linux-toradex.git/kernel/trace/ftrace.c, branch v2.6.32.60

ftrace: Only update the function code on write to filter files

2011-06-23T22:24:00+00:00

commit 058e297d34a404caaa5ed277de15698d8dc43000 upstream.

If function tracing is enabled, a read of the filter files will
cause the call to stop_machine to update the function trace sites.
It should only call stop_machine on write.

Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

ftrace: Fix memory leak with function graph and cpu hotplug

2011-03-23T20:16:39+00:00

commit 868baf07b1a259f5f3803c1dc2777b6c358f83cf upstream.

When the fuction graph tracer starts, it needs to make a special
stack for each task to save the real return values of the tasks.
All running tasks have this stack created, as well as any new
tasks.

On CPU hot plug, the new idle task will allocate a stack as well
when init_idle() is called. The problem is that cpu hotplug does
not create a new idle_task. Instead it uses the idle task that
existed when the cpu went down.

ftrace_graph_init_task() will add a new ret_stack to the task
that is given to it. Because a clone will make the task
have a stack of its parent it does not check if the task's
ret_stack is already NULL or not. When the CPU hotplug code
starts a CPU up again, it will allocate a new stack even
though one already existed for it.

The solution is to treat the idle_task specially. In fact, the
function_graph code already does, just not at init_idle().
Instead of using the ftrace_graph_init_task() for the idle task,
which that function expects the task to be a clone, have a
separate ftrace_graph_init_idle_task(). Also, we will create a
per_cpu ret_stack that is used by the idle task. When we call
ftrace_graph_init_idle_task() it will check if the idle task's
ret_stack is NULL, if it is, then it will assign it the per_cpu
ret_stack.

Reported-by: Benjamin Herrenschmidt 
Suggested-by: Peter Zijlstra 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: t_start: reset FTRACE_ITER_HASH in case of seek/pread

2010-09-20T20:17:52+00:00

commit df09162550fbb53354f0c88e85b5d0e6129ee9cc upstream.

Be sure to avoid entering t_show() with FTRACE_ITER_HASH set without
having properly started the iterator to iterate the hash.  This case is
degenerate and, as discovered by Robert Swiecki, can cause t_hash_show()
to misuse a pointer.  This causes a NULL ptr deref with possible security
implications.  Tracked as CVE-2010-3079.

Cc: Robert Swiecki 
Cc: Eugene Teo 
Signed-off-by: Chris Wright 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Do not allow llseek to set_ftrace_filter

2010-09-20T20:17:52+00:00

commit 9c55cb12c1c172e2d51e85fbb5a4796ca86b77e7 upstream.

Reading the file set_ftrace_filter does three things.

1) shows whether or not filters are set for the function tracer
2) shows what functions are set for the function tracer
3) shows what triggers are set on any functions

3 is independent from 1 and 2.

The way this file currently works is that it is a state machine,
and as you read it, it may change state. But this assumption breaks
when you use lseek() on the file. The state machine gets out of sync
and the t_show() may use the wrong pointer and cause a kernel oops.

Luckily, this will only kill the app that does the lseek, but the app
dies while holding a mutex. This prevents anyone else from using the
set_ftrace_filter file (or any other function tracing file for that matter).

A real fix for this is to rewrite the code, but that is too much for
a -rc release or stable. This patch simply disables llseek on the
set_ftrace_filter() file for now, and we can do the proper fix for the
next major release.

Reported-by: Robert Swiecki 
Cc: Chris Wright 
Cc: Tavis Ormandy 
Cc: Eugene Teo 
Cc: vendor-sec@lst.de
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Fix a race in function profile

2010-09-20T20:17:51+00:00

commit 3aaba20f26f58843e8f20611e5c0b1c06954310f upstream.

While we are reading trace_stat/functionX and someone just
disabled function_profile at that time, we can trigger this:

	divide error: 0000 [#1] PREEMPT SMP
	...
	EIP is at function_stat_show+0x90/0x230
	...

This fix just takes the ftrace_profile_lock and checks if
rec->counter is 0. If it's 0, we know the profile buffer
has been reset.

Signed-off-by: Li Zefan 
LKML-Reference: <4C723644.4040708@cn.fujitsu.com>
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

function-graph: Init curr_ret_stack with ret_stack

2010-04-01T22:58:10+00:00

commit ea14eb714041d40fcc5180b5a586034503650149 upstream.

If the graph tracer is active, and a task is forked but the allocating of
the processes graph stack fails, it can cause crash later on.

This is due to the temporary stack being NULL, but the curr_ret_stack
variable is copied from the parent. If it is not -1, then in
ftrace_graph_probe_sched_switch() the following:

	for (index = next->curr_ret_stack; index >= 0; index--)
		next->ret_stack[index].calltime += timestamp;

Will cause a kernel OOPS.

Found with Li Zefan's ftrace_stress_test.

Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

ftrace: Fix unmatched locking in ftrace_regex_write()

2009-11-04T06:42:10+00:00

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 
LKML-Reference: <4AEF7F8A.3080300@cn.fujitsu.com>
Signed-off-by: Steven Rostedt

tracing: Update *ppos instead of filp->f_pos

2009-10-24T09:07:49+00:00

Instead of directly updating filp->f_pos we should update the *ppos
argument. The filp->f_pos gets updated within the file_pos_write()
function called from sys_write().

Signed-off-by: Jiri Olsa 
Signed-off-by: Steven Rostedt 
Cc: Frederic Weisbecker 
LKML-Reference: <20091023233646.399670810@goodmis.org>
Signed-off-by: Ingo Molnar

Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-10-08T19:06:09+00:00

* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  tracing: user local buffer variable for trace branch tracer
  tracing: fix warning on kernel/trace/trace_branch.c andtrace_hw_branches.c
  ftrace: check for failure for all conversions
  tracing: correct module boundaries for ftrace_release
  tracing: fix transposed numbers of lock_depth and preempt_count
  trace: Fix missing assignment in trace_ctxwake_*
  tracing: Use free_percpu instead of kfree
  tracing: Check total refcount before releasing bufs in profile_enable failure

ftrace: check for failure for all conversions

2009-10-07T21:22:24+00:00

Due to legacy code from back when the dynamic tracer used a daemon,
only core kernel code was checking for failures. This is no longer
the case. We must check for failures any time we perform text modifications.

Cc: stable@kernel.org
Signed-off-by: Steven Rostedt