linux-stable.git/tools/perf/util/map.c, branch linux-4.9.y

perf map: Tighten snprintf() string precision to pass gcc check on some 32-bit arches

2021-04-16T09:59:12+00:00

commit 77d02bd00cea9f1a87afe58113fa75b983d6c23a upstream.

Noticed on a debian:experimental mips and mipsel cross build build
environment:

  perfbuilder@ec265a086e9b:~$ mips-linux-gnu-gcc --version | head -1
  mips-linux-gnu-gcc (Debian 10.2.1-3) 10.2.1 20201224
  perfbuilder@ec265a086e9b:~$

    CC       /tmp/build/perf/util/map.o
  util/map.c: In function 'map__new':
  util/map.c:109:5: error: '%s' directive output may be truncated writing between 1 and 2147483645 bytes into a region of size 4096 [-Werror=format-truncation=]
    109 |    "%s/platforms/%s/arch-%s/usr/lib/%s",
        |     ^~
  In file included from /usr/mips-linux-gnu/include/stdio.h:867,
                   from util/symbol.h:11,
                   from util/map.c:2:
  /usr/mips-linux-gnu/include/bits/stdio2.h:67:10: note: '__builtin___snprintf_chk' output 32 or more bytes (assuming 4294967321) into a destination of size 4096
     67 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
        |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     68 |        __bos (__s), __fmt, __va_arg_pack ());
        |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cc1: all warnings being treated as errors

Since we have the lenghts for what lands in that place, use it to give
the compiler more info and make it happy.

Signed-off-by: Arnaldo Carvalho de Melo 
Cc: Anders Roxell 
Signed-off-by: Greg Kroah-Hartman

perf map: Fix off by one in strncpy() size argument

2020-04-02T15:20:41+00:00

commit db2c549407d4a76563c579e4768f7d6d32afefba upstream.

This patch fixes an off-by-one error in strncpy size argument in
tools/perf/util/map.c. The issue is that in:

        strncmp(filename, "/system/lib/", 11)

the passed string literal: "/system/lib/" has 12 bytes (without the NULL
byte) and the passed size argument is 11. As a result, the logic won't
match the ending "/" byte and will pass filepaths that are stored in
other directories e.g. "/system/libmalicious/bin" or just
"/system/libmalicious".

This functionality seems to be present only on Android. I assume the
/system/ directory is only writable by the root user, so I don't think
this bug has much (or any) security impact.

Fixes: eca818369996 ("perf tools: Add automatic remapping of Android libraries")
Signed-off-by: disconnect3d 
Cc: Alexander Shishkin 
Cc: Changbin Du 
Cc: Jiri Olsa 
Cc: John Keeping 
Cc: Mark Rutland 
Cc: Michael Lentine 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Song Liu 
Cc: Stephane Eranian 
Link: http://lore.kernel.org/lkml/20200309104855.3775-1-dominik.b.czarnota@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Greg Kroah-Hartman

perf map: Fix overlapped map handling

2019-11-06T11:18:05+00:00

[ Upstream commit ee212d6ea20887c0ef352be8563ca13dbf965906 ]

Whenever an mmap/mmap2 event occurs, the map tree must be updated to add a new
entry. If a new map overlaps a previous map, the overlapped section of the
previous map is effectively unmapped, but the non-overlapping sections are
still valid.

maps__fixup_overlappings() is responsible for creating any new map entries from
the previously overlapped map. It optionally creates a before and an after map.

When creating the after map the existing code failed to adjust the map.pgoff.
This meant the new after map would incorrectly calculate the file offset
for the ip. This results in incorrect symbol name resolution for any ip in the
after region.

Make maps__fixup_overlappings() correctly populate map.pgoff.

Add an assert that new mapping matches old mapping at the beginning of
the after map.

Committer-testing:

Validated correct parsing of libcoreclr.so symbols from .NET Core 3.0 preview9
(which didn't strip symbols).

Preparation:

  ~/dotnet3.0-preview9/dotnet new webapi -o perfSymbol
  cd perfSymbol
  ~/dotnet3.0-preview9/dotnet publish
  perf record ~/dotnet3.0-preview9/dotnet \
      bin/Debug/netcoreapp3.0/publish/perfSymbol.dll
  ^C

Before:

  perf script --show-mmap-events 2>&1 | grep -e MMAP -e unknown |\
     grep libcoreclr.so | head -n 4
        dotnet  1907 373352.698780: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615726000(0x768000) @ 0 08:02 5510620 765057155]: \
            r-xp .../3.0.0-preview9-19423-09/libcoreclr.so
        dotnet  1907 373352.701091: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615974000(0x1000) @ 0x24e000 08:02 5510620 765057155]: \
            rwxp .../3.0.0-preview9-19423-09/libcoreclr.so
        dotnet  1907 373352.701241: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615c42000(0x1000) @ 0x51c000 08:02 5510620 765057155]: \
            rwxp .../3.0.0-preview9-19423-09/libcoreclr.so
        dotnet  1907 373352.705249:     250000 cpu-clock: \
             7fe6159a1f99 [unknown] \
             (.../3.0.0-preview9-19423-09/libcoreclr.so)

After:

  perf script --show-mmap-events 2>&1 | grep -e MMAP -e unknown |\
     grep libcoreclr.so | head -n 4
        dotnet  1907 373352.698780: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615726000(0x768000) @ 0 08:02 5510620 765057155]: \
            r-xp .../3.0.0-preview9-19423-09/libcoreclr.so
        dotnet  1907 373352.701091: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615974000(0x1000) @ 0x24e000 08:02 5510620 765057155]: \
            rwxp .../3.0.0-preview9-19423-09/libcoreclr.so
        dotnet  1907 373352.701241: PERF_RECORD_MMAP2 1907/1907: \
            [0x7fe615c42000(0x1000) @ 0x51c000 08:02 5510620 765057155]: \
            rwxp .../3.0.0-preview9-19423-09/libcoreclr.so

All the [unknown] symbols were resolved.

Signed-off-by: Steve MacLean 
Tested-by: Brian Robbins 
Acked-by: Jiri Olsa 
Cc: Alexander Shishkin 
Cc: Andi Kleen 
Cc: Davidlohr Bueso 
Cc: Eric Saint-Etienne 
Cc: John Keeping 
Cc: John Salem 
Cc: Leo Yan 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Song Liu 
Cc: Stephane Eranian 
Cc: Tom McDonald 
Link: http://lore.kernel.org/lkml/BN8PR21MB136270949F22A6A02335C238F7800@BN8PR21MB1362.namprd21.prod.outlook.com
Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Sasha Levin

perf tools: Do hugetlb handling in more systems

2016-09-13T18:26:30+00:00

The csets:

  0ac3348e5024 ("perf tools: Recognize hugetlb mapping as anon mapping")
  d7e404af115b ("perf record: Mark MAP_HUGETLB when synthesizing mmap events")

Added code conditional on MAP_HUGETLB, to make it build in older systems
where that define wasn't available. Now that we grabbed copies of
uapi/linux/mmap.h to have all those definitions in tools/, use it so
that we can support building the tools for older systems (without the
MAP_HUGETLB define in its libc headers) using new kernels that support
such maps.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Cc: Zefan Li 
Link: http://lkml.kernel.org/n/tip-wv6oqbfkpxbix4umj2kcfmaz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Recognize hugetlb mapping as anon mapping

2016-09-08T15:28:06+00:00

Hugetlbfs mapping should be recognized as anon mapping so user has a
chance to create /tmp/perf-.map file for symbol resolving. This
patch utilizes MAP_HUGETLB to identify hugetlb mapping.

After this patch, if perf is started before a program starts using huge
pages (so perf gets MMAP2 events from kernel), perf is able to recognize
hugetlb mapping as anon mapping.

Signed-off-by: Wang Nan 
Cc: He Kuang 
Cc: Nilay Vaish 
Cc: Zefan Li 
Link: http://lkml.kernel.org/r/1473137909-142064-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Hou Pengyang 
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Remove symbol_filter_t machinery

2016-09-05T14:14:50+00:00

We're not using it anymore, few users were, but we really could do
without it, simplify lots of functions by removing it.

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: http://lkml.kernel.org/n/tip-1zng8wdznn00iiz08bb7q3vn@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf probe: Warn unmatched function filter correctly

2016-07-18T22:46:34+00:00

Warn unmatched function filter correctly instead of warning
"symbol-loading error", since that can be a filter issue.

From the technical point of view, this adds a filter chech in map__load
and if there is a filter, it returns -2 (filter-out), instead of -1
(error), and perf-probe checks it and change message.

E.g. without this fix:

  # perf probe -F rt_sp*
  no symbols found in [kernel.kallsyms], maybe install a debug package?
  Failed to load symbols in kernel

With this fix:

  # perf probe -F rt_sp*
  no symbols passed the given filter.
  Failed to find symbols matched to "rt_sp*"
    Error: Failed to show functions.

Reported-and-Tested-by: Arnaldo Carvalho de Melo 
Signed-off-by: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/146885835596.16106.2293540792775552481.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo

perf unwind: Call unwind__prepare_access for forked thread

2016-07-04T23:27:25+00:00

Currently we call unwind__prepare_access for map event.  In case we
report fork event the thread inherits its parent's maps and
unwind__prepare_access is never called for the thread.

This causes unwind__get_entries seeing uninitialized
unwind_libunwind_ops and thus returning no callchain.

Adding unwind__prepare_access calls for fork even processing.

Signed-off-by: Jiri Olsa 
Cc: David Ahern 
Cc: He Kuang 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1467634583-29147-5-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Use SBUILD_ID_SIZE where applicable

2016-05-11T16:06:06+00:00

Use the existing SBUILD_ID_SIZE macro instead of the equivalent
BUILD_ID_SIZE * 2 + 1 expression for allocating a buffer for build-id
strings.

Signed-off-by: Masami Hiramatsu 
Cc: Ananth N Mavinakayanahalli 
Cc: Brendan Gregg 
Cc: Hemant Kumar 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20160511135159.23943.57120.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo

perf symbols: Record text offset in dso to calculate objdump address

2016-04-08T12:58:14+00:00

In this patch, the offset of '.text' section is stored into dso
and used here to re-calculate address to objdump.

In most of the cases, executable code is in '.text' section, so the
adjustment made to a symbol in dso__load_sym (using
sym.st_value -= shdr.sh_addr - shdr.sh_offset) should equal to
'sym.st_value -= dso->text_offset'. Therefore, adding text_offset back
get objdump address from symbol address (rip). However, it is not true
for kernel and kernel module since there could be multiple executable
sections with different offset. Exclude kernel for this reason.

After this patch, even dso->adjust_symbols is set to true for shared
objects, map__rip_2objdump() and map__objdump_2mem() would return
correct result, so perf behavior of annotate won't be changed.

Signed-off-by: Wang Nan 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Adrian Hunter 
Cc: Cody P Schafer 
Cc: He Kuang 
Cc: Jiri Olsa 
Cc: Kirill Smelkov 
Cc: Li Zefan 
Cc: Masami Hiramatsu 
Cc: Namhyung Kim 
Cc: Zefan Li 
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1460024671-64774-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo