Re: [PATCH v2] perf check: Add sanitizer feature and use to avoid test failure

[Namhyung Kim <namhyung@kernel.org>]

On Wed, Oct 23, 2024 at 03:19:38PM -0700, Namhyung Kim wrote:
> On Tue, Oct 22, 2024 at 11:18:18PM -0700, Namhyung Kim wrote:
> > On Tue, Oct 22, 2024 at 10:39:36AM -0700, Ian Rogers wrote:
> > > Sure, the reproduction is trivial, just add -fsanitize=address, so I'm
> > > surprised you're not already seeing it:
> > > ```
> > > $ perf test annotate -v
> > > --- start ---
> > > test child forked, pid 444258
> > >  68e8a0-68e96b l noploop
> > > perf does have symbol 'noploop'
> > > Basic perf annotate test
> > >          : 0      0x68e8a0 <noploop>:
> > >     0.00 :   68e8a0:       pushq   %rbp
> > >     0.00 :   68e8a1:       movq    %rsp, %rbp
> > >     0.00 :   68e8a4:       subq    $0x30, %rsp
> [...]
> > >     0.00 :   92d6:       shrl    %cl, %edx
> > >     0.00 :   92d8:       movl    %edx, %ecx
> > >     0.00 :   92da:       movq    %rax, %rdx
> > > Basic annotate [Failed: missing disasm output when specifying the target symbol]
> > 
> > Hmm.. this is strange.  The error message says it failed when it
> > specified the target symbol (noploop) for perf annotate.
> > 
> > As it's the dominant symbol, it should have the same output for the
> > first function (noploop) whether it has target symbol or not and it
> > should match the disasm_regex.  I'm curious how it can fail here.
> 
> Hmm.. ok.  For some reason, it wasn't failed when I add DEBUG=1.

Oh, now I'm seeing why.  We skip perf_session__delete() on !DEBUG build.
:(

> 
> Without DEBUG, I can see it now.
> 
> =================================================================
> ==1053492==ERROR: LeakSanitizer: detected memory leaks
> 
> Direct leak of 33 byte(s) in 1 object(s) allocated from:
>     #0 0x7f1ad78edd20 in strdup ../../../../src/libsanitizer/asan/asan_interceptors.cpp:566
>     #1 0x55eda19cb76f in perf_data__open (linux/tools/perf/perf+0x65276f) (BuildId: 6fc1b7cdc123c7bd586ce55ea8b727875f42cda2)
>     #2 0x55eda18ffafa in __perf_session__new (linux/tools/perf/perf+0x586afa) (BuildId: 6fc1b7cdc123c7bd586ce55ea8b727875f42cda2)
>     #3 0x55eda15485d3 in cmd_annotate (linux/tools/perf/perf+0x1cf5d3) (BuildId: 6fc1b7cdc123c7bd586ce55ea8b727875f42cda2)
>     #4 0x55eda1695467 in run_builtin (linux/tools/perf/perf+0x31c467) (BuildId: 6fc1b7cdc123c7bd586ce55ea8b727875f42cda2)
>     #5 0x55eda1695c0e in handle_internal_command (linux/tools/perf/perf+0x31cc0e) (BuildId: 6fc1b7cdc123c7bd586ce55ea8b727875f42cda2)
>     #6 0x55eda153ba72 in main (linux/tools/perf/perf+0x1c2a72) (BuildId: 6fc1b7cdc123c7bd586ce55ea8b727875f42cda2)
>     #7 0x7f1acda43b89 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
> 
> SUMMARY: AddressSanitizer: 33 byte(s) leaked in 1 allocation(s).
> Unexpected signal in test_basic
> 
> No idea how it can leak the data->file.path (that's what I can find
> where strdup is used in the function).

Maybe we need to revisit how much speed up it can give.

Thanks,
Namhyung