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The function ftrace_graph_get_ret_stack() takes a task struct descriptor but
uses current as the task to perform the operations on. In pretty much all
cases the task decriptor is the same as current, so this wasn't an issue.
But there is a case in the ARM architecture that passes in a task that is
not current, and expects a result from that task, and this code breaks it.
Fixes: 51584396cff5 ("arm64: Use ftrace_graph_get_ret_stack() instead of curr_ret_stack")
Reported-by: James Morse <james.morse@arm.com>
Tested-by: James Morse <james.morse@arm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Daniel Borkmann says:
====================
pull-request: bpf-next 2018-12-21
The following pull-request contains BPF updates for your *net-next* tree.
There is a merge conflict in test_verifier.c. Result looks as follows:
[...]
},
{
"calls: cross frame pruning",
.insns = {
[...]
.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
.errstr_unpriv = "function calls to other bpf functions are allowed for root only",
.result_unpriv = REJECT,
.errstr = "!read_ok",
.result = REJECT,
},
{
"jset: functional",
.insns = {
[...]
{
"jset: unknown const compare not taken",
.insns = {
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
BPF_FUNC_get_prandom_u32),
BPF_JMP_IMM(BPF_JSET, BPF_REG_0, 1, 1),
BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
.errstr_unpriv = "!read_ok",
.result_unpriv = REJECT,
.errstr = "!read_ok",
.result = REJECT,
},
[...]
{
"jset: range",
.insns = {
[...]
},
.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
.result_unpriv = ACCEPT,
.result = ACCEPT,
},
The main changes are:
1) Various BTF related improvements in order to get line info
working. Meaning, verifier will now annotate the corresponding
BPF C code to the error log, from Martin and Yonghong.
2) Implement support for raw BPF tracepoints in modules, from Matt.
3) Add several improvements to verifier state logic, namely speeding
up stacksafe check, optimizations for stack state equivalence
test and safety checks for liveness analysis, from Alexei.
4) Teach verifier to make use of BPF_JSET instruction, add several
test cases to kselftests and remove nfp specific JSET optimization
now that verifier has awareness, from Jakub.
5) Improve BPF verifier's slot_type marking logic in order to
allow more stack slot sharing, from Jiong.
6) Add sk_msg->size member for context access and add set of fixes
and improvements to make sock_map with kTLS usable with openssl
based applications, from John.
7) Several cleanups and documentation updates in bpftool as well as
auto-mount of tracefs for "bpftool prog tracelog" command,
from Quentin.
8) Include sub-program tags from now on in bpf_prog_info in order to
have a reliable way for user space to get all tags of the program
e.g. needed for kallsyms correlation, from Song.
9) Add BTF annotations for cgroup_local_storage BPF maps and
implement bpf fs pretty print support, from Roman.
10) Fix bpftool in order to allow for cross-compilation, from Ivan.
11) Update of bpftool license to GPLv2-only + BSD-2-Clause in order
to be compatible with libbfd and allow for Debian packaging,
from Jakub.
12) Remove an obsolete prog->aux sanitation in dump and get rid of
version check for prog load, from Daniel.
13) Fix a memory leak in libbpf's line info handling, from Prashant.
14) Fix cpumap's frame alignment for build_skb() so that skb_shared_info
does not get unaligned, from Jesper.
15) Fix test_progs kselftest to work with older compilers which are less
smart in optimizing (and thus throwing build error), from Stanislav.
16) Cleanup and simplify AF_XDP socket teardown, from Björn.
17) Fix sk lookup in BPF kselftest's test_sock_addr with regards
to netns_id argument, from Andrey.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Distributions build drivers as modules, including network and filesystem
drivers which export numerous tracepoints. This enables
bpf(BPF_RAW_TRACEPOINT_OPEN) to attach to those tracepoints.
Signed-off-by: Matt Mullins <mmullins@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"While running various ftrace tests on new development code, the
kmemleak detector found some allocations that were not freed
correctly.
This fixes a couple of leaks in the event trigger code as well as in
adding function trace filters in trace instances"
* tag 'trace-v4.20-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix memory leak of instance function hash filters
tracing: Fix memory leak in set_trigger_filter()
tracing: Fix memory leak in create_filter()
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The following commands will cause a memory leak:
# cd /sys/kernel/tracing
# mkdir instances/foo
# echo schedule > instance/foo/set_ftrace_filter
# rmdir instances/foo
The reason is that the hashes that hold the filters to set_ftrace_filter and
set_ftrace_notrace are not freed if they contain any data on the instance
and the instance is removed.
Found by kmemleak detector.
Cc: stable@vger.kernel.org
Fixes: 591dffdade9f ("ftrace: Allow for function tracing instance to filter functions")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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When create_event_filter() fails in set_trigger_filter(), the filter may
still be allocated and needs to be freed. The caller expects the
data->filter to be updated with the new filter, even if the new filter
failed (we could add an error message by setting set_str parameter of
create_event_filter(), but that's another update).
But because the error would just exit, filter was left hanging and
nothing could free it.
Found by kmemleak detector.
Cc: stable@vger.kernel.org
Fixes: bac5fb97a173a ("tracing: Add and use generic set_trigger_filter() implementation")
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The create_filter() calls create_filter_start() which allocates a
"parse_error" descriptor, but fails to call create_filter_finish() that
frees it.
The op_stack and inverts in predicate_parse() were also not freed.
Found by kmemleak detector.
Cc: stable@vger.kernel.org
Fixes: 80765597bc587 ("tracing: Rewrite filter logic to be simpler and faster")
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The ret_stack should not be accessed directly via the curr_ret_stack
variable on the task_struct. This is because the ret_stack is going to be
converted into a series of longs and not an array of ret_stack structures.
The way that a ret_stack should be retrieved is via the
ftrace_graph_get_ret_stack structure, but it needs to be documented on how
to use it.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The function ftrace_replace_code() is the ftrace engine that does the
work to modify all the nops into the calls to the function callback in
all the functions being traced.
The generic version which is normally called from stop machine, but an
architecture can implement a non stop machine version and still use the
generic ftrace_replace_code(). When an architecture does this,
ftrace_replace_code() may be called from a schedulable context, where
it can allow the code to be preemptible, and schedule out.
In order to allow an architecture to make ftrace_replace_code()
schedulable, a new command flag is added called:
FTRACE_MAY_SLEEP
Which can be or'd to the command that is passed to
ftrace_modify_all_code() that calls ftrace_replace_code() and will have
it call cond_resched() in the loop that modifies the nops into the
calls to the ftrace trampolines.
Link: http://lkml.kernel.org/r/20181204192903.8193-1-anders.roxell@linaro.org
Link: http://lkml.kernel.org/r/20181205183303.828422192@goodmis.org
Reported-by: Anders Roxell <anders.roxell@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Add a generic method to remove event from dynamic event
list. This is same as other system under ftrace. You
just need to pass the event name with '!', e.g.
# echo p:new_grp/new_event _do_fork > dynamic_events
This creates an event, and
# echo '!p:new_grp/new_event _do_fork' > dynamic_events
Or,
# echo '!p:new_grp/new_event' > dynamic_events
will remove new_grp/new_event event.
Note that this doesn't check the event prefix (e.g. "p:")
strictly, because the "group/event" name must be unique.
Link: http://lkml.kernel.org/r/154140869774.17322.8887303560398645347.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The trace_add/remove_event_call_nolock() functions were added to allow
the tace_add/remove_event_call() code be called when the event_mutex
lock was already taken. Now that all callers are done within the
event_mutex, there's no reason to have two different interfaces.
Remove the current wrapper trace_add/remove_event_call()s and rename the
_nolock versions back to the original names.
Link: http://lkml.kernel.org/r/154140866955.17322.2081425494660638846.stgit@devbox
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Rmove unneeded synth_event_mutex. This mutex protects the reference
count in synth_event, however, those operational points are already
protected by event_mutex.
1. In __create_synth_event() and create_or_delete_synth_event(),
those synth_event_mutex clearly obtained right after event_mutex.
2. event_hist_trigger_func() is trigger_hist_cmd.func() which is
called by trigger_process_regex(), which is a part of
event_trigger_regex_write() and this function takes event_mutex.
3. hist_unreg_all() is trigger_hist_cmd.unreg_all() which is called
by event_trigger_regex_open() and it takes event_mutex.
4. onmatch_destroy() and onmatch_create() have long call tree,
but both are finally invoked from event_trigger_regex_write()
and event_trace_del_tracer(), former takes event_mutex, and latter
ensures called under event_mutex locked.
Finally, I ensured there is no resource conflict. For safety,
I added lockdep_assert_held(&event_mutex) for each function.
Link: http://lkml.kernel.org/r/154140864134.17322.4796059721306031894.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Use dyn_event framework for synthetic events. This shows
synthetic events on "tracing/dynamic_events" file in addition
to tracing/synthetic_events interface.
User can also define new events via tracing/dynamic_events
with "s:" prefix. So, the new syntax is below;
s:[synthetic/]EVENT_NAME TYPE ARG; [TYPE ARG;]...
To remove events via tracing/dynamic_events, you can use
"-:" prefix as same as other events.
Link: http://lkml.kernel.org/r/154140861301.17322.15454611233735614508.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Use dyn_event framework for uprobe events. This shows
uprobe events on "dynamic_events" file.
User can also define new uprobe events via dynamic_events.
Link: http://lkml.kernel.org/r/154140858481.17322.9091293846515154065.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Use dyn_event framework for kprobe events. This shows
kprobe events on "tracing/dynamic_events" file.
User can also define new events via tracing/dynamic_events.
Link: http://lkml.kernel.org/r/154140855646.17322.6619219995865980392.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Add unified dynamic event framework for ftrace kprobes, uprobes
and synthetic events. Those dynamic events can be co-exist on
same file because those syntax doesn't overlap.
This introduces a framework part which provides a unified tracefs
interface and operations.
Link: http://lkml.kernel.org/r/154140852824.17322.12250362185969352095.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Integrate similar argument parsers for kprobes and uprobes events
into traceprobe_parse_probe_arg().
Link: http://lkml.kernel.org/r/154140850016.17322.9836787731210512176.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Since the event_mutex and synth_event_mutex ordering issue
is gone, we can skip existing event check when adding or
deleting events, and some redundant code in error path.
This changes release_all_synth_events() to abort the process
when it hits any error and returns the error code. It succeeds
only if it has no error.
Link: http://lkml.kernel.org/r/154140847194.17322.17960275728005067803.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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synthetic event is using synth_event_mutex for protecting
synth_event_list, and event_trigger_write() path acquires
locks as below order.
event_trigger_write(event_mutex)
->trigger_process_regex(trigger_cmd_mutex)
->event_hist_trigger_func(synth_event_mutex)
On the other hand, synthetic event creation and deletion paths
call trace_add_event_call() and trace_remove_event_call()
which acquires event_mutex. In that case, if we keep the
synth_event_mutex locked while registering/unregistering synthetic
events, its dependency will be inversed.
To avoid this issue, current synthetic event is using a 2 phase
process to create/delete events. For example, it searches existing
events under synth_event_mutex to check for event-name conflicts, and
unlocks synth_event_mutex, then registers a new event under event_mutex
locked. Finally, it locks synth_event_mutex and tries to add the
new event to the list. But it can introduce complexity and a chance
for name conflicts.
To solve this simpler, this introduces trace_add_event_call_nolock()
and trace_remove_event_call_nolock() which don't acquire
event_mutex inside. synthetic event can lock event_mutex before
synth_event_mutex to solve the lock dependency issue simpler.
Link: http://lkml.kernel.org/r/154140844377.17322.13781091165954002713.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Add a busy check loop in cleanup_all_probes() before
trying to remove all events in uprobe_events, the same way
that kprobe_events does.
Without this change, writing null to uprobe_events will
try to remove events but if one of them is enabled, it will
stop there leaving some events cleared and others not clceared.
With this change, writing null to uprobe_events makes
sure all events are not enabled before removing events.
So, it clears all events, or returns an error (-EBUSY)
with keeping all events.
Link: http://lkml.kernel.org/r/154140841557.17322.12653952888762532401.stgit@devbox
Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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After running several tests, it appears that having the reader wait till
half the buffer is full before starting to read (and causing its own events
to fill up the ring buffer constantly), works well. It keeps trace-cmd (the
main user of this interface) from dominating the traces it records.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Add a "buffer_percentage" file, that allows users to specify how much of the
buffer (percentage of pages) need to be filled before waking up a task
blocked on a per cpu trace_pipe_raw file.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Instead of just waiting for a page to be full before waking up a pending
reader, allow the reader to pass in a "percentage" of pages that have
content before waking up a reader. This should help keep the process of
reading the events not cause wake ups that constantly cause reading of the
buffer.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Dan Carpenter reviewed the trace_stack.c code and figured he found an off by
one bug.
"From reviewing the code, it seems possible for
stack_trace_max.nr_entries to be set to .max_entries and in that case we
would be reading one element beyond the end of the stack_dump_trace[]
array. If it's not set to .max_entries then the bug doesn't affect
runtime."
Although it looks to be the case, it is not. Because we have:
static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES+1] =
{ [0 ... (STACK_TRACE_ENTRIES)] = ULONG_MAX };
struct stack_trace stack_trace_max = {
.max_entries = STACK_TRACE_ENTRIES - 1,
.entries = &stack_dump_trace[0],
};
And:
stack_trace_max.nr_entries = x;
for (; x < i; x++)
stack_dump_trace[x] = ULONG_MAX;
Even if nr_entries equals max_entries, indexing with it into the
stack_dump_trace[] array will not overflow the array. But if it is the case,
the second part of the conditional that tests stack_dump_trace[nr_entries]
to ULONG_MAX will always be true.
By applying Dan's patch, it removes the subtle aspect of it and makes the if
conditional slightly more efficient.
Link: http://lkml.kernel.org/r/20180620110758.crunhd5bfep7zuiz@kili.mountain
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The ret_stack processing is going to change, and that is going
to break anything that is accessing the ret_stack directly. One user is the
function graph profiler. By using the ftrace_graph_get_ret_stack() helper
function, the profiler can access the ret_stack entry without relying on the
implementation details of the stack itself.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Move the function function_graph_ret_addr() to fgraph.c, as the management
of the curr_ret_stack is going to change, and all the accesses to ret_stack
needs to be done in fgraph.c.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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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) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Rearrange the functions in trace_sched_wakeup.c so that there are fewer
#ifdef CONFIG_FUNCTION_TRACER and #ifdef CONFIG_FUNCTION_GRAPH_TRACER,
instead of having the #ifdefs spread all over.
No functional change is made.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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To make the function graph infrastructure more managable, the code needs to
be in its own file (fgraph.c). Move the code that is specific for managing
the function graph infrastructure out of ftrace.c and into fgraph.c
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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configured
When the function profiler is not configured, the "graph_time" option is
meaningless, as the function profiler is the only thing that makes use of
it. Do not expose it if the profiler is not configured.
Link: http://lkml.kernel.org/r/20181123061133.GA195223@google.com
Reported-by: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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In order to move function graph infrastructure into its own file (fgraph.h)
it needs to access various functions and variables in ftrace.c that are
currently static. Create a new file called ftrace-internal.h that holds the
function prototypes and the extern declarations of the variables needed by
fgraph.c as well, and make them global in ftrace.c such that they can be
used outside that file.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The curr_ret_stack is no longer set to a negative value when a function is
not to be traced by the function graph tracer. Remove the usage of
FTRACE_NOTRACE_DEPTH, as it is no longer needed.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Prior patches ensured that any bio that interacts with a request_queue
is properly associated with a blkg. This makes bio->bi_css unnecessary
as blkg maintains a reference to blkcg already.
This removes the bio field bi_css and transfers corresponding uses to
access via bi_blkg.
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU changes from Paul E. McKenney:
- Convert RCU's BUG_ON() and similar calls to WARN_ON() and similar.
- Replace calls of RCU-bh and RCU-sched update-side functions
to their vanilla RCU counterparts. This series is a step
towards complete removal of the RCU-bh and RCU-sched update-side
functions.
( Note that some of these conversions are going upstream via their
respective maintainers. )
- Documentation updates, including a number of flavor-consolidation
updates from Joel Fernandes.
- Miscellaneous fixes.
- Automate generation of the initrd filesystem used for
rcutorture testing.
- Convert spin_is_locked() assertions to instead use lockdep.
( Note that some of these conversions are going upstream via their
respective maintainers. )
- SRCU updates, especially including a fix from Dennis Krein
for a bag-on-head-class bug.
- RCU torture-test updates.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull more tracing fixes from Steven Rostedt:
"Two more fixes:
- Change idx variable in DO_TRACE macro to __idx to avoid name
conflicts. A kvm event had "idx" as a parameter and it confused the
macro.
- Fix a race where interrupts would be traced when set_graph_function
was set. The previous patch set increased a race window that
tricked the function graph tracer to think it should trace
interrupts when it really should not have.
The bug has been there before, but was seldom hit. Only the last
patch series made it more common"
* tag 'trace-v4.20-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing/fgraph: Fix set_graph_function from showing interrupts
tracepoint: Use __idx instead of idx in DO_TRACE macro to make it unique
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"While rewriting the function graph tracer, I discovered a design flaw
that was introduced by a patch that tried to fix one bug, but by doing
so created another bug.
As both bugs corrupt the output (but they do not crash the kernel), I
decided to fix the design such that it could have both bugs fixed. The
original fix, fixed time reporting of the function graph tracer when
doing a max_depth of one. This was code that can test how much the
kernel interferes with userspace. But in doing so, it could corrupt
the time keeping of the function profiler.
The issue is that the curr_ret_stack variable was being used for two
different meanings. One was to keep track of the stack pointer on the
ret_stack (shadow stack used by the function graph tracer), and the
other use case was the graph call depth. Although, the two may be
closely related, where they got updated was the issue that lead to the
two different bugs that required the two use cases to be updated
differently.
The big issue with this fix is that it requires changing each
architecture. The good news is, I was able to remove a lot of code
that was duplicated within the architectures and place it into a
single location. Then I could make the fix in one place.
I pushed this code into linux-next to let it settle over a week, and
before doing so, I cross compiled all the affected architectures to
make sure that they built fine.
In the mean time, I also pulled in a patch that fixes the sched_switch
previous tasks state output, that was not actually correct"
* tag 'trace-v4.20-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
sched, trace: Fix prev_state output in sched_switch tracepoint
function_graph: Have profiler use curr_ret_stack and not depth
function_graph: Reverse the order of pushing the ret_stack and the callback
function_graph: Move return callback before update of curr_ret_stack
function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack
function_graph: Make ftrace_push_return_trace() static
sparc/function_graph: Simplify with function_graph_enter()
sh/function_graph: Simplify with function_graph_enter()
s390/function_graph: Simplify with function_graph_enter()
riscv/function_graph: Simplify with function_graph_enter()
powerpc/function_graph: Simplify with function_graph_enter()
parisc: function_graph: Simplify with function_graph_enter()
nds32: function_graph: Simplify with function_graph_enter()
MIPS: function_graph: Simplify with function_graph_enter()
microblaze: function_graph: Simplify with function_graph_enter()
arm64: function_graph: Simplify with function_graph_enter()
ARM: function_graph: Simplify with function_graph_enter()
x86/function_graph: Simplify with function_graph_enter()
function_graph: Create function_graph_enter() to consolidate architecture code
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In order to make the function graph infrastructure more generic, there can
not be code specific for the function_graph tracer in the generic code. This
includes the set_graph_notrace logic, that stops all graph calls when a
function in the set_graph_notrace is hit.
By using the trace_recursion mask, we can use a bit in the current
task_struct to implement the notrace code, and move the logic out of
fgraph.c and into trace_functions_graph.c and keeps it affecting only the
tracer and not all call graph callbacks.
Acked-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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As the function graph infrastructure can be used by thing other than
tracing, moving the code to its own file out of the trace_functions_graph.c
code makes more sense.
The fgraph.c file will only contain the infrastructure required to hook into
functions and their return code.
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Commit 588ca1786f2dd ("function_graph: Use new curr_ret_depth to manage
depth instead of curr_ret_stack") removed a parameter from the call
ftrace_push_return_trace() that made it so that the entire call was under 80
characters, but it did not remove the line break. There's no reason to break
that line up, so make it a single line.
Link: http://lkml.kernel.org/r/20181122100322.GN2131@hirez.programming.kicks-ass.net
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The tracefs file set_graph_function is used to only function graph functions
that are listed in that file (or all functions if the file is empty). The
way this is implemented is that the function graph tracer looks at every
function, and if the current depth is zero and the function matches
something in the file then it will trace that function. When other functions
are called, the depth will be greater than zero (because the original
function will be at depth zero), and all functions will be traced where the
depth is greater than zero.
The issue is that when a function is first entered, and the handler that
checks this logic is called, the depth is set to zero. If an interrupt comes
in and a function in the interrupt handler is traced, its depth will be
greater than zero and it will automatically be traced, even if the original
function was not. But because the logic only looks at depth it may trace
interrupts when it should not be.
The recent design change of the function graph tracer to fix other bugs
caused the depth to be zero while the function graph callback handler is
being called for a longer time, widening the race of this happening. This
bug was actually there for a longer time, but because the race window was so
small it seldom happened. The Fixes tag below is for the commit that widen
the race window, because that commit belongs to a series that will also help
fix the original bug.
Cc: stable@kernel.org
Fixes: 39eb456dacb5 ("function_graph: Use new curr_ret_depth to manage depth instead of curr_ret_stack")
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The profiler uses trace->depth to find its entry on the ret_stack, but the
depth may not match the actual location of where its entry is (if an
interrupt were to preempt the processing of the profiler for another
function, the depth and the curr_ret_stack will be different).
Have it use the curr_ret_stack as the index to find its ret_stack entry
instead of using the depth variable, as that is no longer guaranteed to be
the same.
Cc: stable@kernel.org
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The function graph profiler uses the ret_stack to store the "subtime" and
reuse it by nested functions and also on the return. But the current logic
has the profiler callback called before the ret_stack is updated, and it is
just modifying the ret_stack that will later be allocated (it's just lucky
that the "subtime" is not touched when it is allocated).
This could also cause a crash if we are at the end of the ret_stack when
this happens.
By reversing the order of the allocating the ret_stack and then calling the
callbacks attached to a function being traced, the ret_stack entry is no
longer used before it is allocated.
Cc: stable@kernel.org
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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In the past, curr_ret_stack had two functions. One was to denote the depth
of the call graph, the other is to keep track of where on the ret_stack the
data is used. Although they may be slightly related, there are two cases
where they need to be used differently.
The one case is that it keeps the ret_stack data from being corrupted by an
interrupt coming in and overwriting the data still in use. The other is just
to know where the depth of the stack currently is.
The function profiler uses the ret_stack to save a "subtime" variable that
is part of the data on the ret_stack. If curr_ret_stack is modified too
early, then this variable can be corrupted.
The "max_depth" option, when set to 1, will record the first functions going
into the kernel. To see all top functions (when dealing with timings), the
depth variable needs to be lowered before calling the return hook. But by
lowering the curr_ret_stack, it makes the data on the ret_stack still being
used by the return hook susceptible to being overwritten.
Now that there's two variables to handle both cases (curr_ret_depth), we can
move them to the locations where they can handle both cases.
Cc: stable@kernel.org
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Currently, the depth of the ret_stack is determined by curr_ret_stack index.
The issue is that there's a race between setting of the curr_ret_stack and
calling of the callback attached to the return of the function.
Commit 03274a3ffb44 ("tracing/fgraph: Adjust fgraph depth before calling
trace return callback") moved the calling of the callback to after the
setting of the curr_ret_stack, even stating that it was safe to do so, when
in fact, it was the reason there was a barrier() there (yes, I should have
commented that barrier()).
Not only does the curr_ret_stack keep track of the current call graph depth,
it also keeps the ret_stack content from being overwritten by new data.
The function profiler, uses the "subtime" variable of ret_stack structure
and by moving the curr_ret_stack, it allows for interrupts to use the same
structure it was using, corrupting the data, and breaking the profiler.
To fix this, there needs to be two variables to handle the call stack depth
and the pointer to where the ret_stack is being used, as they need to change
at two different locations.
Cc: stable@kernel.org
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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As all architectures now call function_graph_enter() to do the entry work,
no architecture should ever call ftrace_push_return_trace(). Make it static.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
Cc: stable@kernel.org
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Now that synchronize_rcu() waits for preempt-disable regions of code
as well as RCU read-side critical sections, synchronize_sched() can
be replaced by synchronize_rcu(). Similarly, call_rcu_sched() can be
replaced by call_rcu(). This commit therefore makes these changes.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: <linux-kernel@vger.kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Currently all the architectures do basically the same thing in preparing the
function graph tracer on entry to a function. This code can be pulled into a
generic location and then this will allow the function graph tracer to be
fixed, as well as extended.
Create a new function graph helper function_graph_enter() that will call the
hook function (ftrace_graph_entry) and the shadow stack operation
(ftrace_push_return_trace), and remove the need of the architecture code to
manage the shadow stack.
This is needed to prepare for a fix of a design bug on how the curr_ret_stack
is used.
Cc: stable@kernel.org
Fixes: 03274a3ffb449 ("tracing/fgraph: Adjust fgraph depth before calling trace return callback")
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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A format string consisting of "%p" or "%s" followed by an invalid
specifier (e.g. "%p%\n" or "%s%") could pass the check which
would make format_decode (lib/vsprintf.c) to warn.
Fixes: 9c959c863f82 ("tracing: Allow BPF programs to call bpf_trace_printk()")
Reported-by: syzbot+1ec5c5ec949c4adaa0c4@syzkaller.appspotmail.com
Signed-off-by: Martynas Pumputis <m@lambda.lt>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Fix strpbrk()'s argument order, it must pass acceptable string
in 2nd argument. Note that this can cause a kernel panic where
it recovers backup character to code->data.
Link: http://lkml.kernel.org/r/154108256792.2604.1816052586385217811.stgit@devbox
Fixes: a6682814f371 ("tracing/kprobes: Allow kprobe-events to record module symbol")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Pull block layer fixes from Jens Axboe:
"The biggest part of this pull request is the revert of the blkcg
cleanup series. It had one fix earlier for a stacked device issue, but
another one was reported. Rather than play whack-a-mole with this,
revert the entire series and try again for the next kernel release.
Apart from that, only small fixes/changes.
Summary:
- Indentation fixup for mtip32xx (Colin Ian King)
- The blkcg cleanup series revert (Dennis Zhou)
- Two NVMe fixes. One fixing a regression in the nvme request
initialization in this merge window, causing nvme-fc to not work.
The other is a suspend/resume p2p resource issue (James, Keith)
- Fix sg discard merge, allowing us to merge in cases where we didn't
before (Jianchao Wang)
- Call rq_qos_exit() after the queue is frozen, preventing a hang
(Ming)
- Fix brd queue setup, fixing an oops if we fail setting up all
devices (Ming)"
* tag 'for-linus-20181102' of git://git.kernel.dk/linux-block:
nvme-pci: fix conflicting p2p resource adds
nvme-fc: fix request private initialization
blkcg: revert blkcg cleanups series
block: brd: associate with queue until adding disk
block: call rq_qos_exit() after queue is frozen
mtip32xx: clean an indentation issue, remove extraneous tabs
block: fix the DISCARD request merge
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