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Currently, controllers have to explicitly follow the cgroup hierarchy
to find the parent of a given css. cgroup is moving towards using
cgroup_subsys_state as the main controller interface construct, so
let's provide a way to climb the hierarchy using just csses.
This patch implements css_parent() which, given a css, returns its
parent. The function is guarnateed to valid non-NULL parent css as
long as the target css is not at the top of the hierarchy.
freezer, cpuset, cpu, cpuacct, hugetlb, memory, net_cls and devices
are converted to use css_parent() instead of accessing cgroup->parent
directly.
* __parent_ca() is dropped from cpuacct and its usage is replaced with
parent_ca(). The only difference between the two was NULL test on
cgroup->parent which is now embedded in css_parent() making the
distinction moot. Note that eventually a css->parent field will be
added to css and the NULL check in css_parent() will go away.
This patch shouldn't cause any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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css (cgroup_subsys_state) is usually embedded in a subsys specific
data structure. Subsystems either use container_of() directly to cast
from css to such data structure or has an accessor function wrapping
such cast. As cgroup as whole is moving towards using css as the main
interface handle, add and update such accessors to ease dealing with
css's.
All accessors explicitly handle NULL input and return NULL in those
cases. While this looks like an extra branch in the code, as all
controllers specific data structures have css as the first field, the
casting doesn't involve any offsetting and the compiler can trivially
optimize out the branch.
* blkio, freezer, cpuset, cpu, cpuacct and net_cls didn't have such
accessor. Added.
* memory, hugetlb and devices already had one but didn't explicitly
handle NULL input. Updated.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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Currently, given a cgroup_subsys_state, there's no way to find out
which subsystem the css is for, which we'll need to convert the cgroup
controller API to primarily use @css instead of @cgroup. This patch
adds cgroup_subsys_state->ss which points to the subsystem the @css
belongs to.
While at it, remove the comment about accessing @css->cgroup to
determine the hierarchy. cgroup core will provide API to traverse
hierarchy of css'es and we don't want subsystems to directly walk
cgroup hierarchies anymore.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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cpuset uses "const" qualifiers on struct cpuset in some functions;
however, it doesn't work well when a value derived from returned const
pointer has to be passed to an accessor. It's C after all.
Drop the "const" qualifiers except for the trivially leaf ones. This
patch doesn't make any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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The names of the two struct cgroup_subsys_state accessors -
cgroup_subsys_state() and task_subsys_state() - are somewhat awkward.
The former clashes with the type name and the latter doesn't even
indicate it's somehow related to cgroup.
We're about to revamp large portion of cgroup API, so, let's rename
them so that they're less awkward. Most per-controller usages of the
accessors are localized in accessor wrappers and given the amount of
scheduled changes, this isn't gonna add any noticeable headache.
Rename cgroup_subsys_state() to cgroup_css() and task_subsys_state()
to task_css(). This patch is pure rename.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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for-3.12 branch is about to receive invasive updates which are
dependent on da0a12caff ("cgroup: fix a leak when percpu_ref_init()
fails"). Given the amount of scheduled changes, I think it'd less
painful to pull in for-3.11-fixes as preparation. Pull in
for-3.11-fixes into for-3.12.
Signed-off-by: Tejun Heo <tj@kernel.org>
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ss->css_free() is not called when perfcpu_ref_init() fails.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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task_cgroup_path_from_hierarchy() was added for the planned new users
and none of the currently planned users wants to know about multiple
hierarchies. This patch drops the multiple hierarchy part and makes
it always return the path in the first non-dummy hierarchy.
As unified hierarchy will always have id 1, this is guaranteed to
return the path for the unified hierarchy if mounted; otherwise, it
will return the path from the hierarchy which happens to occupy the
lowest hierarchy id, which will usually be the first hierarchy mounted
after boot.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Jan Kaluža <jkaluza@redhat.com>
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It's a rw_semaphore not a mutex.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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It uses a single label and checks the validity of each pointer. This
is err-prone, and actually we had a bug because one of the check was
insufficient.
Use multi lables as we do in other places.
v2:
- drop initializations of local variables.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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This enables us to lookup a cgroup by its id.
v4:
- add a comment for idr_remove() in cgroup_offline_fn().
v3:
- on success, idr_alloc() returns the id but not 0, so fix the BUG_ON()
in cgroup_init().
- pass the right value to idr_alloc() so that the id for dummy cgroup is 0.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Constantly use @cset for css_set variables and use @cgrp as cgroup
variables.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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We can use struct cfent instead.
v2:
- remove cgroup_seqfile_release().
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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This should have been removed in commit d7eeac1913ff
("cgroup: hold cgroup_mutex before calling css_offline").
While at it, update the comments.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Comment for cpuset_css_offline() was on top of cpuset_css_free().
Move it.
Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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get rid of the useless forward declaration of the struct cpuset cause the
below define it.
Signed-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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rebind_subsystems() performs santiy checks even on subsystems which
aren't specified to be added or removed and the checks aren't all that
useful given that these are in a very cold path while the violations
they check would trip up in much hotter paths.
Let's remove these from rebind_subsystems().
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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Module ref handling in cgroup is rather weird.
parse_cgroupfs_options() grabs all the modules for the specified
subsystems. A module ref is kept if the specified subsystem is newly
bound to the hierarchy. If not, or the operation fails, the refs are
dropped. This scatters module ref handling across multiple functions
making it difficult to track. It also make the function nasty to use
for dynamic subsystem binding which is necessary for the planned
unified hierarchy.
There's nothing which requires the subsystem modules to be pinned
between parse_cgroupfs_options() and rebind_subsystems() in both mount
and remount paths. parse_cgroupfs_options() can just parse and
rebind_subsystems() can handle pinning the subsystems that it wants to
bind, which is a natural part of its task - binding - anyway.
Move module ref handling into rebind_subsystems() which makes the code
a lot simpler - modules are gotten iff it's gonna be bound and put iff
unbound or binding fails.
v2: Li pointed out that if a controller module is unloaded between
parsing and binding, rebind_subsystems() won't notice the missing
controller as it only iterates through existing controllers. Fix
it by updating rebind_subsystems() to compare @added_mask to
@pinned and fail with -ENOENT if they don't match.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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cgroup_remount()
rebind_subsystems() currently fails if the hierarchy has any !root
cgroups; however, on the planned unified hierarchy,
rebind_subsystems() will be used while populated. Move the test to
cgroup_remount(), which is the only place the test is necessary
anyway.
As it's impossible for the other two callers of rebind_subsystems() to
have populated hierarchy, this doesn't make any behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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proper error handling
Currently, creating and removing cgroup files in the root directory
are handled separately from the actual subsystem binding and unbinding
which happens in rebind_subsystems(). Also, rebind_subsystems() users
aren't handling file creation errors properly. Let's integrate
top_cgroup file handling into rebind_subsystems() so that it's simpler
to use and everyone handles file creation errors correctly.
* On a successful return, rebind_subsystems() is guaranteed to have
created all files of the new subsystems and deleted the ones
belonging to the removed subsystems. After a failure, no file is
created or removed.
* cgroup_remount() no longer needs to make explicit populate/clear
calls as it's all handled by rebind_subsystems(), and it gets proper
error handling automatically.
* cgroup_mount() has been updated such that the root dentry and cgroup
are linked before rebind_subsystems(). Also, the init_cred dancing
and base file handling are moved right above rebind_subsystems()
call and proper error handling for the base files is added. While
at it, add a comment explaining what's going on with the cred thing.
* cgroup_kill_sb() calls rebind_subsystems() to unbind all subsystems
which now implies removing all subsystem files which requires the
directory's i_mutex. Grab it. This means that files on the root
cgroup are removed earlier - they used to be deleted from generic
super_block cleanup from vfs. This doesn't lead to any functional
difference and it's cleaner to do the clean up explicitly for all
files.
Combined with the previous changes, this makes all cgroup file
creation errors handled correctly.
v2: Added comment on init_cred.
v3: Li spotted that cgroup_mount() wasn't freeing tmp_links after base
file addition failure. Fix it by adding free_tmp_links error
handling label.
v4: v3 introduced build bugs which got noticed by Fengguang's awesome
kbuild test robot. Fixed, and shame on me.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
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cgroup_populate/clear_dir()
rebind_subsystems() will be updated to handle file creations and
removals with proper error handling and to do that will need to
perform file operations before actually adding the subsystem to the
hierarchy.
To enable such usage, update cgroup_populate/clear_dir() to use
for_each_subsys() instead of for_each_root_subsys() so that they
operate on all subsystems specified by @subsys_mask whether that
subsystem is currently bound to the hierarchy or not.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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cgroup_populate_dir() didn't use to check whether the actual file
creations were successful and could return success with only subset of
the requested files created, which is nasty.
This patch udpates cgroup_populate_dir() so that it either succeeds
with all files or fails with no file.
v2: The original patch also converted for_each_root_subsys() usages to
for_each_subsys() without explaining why. That part has been
moved to a separate patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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cgroup_populate/clear_dir()
cgroup_populate/clear_dir() currently take @base_files and adds and
removes, respectively, cgroup_base_files[] to the directory. File
additions and removals are being reorganized for proper error handling
and more dynamic handling for the unified hierarchy, and mixing base
and subsys file handling into the same functions gets a bit confusing.
This patch moves base file handling out of cgroup_populate/clear_dir()
into their users - cgroup_mount(), cgroup_create() and
cgroup_destroy_locked().
Note that this changes the behavior of base file removal. If
@base_files is %true, cgroup_clear_dir() used to delete files
regardless of cftype until there's no files left. Now, only files
with matching cfts are removed. As files can only be created by the
base or registered cftypes, this shouldn't result in any behavior
difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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cgroup_add_cftypes() uses cgroup_cfts_commit() to actually create the
files; however, both functions ignore actual file creation errors and
just assume success. This can lead to, for example, blkio hierarchy
with some of the cgroups with only subset of interface files populated
after cfq-iosched is loaded under heavy memory pressure, which is
nasty.
This patch updates cgroup_cfts_commit() and cgroup_add_cftypes() to
guarantee that all files are created on success and no file is created
on failure.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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cgroup_addrm_files() mishandled error return value from
cgroup_add_file() and returns error iff the last file fails to create.
As we're in the process of cleaning up file add/rm error handling and
will reliably propagate file creation failures, there's no point in
keeping adding files after a failure.
Replace the broken error collection logic with immediate error return.
While at it, add lockdep assertions and function comment.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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* Rename it to cgroup_clear_dir() and make it take the pointer to the
target cgroup instead of the the dentry. This makes the function
consistent with its counterpart - cgroup_populate_dir().
* Move cgroup_clear_directory() invocation from cgroup_d_remove_dir()
to cgroup_remount() so that the function doesn't have to determine
the cgroup pointer back from the dentry. cgroup_d_remove_dir() now
only deals with vfs, which is slightly cleaner.
This patch doesn't introduce any functional differences.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing changes from Steven Rostedt:
"The majority of the changes here are cleanups for the large changes
that were added to 3.10, which includes several bug fixes that have
been marked for stable.
As for new features, there were a few, but nothing to write to LWN
about. These include:
New function trigger called "dump" and "cpudump" that will cause
ftrace to dump its buffer to the console when the function is called.
The difference between "dump" and "cpudump" is that "dump" will dump
the entire contents of the ftrace buffer, where as "cpudump" will only
dump the contents of the ftrace buffer for the CPU that called the
function.
Another small enhancement is a new sysctl switch called
"traceoff_on_warning" which, when enabled, will disable tracing if any
WARN_ON() is triggered. This is useful if you want to debug what
caused a warning and do not want to risk losing your trace data by the
ring buffer overwriting the data before you can disable it. There's
also a kernel command line option that will make this enabled at boot
up called the same thing"
* tag 'trace-3.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (34 commits)
tracing: Make tracing_open_generic_{tr,tc}() static
tracing: Remove ftrace() function
tracing: Remove TRACE_EVENT_TYPE enum definition
tracing: Make tracer_tracing_{off,on,is_on}() static
tracing: Fix irqs-off tag display in syscall tracing
uprobes: Fix return value in error handling path
tracing: Fix race between deleting buffer and setting events
tracing: Add trace_array_get/put() to event handling
tracing: Get trace_array ref counts when accessing trace files
tracing: Add trace_array_get/put() to handle instance refs better
tracing: Protect ftrace_trace_arrays list in trace_events.c
tracing: Make trace_marker use the correct per-instance buffer
ftrace: Do not run selftest if command line parameter is set
tracing/kprobes: Don't pass addr=ip to perf_trace_buf_submit()
tracing: Use flag buffer_disabled for irqsoff tracer
tracing/kprobes: Turn trace_probe->files into list_head
tracing: Fix disabling of soft disable
tracing: Add missing syscall_metadata comment
tracing: Simplify code for showing of soft disabled flag
tracing/kprobes: Kill probe_enable_lock
...
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I have patches that will use tracing_open_generic_tr/tc() in other
files, but as they are not ready to be merged yet, and Fengguang Wu's
sparse scripts pointed out that these functions were not declared
anywhere, I'll make them static for now.
When these functions are required to be used elsewhere, I'll remove
the static then.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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The only caller of function ftrace(...) was removed a long time ago,
so remove the function body as well.
Link: http://lkml.kernel.org/r/1365564393-10972-10-git-send-email-jovi.zhangwei@huawei.com
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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TRACE_EVENT_TYPE enum is not used at present, remove it.
Link: http://lkml.kernel.org/r/1365564393-10972-8-git-send-email-jovi.zhangwei@huawei.com
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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I have patches that will use tracer_tracing_on/off/is_on() in other
files, but as they are not ready to be merged yet, and Fengguang Wu's
sparse scripts pointed out that these functions were not declared
anywhere, I'll make them static for now.
When these functions are required to be used elsewhere, I'll remove
the static then.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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All syscall tracing irqs-off tags are wrong, the syscall enter entry doesn't
disable irqs.
[root@jovi tracing]#echo "syscalls:sys_enter_open" > set_event
[root@jovi tracing]# cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 13/13 #P:2
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
irqbalance-513 [000] d... 56115.496766: sys_open(filename: 804e1a6, flags: 0, mode: 1b6)
irqbalance-513 [000] d... 56115.497008: sys_open(filename: 804e1bb, flags: 0, mode: 1b6)
sendmail-771 [000] d... 56115.827982: sys_open(filename: b770e6d1, flags: 0, mode: 1b6)
The reason is syscall tracing doesn't record irq_flags into buffer.
The proper display is:
[root@jovi tracing]#echo "syscalls:sys_enter_open" > set_event
[root@jovi tracing]# cat trace
# tracer: nop
#
# entries-in-buffer/entries-written: 14/14 #P:2
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
irqbalance-514 [001] .... 46.213921: sys_open(filename: 804e1a6, flags: 0, mode: 1b6)
irqbalance-514 [001] .... 46.214160: sys_open(filename: 804e1bb, flags: 0, mode: 1b6)
<...>-920 [001] .... 47.307260: sys_open(filename: 4e82a0c5, flags: 80000, mode: 0)
Link: http://lkml.kernel.org/r/1365564393-10972-3-git-send-email-jovi.zhangwei@huawei.com
Cc: stable@vger.kernel.org # 2.6.35
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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When wrong argument is passed into uprobe_events it does not return
an error:
[root@jovi tracing]# echo 'p:myprobe /bin/bash' > uprobe_events
[root@jovi tracing]#
The proper response is:
[root@jovi tracing]# echo 'p:myprobe /bin/bash' > uprobe_events
-bash: echo: write error: Invalid argument
Link: http://lkml.kernel.org/r/51B964FF.5000106@huawei.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <srikar@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # 3.5+
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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While analyzing the code, I discovered that there's a potential race between
deleting a trace instance and setting events. There are a few races that can
occur if events are being traced as the buffer is being deleted. Mostly the
problem comes with freeing the descriptor used by the trace event callback.
To prevent problems like this, the events are disabled before the buffer is
deleted. The problem with the current solution is that the event_mutex is let
go between disabling the events and freeing the files, which means that the events
could be enabled again while the freeing takes place.
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Commit a695cb58162 "tracing: Prevent deleting instances when they are being read"
tried to fix a race between deleting a trace instance and reading contents
of a trace file. But it wasn't good enough. The following could crash the kernel:
# cd /sys/kernel/debug/tracing/instances
# ( while :; do mkdir foo; rmdir foo; done ) &
# ( while :; do echo 1 > foo/events/sched/sched_switch 2> /dev/null; done ) &
Luckily this can only be done by root user, but it should be fixed regardless.
The problem is that a delete of the file can happen after the write to the event
is opened, but before the enabling happens.
The solution is to make sure the trace_array is available before succeeding in
opening for write, and incerment the ref counter while opened.
Now the instance can be deleted when the events are writing to the buffer,
but the deletion of the instance will disable all events before the instance
is actually deleted.
Cc: stable@vger.kernel.org # 3.10
Reported-by: Alexander Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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When a trace file is opened that may access a trace array, it must
increment its ref count to prevent it from being deleted.
Cc: stable@vger.kernel.org # 3.10
Reported-by: Alexander Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Commit a695cb58162 "tracing: Prevent deleting instances when they are being read"
tried to fix a race between deleting a trace instance and reading contents
of a trace file. But it wasn't good enough. The following could crash the kernel:
# cd /sys/kernel/debug/tracing/instances
# ( while :; do mkdir foo; rmdir foo; done ) &
# ( while :; do cat foo/trace &> /dev/null; done ) &
Luckily this can only be done by root user, but it should be fixed regardless.
The problem is that a delete of the file can happen after the reader starts
to open the file but before it grabs the trace_types_mutex.
The solution is to validate the trace array before using it. If the trace
array does not exist in the list of trace arrays, then it returns -ENODEV.
There's a possibility that a trace_array could be deleted and a new one
created and the open would open its file instead. But that is very minor as
it will just return the data of the new trace array, it may confuse the user
but it will not crash the system. As this can only be done by root anyway,
the race will only occur if root is deleting what its trying to read at
the same time.
Cc: stable@vger.kernel.org # 3.10
Reported-by: Alexander Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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There are multiple places where the ftrace_trace_arrays list is accessed in
trace_events.c without the trace_types_lock held.
Link: http://lkml.kernel.org/r/1372732674-22726-1-git-send-email-azl@google.com
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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The trace_marker file was present for each new instance created, but it
added the trace mark to the global trace buffer instead of to
the instance's buffer.
Link: http://lkml.kernel.org/r/1372717885-4543-2-git-send-email-azl@google.com
Cc: David Sharp <dhsharp@google.com>
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: Alexander Z Lam <lambchop468@gmail.com>
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Alexander Z Lam <azl@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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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 <rostedt@goodmis.org>
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kprobe_perf_func() and kretprobe_perf_func() pass addr=ip to
perf_trace_buf_submit() for no reason.
This sets perf_sample_data->addr for PERF_SAMPLE_ADDR, we already
have perf_sample_data->ip initialized if PERF_SAMPLE_IP.
Link: http://lkml.kernel.org/r/20130620173811.GA13161@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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If the ring buffer is disabled and the irqsoff tracer records a trace it
will clear out its buffer and lose the data it had previously recorded.
Currently there's a callback when writing to the tracing_of file, but if
tracing is disabled via the function tracer trigger, it will not inform
the irqsoff tracer to stop recording.
By using the "mirror" flag (buffer_disabled) in the trace_array, that keeps
track of the status of the trace_array's buffer, it gives the irqsoff
tracer a fast way to know if it should record a new trace or not.
The flag may be a little behind the real state of the buffer, but it
should not affect the trace too much. It's more important for the irqsoff
tracer to be fast.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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I think that "ftrace_event_file *trace_probe[]" complicates the
code for no reason, turn it into list_head to simplify the code.
enable_trace_probe() no longer needs synchronize_sched().
This needs the extra sizeof(list_head) memory for every attached
ftrace_event_file, hopefully not a problem in this case.
Link: http://lkml.kernel.org/r/20130620173814.GA13165@redhat.com
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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The comment on the soft disable 'disable' case of
__ftrace_event_enable_disable() states that the soft disable bit
should be cleared in that case, but currently only the soft mode bit
is actually cleared.
This essentially leaves the standard non-soft-enable enable/disable
paths as the only way to clear the soft disable flag, but the soft
disable bit should also be cleared when removing a trigger with '!'.
Also, the SOFT_DISABLED bit should never be set if SOFT_MODE is
cleared.
This fixes the above discrepancies.
Link: http://lkml.kernel.org/r/b9c68dd50bc07019e6c67d3f9b29be4ef1b2badb.1372479499.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Rather than enumerating each permutation, build the enable state
string up from the combination of states. This also allows for the
simpler addition of more states.
Link: http://lkml.kernel.org/r/9aff5af6dee2f5a40ca30df41c39d5f33e998d7a.1372479499.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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enable_trace_probe() and disable_trace_probe() should not worry about
serialization, the caller (perf_trace_init or __ftrace_set_clr_event)
holds event_mutex.
They are also called by kprobe_trace_self_tests_init(), but this __init
function can't race with itself or trace_events.c
And note that this code depended on event_mutex even before 41a7dd420c
which introduced probe_enable_lock. In fact it assumes that the caller
kprobe_register() can never race with itself. Otherwise, say, tp->flags
manipulations are racy.
Link: http://lkml.kernel.org/r/20130620173809.GA13158@redhat.com
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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perf_trace_buf_prepare() + perf_trace_buf_submit() make no sense
if this task/CPU has no active counters. Change kprobe_perf_func()
and kretprobe_perf_func() to check call->perf_events beforehand
and return if this list is empty.
For example, "perf record -e some_probe -p1". Only /sbin/init will
report, all other threads which hit the same probe will do
perf_trace_buf_prepare/perf_trace_buf_submit just to realize that
nobody wants perf_swevent_event().
Link: http://lkml.kernel.org/r/20130620173806.GA13151@redhat.com
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Running the following:
# cd /sys/kernel/debug/tracing
# echo p:i do_sys_open > kprobe_events
# echo p:j schedule >> kprobe_events
# cat kprobe_events
p:kprobes/i do_sys_open
p:kprobes/j schedule
# echo p:i do_sys_open >> kprobe_events
# cat kprobe_events
p:kprobes/j schedule
p:kprobes/i do_sys_open
# ls /sys/kernel/debug/tracing/events/kprobes/
enable filter j
Notice that the 'i' is missing from the kprobes directory.
The console produces:
"Failed to create system directory kprobes"
This is because kprobes passes in a allocated name for the system
and the ftrace event subsystem saves off that name instead of creating
a duplicate for it. But the kprobes may free the system name making
the pointer to it invalid.
This bug was introduced by 92edca073c37 "tracing: Use direct field, type
and system names" which switched from using kstrdup() on the system name
in favor of just keeping apointer to it, as the internal ftrace event
system names are static and exist for the life of the computer being booted.
Instead of reverting back to duplicating system names again, we can use
core_kernel_data() to determine if the passed in name was allocated or
static. Then use the MSB of the ref_count to be a flag to keep track if
the name was allocated or not. Then we can still save from having to duplicate
strings that will always exist, but still copy the ones that may be freed.
Cc: stable@vger.kernel.org # 3.10
Reported-by: "zhangwei(Jovi)" <jovi.zhangwei@huawei.com>
Reported-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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When FUNCTION_GRAPH_TRACER is enabled, ftrace can profile kernel functions
and print basic statistics about them. Unfortunately, running stddev
calculation is wrong. This patch corrects it implementing Welford’s method:
s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2) .
Link: http://lkml.kernel.org/r/1371031398-24048-1-git-send-email-juri.lelli@gmail.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Since tp->flags assignment was moved into function enable_trace_probe(),
there is no need to use trace_probe_is_enabled to check flags
in the same function.
Remove the unnecessary checking.
Link: http://lkml.kernel.org/r/51BA7B9E.3040807@huawei.com
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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