linux-stable.git/tools/perf/util, branch v3.19

perf probe: Fix probing kretprobes

2015-01-21T13:06:24+00:00

The commit dfef99cd0b2c ("perf probe: Use ref_reloc_sym based address
instead of the symbol name") converts kprobes to use ref_reloc_sym (i.e.
_stext) and offset instead of using symbol's name directly.  So on my
system, adding do_fork ends up with like below:

  $ sudo perf probe -v --add do_fork%return
  probe-definition(0): do_fork%return
  symbol:do_fork file:(null) line:0 offset:0 return:1 lazy:(null)
  0 arguments
  Looking at the vmlinux_path (7 entries long)
  Using /lib/modules/3.17.6-1-ARCH/build/vmlinux for symbols
  Could not open debuginfo. Try to use symbols.
  Opening /sys/kernel/debug/tracing/kprobe_events write=1
  Added new event:
  Writing event: r:probe/do_fork _stext+456136
  Failed to write event: Invalid argument
  Error: Failed to add events. Reason: Operation not permitted (Code: -1)

As you can see, the do_fork was translated to _stext+456136.  This was
because to support (local) symbols that have same name.  But the problem
is that kretprobe requires to be inserted at function start point so it
simply checks whether it's called with offset 0.  And if not, it'll
return with -EINVAL.  You can see it with dmesg.

  $ dmesg | tail -1
    [125621.764103] Return probe must be used without offset.

So we need to use the symbol name instead of ref_reloc_sym in case of
return probes.

Reported-by: Jiri Olsa 
Signed-off-by: Namhyung Kim 
Tested-by: Jiri Olsa 
Acked-by: Masami Hiramatsu 
Cc: David Ahern 
Link: http://lkml.kernel.org/r/1421234288-22758-4-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Introduce 'for' method to iterate over the symbols with a given name

2015-01-21T13:06:15+00:00

Removing boilerplate from two places, where one would have to find the
first entry, then iterate using symbol__next_by_name + strcmp to see if
the next member had the same name.

Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Link: http://lkml.kernel.org/n/tip-eh73z8gthv20yowirmx2yk38@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Do not rely on map__load() filter to find symbols

2015-01-21T13:06:02+00:00

The find_probe_trace_events_from_map() searches matching symbol from a
map (so from a backing dso).  For uprobes, it'll create a new map (and
dso) and loads it using a filter.  It's a little bit inefficient in that
it'll read out the symbol table everytime but works well anyway.

For kprobes however, it'll reuse existing kernel map which might be
loaded before.  In this case map__load() just returns with no result.
It makes kprobes always failed to find symbol even if it exists in the
map (dso).

To fix it, use map__find_symbol_by_name() instead.  It'll load a map
with full symbols and sorts them by name.  It needs to search sibing
nodes since there can be multiple (local) symbols with same name.

Signed-off-by: Namhyung Kim 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Link: http://lkml.kernel.org/r/1421234288-22758-3-git-send-email-namhyung@kernel.org
[ Use symbol__next_by_name ]
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Introduce method to iterate symbols ordered by name

2015-01-21T13:05:54+00:00

Given a symbol, go to the next entry in a rbtree sorted by symbol name.

Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Link: http://lkml.kernel.org/n/tip-aq210drxprnu2so4dye5xa3j@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Return the first entry with a given name in find_by_name method

2015-01-21T13:05:44+00:00

When a dso contains multiple symbols which have same name, current
dso__find_symbol_by_name() only finds an one of them and there's no way
to get the all symbols without going through the rbtree.

So make symbols__find_by_name() return the first entry with the given
name and the next patch in this series will provide a way to iterate
from there, by the name ordered rb_tree, till a suitable symbol is
found.

Signed-off-by: Namhyung Kim 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Link: http://lkml.kernel.org/r/1421234288-22758-2-git-send-email-namhyung@kernel.org
[ Yanked this independent hunk, without changes, from a larger patch  ]
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Fix memory leaks in LOCK handling

2015-01-21T13:05:32+00:00

The lock prefix handling fails to free the strdup()'d name as well as
the fields allocated by the instruction parsing.

Signed-off-by: Rabin Vincent 
Cc: Paul Mackerras 
Link: http://lkml.kernel.org/r/1421607621-15005-2-git-send-email-rabin@rab.in
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Handle ins parsing failures

2015-01-21T13:05:17+00:00

Don't use the ins's ->sncprintf() if the parsing failed.

For example, this fixes the display of "imul %edx".  Without this patch:

       |      imul   (null),(null)

After this patch:

       |      imul   %edx

Signed-off-by: Rabin Vincent 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1421607621-15005-1-git-send-email-rabin@rab.in
Signed-off-by: Arnaldo Carvalho de Melo

perf evlist: Remove extraneous 'was' on error message

2015-01-21T13:04:15+00:00

  [acme@mica ~]$ trace -p 3330
  Error:  Unable to find debugfs
  Hint:   Was your kernel was compiled with debugfs support?
                          ^^^
                          ^^^
  Hint:   Is the debugfs filesystem mounted?
  Hint:   Try 'sudo mount -t debugfs nodev /sys/kernel/debug'

Fix it.

Cc: Adrian Hunter 
Cc: Borislav Petkov 
Cc: David Ahern 
Cc: Don Zickus 
Cc: Frederic Weisbecker 
Cc: Jiri Olsa 
Cc: Mike Galbraith 
Cc: Namhyung Kim 
Cc: Stephane Eranian 
Link: http://lkml.kernel.org/n/tip-kb9s0xy5z8i51abdu4bgm3rv@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix segfault for symbol annotation on TUI

2015-01-16T20:49:29+00:00

Currently the symbol structure is allocated with symbol_conf.priv_size
to carry sideband information like annotation, map browser on TUI and
sort-by-name tree node.  So retrieving these information from symbol
needs to care about the details of such placement.

However the annotation code just assumes that the symbol is placed after
the struct annotation.  But actually there's other info between them.
So accessing those struct will lead to an undefined behavior (usually a
crash) after they write their info to the same location.

To reproduce the problem, please follow the steps below:

  1. run perf report (TUI of course) with -v option
  2. open map browser (by pressing right arrow key for any entry)
  3. search any function (by pressing '/' key and input whatever..)
  4. return to the hist browser (by pressing 'q' or left arrow key)
  5. open annotation window for the same entry (by pressing 'a' key)

Signed-off-by: Namhyung Kim 
Cc: David Ahern 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1421234288-22758-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf test: Fix dwarf unwind using libunwind.

2015-01-16T20:49:29+00:00

Perf tool fails to unwind user stack if the event raises in a shared
object. This patch improves tests/dwarf-unwind.c to demonstrate the
problem by utilizing commonly used glibc function "bsearch". If perf is
not statically linked, the testcase will try to unwind a mixed call
trace.

By debugging libunwind I found that there is a bug in unwind-libunwind:
it always passes 0 as segbase to libunwind, cause libunwind unable to
locate debug_frame entry fir first level ip address (I add some more
debugging output into libunwind to make things clear):

               >_Uarm_dwarf_find_debug_frame: start_ip = 10be98, end_ip = 10c2a4
               >_Uarm_dwarf_find_debug_frame: found debug_frame table `/lib/libc-2.18.so': segbase=0x0, len=7, gp=0x0, table_data=0x449388
               >_Uarm_dwarf_search_unwind_table: call lookup:ip = b6cd3bcc, segbase = 0, rel_ip = b6cd3bcc
               >lookup: e->start_ip_offset = bcf18 (rel_ip = b6cd3bcc)
               >lookup: e->start_ip_offset = 6d314 (rel_ip = b6cd3bcc)
               >lookup: e->start_ip_offset = 33d0c (rel_ip = b6cd3bcc)
                ...
               >lookup: e->start_ip_offset = 15d0c (rel_ip = b6cd3bcc)
               >lookup: e->start_ip_offset = 15c40 (rel_ip = b6cd3bcc)
 >_Uarm_dwarf_search_unwind_table: IP b6cd3bcc inside range b6c12000-b6d4c000, but no explicit unwind info found
                >put_rs_cache: unmasking signals/interrupts and releasing lock
               >_Uarm_dwarf_step: returning -10
 >_Uarm_step: dwarf_step()=-10

This patch passes map->start as segbase to dwarf_find_debug_frame(), so
di will be initialized correctly.

In addition, dso and executable are different when setting segbase. This
patch first check whether the elf is executable, and pass segbase only
for shared object.

Signed-off-by: Wang Nan 
Acked-by: Jiri Olsa 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Li Zefan 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1421203007-75799-1-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo