linux.git/tools/perf, branch v4.19-rc4

perf tools: Fix maps__find_symbol_by_name()

2018-09-11T17:12:51+00:00

Commit 1c5aae7710bb ("perf machine: Create maps for x86 PTI entry
trampolines") revealed a problem with maps__find_symbol_by_name() that
resulted in probes not being found e.g.

	$ sudo perf probe xsk_mmap
	xsk_mmap is out of .text, skip it.
	Probe point 'xsk_mmap' not found.
	   Error: Failed to add events.

maps__find_symbol_by_name() can optionally return the map of the found
symbol. It can get the map wrong because, in fact, the symbol is found
on the map's dso, not allowing for the possibility that the dso has more
than one map. Fix by always checking the map contains the symbol.

Reported-by: Björn Töpel 
Signed-off-by: Adrian Hunter 
Tested-by: Björn Töpel 
Cc: Jiri Olsa 
Cc: stable@vger.kernel.org
Fixes: 1c5aae7710bb ("perf machine: Create maps for x86 PTI entry trampolines")
Link: http://lkml.kernel.org/r/20180907085116.25782-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Fix parsing aarch64 branch instructions after objdump update

2018-08-30T18:51:54+00:00

Starting with binutils 2.28, aarch64 objdump adds comments to the
disassembly output to show the alternative names of a condition code
[1].

It is assumed that commas in objdump comments could occur in other
arches now or in the future, so this fix is arch-independent.

The fix could have been done with arm64 specific jump__parse and
jump__scnprintf functions, but the jump__scnprintf instruction would
have to have its comment character be a literal, since the scnprintf
functions cannot receive a struct arch easily.

This inconvenience also applies to the generic jump__scnprintf, which is
why we add a raw_comment pointer to struct ins_operands, so the __parse
function assigns it to be re-used by its corresponding __scnprintf
function.

Example differences in 'perf annotate --stdio2' output on an aarch64
perf.data file:

BEFORE: → b.cs   ffff200008133d1c   // b.hs, dffff7ecc47b
AFTER : ↓ b.cs   18c

BEFORE: → b.cc   ffff200008d8d9cc   // b.lo, b.ul, dffff727295b
AFTER : ↓ b.cc   31c

The branch target labels 18c and 31c also now appear in the output:

BEFORE:        add    x26, x29, #0x80
AFTER : 18c:   add    x26, x29, #0x80

BEFORE:        add    x21, x21, #0x8
AFTER : 31c:   add    x21, x21, #0x8

The Fixes: tag below is added so stable branches will get the update; it
doesn't necessarily mean that commit was broken at the time, rather it
didn't withstand the aarch64 objdump update.

Tested no difference in output for sample x86_64, power arch perf.data files.

[1] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=bb7eff5206e4795ac79c177a80fe9f4630aaf730

Signed-off-by: Kim Phillips 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Alexander Shishkin 
Cc: Anton Blanchard 
Cc: Christian Borntraeger 
Cc: Jiri Olsa 
Cc: Mark Rutland 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Robin Murphy 
Cc: Taeung Song 
Cc: linux-arm-kernel@lists.infradead.org
Fixes: b13bbeee5ee6 ("perf annotate: Fix branch instruction with multiple operands")
Link: http://lkml.kernel.org/r/20180827125340.a2f7e291901d17cea05daba4@arm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf probe powerpc: Ignore SyS symbols irrespective of endianness

2018-08-30T18:15:11+00:00

This makes sure that the SyS symbols are ignored for any powerpc system,
not just the big endian ones.

Reported-by: Naveen N. Rao 
Signed-off-by: Sandipan Das 
Reviewed-by: Kamalesh Babulal 
Acked-by: Naveen N. Rao 
Cc: Jiri Olsa 
Cc: Ravi Bangoria 
Fixes: fb6d59423115 ("perf probe ppc: Use the right prefix when ignoring SyS symbols on ppc")
Link: http://lkml.kernel.org/r/20180828090848.1914-1-sandipan@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf event-parse: Use fixed size string for comms

2018-08-30T17:51:45+00:00

Some implementations of libc do not support the 'm' width modifier as
part of the scanf string format specifier. This can cause the parsing to
fail.  Since the parser never checks if the scanf parsing was
successesful, this can result in a crash.

Change the comm string to be allocated as a fixed size instead of
dynamically using 'm' scanf width modifier. This can be safely done
since comm size is limited to 16 bytes by TASK_COMM_LEN within the
kernel.

This change prevents perf from crashing when linked against bionic as
well as reduces the total number of heap allocations and frees invoked
while accomplishing the same task.

Signed-off-by: Chris Phlipot 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180830021950.15563-1-cphlipot0@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo

perf util: Fix bad memory access in trace info.

2018-08-30T17:50:50+00:00

In the write to the output_fd in the error condition of
record_saved_cmdline(), we are writing 8 bytes from a memory location on
the stack that contains a primitive that is only 4 bytes in size.
Change the primitive to 8 bytes in size to match the size of the write
in order to avoid reading unknown memory from the stack.

Signed-off-by: Chris Phlipot 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180829061954.18871-1-cphlipot0@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Streamline bpf examples and headers installation

2018-08-30T17:49:25+00:00

We were emitting 4 lines, two of them misleading:

  make: Entering directory '/home/acme/git/perf/tools/perf'
  
    INSTALL  lib
    INSTALL  include/bpf
    INSTALL  lib
    INSTALL  examples/bpf
  
  make: Leaving directory '/home/acme/git/perf/tools/perf'

Make it more compact by showing just two lines:

  make: Entering directory '/home/acme/git/perf/tools/perf'
    INSTALL  bpf-headers
    INSTALL  bpf-examples
  make: Leaving directory '/home/acme/git/perf/tools/perf'

Cc: Adrian Hunter 
Cc: David Ahern 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Wang Nan 
Link: https://lkml.kernel.org/n/tip-0nvkyciqdkrgy829lony5925@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf evsel: Fix potential null pointer dereference in perf_evsel__new_idx()

2018-08-30T17:49:25+00:00

If evsel is NULL, we should return NULL to avoid a NULL pointer
dereference a bit later in the code.

Signed-off-by: Hisao Tanabe 
Acked-by: Namhyung Kim 
Cc: Jiri Olsa 
Cc: Wang Nan 
Fixes: 03e0a7df3efd ("perf tools: Introduce bpf-output event")
LPU-Reference: 20180824154556.23428-1-xtanabe@gmail.com
Link: https://lkml.kernel.org/n/tip-e5plzjhx6595a5yjaf22jss3@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf arm64: Fix include path for asm-generic/unistd.h

2018-08-30T17:49:24+00:00

The new syscall table support for arm64 mistakenly used the system's
asm-generic/unistd.h file when processing the
tools/arch/arm64/include/uapi/asm/unistd.h file's include directive:

	#include 

See "Committer notes" section of commit 2b5882435606 "perf arm64:
Generate system call table from asm/unistd.h" for more details.

This patch removes the committer's temporary workaround, and instructs
the host compiler to search the build tree's include path for the right
copy of the unistd.h file, instead of the one on the system's
/usr/include path.

It thus fixes the committer's test that cross-builds an arm64 perf on an
x86 platform running Ubuntu 14.04.5 LTS with an old toolchain:

$ tools/perf/arch/arm64/entry/syscalls/mksyscalltbl /gcc-linaro-5.4.1-2017.05-x86_64_aarch64-linux-gnu/bin/aarch64-linux-gnu-gcc gcc `pwd`/tools tools/arch/arm64/include/uapi/asm/unistd.h | grep bpf
	[280] = "bpf",

Signed-off-by: Kim Phillips 
Cc: Alexander Shishkin 
Cc: Hendrik Brueckner 
Cc: Jiri Olsa 
Cc: Michael Ellerman 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Ravi Bangoria 
Cc: Thomas Richter 
Fixes: 2b5882435606 ("perf arm64: Generate system call table from asm/unistd.h")
Link: http://lkml.kernel.org/r/20180806172800.bbcec3cfcc51e2facc978bf2@arm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf tests: Add breakpoint modify tests

2018-08-30T17:49:22+00:00

Adding to tests that aims on kernel breakpoint modification bugs.

First test creates HW breakpoint, tries to change it and checks it was
properly changed. It aims on kernel issue that prevents HW breakpoint to
be changed via ptrace interface.

The first test forks, the child sets itself as ptrace tracee and waits
in signal for parent to trace it, then it calls bp_1 and quits.

The parent does following steps:

 - creates a new breakpoint (id 0) for bp_2 function
 - changes that breakpoint to bp_1 function
 - waits for the breakpoint to hit and checks
   it has proper rip of bp_1 function

This test aims on an issue in kernel preventing to change disabled
breakpoints

Second test mimics the first one except for few steps
in the parent:
 - creates a new breakpoint (id 0) for bp_1 function
 - changes that breakpoint to bogus (-1) address
 - waits for the breakpoint to hit and checks
   it has proper rip of bp_1 function

This test aims on an issue in kernel disabling enabled
breakpoint after unsuccesful change.

Committer testing:

  # uname -a
  Linux jouet 4.18.0-rc8-00002-g1236568ee3cb #12 SMP Tue Aug 7 14:08:26 -03 2018 x86_64 x86_64 x86_64 GNU/Linux
  # perf test -v "bp modify"
  62: x86 bp modify                                         :
  --- start ---
  test child forked, pid 25671
  in bp_1
  tracee exited prematurely 2
  FAILED arch/x86/tests/bp-modify.c:209 modify test 1 failed

  test child finished with -1
  ---- end ----
  x86 bp modify: FAILED!
  #

Signed-off-by: Jiri Olsa 
Tested-by: Arnaldo Carvalho de Melo 
Cc: Alexander Shishkin 
Cc: David Ahern 
Cc: Milind Chabbi 
Cc: Namhyung Kim 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20180827091228.2878-2-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo

perf annotate: Properly interpret indirect call

2018-08-30T17:49:22+00:00

The patch changes the parsing of:

	callq  *0x8(%rbx)

from:

  0.26 │     → callq  *8

to:

  0.26 │     → callq  *0x8(%rbx)

in this case an address is followed by a register, thus one can't parse
only the address.

Committer testing:

1) run 'perf record sleep 10'
2) before applying the patch, run:

     perf annotate --stdio2 > /tmp/before

3) after applying the patch, run:

     perf annotate --stdio2 > /tmp/after

4) diff /tmp/before /tmp/after:
  --- /tmp/before 2018-08-28 11:16:03.238384143 -0300
  +++ /tmp/after  2018-08-28 11:15:39.335341042 -0300
  @@ -13274,7 +13274,7 @@
                ↓ jle    128
                  hash_value = hash_table->hash_func (key);
                  mov    0x8(%rsp),%rdi
  -  0.91       → callq  *30
  +  0.91       → callq  *0x30(%r12)
                  mov    $0x2,%r8d
                  cmp    $0x2,%eax
                  node_hash = hash_table->hashes[node_index];
  @@ -13848,7 +13848,7 @@
                   mov    %r14,%rdi
                   sub    %rbx,%r13
                   mov    %r13,%rdx
  -              → callq  *38
  +              → callq  *0x38(%r15)
                   cmp    %rax,%r13
     1.91        ↓ je     240
            1b4:   mov    $0xffffffff,%r13d
  @@ -14026,7 +14026,7 @@
                   mov    %rcx,-0x500(%rbp)
                   mov    %r15,%rsi
                   mov    %r14,%rdi
  -              → callq  *38
  +              → callq  *0x38(%rax)
                   mov    -0x500(%rbp),%rcx
                   cmp    %rax,%rcx
                 ↓ jne    9b0


Signed-off-by: Martin Liška 
Tested-by: Arnaldo Carvalho de Melo 
Tested-by: Kim Phillips 
Cc: Jiri Olsa 
Link: http://lkml.kernel.org/r/bd1f3932-be2b-85f9-7582-111ee0a43b07@suse.cz
Signed-off-by: Arnaldo Carvalho de Melo