perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offs

perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offset for global data symbols. This is a common
issue on both x86 and Arm64 platforms.

Let's see an example, for a test program, below is the disassembly for
its .bss section which is dumped with objdump:

...

Disassembly of section .bss:

0000000000004040 <completed.0>:
...

0000000000004080 <buf1>:
...

00000000000040c0 <buf2>:
...

0000000000004100 <thread>:
...

First we used 'perf mem record' to run the test program and then used
'perf --debug verbose=4 mem report' to observe what's the symbol info
for 'buf1' and 'buf2' structures.

# ./perf mem record -e ldlat-loads,ldlat-stores -- false_sharing.exe 8
# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf2 0x30a8-0x30e8
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf1 0x3068-0x30a8
...

The perf tool relies on libelf to parse symbols, in executable and
shared object files, 'st_value' holds a virtual address; 'sh_addr' is
the address at which section's first byte should reside in memory, and
'sh_offset' is the byte offset from the beginning of the file to the
first byte in the section. The perf tool uses below formula to convert
a symbol's memory address to a file address:

file_address = st_value - sh_addr + sh_offset
^
` Memory address

We can see the final adjusted address ranges for buf1 and buf2 are
[0x30a8-0x30e8) and [0x3068-0x30a8) respectively, apparently this is
incorrect, in the code, the structure for 'buf1' and 'buf2' specifies
compiler attribute with 64-byte alignment.

The problem happens for 'sh_offset', libelf returns it as 0x3028 which
is not 64-byte aligned, combining with disassembly, it's likely libelf
doesn't respect the alignment for .bss section, therefore, it doesn't
return the aligned value for 'sh_offset'.

Suggested by Fangrui Song, ELF file contains program header which
contains PT_LOAD segments, the fields p_vaddr and p_offset in PT_LOAD
segments contain the execution info. A better choice for converting
memory address to file address is using the formula:

file_address = st_value - p_vaddr + p_offset

This patch introduces elf_read_program_header() which returns the
program header based on the passed 'st_value', then it uses the formula
above to calculate the symbol file address; and the debugging log is
updated respectively.

After applying the change:

# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf2 0x30c0-0x3100
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf1 0x3080-0x30c0
...

Fixes: f17e04afaff84b5c ("perf report: Fix ELF symbol parsing")
Reported-by: Chang Rui <changruinj@gmail.com>
Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220724060013.171050-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offs

perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offset for global data symbols. This is a common
issue on both x86 and Arm64 platforms.

Let's see an example, for a test program, below is the disassembly for
its .bss section which is dumped with objdump:

...

Disassembly of section .bss:

0000000000004040 <completed.0>:
...

0000000000004080 <buf1>:
...

00000000000040c0 <buf2>:
...

0000000000004100 <thread>:
...

First we used 'perf mem record' to run the test program and then used
'perf --debug verbose=4 mem report' to observe what's the symbol info
for 'buf1' and 'buf2' structures.

# ./perf mem record -e ldlat-loads,ldlat-stores -- false_sharing.exe 8
# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf2 0x30a8-0x30e8
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf1 0x3068-0x30a8
...

The perf tool relies on libelf to parse symbols, in executable and
shared object files, 'st_value' holds a virtual address; 'sh_addr' is
the address at which section's first byte should reside in memory, and
'sh_offset' is the byte offset from the beginning of the file to the
first byte in the section. The perf tool uses below formula to convert
a symbol's memory address to a file address:

file_address = st_value - sh_addr + sh_offset
^
` Memory address

We can see the final adjusted address ranges for buf1 and buf2 are
[0x30a8-0x30e8) and [0x3068-0x30a8) respectively, apparently this is
incorrect, in the code, the structure for 'buf1' and 'buf2' specifies
compiler attribute with 64-byte alignment.

The problem happens for 'sh_offset', libelf returns it as 0x3028 which
is not 64-byte aligned, combining with disassembly, it's likely libelf
doesn't respect the alignment for .bss section, therefore, it doesn't
return the aligned value for 'sh_offset'.

Suggested by Fangrui Song, ELF file contains program header which
contains PT_LOAD segments, the fields p_vaddr and p_offset in PT_LOAD
segments contain the execution info. A better choice for converting
memory address to file address is using the formula:

file_address = st_value - p_vaddr + p_offset

This patch introduces elf_read_program_header() which returns the
program header based on the passed 'st_value', then it uses the formula
above to calculate the symbol file address; and the debugging log is
updated respectively.

After applying the change:

# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf2 0x30c0-0x3100
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf1 0x3080-0x30c0
...

Fixes: f17e04afaff84b5c ("perf report: Fix ELF symbol parsing")
Reported-by: Chang Rui <changruinj@gmail.com>
Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220724060013.171050-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offs

perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offset for global data symbols. This is a common
issue on both x86 and Arm64 platforms.

Let's see an example, for a test program, below is the disassembly for
its .bss section which is dumped with objdump:

...

Disassembly of section .bss:

0000000000004040 <completed.0>:
...

0000000000004080 <buf1>:
...

00000000000040c0 <buf2>:
...

0000000000004100 <thread>:
...

First we used 'perf mem record' to run the test program and then used
'perf --debug verbose=4 mem report' to observe what's the symbol info
for 'buf1' and 'buf2' structures.

# ./perf mem record -e ldlat-loads,ldlat-stores -- false_sharing.exe 8
# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf2 0x30a8-0x30e8
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf1 0x3068-0x30a8
...

The perf tool relies on libelf to parse symbols, in executable and
shared object files, 'st_value' holds a virtual address; 'sh_addr' is
the address at which section's first byte should reside in memory, and
'sh_offset' is the byte offset from the beginning of the file to the
first byte in the section. The perf tool uses below formula to convert
a symbol's memory address to a file address:

file_address = st_value - sh_addr + sh_offset
^
` Memory address

We can see the final adjusted address ranges for buf1 and buf2 are
[0x30a8-0x30e8) and [0x3068-0x30a8) respectively, apparently this is
incorrect, in the code, the structure for 'buf1' and 'buf2' specifies
compiler attribute with 64-byte alignment.

The problem happens for 'sh_offset', libelf returns it as 0x3028 which
is not 64-byte aligned, combining with disassembly, it's likely libelf
doesn't respect the alignment for .bss section, therefore, it doesn't
return the aligned value for 'sh_offset'.

Suggested by Fangrui Song, ELF file contains program header which
contains PT_LOAD segments, the fields p_vaddr and p_offset in PT_LOAD
segments contain the execution info. A better choice for converting
memory address to file address is using the formula:

file_address = st_value - p_vaddr + p_offset

This patch introduces elf_read_program_header() which returns the
program header based on the passed 'st_value', then it uses the formula
above to calculate the symbol file address; and the debugging log is
updated respectively.

After applying the change:

# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf2 0x30c0-0x3100
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf1 0x3080-0x30c0
...

Fixes: f17e04afaff84b5c ("perf report: Fix ELF symbol parsing")
Reported-by: Chang Rui <changruinj@gmail.com>
Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220724060013.171050-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offs

perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offset for global data symbols. This is a common
issue on both x86 and Arm64 platforms.

Let's see an example, for a test program, below is the disassembly for
its .bss section which is dumped with objdump:

...

Disassembly of section .bss:

0000000000004040 <completed.0>:
...

0000000000004080 <buf1>:
...

00000000000040c0 <buf2>:
...

0000000000004100 <thread>:
...

First we used 'perf mem record' to run the test program and then used
'perf --debug verbose=4 mem report' to observe what's the symbol info
for 'buf1' and 'buf2' structures.

# ./perf mem record -e ldlat-loads,ldlat-stores -- false_sharing.exe 8
# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf2 0x30a8-0x30e8
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf1 0x3068-0x30a8
...

The perf tool relies on libelf to parse symbols, in executable and
shared object files, 'st_value' holds a virtual address; 'sh_addr' is
the address at which section's first byte should reside in memory, and
'sh_offset' is the byte offset from the beginning of the file to the
first byte in the section. The perf tool uses below formula to convert
a symbol's memory address to a file address:

file_address = st_value - sh_addr + sh_offset
^
` Memory address

We can see the final adjusted address ranges for buf1 and buf2 are
[0x30a8-0x30e8) and [0x3068-0x30a8) respectively, apparently this is
incorrect, in the code, the structure for 'buf1' and 'buf2' specifies
compiler attribute with 64-byte alignment.

The problem happens for 'sh_offset', libelf returns it as 0x3028 which
is not 64-byte aligned, combining with disassembly, it's likely libelf
doesn't respect the alignment for .bss section, therefore, it doesn't
return the aligned value for 'sh_offset'.

Suggested by Fangrui Song, ELF file contains program header which
contains PT_LOAD segments, the fields p_vaddr and p_offset in PT_LOAD
segments contain the execution info. A better choice for converting
memory address to file address is using the formula:

file_address = st_value - p_vaddr + p_offset

This patch introduces elf_read_program_header() which returns the
program header based on the passed 'st_value', then it uses the formula
above to calculate the symbol file address; and the debugging log is
updated respectively.

After applying the change:

# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf2 0x30c0-0x3100
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf1 0x3080-0x30c0
...

Fixes: f17e04afaff84b5c ("perf report: Fix ELF symbol parsing")
Reported-by: Chang Rui <changruinj@gmail.com>
Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220724060013.171050-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offs

perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offset for global data symbols. This is a common
issue on both x86 and Arm64 platforms.

Let's see an example, for a test program, below is the disassembly for
its .bss section which is dumped with objdump:

...

Disassembly of section .bss:

0000000000004040 <completed.0>:
...

0000000000004080 <buf1>:
...

00000000000040c0 <buf2>:
...

0000000000004100 <thread>:
...

First we used 'perf mem record' to run the test program and then used
'perf --debug verbose=4 mem report' to observe what's the symbol info
for 'buf1' and 'buf2' structures.

# ./perf mem record -e ldlat-loads,ldlat-stores -- false_sharing.exe 8
# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf2 0x30a8-0x30e8
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf1 0x3068-0x30a8
...

The perf tool relies on libelf to parse symbols, in executable and
shared object files, 'st_value' holds a virtual address; 'sh_addr' is
the address at which section's first byte should reside in memory, and
'sh_offset' is the byte offset from the beginning of the file to the
first byte in the section. The perf tool uses below formula to convert
a symbol's memory address to a file address:

file_address = st_value - sh_addr + sh_offset
^
` Memory address

We can see the final adjusted address ranges for buf1 and buf2 are
[0x30a8-0x30e8) and [0x3068-0x30a8) respectively, apparently this is
incorrect, in the code, the structure for 'buf1' and 'buf2' specifies
compiler attribute with 64-byte alignment.

The problem happens for 'sh_offset', libelf returns it as 0x3028 which
is not 64-byte aligned, combining with disassembly, it's likely libelf
doesn't respect the alignment for .bss section, therefore, it doesn't
return the aligned value for 'sh_offset'.

Suggested by Fangrui Song, ELF file contains program header which
contains PT_LOAD segments, the fields p_vaddr and p_offset in PT_LOAD
segments contain the execution info. A better choice for converting
memory address to file address is using the formula:

file_address = st_value - p_vaddr + p_offset

This patch introduces elf_read_program_header() which returns the
program header based on the passed 'st_value', then it uses the formula
above to calculate the symbol file address; and the debugging log is
updated respectively.

After applying the change:

# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf2 0x30c0-0x3100
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf1 0x3080-0x30c0
...

Fixes: f17e04afaff84b5c ("perf report: Fix ELF symbol parsing")
Reported-by: Chang Rui <changruinj@gmail.com>
Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220724060013.171050-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offs

perf symbol: Correct address for bss symbols

[ Upstream commit 2d86612aacb7805f72873691a2644d7279ed0630 ]

When using 'perf mem' and 'perf c2c', an issue is observed that tool
reports the wrong offset for global data symbols. This is a common
issue on both x86 and Arm64 platforms.

Let's see an example, for a test program, below is the disassembly for
its .bss section which is dumped with objdump:

...

Disassembly of section .bss:

0000000000004040 <completed.0>:
...

0000000000004080 <buf1>:
...

00000000000040c0 <buf2>:
...

0000000000004100 <thread>:
...

First we used 'perf mem record' to run the test program and then used
'perf --debug verbose=4 mem report' to observe what's the symbol info
for 'buf1' and 'buf2' structures.

# ./perf mem record -e ldlat-loads,ldlat-stores -- false_sharing.exe 8
# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf2 0x30a8-0x30e8
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 sh_addr: 0x4040 sh_offset: 0x3028
symbol__new: buf1 0x3068-0x30a8
...

The perf tool relies on libelf to parse symbols, in executable and
shared object files, 'st_value' holds a virtual address; 'sh_addr' is
the address at which section's first byte should reside in memory, and
'sh_offset' is the byte offset from the beginning of the file to the
first byte in the section. The perf tool uses below formula to convert
a symbol's memory address to a file address:

file_address = st_value - sh_addr + sh_offset
^
` Memory address

We can see the final adjusted address ranges for buf1 and buf2 are
[0x30a8-0x30e8) and [0x3068-0x30a8) respectively, apparently this is
incorrect, in the code, the structure for 'buf1' and 'buf2' specifies
compiler attribute with 64-byte alignment.

The problem happens for 'sh_offset', libelf returns it as 0x3028 which
is not 64-byte aligned, combining with disassembly, it's likely libelf
doesn't respect the alignment for .bss section, therefore, it doesn't
return the aligned value for 'sh_offset'.

Suggested by Fangrui Song, ELF file contains program header which
contains PT_LOAD segments, the fields p_vaddr and p_offset in PT_LOAD
segments contain the execution info. A better choice for converting
memory address to file address is using the formula:

file_address = st_value - p_vaddr + p_offset

This patch introduces elf_read_program_header() which returns the
program header based on the passed 'st_value', then it uses the formula
above to calculate the symbol file address; and the debugging log is
updated respectively.

After applying the change:

# ./perf --debug verbose=4 mem report
...
dso__load_sym_internal: adjusting symbol: st_value: 0x40c0 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf2 0x30c0-0x3100
...
dso__load_sym_internal: adjusting symbol: st_value: 0x4080 p_vaddr: 0x3d28 p_offset: 0x2d28
symbol__new: buf1 0x3080-0x30c0
...

Fixes: f17e04afaff84b5c ("perf report: Fix ELF symbol parsing")
Reported-by: Chang Rui <changruinj@gmail.com>
Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220724060013.171050-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

perf symbol: Pass is_kallsyms to symbols__fixup_end()

commit 838425f2defe5262906b698752d28fd2fca1aac2 upstream.

The symbol fixup is necessary for symbols in kallsyms since they don't
have size info

perf symbol: Pass is_kallsyms to symbols__fixup_end()

commit 838425f2defe5262906b698752d28fd2fca1aac2 upstream.

The symbol fixup is necessary for symbols in kallsyms since they don't
have size info. So we use the next symbol's address to calculate the
size. Now it's also used for user binaries because sometimes they miss
size for hand-written asm functions.

There's a arch-specific function to handle kallsyms differently but
currently it cannot distinguish kallsyms from others. Pass this
information explicitly to handle it properly. Note that those arch
functions will be moved to the generic function so I didn't added it to
the arch-functions.

Fixes: 3cf6a32f3f2a4594 ("perf symbols: Fix symbol size calculation condition")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-s390@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20220416004048.1514900-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

perf top: Fix overflow in elf_sec__is_text()

ASan reports a heap-buffer-overflow in elf_sec__is_text when using perf-top.

The bug is caused by the fact that secstrs is built from runtime_ss, while

perf top: Fix overflow in elf_sec__is_text()

ASan reports a heap-buffer-overflow in elf_sec__is_text when using perf-top.

The bug is caused by the fact that secstrs is built from runtime_ss, while
shdr is built from syms_ss if shdr.sh_type != SHT_NOBITS. Therefore, they
point to two different ELF files.

This patch renames secstrs to secstrs_run and adds secstrs_sym, so that
the correct secstrs is chosen depending on shdr.sh_type.

$ ASAN_OPTIONS=abort_on_error=1:disable_coredump=0:unmap_shadow_on_exit=1 ./perf top
=================================================================
==363148==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x61300009add6 at pc 0x00000049875c bp 0x7f4f56446440 sp 0x7f4f56445bf0
READ of size 1 at 0x61300009add6 thread T6
#0 0x49875b in StrstrCheck(void*, char*, char const*, char const*) (/home/user/linux/tools/perf/perf+0x49875b)
#1 0x4d13a2 in strstr (/home/user/linux/tools/perf/perf+0x4d13a2)
#2 0xacae36 in elf_sec__is_text /home/user/linux/tools/perf/util/symbol-elf.c:176:9
#3 0xac3ec9 in elf_sec__filter /home/user/linux/tools/perf/util/symbol-elf.c:187:9
#4 0xac2c3d in dso__load_sym /home/user/linux/tools/perf/util/symbol-elf.c:1254:20
#5 0x883981 in dso__load /home/user/linux/tools/perf/util/symbol.c:1897:9
#6 0x8e6248 in map__load /home/user/linux/tools/perf/util/map.c:332:7
#7 0x8e66e5 in map__find_symbol /home/user/linux/tools/perf/util/map.c:366:6
#8 0x7f8278 in machine__resolve /home/user/linux/tools/perf/util/event.c:707:13
#9 0x5f3d1a in perf_event__process_sample /home/user/linux/tools/perf/builtin-top.c:773:6
#10 0x5f30e4 in deliver_event /home/user/linux/tools/perf/builtin-top.c:1197:3
#11 0x908a72 in do_flush /home/user/linux/tools/perf/util/ordered-events.c:244:9
#12 0x905fae in __ordered_events__flush /home/user/linux/tools/perf/util/ordered-events.c:323:8
#13 0x9058db in ordered_events__flush /home/user/linux/tools/perf/util/ordered-events.c:341:9
#14 0x5f19b1 in process_thread /home/user/linux/tools/perf/builtin-top.c:1109:7
#15 0x7f4f6a21a298 in start_thread /usr/src/debug/glibc-2.33-16.fc34.x86_64/nptl/pthread_create.c:481:8
#16 0x7f4f697d0352 in clone ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

0x61300009add6 is located 10 bytes to the right of 332-byte region [0x61300009ac80,0x61300009adcc)
allocated by thread T6 here:

#0 0x4f3f7f in malloc (/home/user/linux/tools/perf/perf+0x4f3f7f)
#1 0x7f4f6a0a88d9 (/lib64/libelf.so.1+0xa8d9)

Thread T6 created by T0 here:

#0 0x464856 in pthread_create (/home/user/linux/tools/perf/perf+0x464856)
#1 0x5f06e0 in __cmd_top /home/user/linux/tools/perf/builtin-top.c:1309:6
#2 0x5ef19f in cmd_top /home/user/linux/tools/perf/builtin-top.c:1762:11
#3 0x7b28c0 in run_builtin /home/user/linux/tools/perf/perf.c:313:11
#4 0x7b119f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8
#5 0x7b2423 in run_argv /home/user/linux/tools/perf/perf.c:409:2
#6 0x7b0c19 in main /home/user/linux/tools/perf/perf.c:539:3
#7 0x7f4f696f7b74 in __libc_start_main /usr/src/debug/glibc-2.33-16.fc34.x86_64/csu/../csu/libc-start.c:332:16

SUMMARY: AddressSanitizer: heap-buffer-overflow (/home/user/linux/tools/perf/perf+0x49875b) in StrstrCheck(void*, char*, char const*, char const*)
Shadow bytes around the buggy address:
0x0c268000b560: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c268000b570: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c268000b580: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c268000b590: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c268000b5a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c268000b5b0: 00 00 00 00 00 00 00 00 00 04[fa]fa fa fa fa fa
0x0c268000b5c0: fa fa fa fa fa fa fa fa 00 00 00 00 00 00 00 00
0x0c268000b5d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c268000b5e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c268000b5f0: 07 fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c268000b600: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
Shadow gap: cc
==363148==ABORTING

Suggested-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Fabian Hemmer <copy@copy.sh>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Remi Bernon <rbernon@codeweavers.com>
Link: http://lore.kernel.org/lkml/20210621222108.196219-1-rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf symbol-elf: Decode dynsym even if symtab exists

In Fedora34, libc-2.33.so has both .dynsym and .symtab sections and
most of (not all) symbols moved to .dynsym. In this case, perf only
decode th

perf symbol-elf: Decode dynsym even if symtab exists

In Fedora34, libc-2.33.so has both .dynsym and .symtab sections and
most of (not all) symbols moved to .dynsym. In this case, perf only
decode the symbols in .symtab, and perf probe can not list up the
functions in the library.

To fix this issue, decode both .symtab and .dynsym sections.

Without this fix,
-----
$ ./perf probe -x /usr/lib64/libc-2.33.so -F
@plt
@plt
calloc@plt
free@plt
malloc@plt
memalign@plt
realloc@plt
-----

With this fix.

-----
$ ./perf probe -x /usr/lib64/libc-2.33.so -F
@plt
@plt
a64l
abort
abs
accept
accept4
access
acct
addmntent
-----

Reported-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Stefan Liebler <stli@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Link: http://lore.kernel.org/lkml/162532652681.393143.10163733179955267999.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf symbol-elf: Fix memory leak by freeing sdt_note.args

Reported by ASan.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <a

perf symbol-elf: Fix memory leak by freeing sdt_note.args

Reported by ASan.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Fabian Hemmer <copy@copy.sh>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Remi Bernon <rbernon@codeweavers.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Link: http://lore.kernel.org/lkml/20210602220833.285226-1-rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf tools: Fix various typos in comments

Fix ~124 single-word typos and a few spelling errors in the perf tooling code,
accumulated over the years.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc

perf tools: Fix various typos in comments

Fix ~124 single-word typos and a few spelling errors in the perf tooling code,
accumulated over the years.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210321113734.GA248990@gmail.com
Link: http://lore.kernel.org/lkml/20210323160915.GA61903@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf tools: Add OCaml demangling

Detect symbols generated by the OCaml compiler based on their prefix.

Demangle OCaml symbols, returning a newly allocated string (like the
existing Java demangling

perf tools: Add OCaml demangling

Detect symbols generated by the OCaml compiler based on their prefix.

Demangle OCaml symbols, returning a newly allocated string (like the
existing Java demangling functionality).

Move a helper function (hex) from tests/code-reading.c to util/string.c

To test:

echo 'Printf.printf "%d\n" (Random.int 42)' > test.ml
perf record ocamlopt.opt test.ml
perf report -d ocamlopt.opt

Signed-off-by: Fabian Hemmer <copy@copy.sh>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LPU-Reference: 20210203211537.b25ytjb6dq5jfbwx@nyu
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf symbols: Resolve symbols against debug file first

With LTO, there are symbols like these:

/usr/lib/debug/usr/lib64/libantlr4-runtime.so.4.8-4.8-1.4.x86_64.debug
10305: 0000000000955fa4 0

perf symbols: Resolve symbols against debug file first

With LTO, there are symbols like these:

/usr/lib/debug/usr/lib64/libantlr4-runtime.so.4.8-4.8-1.4.x86_64.debug
10305: 0000000000955fa4 0 NOTYPE LOCAL DEFAULT 29 Predicate.cpp.2bc410e7

This comes from a runtime/debug split done by the standard way:

objcopy --only-keep-debug $runtime $debug
objcopy --add-gnu-debuglink=$debugfn -R .comment -R .GCC.command.line --strip-all $runtime

perf currently cannot resolve such symbols (relicts of LTO), as section
29 exists only in the debug file (29 is .debug_info). And perf resolves
symbols only against runtime file. This results in all symbols from such
a library being unresolved:

0.38% main2 libantlr4-runtime.so.4.8 [.] 0x00000000000671e0

So try resolving against the debug file first. And only if it fails (the
section has NOBITS set), try runtime file. We can do this, as "objcopy
--only-keep-debug" per documentation preserves all sections, but clears
data of some of them (the runtime ones) and marks them as NOBITS.

The correct result is now:
0.38% main2 libantlr4-runtime.so.4.8 [.] antlr4::IntStream::~IntStream

Note that these LTO symbols are properly skipped anyway as they belong
neither to *text* nor to *data* (is_label && !elf_sec__filter(&shdr,
secstrs) is true).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210217122125.26416-1-jslaby@suse.cz
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf tools: Add support to read build id from compressed elf

Adding support to decompress file before reading build id.

Adding filename__read_build_id and change its current versions to
read_build_

perf tools: Add support to read build id from compressed elf

Adding support to decompress file before reading build id.

Adding filename__read_build_id and change its current versions to
read_build_id.

Shutting down stderr output of perf list in the shell test:
82: Check open filename arg using perf trace + vfs_getname : Ok

because with decompression code in the place we the
filename__read_build_id function is more verbose in case
of error and the test did not account for that.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Budankov <abudankov@huawei.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20201214105457.543111-7-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf symbol-elf: Fix memory leak by freeing sdt_note.args

commit 69c9ffed6cede9c11697861f654946e3ae95a930 upstream.

Reported by ASan.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Acked-by

perf symbol-elf: Fix memory leak by freeing sdt_note.args

commit 69c9ffed6cede9c11697861f654946e3ae95a930 upstream.

Reported by ASan.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Fabian Hemmer <copy@copy.sh>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Remi Bernon <rbernon@codeweavers.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Link: http://lore.kernel.org/lkml/20210602220833.285226-1-rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

perf tools: Pass build_id object to dso__build_id_equal()

Passing build_id object to dso__build_id_equal(), so we can properly
check build id with different size than sha1.

Signed-off-by: Jiri Olsa

perf tools: Pass build_id object to dso__build_id_equal()

Passing build_id object to dso__build_id_equal(), so we can properly
check build id with different size than sha1.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20201013192441.1299447-7-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf tools: Pass build id object to sysfs__read_build_id()

Passing build id object to sysfs__read_build_id function, so it can
populate the size of the build_id object.

Signed-off-by: Jiri Olsa <jo

perf tools: Pass build id object to sysfs__read_build_id()

Passing build id object to sysfs__read_build_id function, so it can
populate the size of the build_id object.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20201013192441.1299447-4-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf tools: Pass build_id object to filename__read_build_id()

Pass a build_id object to filename__read_build_id function, so it can
populate the size of the build_id object.

Changing filename__read

perf tools: Pass build_id object to filename__read_build_id()

Pass a build_id object to filename__read_build_id function, so it can
populate the size of the build_id object.

Changing filename__read_build_id() code for both ELF/non-ELF code.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20201013192441.1299447-3-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf dso: Use libbfd to read build_id and .gnu_debuglink section

Wine generates PE binaries for most of its modules and perf is unable to
parse these files to get build_id or .gnu_debuglink section.

perf dso: Use libbfd to read build_id and .gnu_debuglink section

Wine generates PE binaries for most of its modules and perf is unable to
parse these files to get build_id or .gnu_debuglink section.

Using libbfd when available, instead of libelf, makes it possible to
resolve debug file location regardless of the dso binary format.

Committer notes:

Made the filename__read_build_id() variant that uses abfd->build_id
depend on the feature test that defines HAVE_LIBBFD_BUILDID_SUPPORT, to
get this to continue building with older libbfd/binutils.

Signed-off-by: Remi Bernon <rbernon@codeweavers.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jacek Caban <jacek@codeweavers.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200821165238.1340315-1-rbernon@codeweavers.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf tools: Fix module symbol processing

The 'dso->kernel' condition is true also for kernel modules now,
and there are several places that were omited by the initial change:

- we need to identif

perf tools: Fix module symbol processing

The 'dso->kernel' condition is true also for kernel modules now,
and there are several places that were omited by the initial change:

- we need to identify modules separately in dso__process_kernel_symbol
- we need to set 'dso->kernel' for module from buildid table
- there's no need to use 'dso->kernel || kmodule' in one condition

Committer testing:

Before:

# perf test -v object
<SNIP>
Objdump command is: objdump -z -d --start-address=0xffffffff813e682f --stop-address=0xffffffff813e68af /usr/lib/debug/lib/modules/5.7.14-200.fc32.x86_64/vmlinux
Bytes read match those read by objdump
Reading object code for memory address: 0xffffffffc02dc257
File is: /lib/modules/5.7.14-200.fc32.x86_64/kernel/arch/x86/crypto/crc32c-intel.ko.xz
On file address is: 0xffffffffc02dc2e7
dso__data_read_offset failed
test child finished with -1
---- end ----
Object code reading: FAILED!
#

After:

# perf test object
26: Object code reading : Ok
# perf test object
26: Object code reading : Ok
# perf test object
26: Object code reading : Ok
# perf test object
26: Object code reading : Ok
# perf test object
26: Object code reading : Ok
#

Fixes: 02213cec64bb ("perf maps: Mark module DSOs with kernel type")
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>

show more ...

perf tools: Rename 'enum dso_kernel_type' to 'enum dso_space_type'

Rename enum dso_kernel_type to enum dso_space_type, which seems like
better fit.

Committer notes:

This is used with 'struct dso'-

perf tools: Rename 'enum dso_kernel_type' to 'enum dso_space_type'

Rename enum dso_kernel_type to enum dso_space_type, which seems like
better fit.

Committer notes:

This is used with 'struct dso'->kernel, which once was a boolean, so
DSO_SPACE__USER is zero, !zero means some sort of kernel space, be it
the host kernel space or a guest kernel space.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...

perf kcore_copy: Fix module map when there are no modules loaded

In the absence of any modules, no "modules" map is created, but there
are other executable pages to map, due to eBPF JIT, kprobe or f

perf kcore_copy: Fix module map when there are no modules loaded

In the absence of any modules, no "modules" map is created, but there
are other executable pages to map, due to eBPF JIT, kprobe or ftrace.
Map them by recognizing that the first "module" symbol is not
necessarily from a module, and adjust the map accordingly.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: x86@kernel.org
Link: http://lore.kernel.org/lkml/20200512121922.8997-10-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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perf symbols: Consolidate symbol fixup issue

After copying Arm64's perf archive with object files and perf.data file
to x86 laptop, the x86's perf kernel symbol resolution fails. It
outputs 'unknow

perf symbols: Consolidate symbol fixup issue

After copying Arm64's perf archive with object files and perf.data file
to x86 laptop, the x86's perf kernel symbol resolution fails. It
outputs 'unknown' for all symbols parsing.

This issue is root caused by the function elf__needs_adjust_symbols(),
x86 perf tool uses one weak version, Arm64 (and powerpc) has rewritten
their own version. elf__needs_adjust_symbols() decides if need to parse
symbols with the relative offset address; but x86 building uses the weak
function which misses to check for the elf type 'ET_DYN', so that it
cannot parse symbols in Arm DSOs due to the wrong result from
elf__needs_adjust_symbols().

The DSO parsing should not depend on any specific architecture perf
building; e.g. x86 perf tool can parse Arm and Arm64 DSOs, vice versa.
And confirmed by Naveen N. Rao that powerpc64 kernels are not being
built as ET_DYN anymore and change to ET_EXEC.

This patch removes the arch specific functions for Arm64 and powerpc and
changes elf__needs_adjust_symbols() as a common function.

In the common elf__needs_adjust_symbols(), it checks an extra condition
'ET_DYN' for elf header type. With this fixing, the Arm64 DSO can be
parsed properly with x86's perf tool.

Before:

# perf script
main 3258 1 branches: 0 [unknown] ([unknown]) => ffff800010c4665c [unknown] ([kernel.kallsyms])
main 3258 1 branches: ffff800010c46670 [unknown] ([kernel.kallsyms]) => ffff800010c4eaec [unknown] ([kernel.kallsyms])
main 3258 1 branches: ffff800010c4eaec [unknown] ([kernel.kallsyms]) => ffff800010c4eb00 [unknown] ([kernel.kallsyms])
main 3258 1 branches: ffff800010c4eb08 [unknown] ([kernel.kallsyms]) => ffff800010c4e780 [unknown] ([kernel.kallsyms])
main 3258 1 branches: ffff800010c4e7a0 [unknown] ([kernel.kallsyms]) => ffff800010c4eeac [unknown] ([kernel.kallsyms])
main 3258 1 branches: ffff800010c4eebc [unknown] ([kernel.kallsyms]) => ffff800010c4ed80 [unknown] ([kernel.kallsyms])

After:

# perf script
main 3258 1 branches: 0 [unknown] ([unknown]) => ffff800010c4665c coresight_timeout+0x54 ([kernel.kallsyms])
main 3258 1 branches: ffff800010c46670 coresight_timeout+0x68 ([kernel.kallsyms]) => ffff800010c4eaec etm4_enable_hw+0x3cc ([kernel.kallsyms])
main 3258 1 branches: ffff800010c4eaec etm4_enable_hw+0x3cc ([kernel.kallsyms]) => ffff800010c4eb00 etm4_enable_hw+0x3e0 ([kernel.kallsyms])
main 3258 1 branches: ffff800010c4eb08 etm4_enable_hw+0x3e8 ([kernel.kallsyms]) => ffff800010c4e780 etm4_enable_hw+0x60 ([kernel.kallsyms])
main 3258 1 branches: ffff800010c4e7a0 etm4_enable_hw+0x80 ([kernel.kallsyms]) => ffff800010c4eeac etm4_enable+0x2d4 ([kernel.kallsyms])
main 3258 1 branches: ffff800010c4eebc etm4_enable+0x2e4 ([kernel.kallsyms]) => ffff800010c4ed80 etm4_enable+0x1a8 ([kernel.kallsyms])

v3: Changed to check for ET_DYN across all architectures.

v2: Fixed Arm64 and powerpc native building.

Reported-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Enrico Weigelt <info@metux.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.vnet.ibm.com>
Link: http://lore.kernel.org/lkml/20200306015759.10084-1-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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perf map: Set kmap->kmaps backpointer for main kernel map chunks

When a map is create to represent the main kernel area (vmlinux) with
map__new2() we allocate an extra area to store a pointer to the

perf map: Set kmap->kmaps backpointer for main kernel map chunks

When a map is create to represent the main kernel area (vmlinux) with
map__new2() we allocate an extra area to store a pointer to the 'struct
maps' for the kernel maps, so that we can access that struct when
loading ELF files or kallsyms, as we will need to split it in multiple
maps, one per kernel module or ELF section (such as ".init.text").

So when map->dso->kernel is non-zero, it is expected that
map__kmap(map)->kmaps to be set to the tree of kernel maps (modules,
chunks of the main kernel, bpf progs put in place via
PERF_RECORD_KSYMBOL, the main kernel).

This was not the case when we were splitting the main kernel into chunks
for its ELF sections, which ended up making 'perf report --children'
processing a perf.data file with callchains to trip on
__map__is_kernel(), when we press ENTER to see the popup menu for main
histogram entries that starts at a symbol in the ".init.text" ELF
section, e.g.:

- 8.83% 0.00% swapper [kernel.vmlinux].init.text [k] start_kernel
start_kernel
cpu_startup_entry
do_idle
cpuidle_enter
cpuidle_enter_state
intel_idle

Fix it.

Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/lkml/20191218190120.GB13282@kernel.org/
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

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perf maps: Rename map_groups.h to maps.h

One more step in the merge of 'struct maps' with 'struct map_groups'.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ji

perf maps: Rename map_groups.h to maps.h

One more step in the merge of 'struct maps' with 'struct map_groups'.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-9ibtn3vua76f934t7woyf26w@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

show more ...