaller systems, rcutorture doesn't start doing hotplug
operations until 30 seconds after the start of boot, which on most
systems also means the better part of 30 seconds after the end of boot.
This commit therefore provides a new torture.disable_onoff_at_boot kernel
boot parameter that suppresses CPU-hotplug torture operations until
about the time that init is spawned.

Of course, if you know of a need for boottime CPU-hotplug operations,
then you should avoid passing this argument to any of the torture tests.
You might also want to look at the splats linked to below.

Link: https://lore.kernel.org/lkml/20191206185208.GA25636@paulmck-ThinkPad-P72/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-02-20 16:03:30 -08:00
Paul E. McKenney a59ee765a6 torture: Forgive -EBUSY from boottime CPU-hotplug operations
During boot, CPU hotplug is often disabled, for example by PCI probing.
On large systems that take substantial time to boot, this can result
in spurious RCU_HOTPLUG errors.  This commit therefore forgives any
boottime -EBUSY CPU-hotplug failures by adjusting counters to pretend
that the corresponding attempt never happened.  A non-splat record
of the failed attempt is emitted to the console with the added string
"(-EBUSY forgiven during boot)".

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-02-20 16:03:30 -08:00
Denis Efremov 21f57546ce torture: Remove exporting of internal functions
The functions torture_onoff_cleanup() and torture_shuffle_cleanup()
are declared static and marked EXPORT_SYMBOL_GPL(), which is at best an
odd combination.  Because these functions are not used outside of the
kernel/torture.c file they are defined in, this commit removes their
EXPORT_SYMBOL_GPL() marking.

Fixes: cc47ae0830 ("rcutorture: Abstract torture-test cleanup")
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-08-01 14:30:22 -07:00
Paul E. McKenney ff3bf92d90 torture: Allow inter-stutter interval to be specified
Currently, the inter-stutter interval is the same as the stutter duration,
that is, whatever number of jiffies is passed into torture_stutter_init().
This has worked well for quite some time, but the addition of
forward-progress testing to rcutorture can delay processes for several
seconds, which can triple the time that they are stuttered.

This commit therefore adds a second argument to torture_stutter_init()
that specifies the inter-stutter interval.  While locktorture preserves
the current behavior, rcutorture uses the RCU CPU stall warning interval
to provide a wider inter-stutter interval.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-05-28 09:06:09 -07:00
Paul E. McKenney e8516c64fe rcutorture: Fix stutter_wait() return value and freelist checks
The stutter_wait() function is supposed to return true if it actually
waits and false otherwise, but it instead unconditionally returns false.
Which hides a bug in rcu_torture_writer() that fails to account for
the fact that one of the rcu_tortures[] array elements will normally be
referenced by rcu_torture_current, and thus not be on the freelist.

This commit therefore corrects the stutter_wait() return value and adds a
check for rcu_torture_current to rcu_torture_writer()'s check that things
get freed after everything goes quiescent.  In addition, this commit
causes torture_stutter() to give a bit more than one second (instead of
only one jiffy) warning of the end of the stutter interval.  Finally,
this commit disables long-delay readers and aggressive update-side
forward-progress checks while forward-progress testing is in flight.

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-05-28 09:06:09 -07:00
Paul E. McKenney 24aca4aea4 torture: Don't try to offline the last CPU
If there is only one online CPU, it doesn't make sense to try to offline
it, as any such attempt is guaranteed to fail.  This commit therefore
check for this condition and refuses to attempt the nonsensical.

Reported-by: Su Yue <suy.fnst@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Tested-By: Su Yue <suy.fnst@cn.fujitsu.com>
2019-03-26 14:42:53 -07:00
Paul E. McKenney e7ffb4eb9a Merge branches 'doc.2019.01.26a', 'fixes.2019.01.26a', 'sil.2019.01.26a', 'spdx.2019.02.09a', 'srcu.2019.01.26a' and 'torture.2019.01.26a' into HEAD
doc.2019.01.26a:  Documentation updates.
fixes.2019.01.26a:  Miscellaneous fixes.
sil.2019.01.26a:  Removal of a few more spin_is_locked() instances.
spdx.2019.02.09a:  Add SPDX identifiers to RCU files
srcu.2019.01.26a:  SRCU updates.
torture.2019.01.26a: Torture-test updates.
2019-02-09 08:47:52 -08:00
Paul E. McKenney 8f8e76c09c torture: Convert to SPDX license identifier
Replace the license boiler plate with a SPDX license identifier.
While in the area, update an email address.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
2019-02-09 08:46:10 -08:00
Paul E. McKenney 3a6cb58f15 rcutorture: Add grace period after CPU offline
Beyond a certain point in the CPU-hotplug offline process, timers get
stranded on the outgoing CPU, and won't fire until that CPU comes back
online, which might well be never.  This commit therefore adds a hook
in torture_onoff_init() that is invoked from torture_offline(), which
rcutorture uses to occasionally wait for a grace period.  This should
result in failures for RCU implementations that rely on stranded timers
eventually firing in the absence of the CPU coming back online.

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2019-01-25 15:37:10 -08:00
Pierce Griffiths 2a7d968816 torture: Remove unnecessary "ret" variables
Remove return variables (declared as "ret") in cases where,
depending on whether a condition evaluates as true, the result of a
function call can be immediately returned instead of storing the result in
the return variable. When the condition evaluates as false, the constant
initially stored in the return variable at declaration is returned instead.

Signed-off-by: Pierce Griffiths <pierceagriffiths@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
2018-12-01 12:45:35 -08:00
Paul E. McKenney 28cf5952f5 torture: Bring any extra CPUs online during kernel startup
Currently, the torture scripts rely on the initrd/init script to bring
any extra CPUs online, for example, in the case where the kernel and
qemu have different ideas about how many CPUs are present.  This works,
but is an unnecessary dependency on initrd, which needs to vary depending
on the distro.  This commit therefore causes torture_onoff() to check
for additional CPUs, attempting to bring any found online. Errors are
ignored, just as they are by the initrd/init script.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2018-12-01 12:45:32 -08:00
Paul E. McKenney 474e59b476 rcutorture: Check GP completion at stutter end
The rcu_torture_writer() function invokes stutter_wait() at the end of
each writer pass, which occasionally blocks for an extended time period
in order to ensure that RCU can handle intermittent loads.  But part of
handling a busy period is invoking all the callbacks before the end of
the idle period induced by stutter_wait().

This commit therefore adds a return value to stutter_wait() indicating
whether stutter_wait() actually waited.  In addition, this commit causes
rcu_torture_writer() to test this value and if set, checks that all the
elements of the rcu_tortures[] array have been freed up.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2018-08-29 09:20:48 -07:00
Paul E. McKenney 6050003763 torture: Keep old-school dmesg format
This commit adds "#define pr_fmt(fmt) fmt" to the torture-test files
in order to keep the current dmesg format.  Once Joe's commits have
hit mainline, these definitions will be changed in order to automatically
generate the dmesg line prefix that the scripts expect.  This will have
the beneficial side-effect of allowing printk() formats to be used more
widely and of shortening some pr_*() lines.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Joe Perches <joe@perches.com>
2018-06-25 11:30:10 -07:00
Paul E. McKenney 90127d605f torture: Make online/offline messages appear only for verbose=2
Some bugs reproduce quickly only at high CPU-hotplug rates, so the
rcutorture TREE03 scenario now has only 200 milliseconds spacing between
CPU-hotplug operations.  At this rate, the torture-test pair of console
messages per operation becomes a bit voluminous.  This commit therefore
converts the torture-test set of "verbose" kernel-boot arguments from
bool to int, and prints the extra console messages only when verbose=2.
The default is still verbose=1.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2018-06-25 11:30:10 -07:00
Paul E. McKenney cee4393989 rcu: Rename cond_resched_rcu_qs() to cond_resched_tasks_rcu_qs()
Commit e31d28b6ab ("trace: Eliminate cond_resched_rcu_qs() in favor
of cond_resched()") substituted cond_resched() for the earlier call
to cond_resched_rcu_qs().  However, the new-age cond_resched() does
not do anything to help RCU-tasks grace periods because (1) RCU-tasks
is only enabled when CONFIG_PREEMPT=y and (2) cond_resched() is a
complete no-op when preemption is enabled.  This situation results
in hangs when running the trace benchmarks.

A number of potential fixes were discussed on LKML
(https://lkml.kernel.org/r/20180224151240.0d63a059@vmware.local.home),
including making cond_resched() not be a no-op; making cond_resched()
not be a no-op, but only when running tracing benchmarks; reverting
the aforementioned commit (which works because cond_resched_rcu_qs()
does provide an RCU-tasks quiescent state; and adding a call to the
scheduler/RCU rcu_note_voluntary_context_switch() function.  All were
deemed unsatisfactory, either due to added cond_resched() overhead or
due to magic functions inviting cargo culting.

This commit renames cond_resched_rcu_qs() to cond_resched_tasks_rcu_qs(),
which provides a clear hint as to what this function is doing and
why and where it should be used, and then replaces the call to
cond_resched() with cond_resched_tasks_rcu_qs() in the trace benchmark's
benchmark_event_kthread() function.

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Nicholas Piggin <npiggin@gmail.com>
2018-05-15 10:27:29 -07:00
Paul E. McKenney 29d3939084 torture: Save a line in stutter_wait(): while -> for
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2017-12-11 09:18:30 -08:00
Paul E. McKenney a2f2577d96 torture: Eliminate torture_runnable and perf_runnable
The purpose of torture_runnable is to allow rcutorture and locktorture
to be started and stopped via sysfs when they are built into the kernel
(as in not compiled as loadable modules).  However, the 0444 permissions
for both instances of torture_runnable prevent this use case from ever
being put into practice.  Given that there have been no complaints
about this deficiency, it is reasonable to conclude that no one actually
makes use of this sysfs capability.  The perf_runnable module parameter
for rcuperf is in the same situation.

This commit therefore removes both torture_runnable instances as well
as perf_runnable.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2017-12-11 09:18:29 -08:00
Paul E. McKenney 4ced3314fd torture: Make stutter less vulnerable to compilers and races
The stutter_wait() function repeatedly fetched stutter_pause_test, and
should really just fetch it once on each pass.  The races should be
harmless, but why have the races?  Also, the whole point of the value
"2" for stutter_pause_test is to get everyone to start at very nearly
the same time, but the value "2" was the first jiffy of the stutter
rather than the last jiffy of the stutter.

This commit rearranges the code to be more sensible.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2017-12-11 09:18:29 -08:00
Paul E. McKenney dac9590600 torture: Suppress CPU stall warnings during shutdown ftrace dump
The torture_shutdown() function directly invokes ftrace_dump(), which
can result in RCU CPU stall warnings when the ftrace buffer is large,
which it usually is.  This commit therefore invoks rcu_ftrace_dump()
in place of ftrace_dump(), suppressing RCU CPU stall warnings during
this time.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2017-11-28 15:54:26 -08:00
Paul E. McKenney a2b2df207a torture: Fix typo suppressing CPU-hotplug statistics
The torture status line contains a series of values preceded by "onoff:".
The last value in that line, the one preceding the "HZ=" string, is
always zero.  The reason that it is always zero is that torture_offline()
was incrementing the sum_offl pointer instead of the value that this
pointer referenced.  This commit therefore makes this increment operate
on the statistic rather than the pointer to the statistic.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2017-07-25 13:04:45 -07:00
Ingo Molnar e601757102 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/clock.h>
We are going to split <linux/sched/clock.h> out of <linux/sched.h>, which
will have to be picked up from other headers and .c files.

Create a trivial placeholder <linux/sched/clock.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:27 +01:00
Masahiro Yamada b564d62e67 scripts/spelling.txt: add "varible" pattern and fix typo instances
Fix typos and add the following to the scripts/spelling.txt:

  varible||variable

While we are here, tidy up the comment blocks that fit in a single line
for drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c and
net/sctp/transport.c.

Link: http://lkml.kernel.org/r/1481573103-11329-11-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:47 -08:00
Paul E. McKenney 31257c3c8b torture: Convert torture_shutdown() to hrtimer
Upcoming changes to the timer wheel introduce significant inaccuracy
and possibly also an ultimate limit on timeout duration.  This is a
problem for the current implementation of torture_shutdown() because
(1) shutdown times are user-specified, and can therefore be quite long,
and (2) the torture scripting will kill a test instance that runs for
more than a few minutes longer than scheduled.  This commit therefore
converts the torture_shutdown() timed waits to an hrtimer, thus avoiding
too-short torture test runs as well as death by scripting.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
2016-08-22 10:01:49 -07:00
Boqun Feng 750db0f5f7 torture: Stop onoff task if there is only one cpu
If the whole system has only one cpu, that cpu won't be able to be
offlined, so there is no need onoff task is stil running.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-06-14 16:03:28 -07:00
Paul E. McKenney d95f5ba90f torture: Break online and offline functions out of torture_onoff()
This commit breaks torture_online() and torture_offline() out of
torture_onoff() in preparation for allowing waketorture finer-grained
control of its CPU-hotplug workload.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-06-14 16:02:16 -07:00
Paul E. McKenney e9fb365a88 rcutorture: Dump trace buffer upon shutdown
When running from the scripts, rcutorture is completely headless,
so there is no way to to manually dump the trace buffer.  This commit
therefore unconditionally dumps the trace buffer upon timed shutdown.
However, if you are using rmmod to end the test, it is still up to you
to manually dump the trace buffer.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-04-21 13:47:04 -07:00
Paul E. McKenney 9eb5188a07 torture: Clarify refusal to run more than one torture test
This commit clarifies error messages -- you only get to run one torture
test at a time!

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2016-03-31 13:39:52 -07:00
Paul E. McKenney 3836f5337f torture: Consolidate cond_resched_rcu_qs() into stutter_wait()
This commit moves cond_resched_rcu_qs() into stutter_wait(), saving
a line and also avoiding RCU CPU stall warnings from all torture
loops containing a stutter_wait().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2015-10-06 11:25:01 -07:00
Paul E. McKenney 7d0ae8086b rcu: Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()
This commit moves from the old ACCESS_ONCE() API to the new READ_ONCE()
and WRITE_ONCE() APIs.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck:  Updated to include kernel/torture.c as suggested by Jason Low. ]
2015-05-27 12:56:15 -07:00
Davidlohr Bueso d36a7a0d5e torture: Address race in module cleanup
When performing module cleanups by calling torture_cleanup() the
'torture_type' string in nullified However, callers are not necessarily
done, and might still need to reference the variable. This impacts
both rcutorture and locktorture, causing printing things like:

[   94.226618] (null)-torture: Stopping lock_torture_writer task
[   94.226624] (null)-torture: Stopping lock_torture_stats task

Thus delay this operation until the very end of the cleanup process.
The consequence (which shouldn't matter for this kid of program) is,
of course, that we delay the window between rmmod and modprobing,
for instance in module_torture_begin().

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-16 13:41:06 -07:00
Joe Perches eea203fea3 rcu: Use pr_alert/pr_cont for printing logs
User pr_alert/pr_cont for printing the logs from rcutorture module directly
instead of writing it to a buffer and then printing it. This allows us from not
having to allocate such buffers. Also remove a resulting empty function.

I tested this using the parse-torture.sh script as follows:

$ dmesg | grep torture > log.txt
$ bash parse-torture.sh log.txt test
$

There were no warnings which means that parsing went fine.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-09-07 16:24:47 -07:00
Kees Cook 6945915e7f torture: Avoid format string leak to thead name
Since the torture-test thread creation interface does not include
format string arguments, this commit makes sure the name can never be
accidentally processed as a format string.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-07-07 10:12:56 -07:00
Pranith Kumar 2b3f8ffe46 torture: Remove __init from torture_init_begin/end
Loading rcutorture as a module (as opposed to building it directly into
the kernel) results in the following splat:

[Wed Apr 16 15:29:33 2014] BUG: unable to handle kernel paging request at ffffffffa0003000
[Wed Apr 16 15:29:33 2014] IP: [<ffffffffa0003000>] 0xffffffffa0003000
[Wed Apr 16 15:29:33 2014] PGD 1c0f067 PUD 1c10063 PMD 378a6067 PTE 0
[Wed Apr 16 15:29:33 2014] Oops: 0010 [#1] SMP
[Wed Apr 16 15:29:33 2014] Modules linked in: rcutorture(+) torture
[Wed Apr 16 15:29:33 2014] CPU: 0 PID: 4257 Comm: modprobe Not tainted 3.15.0-rc1 #10
[Wed Apr 16 15:29:33 2014] Hardware name: innotek GmbH VirtualBox, BIOS VirtualBox 12/01/2006
[Wed Apr 16 15:29:33 2014] task: ffff8800db1e88d0 ti: ffff8800db25c000 task.ti: ffff8800db25c000
[Wed Apr 16 15:29:33 2014] RIP: 0010:[<ffffffffa0003000>]  [<ffffffffa0003000>] 0xffffffffa0003000
[Wed Apr 16 15:29:33 2014] RSP: 0018:ffff8800db25dca0  EFLAGS: 00010282
[Wed Apr 16 15:29:33 2014] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[Wed Apr 16 15:29:33 2014] RDX: ffffffffa00090a8 RSI: 0000000000000001 RDI: ffffffffa0008337
[Wed Apr 16 15:29:33 2014] RBP: ffff8800db25dd50 R08: 0000000000000000 R09: 0000000000000000
[Wed Apr 16 15:29:33 2014] R10: ffffea000357b680 R11: ffffffff8113257a R12: ffffffffa000d000
[Wed Apr 16 15:29:33 2014] R13: ffffffffa00094c0 R14: ffffffffa0009510 R15: 0000000000000001
[Wed Apr 16 15:29:33 2014] FS:  00007fee30ce5700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
[Wed Apr 16 15:29:33 2014] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[Wed Apr 16 15:29:33 2014] CR2: ffffffffa0003000 CR3: 00000000d5eb1000 CR4: 00000000000006f0
[Wed Apr 16 15:29:33 2014] Stack:
[Wed Apr 16 15:29:33 2014]  ffffffffa000d02c 0000000000000000 ffff88021700d400 0000000000000000
[Wed Apr 16 15:29:33 2014]  ffff8800db25dd40 ffffffff81647951 ffff8802162bd000 ffff88021541846c
[Wed Apr 16 15:29:33 2014]  0000000000000000 ffffffff817dbe2d ffffffff817dbe2d 0000000000000001
[Wed Apr 16 15:29:33 2014] Call Trace:
[Wed Apr 16 15:29:33 2014]  [<ffffffffa000d02c>] ? rcu_torture_init+0x2c/0x8b4 [rcutorture]
[Wed Apr 16 15:29:33 2014]  [<ffffffff81647951>] ? netlink_broadcast_filtered+0x121/0x3a0
[Wed Apr 16 15:29:33 2014]  [<ffffffff817dbe2d>] ? mutex_lock+0xd/0x2a
[Wed Apr 16 15:29:33 2014]  [<ffffffff817dbe2d>] ? mutex_lock+0xd/0x2a
[Wed Apr 16 15:29:33 2014]  [<ffffffff810e7022>] ? trace_module_notify+0x62/0x1d0
[Wed Apr 16 15:29:33 2014]  [<ffffffffa000d000>] ? 0xffffffffa000cfff
[Wed Apr 16 15:29:33 2014]  [<ffffffff8100034a>] do_one_initcall+0xfa/0x140
[Wed Apr 16 15:29:33 2014]  [<ffffffff8106b4ce>] ? __blocking_notifier_call_chain+0x5e/0x80
[Wed Apr 16 15:29:33 2014]  [<ffffffff810b3481>] load_module+0x1931/0x21b0
[Wed Apr 16 15:29:33 2014]  [<ffffffff810b0330>] ? show_initstate+0x50/0x50
[Wed Apr 16 15:29:33 2014]  [<ffffffff810b3d9e>] SyS_init_module+0x9e/0xc0
[Wed Apr 16 15:29:33 2014]  [<ffffffff817e4c22>] system_call_fastpath+0x16/0x1b
[Wed Apr 16 15:29:33 2014] Code:  Bad RIP value.
[Wed Apr 16 15:29:33 2014] RIP  [<ffffffffa0003000>] 0xffffffffa0003000
[Wed Apr 16 15:29:33 2014]  RSP <ffff8800db25dca0>
[Wed Apr 16 15:29:33 2014] CR2: ffffffffa0003000
[Wed Apr 16 15:29:33 2014] ---[ end trace 3e88c173037af84b ]---

This splat is due to the fact that torture_init_begin() and
torture_init_end() are both marked with __init, despite their use
at runtime.  This commit therefore removes __init from both functions.

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:30 -07:00
Paul E. McKenney 5228084eed torture: Check for multiple concurrent torture tests
The torture tests are designed to run in isolation, but do not enforce
this isolation.  This commit therefore checks for concurrent torture
tests, and refuses to start new tests while old tests are running.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:29 -07:00
Iulia Manda 5ed63b199c torture: Notice if an all-zero cpumask is passed inside a critical section
In torture_shuffle_tasks function, the check if an all-zero mask can
be passed to set_cpus_allowed_ptr() is redundant after clearing the
shuffle_idle_cpu bit. If the mask had more than one bit set, after
clearing a bit it has at least one bit set. If the mask had only
one bit set, a check is made at the beginning, where the function
returns, as there is no need to shuffle only one cpu.

Also, this code is executed inside a critical section, delimited by
get_online_cpus(), and put_online_cpus(), preventing CPUs from leaving between
the check of num_online_cpus and the calls to set_cpus_allowed_ptr() function.

Signed-off-by: Iulia Manda <iulia.manda21@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:14 -07:00
Paul E. McKenney ab7d45053f torture: Increase stutter-end intensity
Currently, all stuttered kthreads block a jiffy at a time, which can
result in them starting at different times.  (Note: This is not an
energy-efficiency problem unless you run torture tests in production,
in which case you have other problems!)  This commit increases the
intensity of the restart event by causing kthreads to spin through the
last jiffy, restarting when they see the variable change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-05-14 09:46:02 -07:00
Paul E. McKenney 0d6821d5f7 torture: Include "Stopping" string to torture_kthread_stopping()
Currently, torture_kthread_stopping() prints only the name of the
kthread that is stopping, which can be unedifying.  This commit therefore
adds "Stopping" to make things more evident.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-05-14 09:45:59 -07:00
Paul E. McKenney f881825a73 rcutorture: Gracefully handle NULL cleanup hooks
Although most torture tests will have some cleanup hook, it is possible
that one might not.  This commit therefore enables graceful handling of
a NULL cleanup hook during torture-test shutdown.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-02-23 09:04:39 -08:00
Paul E. McKenney bfefc73aa1 rcutorture: Stop generic kthreads in torture_cleanup()
The specific torture modules (like rcutorture) need to call
torture_cleanup() in any case, so this commit makes torture_cleanup()
deal with torture_shutdown_cleanup() and torture_stutter_cleanup() so
that the specific modules don't have to deal with these details.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-02-23 09:04:27 -08:00
Paul E. McKenney 9c029b8609 rcutorture: Abstract torture_stop_kthread()
Stopping of kthreads is not RCU-specific, so this commit abstracts
out torture_stop_kthread(), saving a few lines of code in the process.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-02-23 09:04:25 -08:00
Paul E. McKenney 47cf29b9e7 rcutorture: Abstract torture_create_kthread()
Creation of kthreads is not RCU-specific, so this commit abstracts
out torture_create_kthread(), saving a few tens of lines of code in
the process.

This change requires modifying VERBOSE_TOROUT_ERRSTRING() to take a
non-const string, so that _torture_create_kthread() can avoid an
open-coded substitute.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-02-23 09:03:24 -08:00
Paul E. McKenney 7fafaac5b9 rcutorture: Fix rcutorture shutdown races
Not all of the rcutorture kthreads waited for kthread_should_stop()
before returning from their top-level functions, and none of them
used torture_shutdown_absorb() properly.  These problems can result in
segfaults and hangs at shutdown time, and some recent changes perturbed
timing sufficiently to make them much more probable.  This commit
therefore creates a torture_kthread_stopping() function that does the
proper kthread shutdown dance in one centralized location.

Accommodate this grouping by making VERBOSE_TOROUT_STRING() capable of
taking a non-const string as its argument, which allows the new
torture_kthread_stopping() to pass its "title" argument directly to
the updated version of VERBOSE_TOROUT_STRING().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2014-02-23 09:03:21 -08:00
Paul E. McKenney 14562d1cf1 rcutorture: Announce task creation
A few "stealth-start rcutorture kthreads" have accumulated over the years,
so this commit adds console-log announcements (but only if the torture
tests are running verbose).

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-02-23 09:03:20 -08:00
Paul E. McKenney e991dbc077 rcutorture: Abstract torture_shutdown()
Because auto-shutdown of torture testing is not specific to RCU,
this commit moves the auto-shutdown function to kernel/torture.c.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2014-02-23 09:03:18 -08:00