[4.2.y-ckt stable] Patch "perf symbols: Fix dso lookup by long name and missing buildids" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Thu Jan 14 22:27:37 UTC 2016
This is a note to let you know that I have just added a patch titled
perf symbols: Fix dso lookup by long name and missing buildids
to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue
This patch is scheduled to be released in version 4.2.8-ckt2.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
---8<------------------------------------------------------------
>From ca41ea44f870173c2fb0c2aabffe113f9b6bf2fe Mon Sep 17 00:00:00 2001
From: Adrian Hunter <adrian.hunter at intel.com>
Date: Fri, 13 Nov 2015 11:48:30 +0200
Subject: perf symbols: Fix dso lookup by long name and missing buildids
commit e266a753bf51b2c3b46d0d230349662c35ac5629 upstream.
Commit 4598a0a6d22f ("perf symbols: Improve DSO long names lookup speed
with rbtree") Added a tree to lookup dsos by long name. That tree gets
corrupted whenever a dso long name is changed because the tree is not
updated.
One effect of that is buildid-list does not work with the 'with-hits'
option because dso lookup fails and results in two structs for the same
dso. The first has the buildid but no hits, the second has hits but no
buildid. e.g.
Before:
$ tools/perf/perf record ls
arch certs CREDITS Documentation firmware include
ipc Kconfig lib Makefile net REPORTING-BUGS
scripts sound usr block COPYING crypto
drivers fs init Kbuild kernel MAINTAINERS
mm README samples security tools virt
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.012 MB perf.data (11 samples) ]
$ tools/perf/perf buildid-list
574da826c66538a8d9060d393a8866289bd06005 [kernel.kallsyms]
30c94dc66a1fe95180c3d68d2b89e576d5ae213c /lib/x86_64-linux-gnu/libc-2.19.so
$ tools/perf/perf buildid-list -H
574da826c66538a8d9060d393a8866289bd06005 [kernel.kallsyms]
0000000000000000000000000000000000000000 /lib/x86_64-linux-gnu/libc-2.19.so
After:
$ tools/perf/perf buildid-list -H
574da826c66538a8d9060d393a8866289bd06005 [kernel.kallsyms]
30c94dc66a1fe95180c3d68d2b89e576d5ae213c /lib/x86_64-linux-gnu/libc-2.19.so
The fix is to record the root of the tree on the dso so that
dso__set_long_name() can update the tree when the long name changes.
Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme at redhat.com>
Cc: Adrian Hunter <adrian.hunter at intel.com>
Cc: Don Zickus <dzickus at redhat.com>
Cc: Douglas Hatch <doug.hatch at hp.com>
Cc: Jiri Olsa <jolsa at kernel.org>
Cc: Namhyung Kim <namhyung at kernel.org>
Cc: Peter Zijlstra <peterz at infradead.org>
Cc: Scott J Norton <scott.norton at hp.com>
Cc: Waiman Long <Waiman.Long at hp.com>
Fixes: 4598a0a6d22f ("perf symbols: Improve DSO long names lookup speed with rbtree")
Link: http://lkml.kernel.org/r/1447408112-1920-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
tools/perf/util/dso.c | 17 +++++++++++++++++
tools/perf/util/dso.h | 1 +
tools/perf/util/machine.c | 1 +
3 files changed, 19 insertions(+)
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 7c0c083..425df5c 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -933,6 +933,7 @@ static struct dso *__dso__findlink_by_longname(struct rb_root *root,
/* Add new node and rebalance tree */
rb_link_node(&dso->rb_node, parent, p);
rb_insert_color(&dso->rb_node, root);
+ dso->root = root;
}
return NULL;
}
@@ -945,15 +946,30 @@ static inline struct dso *__dso__find_by_longname(struct rb_root *root,
void dso__set_long_name(struct dso *dso, const char *name, bool name_allocated)
{
+ struct rb_root *root = dso->root;
+
if (name == NULL)
return;
if (dso->long_name_allocated)
free((char *)dso->long_name);
+ if (root) {
+ rb_erase(&dso->rb_node, root);
+ /*
+ * __dso__findlink_by_longname() isn't guaranteed to add it
+ * back, so a clean removal is required here.
+ */
+ RB_CLEAR_NODE(&dso->rb_node);
+ dso->root = NULL;
+ }
+
dso->long_name = name;
dso->long_name_len = strlen(name);
dso->long_name_allocated = name_allocated;
+
+ if (root)
+ __dso__findlink_by_longname(root, dso, NULL);
}
void dso__set_short_name(struct dso *dso, const char *name, bool name_allocated)
@@ -1046,6 +1062,7 @@ struct dso *dso__new(const char *name)
dso->kernel = DSO_TYPE_USER;
dso->needs_swap = DSO_SWAP__UNSET;
RB_CLEAR_NODE(&dso->rb_node);
+ dso->root = NULL;
INIT_LIST_HEAD(&dso->node);
INIT_LIST_HEAD(&dso->data.open_entry);
pthread_mutex_init(&dso->lock, NULL);
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 2fe98bb..b9ec6d8 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -135,6 +135,7 @@ struct dso {
pthread_mutex_t lock;
struct list_head node;
struct rb_node rb_node; /* rbtree node sorted by long name */
+ struct rb_root *root; /* root of rbtree that rb_node is in */
struct rb_root symbols[MAP__NR_TYPES];
struct rb_root symbol_names[MAP__NR_TYPES];
void *a2l;
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index f1a4c83..69c17dc 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -90,6 +90,7 @@ static void dsos__purge(struct dsos *dsos)
list_for_each_entry_safe(pos, n, &dsos->head, node) {
RB_CLEAR_NODE(&pos->rb_node);
+ pos->root = NULL;
list_del_init(&pos->node);
dso__put(pos);
}
--
1.9.1
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