2011-03-03 07:28:08

by Lin Ming

Subject: [PATCH] perf: Avoid resolving [kernel.kallsyms] to real path for buildid cache

kallsyms has a virtual file name [kernel.kallsyms].
Currently, it can't be added to buildid cache successfully
because the code(build_id_cache__add_s) tries to resolve
[kernel.kallsyms]to a real absolute pathname and that fails.

Fixes it by not resolving it and just use the name [kernel.kallsyms].
So dir ~/.debug/[kernel.kallsyms] is created.

Original bug report at:
https://lkml.org/lkml/2011/3/1/524

Tested-by: Han Pingtian <[email protected]>
Signed-off-by: Lin Ming <[email protected]>
---
tools/perf/util/header.c | 11 ++++++++---
1 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 72c124d..1f8883b 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -271,11 +271,15 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
const char *name, bool is_kallsyms)
{
const size_t size = PATH_MAX;
- char *realname = realpath(name, NULL),
- *filename = malloc(size),
+ char *realname, *filename = malloc(size),
*linkname = malloc(size), *targetname;
int len, err = -1;

+ if (is_kallsyms)
+ realname = (char *)name;
+ else
+ realname = realpath(name, NULL);
+
if (realname == NULL || filename == NULL || linkname == NULL)
goto out_free;

@@ -307,7 +311,8 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
if (symlink(targetname, linkname) == 0)
err = 0;
out_free:
- free(realname);
+ if (!is_kallsyms)
+ free(realname);
free(filename);
free(linkname);
return err;
--
1.7.2.3

2011-03-09 14:38:55

by Ming Lin

Subject: Re: [PATCH] perf: Avoid resolving [kernel.kallsyms] to real path for buildid cache

Hi, Arnaldo

Could you have a look at this patch?

Thanks,
Lin Ming

On Thu, Mar 3, 2011 at 11:23 PM, Lin Ming <[email protected]> wrote:
> kallsyms has a virtual file name [kernel.kallsyms].
> Currently, it can't be added to buildid cache successfully
> because the code(build_id_cache__add_s) tries to resolve
> [kernel.kallsyms]to a real absolute pathname and that fails.
>
> Fixes it by not resolving it and just use the name [kernel.kallsyms].
> So dir ~/.debug/[kernel.kallsyms] is created.
>
> Original bug report at:
> https://lkml.org/lkml/2011/3/1/524
>
> Tested-by: Han Pingtian <[email protected]>
> Signed-off-by: Lin Ming <[email protected]>
> ---
> ?tools/perf/util/header.c | ? 11 ++++++++---
> ?1 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 72c124d..1f8883b 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -271,11 +271,15 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
> ? ? ? ? ? ? ? ? ? ? ? ? ?const char *name, bool is_kallsyms)
> ?{
> ? ? ? ?const size_t size = PATH_MAX;
> - ? ? ? char *realname = realpath(name, NULL),
> - ? ? ? ? ? ?*filename = malloc(size),
> + ? ? ? char *realname, *filename = malloc(size),
> ? ? ? ? ? ? *linkname = malloc(size), *targetname;
> ? ? ? ?int len, err = -1;
>
> + ? ? ? if (is_kallsyms)
> + ? ? ? ? ? ? ? realname = (char *)name;
> + ? ? ? else
> + ? ? ? ? ? ? ? realname = realpath(name, NULL);
> +
> ? ? ? ?if (realname == NULL || filename == NULL || linkname == NULL)
> ? ? ? ? ? ? ? ?goto out_free;
>
> @@ -307,7 +311,8 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
> ? ? ? ?if (symlink(targetname, linkname) == 0)
> ? ? ? ? ? ? ? ?err = 0;
> ?out_free:
> - ? ? ? free(realname);
> + ? ? ? if (!is_kallsyms)
> + ? ? ? ? ? ? ? free(realname);
> ? ? ? ?free(filename);
> ? ? ? ?free(linkname);
> ? ? ? ?return err;
> --
> 1.7.2.3
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in
> the body of a message to [email protected]
> More majordomo info at ?http://vger.kernel.org/majordomo-info.html
>

2011-03-09 15:57:50

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH] perf: Avoid resolving [kernel.kallsyms] to real path for buildid cache

Em Wed, Mar 09, 2011 at 10:38:52PM +0800, Lin Ming escreveu:
> Hi, Arnaldo
>
> Could you have a look at this patch?
>
> Thanks,
> Lin Ming

Seems ok, problem was introduced in:

commit 68a7a771ad0e2959983729bf88cbc74a7014438f
Author: Franck Bui-Huu <[email protected]>
Date: Fri Dec 10 22:06:26 2010 +0100

perf buildid-cache: Fix symbolic link handling

This was broken since link(2) doesn't dereference symbolic
links. Instead 'filename' becomes a symbolic link to the same file
that 'name' refers to.

This had the bad effect to create dangling symlinks in the case that
even can't be removed with perf-buildid-cache(1).

LKML-Reference: <[email protected]>
Signed-off-by: Franck Bui-Huu <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

[acme@emilia linux]$ git describe 68a7a771
v2.6.37-rc5-71-g68a7a77

So I'll add a CC: [email protected] when pushing to perf/urgent.

- Arnaldo


> On Thu, Mar 3, 2011 at 11:23 PM, Lin Ming <[email protected]> wrote:
> > kallsyms has a virtual file name [kernel.kallsyms].
> > Currently, it can't be added to buildid cache successfully
> > because the code(build_id_cache__add_s) tries to resolve
> > [kernel.kallsyms]to a real absolute pathname and that fails.
> >
> > Fixes it by not resolving it and just use the name [kernel.kallsyms].
> > So dir ~/.debug/[kernel.kallsyms] is created.
> >
> > Original bug report at:
> > https://lkml.org/lkml/2011/3/1/524
> >
> > Tested-by: Han Pingtian <[email protected]>
> > Signed-off-by: Lin Ming <[email protected]>
> > ---
> > ?tools/perf/util/header.c | ? 11 ++++++++---
> > ?1 files changed, 8 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> > index 72c124d..1f8883b 100644
> > --- a/tools/perf/util/header.c
> > +++ b/tools/perf/util/header.c
> > @@ -271,11 +271,15 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
> > ? ? ? ? ? ? ? ? ? ? ? ? ?const char *name, bool is_kallsyms)
> > ?{
> > ? ? ? ?const size_t size = PATH_MAX;
> > - ? ? ? char *realname = realpath(name, NULL),
> > - ? ? ? ? ? ?*filename = malloc(size),
> > + ? ? ? char *realname, *filename = malloc(size),
> > ? ? ? ? ? ? *linkname = malloc(size), *targetname;
> > ? ? ? ?int len, err = -1;
> >
> > + ? ? ? if (is_kallsyms)
> > + ? ? ? ? ? ? ? realname = (char *)name;
> > + ? ? ? else
> > + ? ? ? ? ? ? ? realname = realpath(name, NULL);
> > +
> > ? ? ? ?if (realname == NULL || filename == NULL || linkname == NULL)
> > ? ? ? ? ? ? ? ?goto out_free;
> >
> > @@ -307,7 +311,8 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
> > ? ? ? ?if (symlink(targetname, linkname) == 0)
> > ? ? ? ? ? ? ? ?err = 0;
> > ?out_free:
> > - ? ? ? free(realname);
> > + ? ? ? if (!is_kallsyms)
> > + ? ? ? ? ? ? ? free(realname);
> > ? ? ? ?free(filename);
> > ? ? ? ?free(linkname);
> > ? ? ? ?return err;
> > --
> > 1.7.2.3
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in
> > the body of a message to [email protected]
> > More majordomo info at ?http://vger.kernel.org/majordomo-info.html
> >

2011-03-10 06:37:31

by Lin Ming

Subject: [tip:perf/urgent] perf symbols: Avoid resolving [kernel.kallsyms] to real path for buildid cache

Commit-ID: 7ee235efe5f86f239ce73915fd2e15f4d14259c6
Gitweb: http://git.kernel.org/tip/7ee235efe5f86f239ce73915fd2e15f4d14259c6
Author: Lin Ming <[email protected]>
AuthorDate: Thu, 3 Mar 2011 23:23:57 +0800
Committer: Arnaldo Carvalho de Melo <[email protected]>
CommitDate: Wed, 9 Mar 2011 13:44:10 -0300

perf symbols: Avoid resolving [kernel.kallsyms] to real path for buildid cache

kallsyms has a virtual file name [kernel.kallsyms]. Currently, it can't
be added to buildid cache successfully because the code
(build_id_cache__add_s) tries to resolve [kernel.kallsyms] to a real
absolute pathname and that fails.

Fixes it by not resolving it and just use the name [kernel.kallsyms].
So dir ~/.debug/[kernel.kallsyms] is created.

Original bug report at:
https://lkml.org/lkml/2011/3/1/524

Tested-by: Han Pingtian <[email protected]>
Cc: Han Pingtian <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Lin Ming <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/util/header.c | 11 ++++++++---
1 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index f6a929e7..0866bcd 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -270,11 +270,15 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
const char *name, bool is_kallsyms)
{
const size_t size = PATH_MAX;
- char *realname = realpath(name, NULL),
- *filename = malloc(size),
+ char *realname, *filename = malloc(size),
*linkname = malloc(size), *targetname;
int len, err = -1;

+ if (is_kallsyms)
+ realname = (char *)name;
+ else
+ realname = realpath(name, NULL);
+
if (realname == NULL || filename == NULL || linkname == NULL)
goto out_free;

@@ -306,7 +310,8 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir,
if (symlink(targetname, linkname) == 0)
err = 0;
out_free:
- free(realname);
+ if (!is_kallsyms)
+ free(realname);
free(filename);
free(linkname);
return err;