mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-15 23:25:07 +00:00
perf tools: Restore proper cwd on return from mnt namespace
[ Upstream commitb01c1f69c8
] 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:843ff37bb5
("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> Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
ca0bcef7c6
commit
d36cc60736
2 changed files with 16 additions and 2 deletions
|
@ -17,6 +17,7 @@
|
|||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
#include <unistd.h>
|
||||
#include <asm/bug.h>
|
||||
|
||||
struct namespaces *namespaces__new(struct namespaces_event *event)
|
||||
{
|
||||
|
@ -185,6 +186,7 @@ void nsinfo__mountns_enter(struct nsinfo *nsi,
|
|||
char curpath[PATH_MAX];
|
||||
int oldns = -1;
|
||||
int newns = -1;
|
||||
char *oldcwd = NULL;
|
||||
|
||||
if (nc == NULL)
|
||||
return;
|
||||
|
@ -198,9 +200,13 @@ 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)
|
||||
|
@ -209,11 +215,13 @@ 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)
|
||||
|
@ -222,11 +230,16 @@ 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));
|
||||
zfree(&nc->oldcwd);
|
||||
}
|
||||
|
||||
if (nc->oldns > -1) {
|
||||
close(nc->oldns);
|
||||
nc->oldns = -1;
|
||||
|
|
|
@ -36,6 +36,7 @@ struct nsinfo {
|
|||
struct nscookie {
|
||||
int oldns;
|
||||
int newns;
|
||||
char *oldcwd;
|
||||
};
|
||||
|
||||
int nsinfo__init(struct nsinfo *nsi);
|
||||
|
|
Loading…
Reference in a new issue