It's confusing both pointers and arrays are printed as *. Let's print
array types with [] so that we can identify them easily. Although it's
interchangable, sometimes it can cause confusion with size like in the
below example.
Note that it is not the same with C syntax where it goes to the variable
names, but we want to have it in the type names (like in Go language).
Before:
mov [20] 0x68(reg5) -> reg0 type='struct page**' size=0x80 (die:0x4e61d32)
After:
mov [20] 0x68(reg5) -> reg0 type='struct page*[]' size=0x80 (die:0x4e61d32)
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240507041338.2081775-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In match_var_offset(), it just checked the end address of the variable
with the given offset because it assumed the register holds a pointer
to the data type and the offset starts from the base.
But I found some cases that the stack pointer (rsp = reg7) register is
used to pointer a stack variable while the frame base is maintained by a
different register (rbp = reg6). In that case, it cannot simply use the
stack pointer as it cannot guarantee that it points to the frame base.
So it needs to check both boundaries of the variable location.
Before:
-----------------------------------------------------------
find data type for 0x7c(reg7) at tcp_getsockopt+0xb62
CU for net/ipv4/tcp.c (die:0x7b5f516)
frame base: cfa=0 fbreg=6
no pointer or no type
check variable "tss" failed (die: 0x7b95801)
variable location: base reg7, offset=0x110
type='struct scm_timestamping_internal' size=0x30 (die:0x7b8c126)
So the current code just checks register number for the non-PC and
non-FB registers and assuming it has offset 0. But this variable has
offset 0x110 so it should not match to this.
After:
-----------------------------------------------------------
find data type for 0x7c(reg7) at tcp_getsockopt+0xb62
CU for net/ipv4/tcp.c (die:0x7b5f516)
frame base: cfa=0 fbreg=6
no pointer or no type
check variable "zc" failed (die: 0x7b9580a)
variable location: base=reg7, offset=0x40
type='struct tcp_zerocopy_receive' size=0x40 (die:7b947f4)
Now it find the correct variable "zc". It was located at reg7 + 0x40
and the size if 0x40 which means it should cover [0x40, 0x80). And the
access was for reg7 + 0x7c so it found the right one. But it still
failed to use the variable and it would be handled in the next patch.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240412183310.2518474-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In match_var_offset(), it checks the offset range with the target type
only for non-pointer types. But it also needs to check the pointer
types with the target type.
This is because there can be more than one pointer variable located in
the same register. Let's look at the following example. It's looking
up a variable for reg3 at tcp_get_info+0x62. It found "sk" variable but
it wasn't the right one since it accesses beyond the target type (struct
'sock' in this case) size.
-----------------------------------------------------------
find data type for 0x7bc(reg3) at tcp_get_info+0x62
CU for net/ipv4/tcp.c (die:0x7b5f516)
frame base: cfa=0 fbreg=6
offset: 1980 is bigger than size: 760
check variable "sk" failed (die: 0x7b92b2c)
variable location: reg3
type='struct sock' size=0x2f8 (die:0x7b63c3a)
Actually there was another variable "tp" in the function and it's
located at the same (reg3) because it's just type-casted like below.
void tcp_get_info(struct sock *sk, struct tcp_info *info)
{
const struct tcp_sock *tp = tcp_sk(sk);
...
The 'struct tcp_sock' contains the 'struct sock' at offset 0 so it can
just use the same address as a pointer to tcp_sock. That means it
should match variables correctly by checking the offset and size.
Actually it cannot distinguish if the offset was smaller than the size
of the original struct sock. But I think it's fine as they are the same
at that part.
So let's check the target type size and retry if it doesn't match.
Now it succeeded to find the correct variable.
-----------------------------------------------------------
find data type for 0x7bc(reg3) at tcp_get_info+0x62
CU for net/ipv4/tcp.c (die:0x7b5f516)
frame base: cfa=0 fbreg=6
found "tp" in scope=1/1 (die: 0x7b92b16) type_offset=0x7bc
variable location: reg3
type='struct tcp_sock' size=0xa68 (die:0x7b81380)
Fixes: bc10db8eb8 ("perf annotate-data: Support stack variables")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240412183310.2518474-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
We want to track type states as instructions are executed. Each
instruction can access compound types like struct or union and load/
store its members to a different location.
The die_deref_ptr_type() is to find a type of memory access with a
pointer variable. If it points to a compound type like struct, the
target memory is a member in the struct. The access will happen with an
offset indicating which member it refers. Let's follow the DWARF info
to figure out the type of the pointer target.
For example, say we have the following code.
struct foo {
int a;
int b;
};
struct foo *p = malloc(sizeof(*p));
p->b = 0;
The last pointer access should produce x86 asm like below:
mov 0x0, 4(%rbx)
And we know %rbx register has a pointer to struct foo. Then offset 4
should return the debug info of member 'b'.
Also variables of compound types can be accessed directly without a
pointer. The die_get_member_type() is to handle a such case.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240319055115.4063940-4-namhyung@kernel.org
[ Check if die_get_real_type() returned NULL ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The DWARF location expression can be fairly complex and it'd be hard
to match it with the condition correctly. So let's be conservative
and only allow simple expressions. For now it just checks the first
operation in the list. The following operations looks ok:
* DW_OP_stack_value
* DW_OP_deref_size
* DW_OP_deref
* DW_OP_piece
To refuse complex (and unsupported) location expressions, add
check_allowed_ops() to compare the rest of the list. It seems earlier
result contained those unsupported expressions. For example, I found
some local struct variable is placed like below.
<2><43d1517>: Abbrev Number: 62 (DW_TAG_variable)
<43d1518> DW_AT_location : 15 byte block: 91 50 93 8 91 78 93 4 93 84 8 91 68 93 4
(DW_OP_fbreg: -48; DW_OP_piece: 8;
DW_OP_fbreg: -8; DW_OP_piece: 4;
DW_OP_piece: 1028;
DW_OP_fbreg: -24; DW_OP_piece: 4)
Another example is something like this.
0057c8be ffffffffffffffff ffffffff812109f0 (base address)
0057c8ce ffffffff812112b5 ffffffff812112c8 (DW_OP_breg3 (rbx): 0;
DW_OP_constu: 18446744073709551612;
DW_OP_and;
DW_OP_stack_value)
It should refuse them. After the change, the stat shows:
Annotate data type stats:
total 294, ok 158 (53.7%), bad 136 (46.3%)
-----------------------------------------------------------
30 : no_sym
32 : no_mem_ops
53 : no_var
14 : no_typeinfo
7 : bad_offset
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240117062657.985479-10-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Local variables are allocated in the stack and the location list
should look like base register(s) and an offset. Extend the
die_find_variable_by_reg() to handle the following expressions
* DW_OP_breg{0..31}
* DW_OP_bregx
* DW_OP_fbreg
Ususally DWARF subprogram entries have frame base information and
use it to locate stack variable like below:
<2><43d1575>: Abbrev Number: 62 (DW_TAG_variable)
<43d1576> DW_AT_location : 2 byte block: 91 7c (DW_OP_fbreg: -4) <--- here
<43d1579> DW_AT_name : (indirect string, offset: 0x2c00c9): i
<43d157d> DW_AT_decl_file : 1
<43d157e> DW_AT_decl_line : 78
<43d157f> DW_AT_type : <0x43d19d7>
I found some differences on saving the frame base between gcc and clang.
The gcc uses the CFA to get the base so it needs to check the current
frame's CFI info. In this case, stack offset needs to be adjusted from
the start of the CFA.
<1><1bb8d>: Abbrev Number: 102 (DW_TAG_subprogram)
<1bb8e> DW_AT_name : (indirect string, offset: 0x74d41): kernel_init
<1bb92> DW_AT_decl_file : 2
<1bb92> DW_AT_decl_line : 1440
<1bb94> DW_AT_decl_column : 18
<1bb95> DW_AT_prototyped : 1
<1bb95> DW_AT_type : <0xcc>
<1bb99> DW_AT_low_pc : 0xffffffff81bab9e0
<1bba1> DW_AT_high_pc : 0x1b2
<1bba9> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa) <------ here
<1bbab> DW_AT_call_all_calls: 1
<1bbab> DW_AT_sibling : <0x1bf5a>
While clang sets it to a register directly and it can check the register
and offset in the instruction directly.
<1><43d1542>: Abbrev Number: 60 (DW_TAG_subprogram)
<43d1543> DW_AT_low_pc : 0xffffffff816a7c60
<43d154b> DW_AT_high_pc : 0x98
<43d154f> DW_AT_frame_base : 1 byte block: 56 (DW_OP_reg6 (rbp)) <---------- here
<43d1551> DW_AT_GNU_all_call_sites: 1
<43d1551> DW_AT_name : (indirect string, offset: 0x3bce91): foo
<43d1555> DW_AT_decl_file : 1
<43d1556> DW_AT_decl_line : 75
<43d1557> DW_AT_prototyped : 1
<43d1557> DW_AT_type : <0x43c7332>
<43d155b> DW_AT_external : 1
Also it needs to update the offset after finding the type like global
variables since the offset was from the frame base. Factor out
match_var_offset() to check global and local variables in the same way.
The type stats are improved too:
Annotate data type stats:
total 294, ok 160 (54.4%), bad 134 (45.6%)
-----------------------------------------------------------
30 : no_sym
32 : no_mem_ops
51 : no_var
14 : no_typeinfo
7 : bad_offset
Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20240117062657.985479-9-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
The die_get_typename() is to return a C-like type name from DWARF debug
entry and it follows data type if the target entry is a pointer type.
But I found that void pointers don't have the type attribute to follow
and then the function returns an error for that case. This results in a
broken type string for void pointer types.
For example, the following type entries are pointer types.
<1><48c>: Abbrev Number: 4 (DW_TAG_pointer_type)
<48d> DW_AT_byte_size : 8
<48d> DW_AT_type : <0x481>
<1><491>: Abbrev Number: 211 (DW_TAG_pointer_type)
<493> DW_AT_byte_size : 8
<1><494>: Abbrev Number: 4 (DW_TAG_pointer_type)
<495> DW_AT_byte_size : 8
<495> DW_AT_type : <0x49e>
The first one at offset 48c and the third one at offset 494 have type
information. Then they are pointer types for the referenced types. But
the second one at offset 491 doesn't have the type attribute.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: linux-toolchains@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Link: https://lore.kernel.org/r/20231110000012.3538610-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
After switching from dwarf_decl_file() to die_get_decl_file(), it is not
possible to add probes for certain functions:
$ perf probe -x /usr/lib/systemd/systemd-logind match_unit_removed
A function DIE doesn't have decl_line. Maybe broken DWARF?
A function DIE doesn't have decl_line. Maybe broken DWARF?
Probe point 'match_unit_removed' not found.
Error: Failed to add events.
The problem is that die_get_decl_file() uses the wrong CU to search for
the file. elfutils commit e1db5cdc9f has some good explanation for this:
dwarf_decl_file uses dwarf_attr_integrate to get the DW_AT_decl_file
attribute. This means the attribute might come from a different DIE
in a different CU. If so, we need to use the CU associated with the
attribute, not the original DIE, to resolve the file name.
This patch uses the same source of information as elfutils: use attribute
DW_AT_decl_file and use this CU to search for the file.
Fixes: dc9a5d2ccd ("perf probe: Fix to get declared file name from clang DWARF5")
Signed-off-by: Georg Müller <georgmueller@gmx.net>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
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: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: regressions@lists.linux.dev
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230628084551.1860532-6-georgmueller@gmx.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix to get the declared file name even if it uses file index 0
in DWARF5, using custom die_get_decl_file() function.
Actually, the DWARF5 standard says file index 0 of the DW_AT_decl_file
is invalid(1), but there is a discussion and maybe this will be updated
[2].
Anyway, clang generates such DWARF5 file for the linux kernel. Thus it
must be handled.
Without this, 'perf probe' returns an error:
$ ./perf probe -k $BIN_PATH/vmlinux -s $SRC_PATH -L vfs_read:10
Debuginfo analysis failed.
Error: Failed to show lines.
With this, it can handle the case correctly:
$ ./perf probe -k $BIN_PATH/vmlinux -s $SRC_PATH -L vfs_read:10
<vfs_read@$SRC_PATH/fs/read_write.c:10>
11 ret = rw_verify_area(READ, file, pos, count);
12 if (ret)
return ret;
[1] DWARF5 specification 2.14 says "The value 0 indicates that no source file has been specified.")
[2] http://wiki.dwarfstd.org/index.php?title=DWARF5_Line_Table_File_Numbers)
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.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>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/166731052936.2100653.13380621874859467731.stgit@devnote3
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since clang generates DWARF5 which sets DW_AT_decl_file as 0,
dwarf_decl_file() thinks that is invalid and returns NULL. In that case
'perf probe' SIGSEGVs because it doesn't expect a NULL decl_file.
This adds a dwarf_decl_file() return value check to avoid such SEGV with
clang generated DWARF5 info.
Without this, 'perf probe' crashes:
$ perf probe -k $BIN_PATH/vmlinux -s $SRC_PATH -L vfs_read:10
Segmentation fault
$
With this, it just warns about it:
$ perf probe -k $BIN_PATH/vmlinux -s $SRC_PATH -L vfs_read:10
Debuginfo analysis failed.
Error: Failed to show lines.
$
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.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>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/166731051077.2100653.15626653369345128302.stgit@devnote3
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The "address" member of "struct probe_trace_point" uses long data type.
If kernel is 64-bit and perf program is 32-bit, size of "address"
variable is 32 bits.
As a result, upper 32 bits of address read from kernel are truncated, an
error occurs during address comparison in kprobe_warn_out_range().
Before:
# perf probe -a schedule
schedule is out of .text, skip it.
Error: Failed to add events.
Solution:
Change data type of "address" variable to u64 and change corresponding
address printing and value assignment.
After:
# perf.new.new probe -a schedule
Added new event:
probe:schedule (on schedule)
You can now use it in all perf tools, such as:
perf record -e probe:schedule -aR sleep 1
# perf probe -l
probe:schedule (on schedule@kernel/sched/core.c)
# perf record -e probe:schedule -aR sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.156 MB perf.data (1366 samples) ]
# perf report --stdio
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 1K of event 'probe:schedule'
# Event count (approx.): 1366
#
# Overhead Command Shared Object Symbol
# ........ ............... ................. ............
#
6.22% migration/0 [kernel.kallsyms] [k] schedule
6.22% migration/1 [kernel.kallsyms] [k] schedule
6.22% migration/2 [kernel.kallsyms] [k] schedule
6.22% migration/3 [kernel.kallsyms] [k] schedule
6.15% migration/10 [kernel.kallsyms] [k] schedule
6.15% migration/11 [kernel.kallsyms] [k] schedule
6.15% migration/12 [kernel.kallsyms] [k] schedule
6.15% migration/13 [kernel.kallsyms] [k] schedule
6.15% migration/14 [kernel.kallsyms] [k] schedule
6.15% migration/15 [kernel.kallsyms] [k] schedule
6.15% migration/4 [kernel.kallsyms] [k] schedule
6.15% migration/5 [kernel.kallsyms] [k] schedule
6.15% migration/6 [kernel.kallsyms] [k] schedule
6.15% migration/7 [kernel.kallsyms] [k] schedule
6.15% migration/8 [kernel.kallsyms] [k] schedule
6.15% migration/9 [kernel.kallsyms] [k] schedule
0.22% rcu_sched [kernel.kallsyms] [k] schedule
...
#
# (Cannot load tips.txt file, please install perf!)
#
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jianlin Lv <jianlin.lv@arm.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Li Huafei <lihuafei1@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Link: http://lore.kernel.org/lkml/20210715063723.11926-1-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
If we just check whether the variable can be converted, 'tvar' should be
a null pointer. However, the null pointer check is missing in the
'Constant value' execution path.
The following cases can trigger this problem:
$ cat test.c
#include <stdio.h>
void main(void)
{
int a;
const int b = 1;
asm volatile("mov %1, %0" : "=r"(a): "i"(b));
printf("a: %d\n", a);
}
$ gcc test.c -o test -O -g
$ sudo ./perf probe -x ./test -L "main"
<main@/home/lhf/test.c:0>
0 void main(void)
{
2 int a;
const int b = 1;
asm volatile("mov %1, %0" : "=r"(a): "i"(b));
6 printf("a: %d\n", a);
}
$ sudo ./perf probe -x ./test -V "main:6"
Segmentation fault
The check on 'tvar' is added. If 'tavr' is a null pointer, we return 0
to indicate that the variable can be converted. Now, we can successfully
show the variables that can be accessed.
$ sudo ./perf probe -x ./test -V "main:6"
Available variables at main:6
@<main+13>
char* __fmt
int a
int b
However, the variable 'b' cannot be tracked.
$ sudo ./perf probe -x ./test -D "main:6 b"
Failed to find the location of the 'b' variable at this address.
Perhaps it has been optimized out.
Use -V with the --range option to show 'b' location range.
Error: Failed to add events.
This is because __die_find_variable_cb() did not successfully match
variable 'b', which has the DW_AT_const_value attribute instead of
DW_AT_location. We added support for DW_AT_const_value in
__die_find_variable_cb(). With this modification, we can successfully
track the variable 'b'.
$ sudo ./perf probe -x ./test -D "main:6 b"
p:probe_test/main_L6 /home/lhf/test:0x1156 b=\1:s32
Fixes: 66f69b2197 ("perf probe: Support DW_AT_const_value constant value")
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Jianlin Lv <jianlin.lv@arm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Zhang Jinhao <zhangjinhao2@huawei.com>
http://lore.kernel.org/lkml/20210601092750.169601-1-lihuafei1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since some gcc generates a broken DWARF which lacks DW_AT_declaration
attribute from the subprogram DIE of function prototype.
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97060)
So, in addition to the DW_AT_declaration check, we also check the
subprogram DIE has DW_AT_inline or actual entry pc.
Committer testing:
# cat /etc/fedora-release
Fedora release 33 (Thirty Three)
#
Before:
# perf test vfs_getname
78: Use vfs_getname probe to get syscall args filenames : FAILED!
79: Check open filename arg using perf trace + vfs_getname : FAILED!
81: Add vfs_getname probe to get syscall args filenames : FAILED!
#
After:
# perf test vfs_getname
78: Use vfs_getname probe to get syscall args filenames : Ok
79: Check open filename arg using perf trace + vfs_getname : Ok
81: Add vfs_getname probe to get syscall args filenames : Ok
#
Reported-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Link: http://lore.kernel.org/lkml/160645613571.2824037.7441351537890235895.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The dwarf_getsrc_die() can return the line which is not a statement nor
the least line number among the lines which shares same address.
This can lead perf probe --list shows incorrect line number for probed
address.
To fix this, this introduces cu_getsrc_die() which returns only a
statement line and which is the least line number (we call it the
representive line for an address), and use it in cu_find_lineinfo().
Also, if the given address is the entry address of a real function,
cu_find_lineinfo() returns the function declared line number instead of
the start line number of the function body.
For example, without this change perf probe -l shows incorrect line as
below.
# perf probe -a kernel_read:2
Added new event:
probe:kernel_read (on kernel_read:2)
You can now use it in all perf tools, such as:
perf record -e probe:kernel_read -aR sleep 1
# perf probe -l
probe:kernel_read (on kernel_read:1@linux-5.0.0/fs/read_write.c)
With this fix, it shows correct line number as below;
# perf probe -l
probe:kernel_read (on kernel_read:2@linux-5.0.0/fs/read_write.c)
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Link: http://lore.kernel.org/lkml/157406471067.24476.17463149618465494448.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix to show calling lines of inlined functions (where an inline function
is called).
die_walk_lines() filtered out the lines inside inlined functions based
on the address. However this also filtered out the lines which call
those inlined functions from the target function.
To solve this issue, check the call_file and call_line attributes and do
not filter out if it matches to the line information.
Without this fix, perf probe -L doesn't show some lines correctly.
(don't see the lines after 17)
# perf probe -L vfs_read
<vfs_read@/home/mhiramat/ksrc/linux/fs/read_write.c:0>
0 ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
1 {
2 ssize_t ret;
4 if (!(file->f_mode & FMODE_READ))
return -EBADF;
6 if (!(file->f_mode & FMODE_CAN_READ))
return -EINVAL;
8 if (unlikely(!access_ok(buf, count)))
return -EFAULT;
11 ret = rw_verify_area(READ, file, pos, count);
12 if (!ret) {
13 if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
15 ret = __vfs_read(file, buf, count, pos);
16 if (ret > 0) {
fsnotify_access(file);
add_rchar(current, ret);
}
With this fix:
# perf probe -L vfs_read
<vfs_read@/home/mhiramat/ksrc/linux/fs/read_write.c:0>
0 ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
1 {
2 ssize_t ret;
4 if (!(file->f_mode & FMODE_READ))
return -EBADF;
6 if (!(file->f_mode & FMODE_CAN_READ))
return -EINVAL;
8 if (unlikely(!access_ok(buf, count)))
return -EFAULT;
11 ret = rw_verify_area(READ, file, pos, count);
12 if (!ret) {
13 if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
15 ret = __vfs_read(file, buf, count, pos);
16 if (ret > 0) {
17 fsnotify_access(file);
18 add_rchar(current, ret);
}
20 inc_syscr(current);
}
Fixes: 4cc9cec636 ("perf probe: Introduce lines walker interface")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157241937995.32002.17899884017011512577.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Filter out instances except for inlined_subroutine and subprogram DIE in
die_walk_instances() and die_is_func_instance().
This fixes an issue that perf probe sets some probes on calling address
instead of a target function itself.
When perf probe walks on instances of an abstruct origin (a kind of
function prototype of inlined function), die_walk_instances() can also
pass a GNU_call_site (a GNU extension for call site) to callback. Since
it is not an inlined instance of target function, we have to filter out
when searching a probe point.
Without this patch, perf probe sets probes on call site address too.This
can happen on some function which is marked "inlined", but has actual
symbol. (I'm not sure why GCC mark it "inlined"):
# perf probe -D vfs_read
p:probe/vfs_read _text+2500017
p:probe/vfs_read_1 _text+2499468
p:probe/vfs_read_2 _text+2499563
p:probe/vfs_read_3 _text+2498876
p:probe/vfs_read_4 _text+2498512
p:probe/vfs_read_5 _text+2498627
With this patch:
Slightly different results, similar tho:
# perf probe -D vfs_read
p:probe/vfs_read _text+2498512
Committer testing:
# uname -a
Linux quaco 5.3.8-200.fc30.x86_64 #1 SMP Tue Oct 29 14:46:22 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Before:
# perf probe -D vfs_read
p:probe/vfs_read _text+3131557
p:probe/vfs_read_1 _text+3130975
p:probe/vfs_read_2 _text+3131047
p:probe/vfs_read_3 _text+3130380
p:probe/vfs_read_4 _text+3130000
# uname -a
Linux quaco 5.3.8-200.fc30.x86_64 #1 SMP Tue Oct 29 14:46:22 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
#
After:
# perf probe -D vfs_read
p:probe/vfs_read _text+3130000
#
Fixes: db0d2c6420 ("perf probe: Search concrete out-of-line instances")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157241937063.32002.11024544873990816590.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Skip end-of-sequence and non-statement lines while walking through lines
list.
The "end-of-sequence" line information means:
"the current address is that of the first byte after the
end of a sequence of target machine instructions."
(DWARF version 4 spec 6.2.2)
This actually means out of scope and we can not probe on it.
On the other hand, the statement lines (is_stmt) means:
"the current instruction is a recommended breakpoint location.
A recommended breakpoint location is intended to “represent”
a line, a statement and/or a semantically distinct subpart
of a statement."
(DWARF version 4 spec 6.2.2)
So, non-statement line info also should be skipped.
These can reduce unneeded probe points and also avoid an error.
E.g. without this patch:
# perf probe -a "clear_tasks_mm_cpumask:1"
Added new events:
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask:1)
probe:clear_tasks_mm_cpumask_1 (on clear_tasks_mm_cpumask:1)
probe:clear_tasks_mm_cpumask_2 (on clear_tasks_mm_cpumask:1)
probe:clear_tasks_mm_cpumask_3 (on clear_tasks_mm_cpumask:1)
probe:clear_tasks_mm_cpumask_4 (on clear_tasks_mm_cpumask:1)
You can now use it in all perf tools, such as:
perf record -e probe:clear_tasks_mm_cpumask_4 -aR sleep 1
#
This puts 5 probes on one line, but acutally it's not inlined function.
This is because there are many non statement instructions at the
function prologue.
With this patch:
# perf probe -a "clear_tasks_mm_cpumask:1"
Added new event:
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask:1)
You can now use it in all perf tools, such as:
perf record -e probe:clear_tasks_mm_cpumask -aR sleep 1
#
Now perf-probe skips unneeded addresses.
Committer testing:
Slightly different results, but similar:
Before:
# uname -a
Linux quaco 5.3.8-200.fc30.x86_64 #1 SMP Tue Oct 29 14:46:22 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
#
# perf probe -a "clear_tasks_mm_cpumask:1"
Added new events:
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask:1)
probe:clear_tasks_mm_cpumask_1 (on clear_tasks_mm_cpumask:1)
probe:clear_tasks_mm_cpumask_2 (on clear_tasks_mm_cpumask:1)
You can now use it in all perf tools, such as:
perf record -e probe:clear_tasks_mm_cpumask_2 -aR sleep 1
#
After:
# perf probe -a "clear_tasks_mm_cpumask:1"
Added new event:
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask:1)
You can now use it in all perf tools, such as:
perf record -e probe:clear_tasks_mm_cpumask -aR sleep 1
# perf probe -l
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask@kernel/cpu.c)
#
Fixes: 4cc9cec636 ("perf probe: Introduce lines walker interface")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157241936090.32002.12156347518596111660.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix to show ranges of variables (--range and --vars option) in functions
which DIE has only ranges but no entry_pc attribute.
Without this fix:
# perf probe --range -V clear_tasks_mm_cpumask
Available variables at clear_tasks_mm_cpumask
@<clear_tasks_mm_cpumask+0>
(No matched variables)
With this fix:
# perf probe --range -V clear_tasks_mm_cpumask
Available variables at clear_tasks_mm_cpumask
@<clear_tasks_mm_cpumask+0>
[VAL] int cpu @<clear_tasks_mm_cpumask+[0-35,317-317,2052-2059]>
Committer testing:
Before:
[root@quaco ~]# perf probe --range -V clear_tasks_mm_cpumask
Available variables at clear_tasks_mm_cpumask
@<clear_tasks_mm_cpumask+0>
(No matched variables)
[root@quaco ~]#
After:
[root@quaco ~]# perf probe --range -V clear_tasks_mm_cpumask
Available variables at clear_tasks_mm_cpumask
@<clear_tasks_mm_cpumask+0>
[VAL] int cpu @<clear_tasks_mm_cpumask+[0-23,23-105,105-106,106-106,1843-1850,1850-1862]>
[root@quaco ~]#
Using it:
[root@quaco ~]# perf probe clear_tasks_mm_cpumask cpu
Added new event:
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask with cpu)
You can now use it in all perf tools, such as:
perf record -e probe:clear_tasks_mm_cpumask -aR sleep 1
[root@quaco ~]# perf probe -l
probe:clear_tasks_mm_cpumask (on clear_tasks_mm_cpumask@kernel/cpu.c with cpu)
[root@quaco ~]#
[root@quaco ~]# perf trace -e probe:*cpumask
^C[root@quaco ~]#
Fixes: 349e8d2611 ("perf probe: Add --range option to show a variable's location range")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157199323018.8075.8179744380479673672.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix die_walk_lines() to list the function entry line correctly. Since
the dwarf_entrypc() does not return the entry pc if the DIE has only
range attribute, __die_walk_funclines() fails to list the declaration
line (entry line) in that case.
To solve this issue, this introduces die_entrypc() which correctly
returns the entry PC (the first address range) even if the DIE has only
range attribute. With this fix die_walk_lines() shows the function entry
line is able to probe correctly.
Fixes: 4cc9cec636 ("perf probe: Introduce lines walker interface")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157190837419.1859.4619125803596816752.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Since some inlined functions are in lexical blocks of given function, we
have to recursively walk through the DIE tree. Without this fix,
perf-probe -L can miss the inlined functions which is in a lexical block
(like if (..) { func() } case.)
However, even though, to walk the lines in a given function, we don't
need to follow the children DIE of inlined functions because those do
not have any lines in the specified function.
We need to walk though whole trees only if we walk all lines in a given
file, because an inlined function can include another inlined function
in the same file.
Fixes: b0e9cb2802 ("perf probe: Fix to search nested inlined functions in CU")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157190836514.1859.15996864849678136353.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Fix die_is_func_instance() to find range-only function instance.
In some case, a function instance can be made without any low PC or
entry PC, but only with address ranges by optimization. (e.g. cold text
partially in "text.unlikely" section) To find such function instance, we
have to check the range attribute too.
Fixes: e1ecbbc3fa ("perf probe: Fix to handle optimized not-inlined functions")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/157190835669.1859.8368628035930950596.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
59 temple place suite 330 boston ma 02111 1307 usa
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 1334 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Match linkage name with mangled name if exists. The linkage_name is used
for storing mangled name of the object.
Thus, this allows 'perf probe' to find appropriate probe point from
mangled symbol as below.
E.g. without this fix:
----
$ perf probe -x /usr/lib64/libstdc++.so.6 \
-D _ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv
Probe point '_ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv'
not found.
Error: Failed to add events.
----
With this fix, perf probe can find the correct one.
----
$ perf probe -x /usr/lib64/libstdc++.so.6 \
-D _ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv
p:probe_libstdc/_ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv
/usr/lib64/libstdc++.so.6.0.22:0x8ca60
----
Committer notes:
After the fix, setting it for real (no -D/--definition, that amounts to
a --dry-run):
# perf probe -x /usr/lib64/libstdc++.so.6 _ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv
Added new event:
probe_libstdc:_ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv (on _ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv in /usr/lib64/libstdc++.so.6.0.22)
You can now use it in all perf tools, such as:
perf record -e probe_libstdc:_ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv -aR sleep 1
# perf probe -l probe_libstdc:*
probe_libstdc:_ZNKSt15basic_fstreamXXIwSt11char_traitsIwEE7is_openEv (on is_open@libstdc++-v3/include/fstream in /usr/lib64/libstdc++.so.6.0.22)
#
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/147464493162.29804.16715053505069382443.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
