Re: [PATCH] perf: Avoid resolving [kernel.kallsyms] to real pathfor buildid cache
From: Arnaldo Carvalho de Melo
Date: Wed Mar 09 2011 - 10:57:53 EST
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 <fbuihuu@xxxxxxxxx>
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: <m38vzxxrql.fsf@xxxxxxxxx>
Signed-off-by: Franck Bui-Huu <fbuihuu@xxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
[acme@emilia linux]$ git describe 68a7a771
v2.6.37-rc5-71-g68a7a77
So I'll add a CC: stable@xxxxxxxxxx when pushing to perf/urgent.
- Arnaldo
> On Thu, Mar 3, 2011 at 11:23 PM, Lin Ming <ming.m.lin@xxxxxxxxx> 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 <phan@xxxxxxxxxx>
> > Signed-off-by: Lin Ming <ming.m.lin@xxxxxxxxx>
> > ---
> > 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 majordomo@xxxxxxxxxxxxxxx
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/