linux-stable.git/kernel/trace/ftrace.c, branch v4.13.3

ftrace: Check for null ret_stack on profile function graph entry function

2017-08-24T14:04:01+00:00

There's a small race when function graph shutsdown and the calling of the
registered function graph entry callback. The callback must not reference
the task's ret_stack without first checking that it is not NULL. Note, when
a ret_stack is allocated for a task, it stays allocated until the task exits.
The problem here, is that function_graph is shutdown, and a new task was
created, which doesn't have its ret_stack allocated. But since some of the
functions are still being traced, the callbacks can still be called.

The normal function_graph code handles this, but starting with commit
8861dd303c ("ftrace: Access ret_stack->subtime only in the function
profiler") the profiler code references the ret_stack on function entry, but
doesn't check if it is NULL first.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=196611

Cc: stable@vger.kernel.org
Fixes: 8861dd303c ("ftrace: Access ret_stack->subtime only in the function profiler")
Reported-by: lilydjwg@gmail.com
Signed-off-by: Steven Rostedt (VMware)

trace: fix the errors caused by incompatible type of RCU variables

2017-07-20T13:27:29+00:00

The variables which are processed by RCU functions should be annotated
as RCU, otherwise sparse will report the errors like below:

"error: incompatible types in comparison expression (different
address spaces)"

Link: http://lkml.kernel.org/r/1496823171-7758-1-git-send-email-zhang.chunyan@linaro.org

Signed-off-by: Chunyan Zhang 
[ Updated to not be 100% 80 column strict ]
Signed-off-by: Steven Rostedt (VMware)

ftrace: Fix uninitialized variable in match_records()

2017-07-12T13:48:31+00:00

My static checker complains that if "func" is NULL then "clear_filter"
is uninitialized.  This seems like it could be true, although it's
possible something subtle is happening that I haven't seen.

    kernel/trace/ftrace.c:3844 match_records()
    error: uninitialized symbol 'clear_filter'.

Link: http://lkml.kernel.org/r/20170712073556.h6tkpjcdzjaozozs@mwanda

Cc: stable@vger.kernel.org
Fixes: f0a3b154bd7 ("ftrace: Clarify code for mod command")
Signed-off-by: Dan Carpenter 
Signed-off-by: Steven Rostedt (VMware)

ftrace: Remove an unneeded NULL check

2017-07-12T13:45:42+00:00

"func" can't be NULL and it doesn't make sense to check because we've
already derefenced it.

Link: http://lkml.kernel.org/r/20170712073340.4enzeojeoupuds5a@mwanda

Signed-off-by: Dan Carpenter 
Signed-off-by: Steven Rostedt (VMware)

ftrace: Hide cached module code for !CONFIG_MODULES

2017-07-11T23:29:04+00:00

When modules are disabled, we get a harmless build warning:

kernel/trace/ftrace.c:4051:13: error: 'process_cached_mods' defined but not used [-Werror=unused-function]

This adds the same #ifdef around the new code that exists around
its caller.

Link: http://lkml.kernel.org/r/20170710084413.1820568-1-arnd@arndb.de

Fixes: d7fbf8df7ca0 ("ftrace: Implement cached modules tracing on module load")
Signed-off-by: Arnd Bergmann 
Signed-off-by: Steven Rostedt (VMware)

ftrace: Test for NULL iter->tr in regex for stack_trace_filter changes

2017-07-05T13:52:18+00:00

As writing into stack_trace_filter, the iter-tr is not set and is NULL.
Check if it is NULL before dereferencing it in ftrace_regex_release().

Fixes: 8c08f0d5c6fb ("ftrace: Have cached module filters be an active filter")
Signed-off-by: Steven Rostedt (VMware)

Merge commit '0f17976568b3f72e676450af0c0db6f8752253d6' into trace/ftrace/core

2017-07-05T13:51:24+00:00

Need to get the changes from 0f17976568b3 ("ftrace: Fix regression with
module command in stack_trace_filter") as it is required to fix some other
changes with stack_trace_filter and the new development code.

Signed-off-by: Steven Rostedt (VMware)

ftrace: Fix regression with module command in stack_trace_filter

2017-06-29T14:05:45+00:00

When doing the following command:

 # echo ":mod:kvm_intel" > /sys/kernel/tracing/stack_trace_filter

it triggered a crash.

This happened with the clean up of probes. It required all callers to the
regex function (doing ftrace filtering) to have ops->private be a pointer to
a trace_array. But for the stack tracer, that is not the case.

Allow for the ops->private to be NULL, and change the function command
callbacks to handle the trace_array pointer being NULL as well.

Fixes: d2afd57a4b96 ("tracing/ftrace: Allow instances to have their own function probes")
Signed-off-by: Steven Rostedt (VMware)

ftrace: Decrement count for dyn_ftrace_total_info for init functions

2017-06-28T15:57:03+00:00

Init boot up functions may be traced, but they are also freed when the
kernel finishes booting. These are removed from the ftrace tables, and the
debug variable for dyn_ftrace_total_info needs to reflect that as well.

Signed-off-by: Steven Rostedt (VMware)

ftrace: Unlock hash mutex on failed allocation in process_mod_list()

2017-06-28T13:09:38+00:00

If the new_hash fails to allocate, then unlock the hash mutex on error.

Reported-by: Julia Lawall 
Signed-off-by: Steven Rostedt (VMware)