15 Dec, 2020
1 commit
-
Disable ftrace selftests when any tracer (kernel command line options
like ftrace=, trace_events=, kprobe_events=, and boot-time tracing)
starts running because selftest can disturb it.Currently ftrace= and trace_events= are checked, but kprobe_events
has a different flag, and boot-time tracing didn't checked. This unifies
the disabled flag and all of those boot-time tracing features sets
the flag.This also fixes warnings on kprobe-event selftest
(CONFIG_FTRACE_STARTUP_TEST=y and CONFIG_KPROBE_EVENTS=y) with boot-time
tracing (ftrace.event.kprobes.EVENT.probes) like below;[ 59.803496] trace_kprobe: Testing kprobe tracing:
[ 59.804258] ------------[ cut here ]------------
[ 59.805682] WARNING: CPU: 3 PID: 1 at kernel/trace/trace_kprobe.c:1987 kprobe_trace_self_tests_ib
[ 59.806944] Modules linked in:
[ 59.807335] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.10.0-rc7+ #172
[ 59.808029] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1 04/01/204
[ 59.808999] RIP: 0010:kprobe_trace_self_tests_init+0x5f/0x42b
[ 59.809696] Code: e8 03 00 00 48 c7 c7 30 8e 07 82 e8 6d 3c 46 ff 48 c7 c6 00 b2 1a 81 48 c7 c7 7
[ 59.812439] RSP: 0018:ffffc90000013e78 EFLAGS: 00010282
[ 59.813038] RAX: 00000000ffffffef RBX: 0000000000000000 RCX: 0000000000049443
[ 59.813780] RDX: 0000000000049403 RSI: 0000000000049403 RDI: 000000000002deb0
[ 59.814589] RBP: ffffc90000013e90 R08: 0000000000000001 R09: 0000000000000001
[ 59.815349] R10: 0000000000000001 R11: 0000000000000000 R12: 00000000ffffffef
[ 59.816138] R13: ffff888004613d80 R14: ffffffff82696940 R15: ffff888004429138
[ 59.816877] FS: 0000000000000000(0000) GS:ffff88807dcc0000(0000) knlGS:0000000000000000
[ 59.817772] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 59.818395] CR2: 0000000001a8dd38 CR3: 0000000002222000 CR4: 00000000000006a0
[ 59.819144] Call Trace:
[ 59.819469] ? init_kprobe_trace+0x6b/0x6b
[ 59.819948] do_one_initcall+0x5f/0x300
[ 59.820392] ? rcu_read_lock_sched_held+0x4f/0x80
[ 59.820916] kernel_init_freeable+0x22a/0x271
[ 59.821416] ? rest_init+0x241/0x241
[ 59.821841] kernel_init+0xe/0x10f
[ 59.822251] ret_from_fork+0x22/0x30
[ 59.822683] irq event stamp: 16403349
[ 59.823121] hardirqs last enabled at (16403359): [] console_unlock+0x48e/0x580
[ 59.824074] hardirqs last disabled at (16403368): [] console_unlock+0x3f6/0x580
[ 59.825036] softirqs last enabled at (16403200): [] __do_softirq+0x33a/0x484
[ 59.825982] softirqs last disabled at (16403087): [] asm_call_irq_on_stack+0x10
[ 59.827034] ---[ end trace 200c544775cdfeb3 ]---
[ 59.827635] trace_kprobe: error on probing function entry.Link: https://lkml.kernel.org/r/160741764955.3448999.3347769358299456915.stgit@devnote2
Fixes: 4d655281eb1b ("tracing/boot Add kprobe event support")
Cc: Ingo Molnar
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu
Signed-off-by: Steven Rostedt (VMware)
14 Nov, 2020
1 commit
-
In preparation to have arguments of a function passed to callbacks attached
to functions as default, change the default callback prototype to receive a
struct ftrace_regs as the forth parameter instead of a pt_regs.For callbacks that set the FL_SAVE_REGS flag in their ftrace_ops flags, they
will now need to get the pt_regs via a ftrace_get_regs() helper call. If
this is called by a callback that their ftrace_ops did not have a
FL_SAVE_REGS flag set, it that helper function will return NULL.This will allow the ftrace_regs to hold enough just to get the parameters
and stack pointer, but without the worry that callbacks may have a pt_regs
that is not completely filled.Acked-by: Peter Zijlstra (Intel)
Reviewed-by: Masami Hiramatsu
Signed-off-by: Steven Rostedt (VMware)
06 Nov, 2020
1 commit
-
Now that all callbacks are recursion safe, reverse the meaning of the
RECURSION flag and rename it from RECURSION_SAFE to simply RECURSION.
Now only callbacks that request to have recursion protecting it will
have the added trampoline to do so.Also remove the outdated comment about "PER_CPU" when determining to
use the ftrace_ops_assist_func.Link: https://lkml.kernel.org/r/20201028115613.742454631@goodmis.org
Link: https://lkml.kernel.org/r/20201106023547.904270143@goodmis.orgCc: Peter Zijlstra
Cc: Ingo Molnar
Cc: Josh Poimboeuf
Cc: Jiri Kosina
Cc: Masami Hiramatsu
Cc: Andrew Morton
Cc: Jonathan Corbet
Cc: Sebastian Andrzej Siewior
Cc: Miroslav Benes
Cc: Kamalesh Babulal
Cc: Petr Mladek
Cc: linux-doc@vger.kernel.org
Signed-off-by: Steven Rostedt (VMware)
02 Nov, 2020
1 commit
-
When an interrupt or NMI comes in and switches the context, there's a delay
from when the preempt_count() shows the update. As the preempt_count() is
used to detect recursion having each context have its own bit get set when
tracing starts, and if that bit is already set, it is considered a recursion
and the function exits. But if this happens in that section where context
has changed but preempt_count() has not been updated, this will be
incorrectly flagged as a recursion.To handle this case, create another bit call TRANSITION and test it if the
current context bit is already set. Flag the call as a recursion if the
TRANSITION bit is already set, and if not, set it and continue. The
TRANSITION bit will be cleared normally on the return of the function that
set it, or if the current context bit is clear, set it and clear the
TRANSITION bit to allow for another transition between the current context
and an even higher one.Cc: stable@vger.kernel.org
Fixes: edc15cafcbfa3 ("tracing: Avoid unnecessary multiple recursion checks")
Signed-off-by: Steven Rostedt (VMware)
14 Jan, 2020
1 commit
-
As we are working to remove the generic "ring_buffer" name that is used by
both tracing and perf, the ring_buffer name for tracing will be renamed to
trace_buffer, and perf's ring buffer will be renamed to perf_buffer.As there already exists a trace_buffer that is used by the trace_arrays, it
needs to be first renamed to array_buffer.Link: https://lore.kernel.org/r/20191213153553.GE20583@krava
Signed-off-by: Steven Rostedt (VMware)
22 Apr, 2019
1 commit
-
The function_graph boot up self test emulates the tr->init() function in
order to add a wrapper around the function graph tracer entry code to test
for lock ups and such. But it does not emulate the tr->reset(), and just
calls the function_graph tracer tr->reset() function which will use its own
fgraph_ops to unregister function tracing with. As the fgraph_ops is
becoming more meaningful with the register_ftrace_graph() and
unregister_ftrace_graph() functions, the two need to be the same. The
emulated tr->init() uses its own fgraph_ops descriptor, which means the
unregister_ftrace_graph() must use the same ftrace_ops, which the selftest
currently does not do. By emulating the tr->reset() as the selftest does
with the tr->init() it will be able to pass the same fgraph_ops descriptor
to the unregister_ftrace_graph() as it did with the register_ftrace_graph().Signed-off-by: Steven Rostedt (VMware)
09 Dec, 2018
1 commit
-
Currently the registering of function graph is to pass in a entry and return
function. We need to have a way to associate those functions together where
the entry can determine to run the return hook. Having a structure that
contains both functions will facilitate the process of converting the code
to be able to do such.This is similar to the way function hooks are enabled (it passes in
ftrace_ops). Instead of passing in the functions to use, a single structure
is passed in to the registering function.The unregister function is now passed in the fgraph_ops handle. When we
allow more than one callback to the function graph hooks, this will let the
system know which one to remove.Reviewed-by: Joel Fernandes (Google)
Signed-off-by: Steven Rostedt (VMware)
18 Nov, 2017
1 commit
-
Pull tracing updates from
- allow module init functions to be traced
- clean up some unused or not used by config events (saves space)
- clean up of trace histogram code
- add support for preempt and interrupt enabled/disable events
- other various clean ups
* tag 'trace-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (30 commits)
tracing, thermal: Hide cpu cooling trace events when not in use
tracing, thermal: Hide devfreq trace events when not in use
ftrace: Kill FTRACE_OPS_FL_PER_CPU
perf/ftrace: Small cleanup
perf/ftrace: Fix function trace events
perf/ftrace: Revert ("perf/ftrace: Fix double traces of perf on ftrace:function")
tracing, dma-buf: Remove unused trace event dma_fence_annotate_wait_on
tracing, memcg, vmscan: Hide trace events when not in use
tracing/xen: Hide events that are not used when X86_PAE is not defined
tracing: mark trace_test_buffer as __maybe_unused
printk: Remove superfluous memory barriers from printk_safe
ftrace: Clear hashes of stale ips of init memory
tracing: Add support for preempt and irq enable/disable events
tracing: Prepare to add preempt and irq trace events
ftrace/kallsyms: Have /proc/kallsyms show saved mod init functions
ftrace: Add freeing algorithm to free ftrace_mod_maps
ftrace: Save module init functions kallsyms symbols for tracing
ftrace: Allow module init functions to be traced
ftrace: Add a ftrace_free_mem() function for modules to use
tracing: Reimplement log2
...
02 Nov, 2017
1 commit
-
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
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
13 Oct, 2017
1 commit
-
After trace_selftest_startup_sched_switch is removed, trace_test_buffer()
is only used sometimes, leading to this warning:kernel/trace/trace_selftest.c:62:12: error: 'trace_test_buffer' defined but not used [-Werror=unused-function]
There is no simple #ifdef condition that captures well whether the
function is in fact used or not, so marking it as __maybe_unused is
probably the best way to shut up the warning. The function will then
be silently dropped when there is no user.Link: http://lkml.kernel.org/r/20171013142227.1273469-1-arnd@arndb.de
Fixes: d8c4deee6dc6 ("tracing: Remove obsolete sched_switch tracer selftest")
Signed-off-by: Arnd Bergmann
Signed-off-by: Steven Rostedt (VMware)
04 Oct, 2017
1 commit
-
Since commit 87d80de2800d087ea833cb79bc13f85ff34ed49f ("tracing: Remove
obsolete sched_switch tracer"), the sched_switch tracer selftest is no longer
used. This patch removes the same.Link: http://lkml.kernel.org/r/20170909065517.22262-1-joelaf@google.com
Cc: Ingo Molnar
Cc: kernel-team@android.com
Signed-off-by: Joel Fernandes
Signed-off-by: Steven Rostedt (VMware)
02 Sep, 2017
1 commit
-
In the second iteration of trace_selftest_ops(), the error goto label is
wrong in the case where trace_selftest_test_global_cnt is off. In the
case of error, it leaks the dynamic ops that was allocated.Cc: stable@vger.kernel.org
Fixes: 95950c2e ("ftrace: Add self-tests for multiple function trace users")
Signed-off-by: Steven Rostedt (VMware)
02 Mar, 2017
1 commit
-
We are going to move scheduler ABI details to ,
which will be used from a number of .c files.Create empty placeholder header that maps to .
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds
Cc: Mike Galbraith
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar
12 Oct, 2014
1 commit
-
Pull tracing fixes from Steven Rostedt:
"Seems that Peter Zijlstra added a new check that is making old code
scream nasty warnings:WARNING: CPU: 0 PID: 91 at kernel/sched/core.c:7253 __might_sleep+0x9a/0x378()
do not call blocking ops when !TASK_RUNNING; state=1 set at [] event_test_thread+0x48/0x93
Call Trace:
__might_sleep+0x9a/0x378
down_read+0x26/0x98
exit_signals+0x27/0x1c2
do_exit+0x193/0x10bd
kthread+0x156/0x156
ret_from_fork+0x7a/0xb0These are triggered by some self tests that run at start up when
configure in. Although the code is technically correct, they are a
little sloppy and not very robust. They work now because it runs at
boot up and the tests do not call anything that might trigger a
spurious wake up. But that doesn't mean those tests wont change in
the future.It's best to clean them now to make sure the tests used to test the
internal workings of the system don't cause breakage themselves.This also quiets the warnings made by the new checks"
* tag 'trace-3.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Clean up scheduling in trace_wakeup_test_thread()
tracing: Robustify wait loop
09 Oct, 2014
1 commit
-
Peter's new debugging tool triggers when tasks exit with !TASK_RUNNING.
The code in trace_wakeup_test_thread() also has a single schedule() call
that should be encompassed by a loop.This cleans up the code a little to make it a bit more robust and
also makes the return exit properly with TASK_RUNNING.Link: http://lkml.kernel.org/p/20141008135216.76142204@gandalf.local.home
Reported-by: Peter Zijlstra
Acked-by: Peter Zijlstra
Signed-off-by: Steven Rostedt
13 Sep, 2014
1 commit
-
The ftrace_enabled variable is set to zero in the self tests to keep
delayed functions from being traced and messing with the checks. This
only needs to be done when the checks are being performed, otherwise,
if ftrace_enabled is off when calls back to the utility that is being
tested, it can cause errors to happen and the tests can fail with
false positives.Signed-off-by: Steven Rostedt
22 Apr, 2014
4 commits
-
This patch adds static to the following functions:
-cycle_t buffer_ftrace_now
-void free_snapshot
-int trace_selftest_startup_dynamic_tracingLink: http://lkml.kernel.org/p/20140417214442.d7abc7c0b0e4b90e7fedecc9@skynet.be
Signed-off-by: Fabian Frederick
Signed-off-by: Steven Rostedt -
In preparation for having tracers enabled in instances, the max_lock
should be unique as updating the max for one tracer is a separate
operation than updating it for another tracer using a different max.Signed-off-by: Steven Rostedt
-
In preparation for letting the latency tracers be used by instances,
remove the global tracing_max_latency variable and add a max_latency
field to the trace_array that the latency tracers will now use.Signed-off-by: Steven Rostedt
-
Instead of having a list of global functions that are called,
as only one global function is allow to be enabled at a time, there's
no reason to have a list.Instead, simply have all the users of the global ops, use the global ops
directly, instead of registering their own ftrace_ops. Just switch what
function is used before enabling the function tracer.This removes a lot of code as well as the complexity involved with it.
Signed-off-by: Steven Rostedt
13 Jan, 2014
1 commit
-
It is very likely that systems that wants/needs to use the new
SCHED_DEADLINE policy also want to have the scheduling latency of
the -deadline tasks under control.For this reason a new version of the scheduling wakeup latency,
called "wakeup_dl", is introduced.As a consequence of applying this patch there will be three wakeup
latency tracer:* "wakeup", that deals with all tasks in the system;
* "wakeup_rt", that deals with -rt and -deadline tasks only;
* "wakeup_dl", that deals with -deadline tasks only.Signed-off-by: Dario Faggioli
Signed-off-by: Juri Lelli
Signed-off-by: Peter Zijlstra
Link: http://lkml.kernel.org/r/1383831828-15501-9-git-send-email-juri.lelli@gmail.com
Signed-off-by: Ingo Molnar
02 Jul, 2013
1 commit
-
If the kernel command line ftrace filter parameters are set
(ftrace_filter or ftrace_notrace), force the function self test to
pass, with a warning why it was forced.If the user adds a filter to the kernel command line, it is assumed
that they know what they are doing, and the self test should just not
run instead of failing (which disables function tracing) or clearing
the filter, as that will probably annoy the user.If the user wants the selftest to run, the message will tell them why
it did not.Signed-off-by: Steven Rostedt
30 May, 2013
1 commit
-
The branch selftest calls trace_test_buffer(), but with the new code
it expects the first parameter to be a pointer to a struct trace_buffer.
All self tests were changed but the branch selftest was missed.This caused either a crash or failed test when the branch selftest was
enabled.Link: http://lkml.kernel.org/r/20130529141333.GA24064@localhost
Reported-by: Fengguang Wu
Signed-off-by: Steven Rostedt
16 Mar, 2013
1 commit
-
ftrace_dump() had a lot of issues. What ftrace_dump() does, is when
ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it
will dump out the ftrace buffers to the console when either a oops,
panic, or a sysrq-z occurs.This was written a long time ago when ftrace was fragile to recursion.
But it wasn't written well even for that.There's a possible deadlock that can occur if a ftrace_dump() is happening
and an NMI triggers another dump. This is because it grabs a lock
before checking if the dump ran.It also totally disables ftrace, and tracing for no good reasons.
As the ring_buffer now checks if it is read via a oops or NMI, where
there's a chance that the buffer gets corrupted, it will disable
itself. No need to have ftrace_dump() do the same.ftrace_dump() is now cleaned up where it uses an atomic counter to
make sure only one dump happens at a time. A simple atomic_inc_return()
is enough that is needed for both other CPUs and NMIs. No need for
a spinlock, as if one CPU is running the dump, no other CPU needs
to do it too.The tracing_on variable is turned off and not turned on. The original
code did this, but it wasn't pretty. By just disabling this variable
we get the result of not seeing traces that happen between crashes.For sysrq-z, it doesn't get turned on, but the user can always write
a '1' to the tracing_on file. If they are using sysrq-z, then they should
know about tracing_on.The new code is much easier to read and less error prone. No more
deadlock possibility when an NMI triggers here.Reported-by: zhangwei(Jovi)
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner
Cc: Peter Zijlstra
Cc: Frederic Weisbecker
Signed-off-by: Steven Rostedt
15 Mar, 2013
1 commit
-
Currently, the way the latency tracers and snapshot feature works
is to have a separate trace_array called "max_tr" that holds the
snapshot buffer. For latency tracers, this snapshot buffer is used
to swap the running buffer with this buffer to save the current max
latency.The only items needed for the max_tr is really just a copy of the buffer
itself, the per_cpu data pointers, the time_start timestamp that states
when the max latency was triggered, and the cpu that the max latency
was triggered on. All other fields in trace_array are unused by the
max_tr, making the max_tr mostly bloat.This change removes the max_tr completely, and adds a new structure
called trace_buffer, that holds the buffer pointer, the per_cpu data
pointers, the time_start timestamp, and the cpu where the latency occurred.The trace_array, now has two trace_buffers, one for the normal trace and
one for the max trace or snapshot. By doing this, not only do we remove
the bloat from the max_trace but the instances of traces can now use
their own snapshot feature and not have just the top level global_trace have
the snapshot feature and latency tracers for itself.Signed-off-by: Steven Rostedt
23 Jan, 2013
2 commits
-
The function tracing recursion self test should not crash
the machine if the resursion test fails. If it detects that
the function tracing is recursing when it should not be, then
bail, don't go into an infinite recursive loop.Signed-off-by: Steven Rostedt
-
The test that checks function recursion does things differently
if the arch does not support all ftrace features. But that really
doesn't make a difference with how the test runs, and either way
the count variable should be 2 at the end.Currently the test wrongly fails for archs that don't support all
the ftrace features.Signed-off-by: Steven Rostedt
22 Jan, 2013
1 commit
-
Move SAVE_REGS support flag into Kconfig and rename
it to CONFIG_DYNAMIC_FTRACE_WITH_REGS. This also introduces
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS which indicates
the architecture depending part of ftrace has a code
that saves full registers.
On the other hand, CONFIG_DYNAMIC_FTRACE_WITH_REGS indicates
the code is enabled.Link: http://lkml.kernel.org/r/20120928081516.3560.72534.stgit@ltc138.sdl.hitachi.co.jp
Cc: Ingo Molnar
Cc: Ananth N Mavinakayanahalli
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: "H. Peter Anvin"
Cc: Frederic Weisbecker
Signed-off-by: Masami Hiramatsu
Signed-off-by: Steven Rostedt
02 Nov, 2012
2 commits
-
Have the ring buffer commit function use the irq_work infrastructure to
wake up any waiters waiting on the ring buffer for new data. The irq_work
was created for such a purpose, where doing the actual wake up at the
time of adding data is too dangerous, as an event or function trace may
be in the midst of the work queue locks and cause deadlocks. The irq_work
will either delay the action to the next timer interrupt, or trigger an IPI
to itself forcing an interrupt to do the work (in a safe location).With irq_work, all ring buffer commits can safely do wakeups, removing
the need for the ring buffer commit "nowake" variants, which were used
by events and function tracing. All commits can now safely use the
normal commit, and the "nowake" variants can be removed.Cc: Peter Zijlstra
Signed-off-by: Steven Rostedt -
The tracing_enabled file has been deprecated as it never was able
to serve its purpose well. The tracing_on file has taken over.
Instead of having code to keep tracing_enabled, have the tracing_enabled
file just set tracing_on, and remove the tracing_enabled variable.This allows us to remove the tracing_enabled file. The reason that
the remove is in a different change set and not removed here is
in case we find some lonely userspace tool that requires the file
to exist. Then the removal patch will get reverted, but this one
will not.Cc: Peter Zijlstra
Cc: Thomas Gleixner
Signed-off-by: Steven Rostedt
07 Aug, 2012
1 commit
-
The warkeup_rt self test used msleep() calls to wait for real time
tasks to wake up and run. On bare-metal hardware, this was enough as
the scheduler should let the RT task run way before the non-RT task
wakes up from the msleep(). If it did not, then that would mean the
scheduler was broken.But when dealing with virtual machines, this is a different story.
If the RT task wakes up on a VCPU, it's up to the host to decide when
that task gets to schedule, which can be far behind the time that the
non-RT task wakes up. In this case, the test would fail incorrectly.As we are not testing the scheduler, but instead the wake up tracing,
we can use completions to wait and not depend on scheduler timings
to see if events happen on time.Link: http://lkml.kernel.org/r/1343663105.3847.7.camel@fedora
Reported-by: Fengguang Wu
Tested-by: Fengguang Wu
Signed-off-by: Steven Rostedt
31 Jul, 2012
3 commits
-
Add selftests to test the save-regs functionality of ftrace.
If the arch supports saving regs, then it will make sure that regs is
at least not NULL in the callback.If the arch does not support saving regs, it makes sure that the
registering of the ftrace_ops that requests saving regs fails.
It then tests the registering of the ftrace_ops succeeds if the
'IF_SUPPORTED' flag is set. Then it makes sure that the regs passed to
the function is NULL.Signed-off-by: Steven Rostedt
-
Add selftests to test the function tracing recursion protection actually
does work. It also tests if a ftrace_ops states it will perform its own
protection. Although, even if the ftrace_ops states it will protect itself,
the ftrace infrastructure may still provide protection if the arch does
not support all features or another ftrace_ops is registered.Signed-off-by: Steven Rostedt
-
As more users of the function tracer utility are being added, they do
not always add the necessary recursion protection. To protect from
function recursion due to tracing, if the callback ftrace_ops does not
specifically specify that it protects against recursion (by setting
the FTRACE_OPS_FL_RECURSION_SAFE flag), the list operation will be
called by the mcount trampoline which adds recursion protection.If the flag is set, then the function will be called directly with no
extra protection.Note, the list operation is called if more than one function callback
is registered, or if the arch does not support all of the function
tracer features.Signed-off-by: Steven Rostedt
20 Jul, 2012
2 commits
-
Return as the 4th paramater to the function tracer callback the pt_regs.
Later patches that implement regs passing for the architectures will require
having the ftrace_ops set the SAVE_REGS flag, which will tell the arch
to take the time to pass a full set of pt_regs to the ftrace_ops callback
function. If the arch does not support it then it should pass NULL.If an arch can pass full regs, then it should define:
ARCH_SUPPORTS_FTRACE_SAVE_REGS to 1Link: http://lkml.kernel.org/r/20120702201821.019966811@goodmis.org
Reviewed-by: Masami Hiramatsu
Signed-off-by: Steven Rostedt -
Currently the function trace callback receives only the ip and parent_ip
of the function that it traced. It would be more powerful to also return
the ops that registered the function as well. This allows the same function
to act differently depending on what ftrace_ops registered it.Link: http://lkml.kernel.org/r/20120612225424.267254552@goodmis.org
Reviewed-by: Masami Hiramatsu
Signed-off-by: Steven Rostedt
19 May, 2011
2 commits
-
Add some basic sanity tests for multiple users of the function
tracer at startup.Signed-off-by: Steven Rostedt
-
Since users of the function tracer can now pick and choose which
functions they want to trace agnostically from other users of the
function tracer, we need to pass the ops struct to the ftrace_set_filter()
functions.The functions ftrace_set_global_filter() and ftrace_set_global_notrace()
is added to keep the old filter functions which are used to modify
the generic function tracers.Signed-off-by: Steven Rostedt
07 Jan, 2011
1 commit
-
Function-scope statics are discouraged because they are
easily overlooked and can cause subtle bugs/races due to
their global (non-SMP safe) nature.Linus noticed that we did this for sched_param - at minimum
make the const.Suggested-by: Linus Torvalds
Signed-off-by: Peter Zijlstra
LKML-Reference: Message-ID:
Signed-off-by: Ingo Molnar
23 Oct, 2010
1 commit
-
Andrew Morton pointed out almost all sched_setscheduler() callers are
using fixed parameters and can be converted to static. It reduces runtime
memory use a little.Signed-off-by: KOSAKI Motohiro
Reported-by: Andrew Morton
Acked-by: James Morris
Cc: Ingo Molnar
Cc: Steven Rostedt
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner
Signed-off-by: Ingo Molnar
