linux.git/kernel/trace/trace.c, branch v3.12.11

tracing: Check if tracing is enabled in trace_puts()

2014-02-13T21:50:09+00:00

commit 3132e107d608f8753240d82d61303c500fd515b4 upstream.

If trace_puts() is used very early in boot up, it can crash the machine
if it is called before the ring buffer is allocated. If a trace_printk()
is used with no arguments, then it will be converted into a trace_puts()
and suffer the same fate.

Fixes: 09ae72348ecc "tracing: Add trace_puts() for even faster trace_printk() tracing"
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Have trace buffer point back to trace_array

2014-02-13T21:50:09+00:00

commit dced341b2d4f06668efaab33f88de5d287c0f45b upstream.

The trace buffer has a descriptor pointer that goes back to the trace
array. But it was never assigned. Luckily, nothing uses it (yet), but
it will in the future.

Although nothing currently uses this, if any of the new features get
backported to older kernels, and because this is such a simple change,
I'm marking it for stable too.

Fixes: 12883efb670c "tracing: Consolidate max_tr into main trace_array structure"
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Fix potential out-of-bounds in trace_get_user()

2013-11-20T20:37:36+00:00

commit 057db8488b53d5e4faa0cedb2f39d4ae75dfbdbb upstream.

Andrey reported the following report:

ERROR: AddressSanitizer: heap-buffer-overflow on address ffff8800359c99f3
ffff8800359c99f3 is located 0 bytes to the right of 243-byte region [ffff8800359c9900, ffff8800359c99f3)
Accessed by thread T13003:
  #0 ffffffff810dd2da (asan_report_error+0x32a/0x440)
  #1 ffffffff810dc6b0 (asan_check_region+0x30/0x40)
  #2 ffffffff810dd4d3 (__tsan_write1+0x13/0x20)
  #3 ffffffff811cd19e (ftrace_regex_release+0x1be/0x260)
  #4 ffffffff812a1065 (__fput+0x155/0x360)
  #5 ffffffff812a12de (____fput+0x1e/0x30)
  #6 ffffffff8111708d (task_work_run+0x10d/0x140)
  #7 ffffffff810ea043 (do_exit+0x433/0x11f0)
  #8 ffffffff810eaee4 (do_group_exit+0x84/0x130)
  #9 ffffffff810eafb1 (SyS_exit_group+0x21/0x30)
  #10 ffffffff81928782 (system_call_fastpath+0x16/0x1b)

Allocated by thread T5167:
  #0 ffffffff810dc778 (asan_slab_alloc+0x48/0xc0)
  #1 ffffffff8128337c (__kmalloc+0xbc/0x500)
  #2 ffffffff811d9d54 (trace_parser_get_init+0x34/0x90)
  #3 ffffffff811cd7b3 (ftrace_regex_open+0x83/0x2e0)
  #4 ffffffff811cda7d (ftrace_filter_open+0x2d/0x40)
  #5 ffffffff8129b4ff (do_dentry_open+0x32f/0x430)
  #6 ffffffff8129b668 (finish_open+0x68/0xa0)
  #7 ffffffff812b66ac (do_last+0xb8c/0x1710)
  #8 ffffffff812b7350 (path_openat+0x120/0xb50)
  #9 ffffffff812b8884 (do_filp_open+0x54/0xb0)
  #10 ffffffff8129d36c (do_sys_open+0x1ac/0x2c0)
  #11 ffffffff8129d4b7 (SyS_open+0x37/0x50)
  #12 ffffffff81928782 (system_call_fastpath+0x16/0x1b)

Shadow bytes around the buggy address:
  ffff8800359c9700: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  ffff8800359c9780: fd fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa
  ffff8800359c9800: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  ffff8800359c9880: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  ffff8800359c9900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>ffff8800359c9980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00[03]fb
  ffff8800359c9a00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  ffff8800359c9a80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  ffff8800359c9b00: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
  ffff8800359c9b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  ffff8800359c9c00: 00 00 00 00 00 00 00 00 fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07
  Heap redzone:          fa
  Heap kmalloc redzone:  fb
  Freed heap region:     fd
  Shadow gap:            fe

The out-of-bounds access happens on 'parser->buffer[parser->idx] = 0;'

Although the crash happened in ftrace_regex_open() the real bug
occurred in trace_get_user() where there's an incrementation to
parser->idx without a check against the size. The way it is triggered
is if userspace sends in 128 characters (EVENT_BUF_SIZE + 1), the loop
that reads the last character stores it and then breaks out because
there is no more characters. Then the last character is read to determine
what to do next, and the index is incremented without checking size.

Then the caller of trace_get_user() usually nulls out the last character
with a zero, but since the index is equal to the size, it writes a nul
character after the allocated space, which can corrupt memory.

Luckily, only root user has write access to this file.

Link: http://lkml.kernel.org/r/20131009222323.04fd1a0d@gandalf.local.home

Reported-by: Andrey Konovalov 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

tracing: Make tracing_cpumask available for all instances

2013-08-22T16:45:24+00:00

Allow tracer instances to disable tracing by cpu by moving
the static global tracing_cpumask into trace_array.

Link: http://lkml.kernel.org/r/921622317f239bfc2283cac2242647801ef584f2.1375980149.git.azl@google.com

Cc: Vaibhav Nagarnaik 
Cc: David Sharp 
Cc: Alexander Z Lam 
Signed-off-by: Alexander Z Lam 
Signed-off-by: Steven Rostedt

tracing: Fix reset of time stamps during trace_clock changes

2013-08-03T02:40:09+00:00

Fixed two issues with changing the timestamp clock with trace_clock:

 - The global buffer was reset on instance clock changes. Change this to pass
   the correct per-instance buffer
 - ftrace_now() is used to set buf->time_start in tracing_reset_online_cpus().
   This was incorrect because ftrace_now() used the global buffer's clock to
   return the current time. Change this to use buffer_ftrace_now() which
   returns the current time for the correct per-instance buffer.

Also removed tracing_reset_current() because it is not used anywhere

Link: http://lkml.kernel.org/r/1375493777-17261-2-git-send-email-azl@google.com

Cc: Vaibhav Nagarnaik 
Cc: David Sharp 
Cc: Alexander Z Lam 
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Alexander Z Lam 
Signed-off-by: Steven Rostedt

tracing: Make TRACE_ITER_STOP_ON_FREE stop the correct buffer

2013-08-03T02:39:29+00:00

Releasing the free_buffer file in an instance causes the global buffer
to be stopped when TRACE_ITER_STOP_ON_FREE is enabled. Operate on the
correct buffer.

Link: http://lkml.kernel.org/r/1375493777-17261-1-git-send-email-azl@google.com

Cc: Vaibhav Nagarnaik 
Cc: David Sharp 
Cc: Alexander Z Lam 
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Alexander Z Lam 
Signed-off-by: Steven Rostedt

tracing: Fix fields of struct trace_iterator that are zeroed by mistake

2013-08-03T02:28:41+00:00

tracing_read_pipe zeros all fields bellow "seq". The declaration contains
a comment about that, but it doesn't help.

The first field is "snapshot", it's true when current open file is
snapshot. Looks obvious, that it should not be zeroed.

The second field is "started". It was converted from cpumask_t to
cpumask_var_t (v2.6.28-4983-g4462344), in other words it was
converted from cpumask to pointer on cpumask.

Currently the reference on "started" memory is lost after the first read
from tracing_read_pipe and a proper object will never be freed.

The "started" is never dereferenced for trace_pipe, because trace_pipe
can't have the TRACE_FILE_ANNOTATE options.

Link: http://lkml.kernel.org/r/1375463803-3085183-1-git-send-email-avagin@openvz.org

Cc: stable@vger.kernel.org # 2.6.30
Signed-off-by: Andrew Vagin 
Signed-off-by: Steven Rostedt

tracing: Remove locking trace_types_lock from tracing_reset_all_online_cpus()

2013-07-26T12:57:32+00:00

Commit a82274151af "tracing: Protect ftrace_trace_arrays list in trace_events.c"
added taking the trace_types_lock mutex in trace_events.c as there were
several locations that needed it for protection. Unfortunately, it also
encapsulated a call to tracing_reset_all_online_cpus() which also takes
the trace_types_lock, causing a deadlock.

This happens when a module has tracepoints and has been traced. When the
module is removed, the trace events module notifier will grab the
trace_types_lock, do a bunch of clean ups, and also clears the buffer
by calling tracing_reset_all_online_cpus. This doesn't happen often
which explains why it wasn't caught right away.

Commit a82274151af was marked for stable, which means this must be
sent to stable too.

Link: http://lkml.kernel.org/r/51EEC646.7070306@broadcom.com

Reported-by: Arend van Spril 
Tested-by: Arend van Spriel 
Cc: Alexander Z Lam 
Cc: Vaibhav Nagarnaik 
Cc: David Sharp 
Cc: stable@vger.kernel.org # 3.10
Signed-off-by: Steven Rostedt

tracing: Kill trace_cpu struct/members

2013-07-24T15:22:53+00:00

After the previous changes trace_array_cpu->trace_cpu and
trace_array->trace_cpu becomes write-only. Remove these members
and kill "struct trace_cpu" as well.

As a side effect this also removes memset(per_cpu_memory, 0).
It was not needed, alloc_percpu() returns zero-filled memory.

Link: http://lkml.kernel.org/r/20130723152613.GA23741@redhat.com

Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt

tracing: Change tracing_fops/snapshot_fops to rely on tracing_get_cpu()

2013-07-24T15:22:53+00:00

tracing_open() and tracing_snapshot_open() are racy, the memory
inode->i_private points to can be already freed.

Convert these last users of "inode->i_private == trace_cpu" to
use "i_private = trace_array" and rely on tracing_get_cpu().

v2: incorporate the fix from Steven, tracing_release() must not
    blindly dereference file->private_data unless we know that
    the file was opened for reading.

Link: http://lkml.kernel.org/r/20130723152610.GA23737@redhat.com

Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt