* [PATCH] perf inject jit: Ignore memfd mmap events if jitdump present
@ 2022-08-02 18:25 Brian Robbins
2022-08-04 15:22 ` Ian Rogers
0 siblings, 1 reply; 6+ messages in thread
From: Brian Robbins @ 2022-08-02 18:25 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim
Cc: linux-perf-users, linux-kernel, brianrob
Some processes store jitted code in memfd mappings to avoid having rwx
mappings. These processes map the code with a writeable mapping and a
read-execute mapping. They write the code using the writeable mapping
and then unmap the writeable mapping. All subsequent execution is
through the read-execute mapping.
perf inject --jit ignores //anon* mappings for each process where a
jitdump is present because it expects to inject mmap events for each
jitted code range, and said jitted code ranges will overlap with the
//anon* mappings.
Ignore /memfd: mappings so that jitted code contained in /memfd:
mappings is treated the same way as jitted code contained in //anon*
mappings.
Signed-off-by: Brian Robbins <brianrob@linux.microsoft.com>
---
tools/perf/util/jitdump.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index a23255773c60..335a3c61940b 100644
--- a/tools/perf/util/jitdump.c
+++ b/tools/perf/util/jitdump.c
@@ -845,8 +845,12 @@ jit_process(struct perf_session *session,
if (jit_detect(filename, pid, nsi)) {
nsinfo__put(nsi);
- // Strip //anon* mmaps if we processed a jitdump for this pid
- if (jit_has_pid(machine, pid) && (strncmp(filename, "//anon", 6) == 0))
+ /*
+ * Strip //anon* and /memfd:* mmaps if we processed a jitdump for this pid
+ */
+ if (jit_has_pid(machine, pid) &&
+ ((strncmp(filename, "//anon", 6) == 0) ||
+ (strncmp(filename, "/memfd:", 7) == 0))
return 1;
return 0;
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] perf inject jit: Ignore memfd mmap events if jitdump present
2022-08-02 18:25 [PATCH] perf inject jit: Ignore memfd mmap events if jitdump present Brian Robbins
@ 2022-08-04 15:22 ` Ian Rogers
2022-08-04 17:51 ` Brian Robbins
2022-08-10 13:00 ` Arnaldo Carvalho de Melo
0 siblings, 2 replies; 6+ messages in thread
From: Ian Rogers @ 2022-08-04 15:22 UTC (permalink / raw)
To: Brian Robbins
Cc: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
linux-perf-users, linux-kernel
On Tue, Aug 2, 2022 at 11:25 AM Brian Robbins
<brianrob@linux.microsoft.com> wrote:
>
> Some processes store jitted code in memfd mappings to avoid having rwx
> mappings. These processes map the code with a writeable mapping and a
> read-execute mapping. They write the code using the writeable mapping
> and then unmap the writeable mapping. All subsequent execution is
> through the read-execute mapping.
>
> perf inject --jit ignores //anon* mappings for each process where a
> jitdump is present because it expects to inject mmap events for each
> jitted code range, and said jitted code ranges will overlap with the
> //anon* mappings.
>
> Ignore /memfd: mappings so that jitted code contained in /memfd:
> mappings is treated the same way as jitted code contained in //anon*
> mappings.
>
> Signed-off-by: Brian Robbins <brianrob@linux.microsoft.com>
Acked-by: Ian Rogers <irogers@google.com>
> ---
> tools/perf/util/jitdump.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
> index a23255773c60..335a3c61940b 100644
> --- a/tools/perf/util/jitdump.c
> +++ b/tools/perf/util/jitdump.c
> @@ -845,8 +845,12 @@ jit_process(struct perf_session *session,
> if (jit_detect(filename, pid, nsi)) {
> nsinfo__put(nsi);
>
> - // Strip //anon* mmaps if we processed a jitdump for this pid
> - if (jit_has_pid(machine, pid) && (strncmp(filename, "//anon", 6) == 0))
> + /*
> + * Strip //anon* and /memfd:* mmaps if we processed a jitdump for this pid
> + */
> + if (jit_has_pid(machine, pid) &&
> + ((strncmp(filename, "//anon", 6) == 0) ||
> + (strncmp(filename, "/memfd:", 7) == 0))
Related to this there is the prctl PR_SET_VMA_ANON_NAME which will
name mapping to start with "[anon:"
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/proc.rst#n434
I wonder also we should be checking the pages are executable.
Thanks,
Ian
> return 1;
>
> return 0;
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] perf inject jit: Ignore memfd mmap events if jitdump present
2022-08-04 15:22 ` Ian Rogers
@ 2022-08-04 17:51 ` Brian Robbins
2022-08-10 13:00 ` Arnaldo Carvalho de Melo
1 sibling, 0 replies; 6+ messages in thread
From: Brian Robbins @ 2022-08-04 17:51 UTC (permalink / raw)
To: Ian Rogers
Cc: Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo,
Mark Rutland, Alexander Shishkin, Jiri Olsa, Namhyung Kim,
linux-perf-users, linux-kernel
On Thu, Aug 04, 2022 at 08:22:14AM -0700, Ian Rogers wrote:
> On Tue, Aug 2, 2022 at 11:25 AM Brian Robbins
> <brianrob@linux.microsoft.com> wrote:
> >
> > Some processes store jitted code in memfd mappings to avoid having rwx
> > mappings. These processes map the code with a writeable mapping and a
> > read-execute mapping. They write the code using the writeable mapping
> > and then unmap the writeable mapping. All subsequent execution is
> > through the read-execute mapping.
> >
> > perf inject --jit ignores //anon* mappings for each process where a
> > jitdump is present because it expects to inject mmap events for each
> > jitted code range, and said jitted code ranges will overlap with the
> > //anon* mappings.
> >
> > Ignore /memfd: mappings so that jitted code contained in /memfd:
> > mappings is treated the same way as jitted code contained in //anon*
> > mappings.
> >
> > Signed-off-by: Brian Robbins <brianrob@linux.microsoft.com>
>
> Acked-by: Ian Rogers <irogers@google.com>
>
> > ---
> > tools/perf/util/jitdump.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
> > index a23255773c60..335a3c61940b 100644
> > --- a/tools/perf/util/jitdump.c
> > +++ b/tools/perf/util/jitdump.c
> > @@ -845,8 +845,12 @@ jit_process(struct perf_session *session,
> > if (jit_detect(filename, pid, nsi)) {
> > nsinfo__put(nsi);
> >
> > - // Strip //anon* mmaps if we processed a jitdump for this pid
> > - if (jit_has_pid(machine, pid) && (strncmp(filename, "//anon", 6) == 0))
> > + /*
> > + * Strip //anon* and /memfd:* mmaps if we processed a jitdump for this pid
> > + */
> > + if (jit_has_pid(machine, pid) &&
> > + ((strncmp(filename, "//anon", 6) == 0) ||
> > + (strncmp(filename, "/memfd:", 7) == 0))
>
> Related to this there is the prctl PR_SET_VMA_ANON_NAME which will
> name mapping to start with "[anon:"
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/proc.rst#n434
> I wonder also we should be checking the pages are executable.
>
> Thanks,
> Ian
>
> > return 1;
> >
> > return 0;
> > --
> > 2.25.1
> >
I have not run into this case yet, but I suspect you are right that this should be handled as well. I can create a follow-up patch for this.
Thanks.
--Brian
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] perf inject jit: Ignore memfd mmap events if jitdump present
2022-08-04 15:22 ` Ian Rogers
2022-08-04 17:51 ` Brian Robbins
@ 2022-08-10 13:00 ` Arnaldo Carvalho de Melo
2022-08-10 13:03 ` Arnaldo Carvalho de Melo
1 sibling, 1 reply; 6+ messages in thread
From: Arnaldo Carvalho de Melo @ 2022-08-10 13:00 UTC (permalink / raw)
To: Ian Rogers
Cc: Brian Robbins, Peter Zijlstra, Ingo Molnar, Mark Rutland,
Alexander Shishkin, Jiri Olsa, Namhyung Kim, linux-perf-users,
linux-kernel
Em Thu, Aug 04, 2022 at 08:22:14AM -0700, Ian Rogers escreveu:
> On Tue, Aug 2, 2022 at 11:25 AM Brian Robbins
> <brianrob@linux.microsoft.com> wrote:
> >
> > Some processes store jitted code in memfd mappings to avoid having rwx
> > mappings. These processes map the code with a writeable mapping and a
> > read-execute mapping. They write the code using the writeable mapping
> > and then unmap the writeable mapping. All subsequent execution is
> > through the read-execute mapping.
> >
> > perf inject --jit ignores //anon* mappings for each process where a
> > jitdump is present because it expects to inject mmap events for each
> > jitted code range, and said jitted code ranges will overlap with the
> > //anon* mappings.
> >
> > Ignore /memfd: mappings so that jitted code contained in /memfd:
> > mappings is treated the same way as jitted code contained in //anon*
> > mappings.
> >
> > Signed-off-by: Brian Robbins <brianrob@linux.microsoft.com>
>
> Acked-by: Ian Rogers <irogers@google.com>
CC /tmp/build/perf/util/jitdump.o
CC /tmp/build/perf/pmu-events/pmu-events.o
LD /tmp/build/perf/pmu-events/pmu-events-in.o
util/jitdump.c: In function ‘jit_process’:
util/jitdump.c:853:65: error: expected ‘)’ before ‘return’
853 | (strncmp(filename, "/memfd:", 7) == 0))
| ^
| )
854 | return 1;
| ~~~~~~
util/jitdump.c:851:20: note: to match this ‘(’
851 | if (jit_has_pid(machine, pid) &&
| ^
util/jitdump.c:857:9: error: expected expression before ‘}’ token
857 | }
| ^
make[4]: *** [/var/home/acme/git/perf/tools/build/Makefile.build:96: /tmp/build/perf/util/jitdump.o] Error 1
make[4]: *** Waiting for unfinished jobs....
make[3]: *** [/var/home/acme/git/perf/tools/build/Makefile.build:139: util] Error 2
Trying to fix now.
- Arnaldo
> > ---
> > tools/perf/util/jitdump.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
> > index a23255773c60..335a3c61940b 100644
> > --- a/tools/perf/util/jitdump.c
> > +++ b/tools/perf/util/jitdump.c
> > @@ -845,8 +845,12 @@ jit_process(struct perf_session *session,
> > if (jit_detect(filename, pid, nsi)) {
> > nsinfo__put(nsi);
> >
> > - // Strip //anon* mmaps if we processed a jitdump for this pid
> > - if (jit_has_pid(machine, pid) && (strncmp(filename, "//anon", 6) == 0))
> > + /*
> > + * Strip //anon* and /memfd:* mmaps if we processed a jitdump for this pid
> > + */
> > + if (jit_has_pid(machine, pid) &&
> > + ((strncmp(filename, "//anon", 6) == 0) ||
> > + (strncmp(filename, "/memfd:", 7) == 0))
>
> Related to this there is the prctl PR_SET_VMA_ANON_NAME which will
> name mapping to start with "[anon:"
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/proc.rst#n434
> I wonder also we should be checking the pages are executable.
>
> Thanks,
> Ian
>
> > return 1;
> >
> > return 0;
> > --
> > 2.25.1
> >
--
- Arnaldo
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] perf inject jit: Ignore memfd mmap events if jitdump present
2022-08-10 13:00 ` Arnaldo Carvalho de Melo
@ 2022-08-10 13:03 ` Arnaldo Carvalho de Melo
2022-08-10 15:08 ` Brian Robbins
0 siblings, 1 reply; 6+ messages in thread
From: Arnaldo Carvalho de Melo @ 2022-08-10 13:03 UTC (permalink / raw)
To: Brian Robbins, Ian Rogers
Cc: Peter Zijlstra, Ingo Molnar, Mark Rutland, Alexander Shishkin,
Jiri Olsa, Namhyung Kim, linux-perf-users, linux-kernel
Em Wed, Aug 10, 2022 at 10:00:14AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Thu, Aug 04, 2022 at 08:22:14AM -0700, Ian Rogers escreveu:
> > On Tue, Aug 2, 2022 at 11:25 AM Brian Robbins <brianrob@linux.microsoft.com> wrote:
> > > Signed-off-by: Brian Robbins <brianrob@linux.microsoft.com>
> >
> > Acked-by: Ian Rogers <irogers@google.com>
>
> CC /tmp/build/perf/util/jitdump.o
> CC /tmp/build/perf/pmu-events/pmu-events.o
> LD /tmp/build/perf/pmu-events/pmu-events-in.o
> util/jitdump.c: In function ‘jit_process’:
> util/jitdump.c:853:65: error: expected ‘)’ before ‘return’
> 853 | (strncmp(filename, "/memfd:", 7) == 0))
> | ^
> | )
> 854 | return 1;
> | ~~~~~~
> util/jitdump.c:851:20: note: to match this ‘(’
> 851 | if (jit_has_pid(machine, pid) &&
> | ^
> util/jitdump.c:857:9: error: expected expression before ‘}’ token
> 857 | }
> | ^
> make[4]: *** [/var/home/acme/git/perf/tools/build/Makefile.build:96: /tmp/build/perf/util/jitdump.o] Error 1
> make[4]: *** Waiting for unfinished jobs....
> make[3]: *** [/var/home/acme/git/perf/tools/build/Makefile.build:139: util] Error 2
>
>
> Trying to fix now.
Trivial, please compile test it...
- Arnaldo
diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index 335a3c61940b7b39..9983d21a5c42d70e 100644
--- a/tools/perf/util/jitdump.c
+++ b/tools/perf/util/jitdump.c
@@ -850,7 +850,7 @@ jit_process(struct perf_session *session,
*/
if (jit_has_pid(machine, pid) &&
((strncmp(filename, "//anon", 6) == 0) ||
- (strncmp(filename, "/memfd:", 7) == 0))
+ (strncmp(filename, "/memfd:", 7) == 0)))
return 1;
return 0;
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] perf inject jit: Ignore memfd mmap events if jitdump present
2022-08-10 13:03 ` Arnaldo Carvalho de Melo
@ 2022-08-10 15:08 ` Brian Robbins
0 siblings, 0 replies; 6+ messages in thread
From: Brian Robbins @ 2022-08-10 15:08 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Ian Rogers, Peter Zijlstra, Ingo Molnar, Mark Rutland,
Alexander Shishkin, Jiri Olsa, Namhyung Kim, linux-perf-users,
linux-kernel
On Wed, Aug 10, 2022 at 10:03:17AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Wed, Aug 10, 2022 at 10:00:14AM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Thu, Aug 04, 2022 at 08:22:14AM -0700, Ian Rogers escreveu:
> > > On Tue, Aug 2, 2022 at 11:25 AM Brian Robbins <brianrob@linux.microsoft.com> wrote:
> > > > Signed-off-by: Brian Robbins <brianrob@linux.microsoft.com>
> > >
> > > Acked-by: Ian Rogers <irogers@google.com>
> >
> > CC /tmp/build/perf/util/jitdump.o
> > CC /tmp/build/perf/pmu-events/pmu-events.o
> > LD /tmp/build/perf/pmu-events/pmu-events-in.o
> > util/jitdump.c: In function ‘jit_process’:
> > util/jitdump.c:853:65: error: expected ‘)’ before ‘return’
> > 853 | (strncmp(filename, "/memfd:", 7) == 0))
> > | ^
> > | )
> > 854 | return 1;
> > | ~~~~~~
> > util/jitdump.c:851:20: note: to match this ‘(’
> > 851 | if (jit_has_pid(machine, pid) &&
> > | ^
> > util/jitdump.c:857:9: error: expected expression before ‘}’ token
> > 857 | }
> > | ^
> > make[4]: *** [/var/home/acme/git/perf/tools/build/Makefile.build:96: /tmp/build/perf/util/jitdump.o] Error 1
> > make[4]: *** Waiting for unfinished jobs....
> > make[3]: *** [/var/home/acme/git/perf/tools/build/Makefile.build:139: util] Error 2
> >
> >
> > Trying to fix now.
>
> Trivial, please compile test it...
>
> - Arnaldo
>
> diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
> index 335a3c61940b7b39..9983d21a5c42d70e 100644
> --- a/tools/perf/util/jitdump.c
> +++ b/tools/perf/util/jitdump.c
> @@ -850,7 +850,7 @@ jit_process(struct perf_session *session,
> */
> if (jit_has_pid(machine, pid) &&
> ((strncmp(filename, "//anon", 6) == 0) ||
> - (strncmp(filename, "/memfd:", 7) == 0))
> + (strncmp(filename, "/memfd:", 7) == 0)))
> return 1;
>
> return 0;
Apologies about that. Fixed this in v2.
--Brian
^ permalink raw reply [flat|nested] 6+ messages in thread
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2022-08-02 18:25 [PATCH] perf inject jit: Ignore memfd mmap events if jitdump present Brian Robbins
2022-08-04 15:22 ` Ian Rogers
2022-08-04 17:51 ` Brian Robbins
2022-08-10 13:00 ` Arnaldo Carvalho de Melo
2022-08-10 13:03 ` Arnaldo Carvalho de Melo
2022-08-10 15:08 ` Brian Robbins
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