Impact: prevent crash due to multiple function graph tracers
The function graph tracer can currently only handle a single tracer
being registered. If another tracer registers with the function
graph tracer it can crash the system.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch move the timestamp from happening in the arch specific
code into the general code. This allows for better control by the tracer
to time manipulation.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
If the function profiler does not have any items recorded and one were
to cat the function stat file, the kernel would take a BUG with a NULL
pointer dereference.
Looking further into this, I found that returning NULL from stat_start
did not stop the stat logic, and would later call stat_next. This breaks
from the way seq_file works, so I looked into fixing the stat code.
This is where I noticed that the last next_entry is never freed.
It is allocated, and if the stat_next returns NULL, the code breaks out
of the loop, unlocks the mutex and exits. We never link the next_entry
nor do we free it. Thus it is a real memory leak.
This patch rearranges the code a bit to not only fix the memory leak,
but also to act more like seq_file where nothing is printed if there
is nothing to print. That is, stat_start returns NULL.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: new feature, allow symbolic values in /debug/tracing/act_mask
Print stringified act_mask instead of hex value:
# cat act_mask
read,write,barrier,sync,queue,requeue,issue,complete,fs,pc,ahead,meta,
discard,drv_data
# echo "meta,write" > act_mask
# cat act_mask
write,meta
Also:
- make act_mask accept "ahead", "meta", "discard" and "drv_data"
- use strsep() instead of strchr() to parse user input
- return -EINVAL if a token is not found in the mask map
- fix a bug that 'value' is unsigned, so it can < 0
- propagate error value of blk_trace_mask2str() to userspace, but not
always return -ENXIO.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <49C8AB42.1000802@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix the output of IO type category characters
Trace categories are the upper 16 bits, not the lower 16 bits.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <49C89432.8010805@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Delta patch to address the review comments.
- Implement warning when IRQ_WAKE_THREAD is requested and no
thread handler installed
- coding style fixes
Pointed-out-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Some devices use devres_request_irq() for to install their interrupt
handler. Add support for threaded interrupts to devres as well.
[tglx - simplified and adapted to latest threadirq version]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Add support for threaded interrupt handlers:
A device driver can request that its main interrupt handler runs in a
thread. To achive this the device driver requests the interrupt with
request_threaded_irq() and provides additionally to the handler a
thread function. The handler function is called in hard interrupt
context and needs to check whether the interrupt originated from the
device. If the interrupt originated from the device then the handler
can either return IRQ_HANDLED or IRQ_WAKE_THREAD. IRQ_HANDLED is
returned when no further action is required. IRQ_WAKE_THREAD causes
the genirq code to invoke the threaded (main) handler. When
IRQ_WAKE_THREAD is returned handler must have disabled the interrupt
on the device level. This is mandatory for shared interrupt handlers,
but we need to do it as well for obscure x86 hardware where disabling
an interrupt on the IO_APIC level redirects the interrupt to the
legacy PIC interrupt lines.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Impact: fix filter use boundary condition / crash
Make sure filters for string fields don't use integer values and vice
versa. Getting it wrong can crash the system or produce bogus
results.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237878882.8339.61.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Instead of just using the trace_seq buffer to print the filters, use
trace_seq_printf() as it was intended to be used.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237878871.8339.59.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix (small) per trace filter modification memory leak
Free the current pred when clearing the filters via the filter files.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237878851.8339.58.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
No need to use the safe version here, so use list_for_each_entry instead
of list_for_each_entry_safe in find_event_field().
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237878841.8339.57.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix traces output
Sometimes one can observe an imbalance in the traces between function
calls and function return traces:
func1() {
}
}
The curly brace inside func1() is the return of another function nested
inside func1. The return trace have been inserted in the buffer but not
the entry.
We are storing a return address on the function traces stack while we
haven't inserted its entry on the buffer, hence the imbalance on the
traces.
This is because the tracers doesn't check all failures that can happen
on buffer insertion.
This patch reports the tracing recursion failures and the ring buffer
failures. In such cases, we now restore the original return address for
the function, giving up its return trace.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237843021-11695-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
commit 40ada30f96 ("tracing: clean up menu"),
despite the "clean up" in its purpose, introduced a behavioural
change for Kconfig symbols: we no longer able to select tracing
support on PPC32 (because IRQFLAGS_SUPPORT isn't yet implemented).
The IRQFLAGS_SUPPORT is not mandatory for most tracers, tracing core
has a special case for platforms w/o irqflags (which, by the way, has
become useless as of the commit above).
Though according to Ingo Molnar, there was periodic build failures on
weird, unmaintained architectures that had no irqflags-tracing support
and hence didn't know the raw_irqs_save/restore primitives. Thus we'd
better not enable irqflags-less tracing for all architectures.
This patch restores the old behaviour for PPC32, and thus brings the
tracing back. Other architectures can either add themselves to the
exception list or (better) implement TRACE_IRQFLAGS_SUPPORT.
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-b: Steven Rostedt <rostedt@goodmis.org>
Cc: linuxppc-dev@ozlabs.org
LKML-Reference: <20090323220724.GA9851@oksana.dev.rtsoft.ru>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
See http://bugzilla.kernel.org/show_bug.cgi?id=12911
copy_signal() copies signal->rlim, but RLIMIT_CPU is "lost". Because
posix_cpu_timers_init_group() sets cputime_expires.prof_exp = 0 and thus
fastpath_timer_check() returns false unless we have other cpu timers.
This is the minimal fix for 2.6.29 (tested) and 2.6.28. The patch is not
optimal, we need further cleanups here. With this patch update_rlimit_cpu()
is not really needed, but I don't think it should be removed.
The proper fix (I think) is:
- set_process_cpu_timer() should just start the cputimer->running
logic (it does), no need to change cputime_expires.xxx_exp
- posix_cpu_timers_init_group() should set ->running when needed
- fastpath_timer_check() can check ->running instead of
task_cputime_zero(signal->cputime_expires)
Reported-by: Peter Lojkin <ia6432@inbox.ru>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: <stable@kernel.org> [for 2.6.29.x]
LKML-Reference: <20090323193411.GA17514@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch fixes bug #12208:
Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=12208
Subject : uml is very slow on 2.6.28 host
This turned out to be not a scheduler regression, but an already
existing problem in ptrace being triggered by subtle scheduler
changes.
The problem is this:
- task A is ptracing task B
- task B stops on a trace event
- task A is woken up and preempts task B
- task A calls ptrace on task B, which does ptrace_check_attach()
- this calls wait_task_inactive(), which sees that task B is still on the runq
- task A goes to sleep for a jiffy
- ...
Since UML does lots of the above sequences, those jiffies quickly add
up to make it slow as hell.
This patch solves this by not rescheduling in read_unlock() after
ptrace_stop() has woken up the tracer.
Thanks to Oleg Nesterov and Ingo Molnar for the feedback.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: fix a crash with ftrace={nop,boot} parameter
If the nop or initcall tracers are launched as boot tracers,
they will attempt to create their option directory and files.
But these tracers are registered very early and then assigned
as "boot tracers" very early if asked to.
Since they do this before debugfs has been registered (core initcall),
a crash is triggered.
Another early tracers could also come later. So we fix it by
checking if debugfs is initialized before creating the root
tracing directory.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237759847-21025-3-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, memory leak fix
This patch cleans up filter_add_subsystem_pred():
- searches for the field before creating a copy of the pred
- fixes memory leak in the case a predicate isn't applied
- if -ENOMEM, makes sure there's no longer a reference to the
pred so the caller can free the half-finished filter
- changes the confusing i == MAX_FILTER_PRED - 1 comparison
previously remarked upon
This affects only per-subsystem event filtering.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237796808.7527.40.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix potential crash on subsystem filter expression freeing
When making a copy of the predicate, pred->field_name needs to be
duplicated in the copy as well, otherwise bad things can happen due to
later multiple frees of the same string.
This affects only per-subsystem event filtering.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric?= Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237796802.7527.39.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When we want to filter an event, the filter test is done after
the event is commited to the ring-buffer to be discarded later if
needed.
But a reader could be reading this event while we are trying to discard
it. Other kind of racy events can even happen because the event is
commited and can be read and/or consumed.
What we want is to discard the event before committing it.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <1237763919-21505-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: display events when they arrive
Now that the events don't use wake_up() anymore, we need the nop
tracer to poll waiting for events on the pipe. Especially because
nop is useful to look at orphan traces types (traces types that
don't rely on specific tracers) because it doesn't produce traces
itself.
And unlike other tracers that trigger specific traces periodically,
nop triggers no traces by itself that can wake him.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237759847-21025-5-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix hard-lockup with sched switch events
Some ftrace events, such as sched wakeup, can be traced
while the runqueue lock is hold. Since they are using
trace_current_buffer_unlock_commit(), they call wake_up()
which can try to grab the runqueue lock too, resulting in
a deadlock.
Now for all event, we call a new helper:
trace_nowake_buffer_unlock_commit() which do pretty the same than
trace_current_buffer_unlock_commit() except than it doesn't call
trace_wake_up().
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237759847-21025-4-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We need the filter files to be writable, the current
filter file permissions are only set readable.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <1237759847-21025-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix potential kfree of random data in (rare) failure path
Zero-initialize the field structure.
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <1237710639.7703.46.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch adds per-subsystem filtering to the event tracing subsystem.
It adds a 'filter' debugfs file to each subsystem directory. This file
can be written to to set filters; reading from it will display the
current set of filters set for that subsystem.
Basically what it does is propagate the filter down to each event
contained in the subsystem. If a particular event doesn't have a field
with the name specified in the filter, it simply doesn't get set for
that event. You can verify whether or not the filter was set for a
particular event by looking at the filter file for that event.
As with per-event filters, compound expressions are supported, echoing
'0' to the subsystem's filter file clears all filters in the subsystem,
etc.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237710677.7703.49.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch adds per-event filtering to the event tracing subsystem.
It adds a 'filter' debugfs file to each event directory. This file can
be written to to set filters; reading from it will display the current
set of filters set for that event.
Basically, any field listed in the 'format' file for an event can be
filtered on (including strings, but not yet other array types) using
either matching ('==') or non-matching ('!=') 'predicates'. A
'predicate' can be either a single expression:
# echo pid != 0 > filter
# cat filter
pid != 0
or a compound expression of up to 8 sub-expressions combined using '&&'
or '||':
# echo comm == Xorg > filter
# echo "&& sig != 29" > filter
# cat filter
comm == Xorg
&& sig != 29
Only events having field values matching an expression will be available
in the trace output; non-matching events are discarded.
Note that a compound expression is built up by echoing each
sub-expression separately - it's not the most efficient way to do
things, but it keeps the parser simple and assumes that compound
expressions will be relatively uncommon. In any case, a subsequent
patch introducing a way to set filters for entire subsystems should
mitigate any need to do this for lots of events.
Setting a filter without an '&&' or '||' clears the previous filter
completely and sets the filter to the new expression:
# cat filter
comm == Xorg
&& sig != 29
# echo comm != Xorg
# cat filter
comm != Xorg
To clear a filter, echo 0 to the filter file:
# echo 0 > filter
# cat filter
none
The limit of 8 predicates for a compound expression is arbitrary - for
efficiency, it's implemented as an array of pointers to predicates, and
8 seemed more than enough for any filter...
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237710665.7703.48.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch overloads RINGBUF_TYPE_PADDING to provide a way to discard
events from the ring buffer, for the event-filtering mechanism
introduced in a subsequent patch.
I did the initial version but thanks to Steven Rostedt for adding
the parts that actually made it work. ;-)
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup.
This patch fixes the following sparse warnings:
kernel/trace/trace.c:385:9: warning: symbol 'trace_seq_to_buffer' was
not declared. Should it be static?
kernel/trace/trace_clock.c:29:13: warning: symbol 'trace_clock_local'
was not declared. Should it be static?
kernel/trace/trace_clock.c:54:13: warning: symbol 'trace_clock' was not
declared. Should it be static?
kernel/trace/trace_clock.c:74:13: warning: symbol 'trace_clock_global'
was not declared. Should it be static?
Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.com>
LKML-Reference: <1237741871-5827-4-git-send-email-dmitri.vorobiev@movial.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup.
The global mutex text_mutex if declared in linux/memory.h, so
this file needs to be included into kernel/extable.c, where the
same mutex is defined. This fixes the following sparse warning:
kernel/extable.c:32:1: warning: symbol 'text_mutex' was not declared.
Should it be static?
Signed-off-by: Dmitri Vorobiev <dmitri.vorobiev@movial.com>
LKML-Reference: <1237741871-5827-3-git-send-email-dmitri.vorobiev@movial.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch makes the field descriptions defined for event tracing
available at run-time, for the event-filtering mechanism introduced
in a subsequent patch.
The common event fields are prepended with 'common_' in the format
display, allowing them to be distinguished from the other fields
that might internally have same name and can therefore be
unambiguously used in filters.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1237710639.7703.46.camel@charm-linux>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Instead of using ftrace_dump_on_oops, it's far more convenient
to have the trace leading up to a self-test failure available
in /debug/tracing/trace.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237694675-23509-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: detect tracing related hangs
Sometimes, with some configs, the function graph tracer can make
the timer interrupt too much slow, hanging the kernel in an endless
loop of timer interrupts servicing.
As suggested by Ingo, this patch brings a watchdog which stops the
selftest after a defined number of functions traced, definitely
disabling this tracer.
For those who want to debug the cause of the function graph trace
hang, you can pass the ftrace_dump_on_oops kernel parameter to dump
the traces after this hang detection.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237694675-23509-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
bdev->bd_disk can be NULL, if the block device is not opened.
Try this against an unmounted partition, and you'll see NULL dereference:
# echo 1 > /sys/block/sda/sda5/enable
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49C30098.6080107@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
do_blk_trace_setup() may return EBUSY, but the current code
doesn't decrease blk_probes_ref in this case.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49C2F5FF.80002@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
blk_register_tracepoints() always returns 0, so make it return void,
thus we don't need to use blk_probe_mutex to protect blk_probes_ref.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49C2F5EA.8060606@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It doesn't have to be a counter, and it can be a bool flag instead.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49C2F5D3.8090104@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When we failed to create "block" debugfs dir, we should do some
cleanups.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49C2F5B2.8000800@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: remove a section warning
CONFIG_DEBUG_SECTION_MISMATCH raises the following warning on -tip:
WARNING: kernel/trace/built-in.o(.text+0x5bc5): Section mismatch in
reference from the function ring_buffer_alloc() to the function
.cpuinit.text:rb_cpu_notify()
The function ring_buffer_alloc() references
the function __cpuinit rb_cpu_notify().
This is actually harmless. The code in the ring buffer don't build
rb_cpu_notify and other cpu hotplug stuffs when !CONFIG_HOTPLUG_CPU
so we have no risk to reference freed memory here (it would even
be harmless if we unconditionally build it because register_cpu_notifier
would do nothing when !CONFIG_HOTPLUG_CPU.
But since ring_buffer_alloc() can be called everytime, we don't want it
to be annotated with __cpuinit so we drop the __cpuinit from
rb_cpu_notify.
This is not a waste of memory because it is only defined and used on
CONFIG_HOTPLUG_CPU.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1237606416-22268-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: build fix on SH !CONFIG_MMU
Stephen Rothwell reported this linux-next build failure on the SH
architecture:
kernel/built-in.o: In function `disable_all_kprobes':
kernel/kprobes.c:1382: undefined reference to `text_mutex'
[...]
And observed:
| Introduced by commit 4460fdad85 ("tracing,
| Text Edit Lock - kprobes architecture independent support") from the
| tracing tree. text_mutex is defined in mm/memory.c which is only built
| if CONFIG_MMU is defined, which is not true for sh allmodconfig.
Move this lock to kernel/extable.c (which is already home to various
kernel text related routines), which file is always built-in.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
LKML-Reference: <20090320110602.86351a91.sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
