Commit 843ff37b authored by Krister Johansen's avatar Krister Johansen Committed by Arnaldo Carvalho de Melo

perf symbols: Find symbols in different mount namespace

Teach perf how to resolve symbols from binaries that are in a different
mount namespace from the tool.  This allows perf to generate meaningful
stack traces even if the binary resides in a different mount namespace
from the tool.
Signed-off-by: default avatarKrister Johansen <kjlx@templeofstupid.com>
Tested-by: default avatarBrendan Gregg <brendan.d.gregg@gmail.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1499305693-1599-2-git-send-email-kjlx@templeofstupid.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 86bcdb5a
...@@ -1236,6 +1236,7 @@ void dso__delete(struct dso *dso) ...@@ -1236,6 +1236,7 @@ void dso__delete(struct dso *dso)
dso_cache__free(dso); dso_cache__free(dso);
dso__free_a2l(dso); dso__free_a2l(dso);
zfree(&dso->symsrc_filename); zfree(&dso->symsrc_filename);
nsinfo__zput(dso->nsinfo);
pthread_mutex_destroy(&dso->lock); pthread_mutex_destroy(&dso->lock);
free(dso); free(dso);
} }
......
...@@ -10,6 +10,7 @@ ...@@ -10,6 +10,7 @@
#include <linux/types.h> #include <linux/types.h>
#include <linux/bitops.h> #include <linux/bitops.h>
#include "map.h" #include "map.h"
#include "namespaces.h"
#include "build-id.h" #include "build-id.h"
enum dso_binary_type { enum dso_binary_type {
...@@ -187,6 +188,7 @@ struct dso { ...@@ -187,6 +188,7 @@ struct dso {
void *priv; void *priv;
u64 db_id; u64 db_id;
}; };
struct nsinfo *nsinfo;
refcount_t refcnt; refcount_t refcnt;
char name[0]; char name[0];
}; };
......
...@@ -16,6 +16,7 @@ ...@@ -16,6 +16,7 @@
#include "machine.h" #include "machine.h"
#include <linux/string.h> #include <linux/string.h>
#include "srcline.h" #include "srcline.h"
#include "namespaces.h"
#include "unwind.h" #include "unwind.h"
static void __maps__insert(struct maps *maps, struct map *map); static void __maps__insert(struct maps *maps, struct map *map);
...@@ -200,6 +201,7 @@ struct map *map__new(struct machine *machine, u64 start, u64 len, ...@@ -200,6 +201,7 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
if (type != MAP__FUNCTION) if (type != MAP__FUNCTION)
dso__set_loaded(dso, map->type); dso__set_loaded(dso, map->type);
} }
dso->nsinfo = nsinfo__get(thread->nsinfo);
dso__put(dso); dso__put(dso);
} }
return map; return map;
......
...@@ -9,9 +9,13 @@ ...@@ -9,9 +9,13 @@
#include "namespaces.h" #include "namespaces.h"
#include "util.h" #include "util.h"
#include "event.h" #include "event.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <sched.h>
#include <stdlib.h> #include <stdlib.h>
#include <stdio.h> #include <stdio.h>
#include <string.h> #include <string.h>
#include <unistd.h>
struct namespaces *namespaces__new(struct namespaces_event *event) struct namespaces *namespaces__new(struct namespaces_event *event)
{ {
...@@ -35,3 +39,126 @@ void namespaces__free(struct namespaces *namespaces) ...@@ -35,3 +39,126 @@ void namespaces__free(struct namespaces *namespaces)
{ {
free(namespaces); free(namespaces);
} }
void nsinfo__init(struct nsinfo *nsi)
{
char oldns[PATH_MAX];
char *newns = NULL;
struct stat old_stat;
struct stat new_stat;
if (snprintf(oldns, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
return;
if (asprintf(&newns, "/proc/%d/ns/mnt", nsi->pid) == -1)
return;
if (stat(oldns, &old_stat) < 0)
goto out;
if (stat(newns, &new_stat) < 0)
goto out;
/* Check if the mount namespaces differ, if so then indicate that we
* want to switch as part of looking up dso/map data.
*/
if (old_stat.st_ino != new_stat.st_ino) {
nsi->need_setns = true;
nsi->mntns_path = newns;
newns = NULL;
}
out:
free(newns);
}
struct nsinfo *nsinfo__new(pid_t pid)
{
struct nsinfo *nsi = calloc(1, sizeof(*nsi));
if (nsi != NULL) {
nsi->pid = pid;
nsi->need_setns = false;
nsinfo__init(nsi);
refcount_set(&nsi->refcnt, 1);
}
return nsi;
}
void nsinfo__delete(struct nsinfo *nsi)
{
zfree(&nsi->mntns_path);
free(nsi);
}
struct nsinfo *nsinfo__get(struct nsinfo *nsi)
{
if (nsi)
refcount_inc(&nsi->refcnt);
return nsi;
}
void nsinfo__put(struct nsinfo *nsi)
{
if (nsi && refcount_dec_and_test(&nsi->refcnt))
nsinfo__delete(nsi);
}
void nsinfo__mountns_enter(struct nsinfo *nsi, struct nscookie *nc)
{
char curpath[PATH_MAX];
int oldns = -1;
int newns = -1;
if (nc == NULL)
return;
nc->oldns = -1;
nc->newns = -1;
if (!nsi || !nsi->need_setns)
return;
if (snprintf(curpath, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
return;
oldns = open(curpath, O_RDONLY);
if (oldns < 0)
return;
newns = open(nsi->mntns_path, O_RDONLY);
if (newns < 0)
goto errout;
if (setns(newns, CLONE_NEWNS) < 0)
goto errout;
nc->oldns = oldns;
nc->newns = newns;
return;
errout:
if (oldns > -1)
close(oldns);
if (newns > -1)
close(newns);
}
void nsinfo__mountns_exit(struct nscookie *nc)
{
if (nc == NULL || nc->oldns == -1 || nc->newns == -1)
return;
setns(nc->oldns, CLONE_NEWNS);
if (nc->oldns > -1) {
close(nc->oldns);
nc->oldns = -1;
}
if (nc->newns > -1) {
close(nc->newns);
nc->newns = -1;
}
}
...@@ -11,6 +11,7 @@ ...@@ -11,6 +11,7 @@
#include "../perf.h" #include "../perf.h"
#include <linux/list.h> #include <linux/list.h>
#include <linux/refcount.h>
struct namespaces_event; struct namespaces_event;
...@@ -23,4 +24,36 @@ struct namespaces { ...@@ -23,4 +24,36 @@ struct namespaces {
struct namespaces *namespaces__new(struct namespaces_event *event); struct namespaces *namespaces__new(struct namespaces_event *event);
void namespaces__free(struct namespaces *namespaces); void namespaces__free(struct namespaces *namespaces);
struct nsinfo {
pid_t pid;
bool need_setns;
char *mntns_path;
refcount_t refcnt;
};
struct nscookie {
int oldns;
int newns;
};
void nsinfo__init(struct nsinfo *nsi);
struct nsinfo *nsinfo__new(pid_t pid);
void nsinfo__delete(struct nsinfo *nsi);
struct nsinfo *nsinfo__get(struct nsinfo *nsi);
void nsinfo__put(struct nsinfo *nsi);
void nsinfo__mountns_enter(struct nsinfo *nsi, struct nscookie *nc);
void nsinfo__mountns_exit(struct nscookie *nc);
static inline void __nsinfo__zput(struct nsinfo **nsip)
{
if (nsip) {
nsinfo__put(*nsip);
*nsip = NULL;
}
}
#define nsinfo__zput(nsi) __nsinfo__zput(&nsi)
#endif /* __PERF_NAMESPACES_H */ #endif /* __PERF_NAMESPACES_H */
...@@ -18,6 +18,8 @@ ...@@ -18,6 +18,8 @@
#include "symbol.h" #include "symbol.h"
#include "strlist.h" #include "strlist.h"
#include "intlist.h" #include "intlist.h"
#include "namespaces.h"
#include "vdso.h"
#include "header.h" #include "header.h"
#include "path.h" #include "path.h"
#include "sane_ctype.h" #include "sane_ctype.h"
...@@ -1436,9 +1438,17 @@ int dso__load(struct dso *dso, struct map *map) ...@@ -1436,9 +1438,17 @@ int dso__load(struct dso *dso, struct map *map)
struct symsrc *syms_ss = NULL, *runtime_ss = NULL; struct symsrc *syms_ss = NULL, *runtime_ss = NULL;
bool kmod; bool kmod;
unsigned char build_id[BUILD_ID_SIZE]; unsigned char build_id[BUILD_ID_SIZE];
struct nscookie nsc;
nsinfo__mountns_enter(dso->nsinfo, &nsc);
pthread_mutex_lock(&dso->lock); pthread_mutex_lock(&dso->lock);
/* The vdso files always live in the host container, so don't go looking
* for them in the container's mount namespace.
*/
if (dso__is_vdso(dso))
nsinfo__mountns_exit(&nsc);
/* check again under the dso->lock */ /* check again under the dso->lock */
if (dso__loaded(dso, map->type)) { if (dso__loaded(dso, map->type)) {
ret = 1; ret = 1;
...@@ -1584,6 +1594,7 @@ int dso__load(struct dso *dso, struct map *map) ...@@ -1584,6 +1594,7 @@ int dso__load(struct dso *dso, struct map *map)
out: out:
dso__set_loaded(dso, map->type); dso__set_loaded(dso, map->type);
pthread_mutex_unlock(&dso->lock); pthread_mutex_unlock(&dso->lock);
nsinfo__mountns_exit(&nsc);
return ret; return ret;
} }
......
...@@ -59,6 +59,8 @@ struct thread *thread__new(pid_t pid, pid_t tid) ...@@ -59,6 +59,8 @@ struct thread *thread__new(pid_t pid, pid_t tid)
list_add(&comm->list, &thread->comm_list); list_add(&comm->list, &thread->comm_list);
refcount_set(&thread->refcnt, 1); refcount_set(&thread->refcnt, 1);
RB_CLEAR_NODE(&thread->rb_node); RB_CLEAR_NODE(&thread->rb_node);
/* Thread holds first ref to nsdata. */
thread->nsinfo = nsinfo__new(pid);
} }
return thread; return thread;
...@@ -91,6 +93,7 @@ void thread__delete(struct thread *thread) ...@@ -91,6 +93,7 @@ void thread__delete(struct thread *thread)
comm__free(comm); comm__free(comm);
} }
unwind__finish_access(thread); unwind__finish_access(thread);
nsinfo__zput(thread->nsinfo);
free(thread); free(thread);
} }
......
...@@ -34,6 +34,7 @@ struct thread { ...@@ -34,6 +34,7 @@ struct thread {
void *priv; void *priv;
struct thread_stack *ts; struct thread_stack *ts;
struct nsinfo *nsinfo;
#ifdef HAVE_LIBUNWIND_SUPPORT #ifdef HAVE_LIBUNWIND_SUPPORT
void *addr_space; void *addr_space;
struct unwind_libunwind_ops *unwind_libunwind_ops; struct unwind_libunwind_ops *unwind_libunwind_ops;
......
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