Hello,

On Tue, Jun 25, 2024 at 5:02 AM Adrian Hunter [off-list ref] wrote:

On 25/06/24 14:57, Adrian Hunter wrote:

quoted

On 23/06/24 09:48, Athira Rajeev wrote:

quoted

Perf test for perf probe of function from different CU fails
as below:

     ./perf test -vv "test perf probe of function from different CU"
     116: test perf probe of function from different CU:
     --- start ---
     test child forked, pid 2679
     Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.Msa7iy89bx/testfile
       Error: Failed to add events.
     --- Cleaning up ---
     "foo" does not hit any event.
       Error: Failed to delete events.
     ---- end(-1) ----
     116: test perf probe of function from different CU                   : FAILED!

The test does below to probe function "foo" :

     # gcc -g -Og -flto -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.c
     -o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
     # gcc -g -Og -c /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.c
     -o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o
     # gcc -g -Og -o /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
     /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-foo.o
     /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile-main.o

     # ./perf probe -x /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile foo
     Failed to find symbol foo in /tmp/perf-uprobe-different-cu-sh.XniNxNEVT7/testfile
        Error: Failed to add events.

Perf probe fails to find symbol foo in the executable placed in
/tmp/perf-uprobe-different-cu-sh.XniNxNEVT7

Simple reproduce:

 # mktemp -d /tmp/perf-checkXXXXXXXXXX
   /tmp/perf-checkcWpuLRQI8j

 # gcc -g -o test test.c
 # cp test /tmp/perf-checkcWpuLRQI8j/
 # nm /tmp/perf-checkcWpuLRQI8j/test | grep foo
   00000000100006bc T foo

 # ./perf probe -x /tmp/perf-checkcWpuLRQI8j/test foo
   Failed to find symbol foo in /tmp/perf-checkcWpuLRQI8j/test
      Error: Failed to add events.

But it works with any files like /tmp/perf/test. Only for
patterns with "/tmp/perf-", this fails.

Further debugging, commit 80d496be89ed ("perf report: Add support
for profiling JIT generated code") added support for profiling JIT
generated code. This patch handles dso's of form
"/tmp/perf-$PID.map" .

The check used "if (strncmp(self->name, "/tmp/perf-", 10) == 0)"
to match "/tmp/perf-$PID.map". With this commit, any dso in
/tmp/perf- folder will be considered separately for processing
(not only JIT created map files ). Fix this by changing the
string pattern to check for "/tmp/perf-%d.map". Add a helper
function is_perf_pid_map_name to do this check. In "struct dso",
dso->long_name holds the long name of the dso file. Since the
/tmp/perf-$PID.map check uses the complete name, use dso___long_name for
the string name.

With the fix,
     # ./perf test "test perf probe of function from different CU"
     117: test perf probe of function from different CU                   : Ok

Signed-off-by: Athira Rajeev<redacted>

Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>

Although it could use a Fixes tag

Thanks, I will add

Fixes: 56cbeacf1435 ("perf probe: Add test for regression introduced
by switch to die_get_decl_file()")

Namhyung