linux-toradex.git/tools/perf/util/symbol.c, branch v3.0.46

perf symbols: Fix ppc64 SEGV in dso__load_sym with debuginfo files

2011-10-03T18:41:02+00:00

commit adb091846318f86e4f46c7d6a7b40d2f478abdbe upstream.

64bit PowerPC debuginfo files have an empty function descriptor section.
I hit a SEGV when perf tried to use this section for symbol resolution.

To fix this we need to check the section is valid and we can do this by
checking for type SHT_PROGBITS.

Cc: 
Cc: Ingo Molnar 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Eric B Munson 
Link: http://lkml.kernel.org/r/20110824065242.895239970@samba.org
Signed-off-by: Anton Blanchard 
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf symbols: Handle /proc/sys/kernel/kptr_restrict

2011-05-26T14:15:25+00:00

Perf uses /proc/modules to figure out where kernel modules are loaded.

With the advent of kptr_restrict, non root users get zeroes for all module
start addresses.

So check if kptr_restrict is non zero and don't generate the syntethic
PERF_RECORD_MMAP events for them.

Warn the user about it in perf record and in perf report.

In perf report the reference relocation symbol being zero means that
kptr_restrict was set, thus /proc/kallsyms has only zeroed addresses, so don't
use it to fixup symbol addresses when using a valid kallsyms (in the buildid
cache) or vmlinux (in the vmlinux path) build-id located automatically or
specified by the user.

Provide an explanation about it in 'perf report' if kernel samples were taken,
checking if a suitable vmlinux or kallsyms was found/specified.

Restricted /proc/kallsyms don't go to the buildid cache anymore.

Example:

 [acme@emilia ~]$ perf record -F 100000 sleep 1

 WARNING: Kernel address maps (/proc/{kallsyms,modules}) are restricted, check
 /proc/sys/kernel/kptr_restrict.

 Samples in kernel functions may not be resolved if a suitable vmlinux file is
 not found in the buildid cache or in the vmlinux path.

 Samples in kernel modules won't be resolved at all.

 If some relocation was applied (e.g. kexec) symbols may be misresolved even
 with a suitable vmlinux or kallsyms file.

 [ perf record: Woken up 1 times to write data ]
 [ perf record: Captured and wrote 0.005 MB perf.data (~231 samples) ]
 [acme@emilia ~]$

 [acme@emilia ~]$ perf report --stdio
 Kernel address maps (/proc/{kallsyms,modules}) were restricted,
 check /proc/sys/kernel/kptr_restrict before running 'perf record'.

 If some relocation was applied (e.g. kexec) symbols may be misresolved.

 Samples in kernel modules can't be resolved as well.

 # Events: 13  cycles
 #
 # Overhead  Command      Shared Object                 Symbol
 # ........  .......  .................  .....................
 #
    20.24%    sleep  [kernel.kallsyms]  [k] page_fault
    20.04%    sleep  [kernel.kallsyms]  [k] filemap_fault
    19.78%    sleep  [kernel.kallsyms]  [k] __lru_cache_add
    19.69%    sleep  ld-2.12.so         [.] memcpy
    14.71%    sleep  [kernel.kallsyms]  [k] dput
     4.70%    sleep  [kernel.kallsyms]  [k] flush_signal_handlers
     0.73%    sleep  [kernel.kallsyms]  [k] perf_event_comm
     0.11%    sleep  [kernel.kallsyms]  [k] native_write_msr_safe

 #
 # (For a higher level overview, try: perf report --sort comm,dso)
 #
 [acme@emilia ~]$

This is because it found a suitable vmlinux (build-id checked) in
/lib/modules/2.6.39-rc7+/build/vmlinux (use -v in perf report to see the long
file name).

If we remove that file from the vmlinux path:

 [root@emilia ~]# mv /lib/modules/2.6.39-rc7+/build/vmlinux \
		     /lib/modules/2.6.39-rc7+/build/vmlinux.OFF
 [acme@emilia ~]$ perf report --stdio
 [kernel.kallsyms] with build id 57298cdbe0131f6871667ec0eaab4804dcf6f562
 not found, continuing without symbols

 Kernel address maps (/proc/{kallsyms,modules}) were restricted, check
 /proc/sys/kernel/kptr_restrict before running 'perf record'.

 As no suitable kallsyms nor vmlinux was found, kernel samples can't be
 resolved.

 Samples in kernel modules can't be resolved as well.

 # Events: 13  cycles
 #
 # Overhead  Command      Shared Object  Symbol
 # ........  .......  .................  ......
 #
    80.31%    sleep  [kernel.kallsyms]  [k] 0xffffffff8103425a
    19.69%    sleep  ld-2.12.so         [.] memcpy

 #
 # (For a higher level overview, try: perf report --sort comm,dso)
 #
 [acme@emilia ~]$

Reported-by: Stephane Eranian 
Suggested-by: David Miller 
Cc: Dave Jones 
Cc: David Miller 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Kees Cook 
Cc: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Pekka Enberg 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Tom Zanussi 
Link: http://lkml.kernel.org/n/tip-mt512joaxxbhhp1odop04yit@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Give more useful names to 'self' parameters

2011-04-19T11:18:35+00:00

One more installment on an area that is mostly dormant.

Suggested-by: Thomas Gleixner 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Tom Zanussi 
LKML-Reference: 
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Properly align symbol_conf.priv_size

2011-03-29T17:18:39+00:00

If symbol_conf.priv_size is not a multiple of "sizeof(u64)" we'll bus
error on sparc64 in symbol__new because the "struct symbol *" pointer
is computed by adding symbol_conf.priv_size to the memory allocated.

We cannot isolate the fix to symbol__new and symbol__delete since the
private area is computed by subtracting the priv_size value from a
"struct symbol" pointer, so then the private area can still be
potentially unaligned.

So, simply align the symbol_conf.priv_size value in symbol__init()

Cc: Ingo Molnar 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
LKML-Reference: <20110328.175849.112593455.davem@davemloft.net>
Signed-off-by: David S. Miller 
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Fix vsyscall symbol lookup

2011-03-28T17:44:15+00:00

Perf can't currently trace into the vsyscall page.  It looks like it was
meant to work.

Tested on 2.6.38 and today's -git.

The bug is easy to reproduce.  Compile this:

int main()
{
	int i;
	struct timespec t;
	for(i = 0; i < 10000000; i++)
		clock_gettime(CLOCK_MONOTONIC, &t);
	return 0;
}

and run it through perf record; perf report.  The top entry shows
"[unknown]" and you can't zoom in.

It looks like there are two issues.  The first is a that a test for user
mode executing in kernel space is backwards.  (That's the first hunk
below).  The second (I think) is that something's wrong with the code
that generates lots of little struct dso objects for different sections
-- when it runs on vmlinux it results in bogus long_name values which
cause objdump to fail.

Cc: Ingo Molnar 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
LPU-Reference: 
Signed-off-by: Andy Lutomirski 
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Look at .dynsym again if .symtab not found

2011-03-23T22:29:46+00:00

The original intent of the code was to repeat the search with
want_symtab = 0. But as the code stands now, we never hit the "default"
case of the switch statement. Which means we never repeat the search.

Tested-by: Srikar Dronamraju 
Reported-by: Arun Sharma 
Reported-by: Srikar Dronamraju 
Cc: Dave Martin 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Tom Zanussi 
LKML-Reference: 
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Rename dso->origin to dso->symtab_type

2011-03-11T16:28:45+00:00

And the DSO__ORIG_ enum to SYMTAB__, to clarify that this is about from
where the symtab was obtained.

Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Tom Zanussi 
LKML-Reference: 
Signed-off-by: Arnaldo Carvalho de Melo

perf hists: Remove needless global col lenght calcs

2011-03-06T01:31:04+00:00

To support multiple events we need to do these calcs per 'struct hists'
instance, and it turns out we already do that at:

	__hists__add_entry
		hists__inc_nr_entries
			hists__calc_col_len

for all the unfiltered hist_entry instances we stash in the rb tree, so
trow away the dead code.

Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Tom Zanussi 
LKML-Reference: 
Signed-off-by: Arnaldo Carvalho de Melo

Merge branch 'perf/urgent' into perf/core

2011-03-04T09:40:25+00:00

Merge reason: Pick up updates before queueing up dependent patches.

Signed-off-by: Ingo Molnar

perf symbols: Fix vmlinux path when not using --symfs

2011-02-28T16:54:38+00:00

The ec5761e cset introduced the symfs feature with a bug for loading vmlinux
files that ended up causing this failure:

[root@emilia v2.6.38-rc5+]# strace -e trace=open perf top --vmlinux ./vmlinux 2>&1 | tail -3
open("/./vmlinux", O_RDONLY)            = -1 ENOENT (No such file or directory)
./vmlinux with build id b9266bf40e98dadb5d43a2f3e95d3c5d4aff46dc not found, continuing without symbols
The ./vmlinux file can't be used
[root@emilia v2.6.38-rc5+]#

Remove the extra slash, just like is done in the DSO__ORIG_DSO handling in
dso__load() and other parts of the ec5761e cset.

Reported-by: Ingo Molnar 
Cc: David Ahern 
Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Tom Zanussi 
LKML-Reference: 
Signed-off-by: Arnaldo Carvalho de Melo