Sometimes the group name is not "kprobes",
It'll be better if we can read it from tracing/kprobe_events.
# echo 'r:laijs/vfs_read vfs_read %ax' > kprobe_events
# cat kprobe_events
r:laijs/vfs_read vfs_read %ax=%ax
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4B0CEBAF.6000104@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Kernel breakpoints are created using functions in which we pass
breakpoint parameters as individual variables: address, length
and type.
Although it fits well for x86, this just does not scale across
architectures that may support this api later as these may have
more or different needs. Pass in a perf_event_attr structure
instead because it is meant to evolve as much as possible into
a generic hardware breakpoint parameter structure.
Reported-by: K.Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1259294154-5197-2-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Make perf_swevent_get_recursion_context return a context number
and disable preemption.
This could be used to remove the IRQ disable from the trace bit
and index the per-cpu buffer with.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091123103819.993226816@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When we commit a trace to perf, we first check if we are
recursing in the same buffer so that we don't mess-up the buffer
with a recursing trace. But later on, we do the same check from
perf to avoid commit recursion. The recursion check is desired
early before we touch the buffer but we want to do this check
only once.
Then export the recursion protection from perf and use it from
the trace events before submitting a trace.
v2: Put appropriate Reported-by tag
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <1258864015-10579-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Conflicts:
arch/x86/kernel/kprobes.c
kernel/trace/Makefile
Merge reason: hw-breakpoints perf integration is looking
good in testing and in reviews, plus conflicts
are mounting up - so merge & resolve.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The macro used to be used in both trace_selftest.c and
trace_ksym.c, but no longer, so remove it from header file.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
This patch rebase the implementation of the breakpoints API on top of
perf events instances.
Each breakpoints are now perf events that handle the
register scheduling, thread/cpu attachment, etc..
The new layering is now made as follows:
ptrace kgdb ftrace perf syscall
\ | / /
\ | / /
/
Core breakpoint API /
/
| /
| /
Breakpoints perf events
|
|
Breakpoints PMU ---- Debug Register constraints handling
(Part of core breakpoint API)
|
|
Hardware debug registers
Reasons of this rewrite:
- Use the centralized/optimized pmu registers scheduling,
implying an easier arch integration
- More powerful register handling: perf attributes (pinned/flexible
events, exclusive/non-exclusive, tunable period, etc...)
Impact:
- New perf ABI: the hardware breakpoints counters
- Ptrace breakpoints setting remains tricky and still needs some per
thread breakpoints references.
Todo (in the order):
- Support breakpoints perf counter events for perf tools (ie: implement
perf_bpcounter_event())
- Support from perf tools
Changes in v2:
- Follow the perf "event " rename
- The ptrace regression have been fixed (ptrace breakpoint perf events
weren't released when a task ended)
- Drop the struct hw_breakpoint and store generic fields in
perf_event_attr.
- Separate core and arch specific headers, drop
asm-generic/hw_breakpoint.h and create linux/hw_breakpoint.h
- Use new generic len/type for breakpoint
- Handle off case: when breakpoints api is not supported by an arch
Changes in v3:
- Fix broken CONFIG_KVM, we need to propagate the breakpoint api
changes to kvm when we exit the guest and restore the bp registers
to the host.
Changes in v4:
- Drop the hw_breakpoint_restore() stub as it is only used by KVM
- EXPORT_SYMBOL_GPL hw_breakpoint_restore() as KVM can be built as a
module
- Restore the breakpoints unconditionally on kvm guest exit:
TIF_DEBUG_THREAD doesn't anymore cover every cases of running
breakpoints and vcpu->arch.switch_db_regs might not always be
set when the guest used debug registers.
(Waiting for a reliable optimization)
Changes in v5:
- Split-up the asm-generic/hw-breakpoint.h moving to
linux/hw_breakpoint.h into a separate patch
- Optimize the breakpoints restoring while switching from kvm guest
to host. We only want to restore the state if we have active
breakpoints to the host, otherwise we don't care about messed-up
address registers.
- Add asm/hw_breakpoint.h to Kbuild
- Fix bad breakpoint type in trace_selftest.c
Changes in v6:
- Fix wrong header inclusion in trace.h (triggered a build
error with CONFIG_FTRACE_SELFTEST
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Prasad <prasad@linux.vnet.ibm.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jan Kiszka <jan.kiszka@web.de>
Cc: Jiri Slaby <jirislaby@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
While tracing using events with perf, if one enables the
lockdep:lock_acquire event, it will infect every other perf
trace events.
Basically, you can enable whatever set of trace events through
perf but if this event is part of the set, the only result we
can get is a long list of lock_acquire events of rcu read lock,
and only that.
This is because of a recursion inside perf.
1) When a trace event is triggered, it will fill a per cpu
buffer and submit it to perf.
2) Perf will commit this event but will also protect some data
using rcu_read_lock
3) A recursion appears: rcu_read_lock triggers a lock_acquire
event that will fill the per cpu event and then submit the
buffer to perf.
4) Perf detects a recursion and ignores it
5) Perf continues its work on the previous event, but its buffer
has been overwritten by the lock_acquire event, it has then
been turned into a lock_acquire event of rcu read lock
Such scenario also happens with lock_release with
rcu_read_unlock().
We could turn the rcu_read_lock() into __rcu_read_lock() to drop
the lock debugging from perf fast path, but that would make us
lose the rcu debugging and that doesn't prevent from other
possible kind of recursion from perf in the future.
This patch adds a recursion protection based on a counter on the
perf trace per cpu buffers to solve the problem.
-v2: Fixed lost whitespace, added reviewed-by tag
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <1257477185-7838-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Conflicts:
tools/perf/Makefile
Merge reason: Resolve the conflict, merge to upstream and merge in
perf fixes so we can add a dependent patch.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When a command is passed to the set_ftrace_filter, then
the ftrace_regex_lock is still held going back to user space.
# echo 'do_open : foo' > set_ftrace_filter
(still holding ftrace_regex_lock when returning to user space!)
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4AEF7F8A.3080300@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
We got a sudden panic when we reduced the size of the
ringbuffer.
We can reproduce the panic by the following steps:
echo 1 > events/sched/enable
cat trace_pipe > /dev/null &
while ((1))
do
echo 12000 > buffer_size_kb
echo 512 > buffer_size_kb
done
(not more than 5 seconds, panic ...)
Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4AF01735.9060409@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
trace_seq_printf() return value is a little ambiguous. It
currently returns the length of the space available in the
buffer. printf usually returns the amount written. This is not
adequate here, because:
trace_seq_printf(s, "");
is perfectly legal, and returning 0 would indicate that it
failed.
We can always see the amount written by looking at the before
and after values of s->len. This is not quite the same use as
printf. We only care if the string was successfully written to
the buffer or not.
Make trace_seq_printf() return 0 if the trace oversizes the
buffer's free space, 1 otherwise.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091023233646.631787612@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Conflicts:
tools/perf/Makefile
Merge reason:
- fix the conflict
- pick up the pr_*() infrastructure to queue up dependent patch
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Conflicts:
kernel/Makefile
kernel/trace/Makefile
kernel/trace/trace.h
samples/Makefile
Merge reason: We need to be uptodate with the perf events development
branch because we plan to rewrite the breakpoints API on top of
perf events.
Merge reason: to add event filter support we need the following
commits from the tracing tree:
3f6fe06: tracing/filters: Unify the regex parsing helpers
1889d20: tracing/filters: Provide basic regex support
737f453: tracing/filters: Cleanup useless headers
Signed-off-by: Ingo Molnar <mingo@elte.hu>
set_cmdline_ftrace is a better match against what does this function:
apply a tracer name from the kernel command line.
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
We are using strncpy in the wrong way to copy the ftrace_graph_filter
boot param because we pass the buffer size instead of the max string
size it can contain (buffer size - 1). The end result might not be
NULL terminated as we are abusing the max string size.
Lets use strlcpy() instead.
Reported-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Most of the syscalls metadata processing is done from arch.
But these operations are mostly generic accross archs. Especially now
that we have a common variable name that expresses the number of
syscalls supported by an arch: NR_syscalls, the only remaining bits
that need to reside in arch is the syscall nr to addr translation.
v2: Compare syscalls symbols only after the "sys" prefix so that we
avoid spurious mismatches with archs that have syscalls wrappers,
in which case syscalls symbols have "SyS" prefixed aliases.
(Reported by: Heiko Carstens)
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
I was debuging some module using "function" and "function_graph"
tracers and noticed, that if you load module after you enabled
tracing, the module's hooks will convert only to NOP instructions.
The attached patch enables modules' hooks if there's function trace
allready on, thus allowing to trace module functions.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20091013203425.896285120@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove the ftrace_trace_addr() function as only its off-case is
implemented and there are no users of it currently.
But we keep ftrace_graph_addr() off-case, in case someone come to use
the function graph tracer to profit from top-level callers filtering.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Do this rename because set_ftrace is too much generic and not enough
self-explainable as a name.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
