linux-stable.git/kernel/trace/ftrace.c, branch v4.4.286

ftrace: Do not blindly read the ip address in ftrace_bug()

2021-06-16T09:34:54+00:00

commit 6c14133d2d3f768e0a35128faac8aa6ed4815051 upstream.

It was reported that a bug on arm64 caused a bad ip address to be used for
updating into a nop in ftrace_init(), but the error path (rightfully)
returned -EINVAL and not -EFAULT, as the bug caused more than one error to
occur. But because -EINVAL was returned, the ftrace_bug() tried to report
what was at the location of the ip address, and read it directly. This
caused the machine to panic, as the ip was not pointing to a valid memory
address.

Instead, read the ip address with copy_from_kernel_nofault() to safely
access the memory, and if it faults, report that the address faulted,
otherwise report what was in that location.

Link: https://lore.kernel.org/lkml/20210607032329.28671-1-mark-pk.tsai@mediatek.com/

Cc: stable@vger.kernel.org
Fixes: 05736a427f7e1 ("ftrace: warn on failure to disable mcount callers")
Reported-by: Mark-PK Tsai 
Tested-by: Mark-PK Tsai 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

ftrace: Handle commands when closing set_ftrace_filter file

2021-05-22T08:38:19+00:00

commit 8c9af478c06bb1ab1422f90d8ecbc53defd44bc3 upstream.

 # echo switch_mm:traceoff > /sys/kernel/tracing/set_ftrace_filter

will cause switch_mm to stop tracing by the traceoff command.

 # echo -n switch_mm:traceoff > /sys/kernel/tracing/set_ftrace_filter

does nothing.

The reason is that the parsing in the write function only processes
commands if it finished parsing (there is white space written after the
command). That's to handle:

 write(fd, "switch_mm:", 10);
 write(fd, "traceoff", 8);

cases, where the command is broken over multiple writes.

The problem is if the file descriptor is closed, then the write call is
not processed, and the command needs to be processed in the release code.
The release code can handle matching of functions, but does not handle
commands.

Cc: stable@vger.kernel.org
Fixes: eda1e32855656 ("tracing: handle broken names in ftrace filter")
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

fgraph: Initialize tracing_graph_pause at task creation

2021-02-23T12:58:12+00:00

commit 7e0a9220467dbcfdc5bc62825724f3e52e50ab31 upstream.

On some archs, the idle task can call into cpu_suspend(). The cpu_suspend()
will disable or pause function graph tracing, as there's some paths in
bringing down the CPU that can have issues with its return address being
modified. The task_struct structure has a "tracing_graph_pause" atomic
counter, that when set to something other than zero, the function graph
tracer will not modify the return address.

The problem is that the tracing_graph_pause counter is initialized when the
function graph tracer is enabled. This can corrupt the counter for the idle
task if it is suspended in these architectures.

   CPU 1				CPU 2
   -----				-----
  do_idle()
    cpu_suspend()
      pause_graph_tracing()
          task_struct->tracing_graph_pause++ (0 -> 1)

				start_graph_tracing()
				  for_each_online_cpu(cpu) {
				    ftrace_graph_init_idle_task(cpu)
				      task-struct->tracing_graph_pause = 0 (1 -> 0)

      unpause_graph_tracing()
          task_struct->tracing_graph_pause-- (0 -> -1)

The above should have gone from 1 to zero, and enabled function graph
tracing again. But instead, it is set to -1, which keeps it disabled.

There's no reason that the field tracing_graph_pause on the task_struct can
not be initialized at boot up.

Cc: stable@vger.kernel.org
Fixes: 380c4b1411ccd ("tracing/function-graph-tracer: append the tracing_graph_flag")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211339
Reported-by: pierre.gondois@arm.com
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

ftrace: Setup correct FTRACE_FL_REGS flags for module

2020-10-01T09:11:49+00:00

[ Upstream commit 8a224ffb3f52b0027f6b7279854c71a31c48fc97 ]

When module loaded and enabled, we will use __ftrace_replace_code
for module if any ftrace_ops referenced it found. But we will get
wrong ftrace_addr for module rec in ftrace_get_addr_new, because
rec->flags has not been setup correctly. It can cause the callback
function of a ftrace_ops has FTRACE_OPS_FL_SAVE_REGS to be called
with pt_regs set to NULL.
So setup correct FTRACE_FL_REGS flags for rec when we call
referenced_filters to find ftrace_ops references it.

Link: https://lkml.kernel.org/r/20200728180554.65203-1-zhouchengming@bytedance.com

Cc: stable@vger.kernel.org
Fixes: 8c4f3c3fa9681 ("ftrace: Check module functions being traced on reload")
Signed-off-by: Chengming Zhou 
Signed-off-by: Muchun Song 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Sasha Levin

ftrace: Avoid potential division by zero in function profiler

2020-01-12T10:22:43+00:00

commit e31f7939c1c27faa5d0e3f14519eaf7c89e8a69d upstream.

The ftrace_profile->counter is unsigned long and
do_div truncates it to 32 bits, which means it can test
non-zero and be truncated to zero for division.
Fix this issue by using div64_ul() instead.

Link: http://lkml.kernel.org/r/20200103030248.14516-1-wenyang@linux.alibaba.com

Cc: stable@vger.kernel.org
Fixes: e330b3bcd8319 ("tracing: Show sample std dev in function profiling")
Fixes: 34886c8bc590f ("tracing: add average time in function to function profiler")
Signed-off-by: Wen Yang 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

kprobes: Mark ftrace mcount handler functions nokprobe

2019-04-27T07:34:02+00:00

commit fabe38ab6b2bd9418350284c63825f13b8a6abba upstream.

Mark ftrace mcount handler functions nokprobe since
probing on these functions with kretprobe pushes
return address incorrectly on kretprobe shadow stack.

Reported-by: Francis Deslauriers 
Tested-by: Andrea Righi 
Signed-off-by: Masami Hiramatsu 
Acked-by: Steven Rostedt 
Acked-by: Steven Rostedt (VMware) 
Cc: Linus Torvalds 
Cc: Mathieu Desnoyers 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/155094062044.6137.6419622920568680640.stgit@devbox
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

tracing: Fix memory leak of instance function hash filters

2018-12-21T13:09:51+00:00

commit 2840f84f74035e5a535959d5f17269c69fa6edc5 upstream.

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) 
Signed-off-by: Greg Kroah-Hartman

ftrace: Remove incorrect setting of glob search field

2018-02-16T19:09:47+00:00

commit 7b6586562708d2b3a04fe49f217ddbadbbbb0546 upstream.

__unregister_ftrace_function_probe() will incorrectly parse the glob filter
because it resets the search variable that was setup by filter_parse_regex().

Al Viro reported this:

    After that call of filter_parse_regex() we could have func_g.search not
    equal to glob only if glob started with '!' or '*'.  In the former case
    we would've buggered off with -EINVAL (not = 1).  In the latter we
    would've set func_g.search equal to glob + 1, calculated the length of
    that thing in func_g.len and proceeded to reset func_g.search back to
    glob.

    Suppose the glob is e.g. *foo*.  We end up with
	    func_g.type = MATCH_MIDDLE_ONLY;
	    func_g.len = 3;
	    func_g.search = "*foo";
    Feeding that to ftrace_match_record() will not do anything sane - we
    will be looking for names containing "*foo" (->len is ignored for that
    one).

Link: http://lkml.kernel.org/r/20180127031706.GE13338@ZenIV.linux.org.uk

Fixes: 3ba009297149f ("ftrace: Introduce ftrace_glob structure")
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Reviewed-by: Masami Hiramatsu 
Reported-by: Al Viro 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

ftrace: Fix kmemleak in unregister_ftrace_graph

2017-10-12T09:27:33+00:00

commit 2b0b8499ae75df91455bbeb7491d45affc384fb0 upstream.

The trampoline allocated by function tracer was overwriten by function_graph
tracer, and caused a memory leak. The save_global_trampoline should have
saved the previous trampoline in register_ftrace_graph() and restored it in
unregister_ftrace_graph(). But as it is implemented, save_global_trampoline was
only used in unregister_ftrace_graph as default value 0, and it overwrote the
previous trampoline's value. Causing the previous allocated trampoline to be
lost.

kmmeleak backtrace:
    kmemleak_vmalloc+0x77/0xc0
    __vmalloc_node_range+0x1b5/0x2c0
    module_alloc+0x7c/0xd0
    arch_ftrace_update_trampoline+0xb5/0x290
    ftrace_startup+0x78/0x210
    register_ftrace_function+0x8b/0xd0
    function_trace_init+0x4f/0x80
    tracing_set_tracer+0xe6/0x170
    tracing_set_trace_write+0x90/0xd0
    __vfs_write+0x37/0x170
    vfs_write+0xb2/0x1b0
    SyS_write+0x55/0xc0
    do_syscall_64+0x67/0x180
    return_from_SYSCALL_64+0x0/0x6a

[
  Looking further into this, I found that this was left over from when the
  function and function graph tracers shared the same ftrace_ops. But in
  commit 5f151b2401 ("ftrace: Fix function_profiler and function tracer
  together"), the two were separated, and the save_global_trampoline no
  longer was necessary (and it may have been broken back then too).
  -- Steven Rostedt
]

Link: http://lkml.kernel.org/r/20170912021454.5976-1-shuwang@redhat.com

Fixes: 5f151b2401 ("ftrace: Fix function_profiler and function tracer together")
Signed-off-by: Shu Wang 
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman

ftrace: Fix memleak when unregistering dynamic ops when tracing disabled

2017-09-27T09:00:17+00:00

commit edb096e00724f02db5f6ec7900f3bbd465c6c76f upstream.

If function tracing is disabled by the user via the function-trace option or
the proc sysctl file, and a ftrace_ops that was allocated on the heap is
unregistered, then the shutdown code exits out without doing the proper
clean up. This was found via kmemleak and running the ftrace selftests, as
one of the tests unregisters with function tracing disabled.

 # cat kmemleak
unreferenced object 0xffffffffa0020000 (size 4096):
  comm "swapper/0", pid 1, jiffies 4294668889 (age 569.209s)
  hex dump (first 32 bytes):
    55 ff 74 24 10 55 48 89 e5 ff 74 24 18 55 48 89  U.t$.UH...t$.UH.
    e5 48 81 ec a8 00 00 00 48 89 44 24 50 48 89 4c  .H......H.D$PH.L
  backtrace:
    [] kmemleak_vmalloc+0x85/0xf0
    [] __vmalloc_node_range+0x281/0x3e0
    [] module_alloc+0x4f/0x90
    [] arch_ftrace_update_trampoline+0x160/0x420
    [] ftrace_startup+0xe7/0x300
    [] register_ftrace_function+0x72/0x90
    [] trace_selftest_ops+0x204/0x397
    [] trace_selftest_startup_function+0x394/0x624
    [] run_tracer_selftest+0x15c/0x1d7
    [] init_trace_selftests+0x75/0x192
    [] do_one_initcall+0x90/0x1e2
    [] kernel_init_freeable+0x350/0x3fe
    [] kernel_init+0x13/0x122
    [] ret_from_fork+0x2a/0x40
    [] 0xffffffffffffffff

Fixes: 12cce594fa ("ftrace/x86: Allow !CONFIG_PREEMPT dynamic ops to use allocated trampolines")
Signed-off-by: Steven Rostedt (VMware) 
Signed-off-by: Greg Kroah-Hartman