* Re: [PATCH] perf tools: Restore proper cwd on return from mnt ns
2018-11-01 17:00 [PATCH] perf tools: Restore proper cwd on return from mnt ns Jiri Olsa
@ 2018-11-16 13:03 ` Jiri Olsa
2018-11-16 18:31 ` Arnaldo Carvalho de Melo
` (2 subsequent siblings)
3 siblings, 0 replies; 11+ messages in thread
From: Jiri Olsa @ 2018-11-16 13:03 UTC (permalink / raw)
To: Jiri Olsa
Cc: Arnaldo Carvalho de Melo, Krister Johansen, lkml, Ingo Molnar,
Namhyung Kim, Alexander Shishkin, Peter Zijlstra
ping
jirka
On Thu, Nov 01, 2018 at 06:00:01PM +0100, Jiri Olsa wrote:
> When reporting on 'record' server we try to retrieve/use
> the mnt namespace of the profiled tasks. We use following
> API with cookie to hold the return namespace, roughly:
>
> nsinfo__mountns_enter(struct nsinfo *nsi, struct nscookie *nc)
> setns(newns, 0);
> ...
> new ns related open..
> ...
> nsinfo__mountns_exit(struct nscookie *nc)
> setns(nc->oldns)
>
> Once finished we setns to old namespace, which also sets the
> current working directory (cwd) to "/", trashing the cwd we had.
>
> This is mostly fine, because we use absolute paths almost everywhere,
> but it screws up perf diff:
>
> # perf diff
> failed to open perf.data: No such file or directory (try 'perf record' first)
> ...
>
> Adding the current working directory to be part of the cookie
> and restoring it in the nsinfo__mountns_exit call.
>
> Cc: Krister Johansen <kjlx@templeofstupid.com>
> Fixes: 843ff37bb59e ("perf symbols: Find symbols in different mount namespace")
> Link: http://lkml.kernel.org/n/tip-zg3vz7kjr86cco7lo91v8yhj@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> tools/perf/util/namespaces.c | 18 ++++++++++++++++--
> tools/perf/util/namespaces.h | 1 +
> 2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
> index cf8bd123cf73..fb0458b7e6aa 100644
> --- a/tools/perf/util/namespaces.c
> +++ b/tools/perf/util/namespaces.c
> @@ -18,6 +18,7 @@
> #include <stdio.h>
> #include <string.h>
> #include <unistd.h>
> +#include <asm/bug.h>
>
> struct namespaces *namespaces__new(struct namespaces_event *event)
> {
> @@ -186,6 +187,7 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> char curpath[PATH_MAX];
> int oldns = -1;
> int newns = -1;
> + char *oldcwd = NULL;
>
> if (nc == NULL)
> return;
> @@ -199,9 +201,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
> return;
>
> + oldcwd = get_current_dir_name();
> + if (!oldcwd)
> + return;
> +
> oldns = open(curpath, O_RDONLY);
> if (oldns < 0)
> - return;
> + goto errout;
>
> newns = open(nsi->mntns_path, O_RDONLY);
> if (newns < 0)
> @@ -210,11 +216,14 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> if (setns(newns, CLONE_NEWNS) < 0)
> goto errout;
>
> + nc->oldcwd = oldcwd;
> nc->oldns = oldns;
> nc->newns = newns;
> return;
>
> errout:
> + if (oldcwd)
> + free(oldcwd);
> if (oldns > -1)
> close(oldns);
> if (newns > -1)
> @@ -223,11 +232,16 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
>
> void nsinfo__mountns_exit(struct nscookie *nc)
> {
> - if (nc == NULL || nc->oldns == -1 || nc->newns == -1)
> + if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd)
> return;
>
> setns(nc->oldns, CLONE_NEWNS);
>
> + if (nc->oldcwd) {
> + WARN_ON_ONCE(chdir(nc->oldcwd));
> + free(nc->oldcwd);
> + }
> +
> if (nc->oldns > -1) {
> close(nc->oldns);
> nc->oldns = -1;
> diff --git a/tools/perf/util/namespaces.h b/tools/perf/util/namespaces.h
> index cae1a9a39722..d5f46c09ea31 100644
> --- a/tools/perf/util/namespaces.h
> +++ b/tools/perf/util/namespaces.h
> @@ -38,6 +38,7 @@ struct nsinfo {
> struct nscookie {
> int oldns;
> int newns;
> + char *oldcwd;
> };
>
> int nsinfo__init(struct nsinfo *nsi);
> --
> 2.17.2
>
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH] perf tools: Restore proper cwd on return from mnt ns
2018-11-01 17:00 [PATCH] perf tools: Restore proper cwd on return from mnt ns Jiri Olsa
2018-11-16 13:03 ` Jiri Olsa
@ 2018-11-16 18:31 ` Arnaldo Carvalho de Melo
2018-11-16 18:42 ` Arnaldo Carvalho de Melo
2018-11-19 16:10 ` Arnaldo Carvalho de Melo
2018-11-21 15:02 ` [tip:perf/urgent] perf tools: Restore proper cwd on return from mnt namespace tip-bot for Jiri Olsa
3 siblings, 1 reply; 11+ messages in thread
From: Arnaldo Carvalho de Melo @ 2018-11-16 18:31 UTC (permalink / raw)
To: Jiri Olsa
Cc: Krister Johansen, lkml, Ingo Molnar, Namhyung Kim,
Alexander Shishkin, Peter Zijlstra
Em Thu, Nov 01, 2018 at 06:00:01PM +0100, Jiri Olsa escreveu:
> When reporting on 'record' server we try to retrieve/use
> the mnt namespace of the profiled tasks. We use following
> API with cookie to hold the return namespace, roughly:
>
> nsinfo__mountns_enter(struct nsinfo *nsi, struct nscookie *nc)
> setns(newns, 0);
> ...
> new ns related open..
> ...
> nsinfo__mountns_exit(struct nscookie *nc)
> setns(nc->oldns)
>
> Once finished we setns to old namespace, which also sets the
> current working directory (cwd) to "/", trashing the cwd we had.
>
> This is mostly fine, because we use absolute paths almost everywhere,
> but it screws up perf diff:
>
> # perf diff
> failed to open perf.data: No such file or directory (try 'perf record' first)
> ...
>
> Adding the current working directory to be part of the cookie
> and restoring it in the nsinfo__mountns_exit call.
> Cc: Krister Johansen <kjlx@templeofstupid.com>
> Fixes: 843ff37bb59e ("perf symbols: Find symbols in different mount namespace")
> Link: http://lkml.kernel.org/n/tip-zg3vz7kjr86cco7lo91v8yhj@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
> tools/perf/util/namespaces.c | 18 ++++++++++++++++--
> tools/perf/util/namespaces.h | 1 +
> 2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
> index cf8bd123cf73..fb0458b7e6aa 100644
> --- a/tools/perf/util/namespaces.c
> +++ b/tools/perf/util/namespaces.c
> @@ -18,6 +18,7 @@
> #include <stdio.h>
> #include <string.h>
> #include <unistd.h>
> +#include <asm/bug.h>
>
> struct namespaces *namespaces__new(struct namespaces_event *event)
> {
> @@ -186,6 +187,7 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> char curpath[PATH_MAX];
> int oldns = -1;
> int newns = -1;
> + char *oldcwd = NULL;
>
> if (nc == NULL)
> return;
> @@ -199,9 +201,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
> return;
>
> + oldcwd = get_current_dir_name();
> + if (!oldcwd)
> + return;
> +
> oldns = open(curpath, O_RDONLY);
> if (oldns < 0)
> - return;
> + goto errout;
>
> newns = open(nsi->mntns_path, O_RDONLY);
> if (newns < 0)
> @@ -210,11 +216,14 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> if (setns(newns, CLONE_NEWNS) < 0)
> goto errout;
>
> + nc->oldcwd = oldcwd;
> nc->oldns = oldns;
> nc->newns = newns;
> return;
>
> errout:
> + if (oldcwd)
> + free(oldcwd);
Applied, and while at it I removed the needless if in the above two
lines.
> if (oldns > -1)
> close(oldns);
> if (newns > -1)
> @@ -223,11 +232,16 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
>
> void nsinfo__mountns_exit(struct nscookie *nc)
> {
> - if (nc == NULL || nc->oldns == -1 || nc->newns == -1)
> + if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd)
> return;
>
> setns(nc->oldns, CLONE_NEWNS);
>
> + if (nc->oldcwd) {
> + WARN_ON_ONCE(chdir(nc->oldcwd));
> + free(nc->oldcwd);
> + }
> +
> if (nc->oldns > -1) {
> close(nc->oldns);
> nc->oldns = -1;
> diff --git a/tools/perf/util/namespaces.h b/tools/perf/util/namespaces.h
> index cae1a9a39722..d5f46c09ea31 100644
> --- a/tools/perf/util/namespaces.h
> +++ b/tools/perf/util/namespaces.h
> @@ -38,6 +38,7 @@ struct nsinfo {
> struct nscookie {
> int oldns;
> int newns;
> + char *oldcwd;
> };
>
> int nsinfo__init(struct nsinfo *nsi);
> --
> 2.17.2
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH] perf tools: Restore proper cwd on return from mnt ns
2018-11-16 18:31 ` Arnaldo Carvalho de Melo
@ 2018-11-16 18:42 ` Arnaldo Carvalho de Melo
2018-11-17 9:00 ` Jiri Olsa
0 siblings, 1 reply; 11+ messages in thread
From: Arnaldo Carvalho de Melo @ 2018-11-16 18:42 UTC (permalink / raw)
To: Jiri Olsa
Cc: Krister Johansen, lkml, Ingo Molnar, Namhyung Kim,
Alexander Shishkin, Peter Zijlstra
Em Fri, Nov 16, 2018 at 10:31:43AM -0800, Arnaldo Carvalho de Melo escreveu:
> Em Thu, Nov 01, 2018 at 06:00:01PM +0100, Jiri Olsa escreveu:
> > When reporting on 'record' server we try to retrieve/use
> > the mnt namespace of the profiled tasks. We use following
> > API with cookie to hold the return namespace, roughly:
> >
> > nsinfo__mountns_enter(struct nsinfo *nsi, struct nscookie *nc)
> > setns(newns, 0);
> > ...
> > new ns related open..
> > ...
> > nsinfo__mountns_exit(struct nscookie *nc)
> > setns(nc->oldns)
> >
> > Once finished we setns to old namespace, which also sets the
> > current working directory (cwd) to "/", trashing the cwd we had.
> >
> > This is mostly fine, because we use absolute paths almost everywhere,
> > but it screws up perf diff:
> >
> > # perf diff
> > failed to open perf.data: No such file or directory (try 'perf record' first)
> > ...
> >
> > Adding the current working directory to be part of the cookie
> > and restoring it in the nsinfo__mountns_exit call.
>
> > Cc: Krister Johansen <kjlx@templeofstupid.com>
> > Fixes: 843ff37bb59e ("perf symbols: Find symbols in different mount namespace")
> > Link: http://lkml.kernel.org/n/tip-zg3vz7kjr86cco7lo91v8yhj@git.kernel.org
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> > tools/perf/util/namespaces.c | 18 ++++++++++++++++--
> > tools/perf/util/namespaces.h | 1 +
> > 2 files changed, 17 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
> > index cf8bd123cf73..fb0458b7e6aa 100644
> > --- a/tools/perf/util/namespaces.c
> > +++ b/tools/perf/util/namespaces.c
> > @@ -18,6 +18,7 @@
> > #include <stdio.h>
> > #include <string.h>
> > #include <unistd.h>
> > +#include <asm/bug.h>
> >
> > struct namespaces *namespaces__new(struct namespaces_event *event)
> > {
> > @@ -186,6 +187,7 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> > char curpath[PATH_MAX];
> > int oldns = -1;
> > int newns = -1;
> > + char *oldcwd = NULL;
> >
> > if (nc == NULL)
> > return;
> > @@ -199,9 +201,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> > if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
> > return;
> >
> > + oldcwd = get_current_dir_name();
> > + if (!oldcwd)
> > + return;
> > +
> > oldns = open(curpath, O_RDONLY);
> > if (oldns < 0)
> > - return;
> > + goto errout;
> >
> > newns = open(nsi->mntns_path, O_RDONLY);
> > if (newns < 0)
> > @@ -210,11 +216,14 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> > if (setns(newns, CLONE_NEWNS) < 0)
> > goto errout;
> >
> > + nc->oldcwd = oldcwd;
> > nc->oldns = oldns;
> > nc->newns = newns;
> > return;
> >
> > errout:
> > + if (oldcwd)
> > + free(oldcwd);
>
> Applied, and while at it I removed the needless if in the above two
> lines.
>
> > if (oldns > -1)
> > close(oldns);
> > if (newns > -1)
> > @@ -223,11 +232,16 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> >
> > void nsinfo__mountns_exit(struct nscookie *nc)
> > {
> > - if (nc == NULL || nc->oldns == -1 || nc->newns == -1)
> > + if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd)
> > return;
> >
> > setns(nc->oldns, CLONE_NEWNS);
> >
> > + if (nc->oldcwd) {
> > + WARN_ON_ONCE(chdir(nc->oldcwd));
> > + free(nc->oldcwd);
> > + }
> > +
Also changed the above to zfree(&nc->oldcwd) as this is in a struct
member, that is not freed by the freeing caller
(nsinfo__mountns_exit()), to avoid later possible use-after-free (I
haven't checked if it _actually_ happens with the current codebase, but
it could) also to match the following block, where the resource is
released and then the handler is invalidated.
- Arnaldo
> > if (nc->oldns > -1) {
> > close(nc->oldns);
> > nc->oldns = -1;
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH] perf tools: Restore proper cwd on return from mnt ns
2018-11-16 18:42 ` Arnaldo Carvalho de Melo
@ 2018-11-17 9:00 ` Jiri Olsa
0 siblings, 0 replies; 11+ messages in thread
From: Jiri Olsa @ 2018-11-17 9:00 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Jiri Olsa, Krister Johansen, lkml, Ingo Molnar, Namhyung Kim,
Alexander Shishkin, Peter Zijlstra
On Fri, Nov 16, 2018 at 10:42:45AM -0800, Arnaldo Carvalho de Melo wrote:
> Em Fri, Nov 16, 2018 at 10:31:43AM -0800, Arnaldo Carvalho de Melo escreveu:
> > Em Thu, Nov 01, 2018 at 06:00:01PM +0100, Jiri Olsa escreveu:
> > > When reporting on 'record' server we try to retrieve/use
> > > the mnt namespace of the profiled tasks. We use following
> > > API with cookie to hold the return namespace, roughly:
> > >
> > > nsinfo__mountns_enter(struct nsinfo *nsi, struct nscookie *nc)
> > > setns(newns, 0);
> > > ...
> > > new ns related open..
> > > ...
> > > nsinfo__mountns_exit(struct nscookie *nc)
> > > setns(nc->oldns)
> > >
> > > Once finished we setns to old namespace, which also sets the
> > > current working directory (cwd) to "/", trashing the cwd we had.
> > >
> > > This is mostly fine, because we use absolute paths almost everywhere,
> > > but it screws up perf diff:
> > >
> > > # perf diff
> > > failed to open perf.data: No such file or directory (try 'perf record' first)
> > > ...
> > >
> > > Adding the current working directory to be part of the cookie
> > > and restoring it in the nsinfo__mountns_exit call.
> >
> > > Cc: Krister Johansen <kjlx@templeofstupid.com>
> > > Fixes: 843ff37bb59e ("perf symbols: Find symbols in different mount namespace")
> > > Link: http://lkml.kernel.org/n/tip-zg3vz7kjr86cco7lo91v8yhj@git.kernel.org
> > > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > > ---
> > > tools/perf/util/namespaces.c | 18 ++++++++++++++++--
> > > tools/perf/util/namespaces.h | 1 +
> > > 2 files changed, 17 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
> > > index cf8bd123cf73..fb0458b7e6aa 100644
> > > --- a/tools/perf/util/namespaces.c
> > > +++ b/tools/perf/util/namespaces.c
> > > @@ -18,6 +18,7 @@
> > > #include <stdio.h>
> > > #include <string.h>
> > > #include <unistd.h>
> > > +#include <asm/bug.h>
> > >
> > > struct namespaces *namespaces__new(struct namespaces_event *event)
> > > {
> > > @@ -186,6 +187,7 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> > > char curpath[PATH_MAX];
> > > int oldns = -1;
> > > int newns = -1;
> > > + char *oldcwd = NULL;
> > >
> > > if (nc == NULL)
> > > return;
> > > @@ -199,9 +201,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> > > if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
> > > return;
> > >
> > > + oldcwd = get_current_dir_name();
> > > + if (!oldcwd)
> > > + return;
> > > +
> > > oldns = open(curpath, O_RDONLY);
> > > if (oldns < 0)
> > > - return;
> > > + goto errout;
> > >
> > > newns = open(nsi->mntns_path, O_RDONLY);
> > > if (newns < 0)
> > > @@ -210,11 +216,14 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> > > if (setns(newns, CLONE_NEWNS) < 0)
> > > goto errout;
> > >
> > > + nc->oldcwd = oldcwd;
> > > nc->oldns = oldns;
> > > nc->newns = newns;
> > > return;
> > >
> > > errout:
> > > + if (oldcwd)
> > > + free(oldcwd);
right, ok
> >
> > Applied, and while at it I removed the needless if in the above two
> > lines.
> >
> > > if (oldns > -1)
> > > close(oldns);
> > > if (newns > -1)
> > > @@ -223,11 +232,16 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> > >
> > > void nsinfo__mountns_exit(struct nscookie *nc)
> > > {
> > > - if (nc == NULL || nc->oldns == -1 || nc->newns == -1)
> > > + if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd)
> > > return;
> > >
> > > setns(nc->oldns, CLONE_NEWNS);
> > >
> > > + if (nc->oldcwd) {
> > > + WARN_ON_ONCE(chdir(nc->oldcwd));
> > > + free(nc->oldcwd);
> > > + }
> > > +
>
> Also changed the above to zfree(&nc->oldcwd) as this is in a struct
> member, that is not freed by the freeing caller
> (nsinfo__mountns_exit()), to avoid later possible use-after-free (I
> haven't checked if it _actually_ happens with the current codebase, but
> it could) also to match the following block, where the resource is
> released and then the handler is invalidated.
great, thanks
jirka
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] perf tools: Restore proper cwd on return from mnt ns
2018-11-01 17:00 [PATCH] perf tools: Restore proper cwd on return from mnt ns Jiri Olsa
2018-11-16 13:03 ` Jiri Olsa
2018-11-16 18:31 ` Arnaldo Carvalho de Melo
@ 2018-11-19 16:10 ` Arnaldo Carvalho de Melo
2018-11-20 10:56 ` Jiri Olsa
2018-11-21 15:02 ` [tip:perf/urgent] perf tools: Restore proper cwd on return from mnt namespace tip-bot for Jiri Olsa
3 siblings, 1 reply; 11+ messages in thread
From: Arnaldo Carvalho de Melo @ 2018-11-19 16:10 UTC (permalink / raw)
To: Jiri Olsa
Cc: Krister Johansen, lkml, Ingo Molnar, Namhyung Kim,
Alexander Shishkin, Peter Zijlstra
Em Thu, Nov 01, 2018 at 06:00:01PM +0100, Jiri Olsa escreveu:
> Adding the current working directory to be part of the cookie
> and restoring it in the nsinfo__mountns_exit call.
> diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
> index cf8bd123cf73..fb0458b7e6aa 100644
> --- a/tools/perf/util/namespaces.c
> +++ b/tools/perf/util/namespaces.c
> @@ -199,9 +201,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
> return;
> + oldcwd = get_current_dir_name();
Breaks the build with bionic (Android), where get_current_dir_name() is
not available:
/tmp/build/perf/libperf.a(libperf-in.o):hist.c:function nsinfo__mountns_enter: error: undefined reference to 'get_current_dir_name'
collect2: error: ld returned 1 exit status
Makefile.perf:534: recipe for target '/tmp/build/perf/perf' failed
make[2]: *** [/tmp/build/perf/perf] Error 1
Makefile.perf:206: recipe for target 'sub-make' failed
make[1]: *** [sub-make] Error 2
Makefile:69: recipe for target 'all' failed
make: *** [all] Error 2
make: Leaving directory '/git/linux/tools/perf'
[root@seventh ~]#
The container builds are ongoing, its possoble that this becomes an
issue in uCLibc, wasn't on musl libc (Alpine Linux).
- Arnaldo
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] perf tools: Restore proper cwd on return from mnt ns
2018-11-19 16:10 ` Arnaldo Carvalho de Melo
@ 2018-11-20 10:56 ` Jiri Olsa
2018-11-20 11:23 ` [PATCHv2] " Jiri Olsa
2018-11-20 15:56 ` [PATCH] " Arnaldo Carvalho de Melo
0 siblings, 2 replies; 11+ messages in thread
From: Jiri Olsa @ 2018-11-20 10:56 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Jiri Olsa, Krister Johansen, lkml, Ingo Molnar, Namhyung Kim,
Alexander Shishkin, Peter Zijlstra
On Mon, Nov 19, 2018 at 08:10:06AM -0800, Arnaldo Carvalho de Melo wrote:
> Em Thu, Nov 01, 2018 at 06:00:01PM +0100, Jiri Olsa escreveu:
> > Adding the current working directory to be part of the cookie
> > and restoring it in the nsinfo__mountns_exit call.
>
> > diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
> > index cf8bd123cf73..fb0458b7e6aa 100644
> > --- a/tools/perf/util/namespaces.c
> > +++ b/tools/perf/util/namespaces.c
>
> > @@ -199,9 +201,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> > if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
> > return;
>
> > + oldcwd = get_current_dir_name();
>
> Breaks the build with bionic (Android), where get_current_dir_name() is
> not available:
>
> /tmp/build/perf/libperf.a(libperf-in.o):hist.c:function nsinfo__mountns_enter: error: undefined reference to 'get_current_dir_name'
> collect2: error: ld returned 1 exit status
> Makefile.perf:534: recipe for target '/tmp/build/perf/perf' failed
> make[2]: *** [/tmp/build/perf/perf] Error 1
> Makefile.perf:206: recipe for target 'sub-make' failed
> make[1]: *** [sub-make] Error 2
> Makefile:69: recipe for target 'all' failed
> make: *** [all] Error 2
> make: Leaving directory '/git/linux/tools/perf'
> [root@seventh ~]#
>
> The container builds are ongoing, its possoble that this becomes an
> issue in uCLibc, wasn't on musl libc (Alpine Linux).
will check, thanks
jirka
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCHv2] perf tools: Restore proper cwd on return from mnt ns
2018-11-20 10:56 ` Jiri Olsa
@ 2018-11-20 11:23 ` Jiri Olsa
2018-11-20 15:56 ` [PATCH] " Arnaldo Carvalho de Melo
1 sibling, 0 replies; 11+ messages in thread
From: Jiri Olsa @ 2018-11-20 11:23 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Jiri Olsa, Krister Johansen, lkml, Ingo Molnar, Namhyung Kim,
Alexander Shishkin, Peter Zijlstra
On Tue, Nov 20, 2018 at 11:56:18AM +0100, Jiri Olsa wrote:
> On Mon, Nov 19, 2018 at 08:10:06AM -0800, Arnaldo Carvalho de Melo wrote:
> > Em Thu, Nov 01, 2018 at 06:00:01PM +0100, Jiri Olsa escreveu:
> > > Adding the current working directory to be part of the cookie
> > > and restoring it in the nsinfo__mountns_exit call.
> >
> > > diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
> > > index cf8bd123cf73..fb0458b7e6aa 100644
> > > --- a/tools/perf/util/namespaces.c
> > > +++ b/tools/perf/util/namespaces.c
> >
> > > @@ -199,9 +201,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> > > if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
> > > return;
> >
> > > + oldcwd = get_current_dir_name();
> >
> > Breaks the build with bionic (Android), where get_current_dir_name() is
> > not available:
> >
> > /tmp/build/perf/libperf.a(libperf-in.o):hist.c:function nsinfo__mountns_enter: error: undefined reference to 'get_current_dir_name'
> > collect2: error: ld returned 1 exit status
> > Makefile.perf:534: recipe for target '/tmp/build/perf/perf' failed
> > make[2]: *** [/tmp/build/perf/perf] Error 1
> > Makefile.perf:206: recipe for target 'sub-make' failed
> > make[1]: *** [sub-make] Error 2
> > Makefile:69: recipe for target 'all' failed
> > make: *** [all] Error 2
> > make: Leaving directory '/git/linux/tools/perf'
> > [root@seventh ~]#
> >
> > The container builds are ongoing, its possoble that this becomes an
> > issue in uCLibc, wasn't on musl libc (Alpine Linux).
>
> will check, thanks
how about this one?
thanks,
jirka
---
When reporting on 'record' server we try to retrieve/use
the mnt namespace of the profiled tasks. We use following
API with cookie to hold the return namespace, roughly:
nsinfo__mountns_enter(struct nsinfo *nsi, struct nscookie *nc)
setns(newns, 0);
...
new ns related open..
...
nsinfo__mountns_exit(struct nscookie *nc)
setns(nc->oldns)
Once finished we setns to old namespace, which also sets the
current working directory (cwd) to "/", trashing the cwd we had.
This is mostly fine, because we use absolute paths almost everywhere,
but it screws up perf diff:
# perf diff
failed to open perf.data: No such file or directory (try 'perf record' first)
...
Adding the current working directory to be part of the cookie
and restoring it in the nsinfo__mountns_exit call.
v2: get rid of _GNU_SOURCE get_current_dir_name call [acme]
Cc: Krister Johansen <kjlx@templeofstupid.com>
Fixes: 843ff37bb59e ("perf symbols: Find symbols in different mount namespace")
Link: http://lkml.kernel.org/n/tip-zg3vz7kjr86cco7lo91v8yhj@git.kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/perf/util/namespaces.c | 25 +++++++++++++++++++++++--
tools/perf/util/namespaces.h | 1 +
2 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
index cf8bd123cf73..b759a7ad87e7 100644
--- a/tools/perf/util/namespaces.c
+++ b/tools/perf/util/namespaces.c
@@ -18,6 +18,7 @@
#include <stdio.h>
#include <string.h>
#include <unistd.h>
+#include <asm/bug.h>
struct namespaces *namespaces__new(struct namespaces_event *event)
{
@@ -180,12 +181,20 @@ void nsinfo__put(struct nsinfo *nsi)
nsinfo__delete(nsi);
}
+static char *get_current_dir(void)
+{
+ char path[PATH_MAX];
+
+ return getcwd(path, PATH_MAX) ? strdup(path) : NULL;
+}
+
void nsinfo__mountns_enter(struct nsinfo *nsi,
struct nscookie *nc)
{
char curpath[PATH_MAX];
int oldns = -1;
int newns = -1;
+ char *oldcwd = NULL;
if (nc == NULL)
return;
@@ -199,9 +208,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
return;
+ oldcwd = get_current_dir();
+ if (!oldcwd)
+ return;
+
oldns = open(curpath, O_RDONLY);
if (oldns < 0)
- return;
+ goto errout;
newns = open(nsi->mntns_path, O_RDONLY);
if (newns < 0)
@@ -210,11 +223,14 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
if (setns(newns, CLONE_NEWNS) < 0)
goto errout;
+ nc->oldcwd = oldcwd;
nc->oldns = oldns;
nc->newns = newns;
return;
errout:
+ if (oldcwd)
+ free(oldcwd);
if (oldns > -1)
close(oldns);
if (newns > -1)
@@ -223,11 +239,16 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
void nsinfo__mountns_exit(struct nscookie *nc)
{
- if (nc == NULL || nc->oldns == -1 || nc->newns == -1)
+ if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd)
return;
setns(nc->oldns, CLONE_NEWNS);
+ if (nc->oldcwd) {
+ WARN_ON_ONCE(chdir(nc->oldcwd));
+ free(nc->oldcwd);
+ }
+
if (nc->oldns > -1) {
close(nc->oldns);
nc->oldns = -1;
diff --git a/tools/perf/util/namespaces.h b/tools/perf/util/namespaces.h
index cae1a9a39722..d5f46c09ea31 100644
--- a/tools/perf/util/namespaces.h
+++ b/tools/perf/util/namespaces.h
@@ -38,6 +38,7 @@ struct nsinfo {
struct nscookie {
int oldns;
int newns;
+ char *oldcwd;
};
int nsinfo__init(struct nsinfo *nsi);
--
2.17.2
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH] perf tools: Restore proper cwd on return from mnt ns
2018-11-20 10:56 ` Jiri Olsa
2018-11-20 11:23 ` [PATCHv2] " Jiri Olsa
@ 2018-11-20 15:56 ` Arnaldo Carvalho de Melo
2018-11-20 17:42 ` Jiri Olsa
1 sibling, 1 reply; 11+ messages in thread
From: Arnaldo Carvalho de Melo @ 2018-11-20 15:56 UTC (permalink / raw)
To: Jiri Olsa
Cc: Jiri Olsa, Krister Johansen, lkml, Ingo Molnar, Namhyung Kim,
Alexander Shishkin, Peter Zijlstra
Em Tue, Nov 20, 2018 at 11:56:18AM +0100, Jiri Olsa escreveu:
> On Mon, Nov 19, 2018 at 08:10:06AM -0800, Arnaldo Carvalho de Melo wrote:
> > Em Thu, Nov 01, 2018 at 06:00:01PM +0100, Jiri Olsa escreveu:
> > > Adding the current working directory to be part of the cookie
> > > and restoring it in the nsinfo__mountns_exit call.
> >
> > > diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
> > > index cf8bd123cf73..fb0458b7e6aa 100644
> > > --- a/tools/perf/util/namespaces.c
> > > +++ b/tools/perf/util/namespaces.c
> >
> > > @@ -199,9 +201,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> > > if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
> > > return;
> >
> > > + oldcwd = get_current_dir_name();
> >
> > Breaks the build with bionic (Android), where get_current_dir_name() is
> > not available:
> >
> > /tmp/build/perf/libperf.a(libperf-in.o):hist.c:function nsinfo__mountns_enter: error: undefined reference to 'get_current_dir_name'
> > collect2: error: ld returned 1 exit status
> > Makefile.perf:534: recipe for target '/tmp/build/perf/perf' failed
> > make[2]: *** [/tmp/build/perf/perf] Error 1
> > Makefile.perf:206: recipe for target 'sub-make' failed
> > make[1]: *** [sub-make] Error 2
> > Makefile:69: recipe for target 'all' failed
> > make: *** [all] Error 2
> > make: Leaving directory '/git/linux/tools/perf'
> > [root@seventh ~]#
> >
> > The container builds are ongoing, its possoble that this becomes an
> > issue in uCLibc, wasn't on musl libc (Alpine Linux).
>
> will check, thanks
I fixed this already, by adding a test for that get_current_dir_name()
function and a simple implementation based on strdup(getcwd(bf)), take a
look at my perf/urgent branch
- Arnaldo
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH] perf tools: Restore proper cwd on return from mnt ns
2018-11-20 15:56 ` [PATCH] " Arnaldo Carvalho de Melo
@ 2018-11-20 17:42 ` Jiri Olsa
0 siblings, 0 replies; 11+ messages in thread
From: Jiri Olsa @ 2018-11-20 17:42 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Jiri Olsa, Krister Johansen, lkml, Ingo Molnar, Namhyung Kim,
Alexander Shishkin, Peter Zijlstra
On Tue, Nov 20, 2018 at 12:56:04PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Nov 20, 2018 at 11:56:18AM +0100, Jiri Olsa escreveu:
> > On Mon, Nov 19, 2018 at 08:10:06AM -0800, Arnaldo Carvalho de Melo wrote:
> > > Em Thu, Nov 01, 2018 at 06:00:01PM +0100, Jiri Olsa escreveu:
> > > > Adding the current working directory to be part of the cookie
> > > > and restoring it in the nsinfo__mountns_exit call.
> > >
> > > > diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
> > > > index cf8bd123cf73..fb0458b7e6aa 100644
> > > > --- a/tools/perf/util/namespaces.c
> > > > +++ b/tools/perf/util/namespaces.c
> > >
> > > > @@ -199,9 +201,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
> > > > if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
> > > > return;
> > >
> > > > + oldcwd = get_current_dir_name();
> > >
> > > Breaks the build with bionic (Android), where get_current_dir_name() is
> > > not available:
> > >
> > > /tmp/build/perf/libperf.a(libperf-in.o):hist.c:function nsinfo__mountns_enter: error: undefined reference to 'get_current_dir_name'
> > > collect2: error: ld returned 1 exit status
> > > Makefile.perf:534: recipe for target '/tmp/build/perf/perf' failed
> > > make[2]: *** [/tmp/build/perf/perf] Error 1
> > > Makefile.perf:206: recipe for target 'sub-make' failed
> > > make[1]: *** [sub-make] Error 2
> > > Makefile:69: recipe for target 'all' failed
> > > make: *** [all] Error 2
> > > make: Leaving directory '/git/linux/tools/perf'
> > > [root@seventh ~]#
> > >
> > > The container builds are ongoing, its possoble that this becomes an
> > > issue in uCLibc, wasn't on musl libc (Alpine Linux).
> >
> > will check, thanks
>
> I fixed this already, by adding a test for that get_current_dir_name()
> function and a simple implementation based on strdup(getcwd(bf)), take a
> look at my perf/urgent branch
ok, I saw it.. but it seems little too much for a single function to me
jirka
^ permalink raw reply [flat|nested] 11+ messages in thread
* [tip:perf/urgent] perf tools: Restore proper cwd on return from mnt namespace
2018-11-01 17:00 [PATCH] perf tools: Restore proper cwd on return from mnt ns Jiri Olsa
` (2 preceding siblings ...)
2018-11-19 16:10 ` Arnaldo Carvalho de Melo
@ 2018-11-21 15:02 ` tip-bot for Jiri Olsa
3 siblings, 0 replies; 11+ messages in thread
From: tip-bot for Jiri Olsa @ 2018-11-21 15:02 UTC (permalink / raw)
To: linux-tip-commits
Cc: peterz, mingo, linux-kernel, namhyung, jolsa, alexander.shishkin,
acme, tglx, kjlx, hpa
Commit-ID: b01c1f69c8660eaeab7d365cd570103c5c073a02
Gitweb: https://git.kernel.org/tip/b01c1f69c8660eaeab7d365cd570103c5c073a02
Author: Jiri Olsa <jolsa@kernel.org>
AuthorDate: Thu, 1 Nov 2018 18:00:01 +0100
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 19 Nov 2018 12:12:26 -0800
perf tools: Restore proper cwd on return from mnt namespace
When reporting on 'record' server we try to retrieve/use the mnt
namespace of the profiled tasks. We use following API with cookie to
hold the return namespace, roughly:
nsinfo__mountns_enter(struct nsinfo *nsi, struct nscookie *nc)
setns(newns, 0);
...
new ns related open..
...
nsinfo__mountns_exit(struct nscookie *nc)
setns(nc->oldns)
Once finished we setns to old namespace, which also sets the current
working directory (cwd) to "/", trashing the cwd we had.
This is mostly fine, because we use absolute paths almost everywhere,
but it screws up 'perf diff':
# perf diff
failed to open perf.data: No such file or directory (try 'perf record' first)
...
Adding the current working directory to be part of the cookie and
restoring it in the nsinfo__mountns_exit call.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Krister Johansen <kjlx@templeofstupid.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: 843ff37bb59e ("perf symbols: Find symbols in different mount namespace")
Link: http://lkml.kernel.org/r/20181101170001.30019-1-jolsa@kernel.org
[ No need to check for NULL args for free(), use zfree() for struct members ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/namespaces.c | 17 +++++++++++++++--
tools/perf/util/namespaces.h | 1 +
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
index cf8bd123cf73..aed170bd4384 100644
--- a/tools/perf/util/namespaces.c
+++ b/tools/perf/util/namespaces.c
@@ -18,6 +18,7 @@
#include <stdio.h>
#include <string.h>
#include <unistd.h>
+#include <asm/bug.h>
struct namespaces *namespaces__new(struct namespaces_event *event)
{
@@ -186,6 +187,7 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
char curpath[PATH_MAX];
int oldns = -1;
int newns = -1;
+ char *oldcwd = NULL;
if (nc == NULL)
return;
@@ -199,9 +201,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
return;
+ oldcwd = get_current_dir_name();
+ if (!oldcwd)
+ return;
+
oldns = open(curpath, O_RDONLY);
if (oldns < 0)
- return;
+ goto errout;
newns = open(nsi->mntns_path, O_RDONLY);
if (newns < 0)
@@ -210,11 +216,13 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
if (setns(newns, CLONE_NEWNS) < 0)
goto errout;
+ nc->oldcwd = oldcwd;
nc->oldns = oldns;
nc->newns = newns;
return;
errout:
+ free(oldcwd);
if (oldns > -1)
close(oldns);
if (newns > -1)
@@ -223,11 +231,16 @@ errout:
void nsinfo__mountns_exit(struct nscookie *nc)
{
- if (nc == NULL || nc->oldns == -1 || nc->newns == -1)
+ if (nc == NULL || nc->oldns == -1 || nc->newns == -1 || !nc->oldcwd)
return;
setns(nc->oldns, CLONE_NEWNS);
+ if (nc->oldcwd) {
+ WARN_ON_ONCE(chdir(nc->oldcwd));
+ zfree(&nc->oldcwd);
+ }
+
if (nc->oldns > -1) {
close(nc->oldns);
nc->oldns = -1;
diff --git a/tools/perf/util/namespaces.h b/tools/perf/util/namespaces.h
index cae1a9a39722..d5f46c09ea31 100644
--- a/tools/perf/util/namespaces.h
+++ b/tools/perf/util/namespaces.h
@@ -38,6 +38,7 @@ struct nsinfo {
struct nscookie {
int oldns;
int newns;
+ char *oldcwd;
};
int nsinfo__init(struct nsinfo *nsi);
^ permalink raw reply related [flat|nested] 11+ messages in thread