* [PATCH cgroup/for-3.10] cgroup: make cgroup_path() not print double slashes
@ 2013-04-14 17:37 Tejun Heo
[not found] ` <20130414173704.GB3050-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
0 siblings, 1 reply; 6+ messages in thread
From: Tejun Heo @ 2013-04-14 17:37 UTC (permalink / raw)
To: Li Zefan
Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA,
cgroups-u79uwXL29TY76Z2rM5mHXA
From 277f3d4be79aefe2071d9053a9c7c89c4e5dad30 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Date: Sun, 14 Apr 2013 10:32:19 -0700
While reimplementing cgroup_path(), 65dff759d2 ("cgroup: fix
cgroup_path() vs rename() race") introduced a bug where the path of a
non-root cgroup would have two slahses at the beginning, which is
caused by adding '/' before the name of the root cgroup which is an
empty string.
$ grep systemd /proc/self/cgroup
1:name=systemd://user/root/1
Fix it by special casing root cgroup.
Signed-off-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---
Applying to cgroup/for-3.10.
Thanks.
kernel/cgroup.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 678a22c..faf55f5 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1811,11 +1811,17 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
int ret = -ENAMETOOLONG;
char *start;
+ if (!cgrp->parent) {
+ if (strlcpy(buf, "/", buflen) >= buflen)
+ return -ENAMETOOLONG;
+ return 0;
+ }
+
start = buf + buflen - 1;
*start = '\0';
rcu_read_lock();
- while (cgrp) {
+ do {
const char *name = cgroup_name(cgrp);
int len;
@@ -1824,15 +1830,12 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
goto out;
memcpy(start, name, len);
- if (!cgrp->parent)
- break;
-
if (--start < buf)
goto out;
*start = '/';
cgrp = cgrp->parent;
- }
+ } while (cgrp->parent);
ret = 0;
memmove(buf, start, buf + buflen - start);
out:
--
1.8.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread[parent not found: <20130414173704.GB3050-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>]
* [PATCH UPDATED cgroup/for-3.10] cgroup: make cgroup_path() not print double slashes [not found] ` <20130414173704.GB3050-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org> @ 2013-04-14 17:48 ` Tejun Heo 2013-04-15 3:10 ` [PATCH " Li Zefan 1 sibling, 0 replies; 6+ messages in thread From: Tejun Heo @ 2013-04-14 17:48 UTC (permalink / raw) To: Li Zefan Cc: cgroups-u79uwXL29TY76Z2rM5mHXA, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA From da1f296fd2bfd5ad3c53d72a1ece593e821cf374 Mon Sep 17 00:00:00 2001 From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Date: Sun, 14 Apr 2013 10:32:19 -0700 While reimplementing cgroup_path(), 65dff759d2 ("cgroup: fix cgroup_path() vs rename() race") introduced a bug where the path of a non-root cgroup would have two slahses at the beginning, which is caused by treating the root cgroup which has the name '/' like non-root cgroups. $ grep systemd /proc/self/cgroup 1:name=systemd://user/root/1 Fix it by special casing root cgroup case and not looping over it in the normal path. Signed-off-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Cc: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> --- The description was wrong. Updated. Thanks. kernel/cgroup.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 678a22c..faf55f5 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1811,11 +1811,17 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) int ret = -ENAMETOOLONG; char *start; + if (!cgrp->parent) { + if (strlcpy(buf, "/", buflen) >= buflen) + return -ENAMETOOLONG; + return 0; + } + start = buf + buflen - 1; *start = '\0'; rcu_read_lock(); - while (cgrp) { + do { const char *name = cgroup_name(cgrp); int len; @@ -1824,15 +1830,12 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) goto out; memcpy(start, name, len); - if (!cgrp->parent) - break; - if (--start < buf) goto out; *start = '/'; cgrp = cgrp->parent; - } + } while (cgrp->parent); ret = 0; memmove(buf, start, buf + buflen - start); out: -- 1.8.1.4 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH cgroup/for-3.10] cgroup: make cgroup_path() not print double slashes [not found] ` <20130414173704.GB3050-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org> 2013-04-14 17:48 ` [PATCH UPDATED " Tejun Heo @ 2013-04-15 3:10 ` Li Zefan [not found] ` <516B6FA9.9030301-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> 1 sibling, 1 reply; 6+ messages in thread From: Li Zefan @ 2013-04-15 3:10 UTC (permalink / raw) To: Tejun Heo Cc: cgroups-u79uwXL29TY76Z2rM5mHXA, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA On 2013/4/15 1:37, Tejun Heo wrote: >>From 277f3d4be79aefe2071d9053a9c7c89c4e5dad30 Mon Sep 17 00:00:00 2001 > From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> > Date: Sun, 14 Apr 2013 10:32:19 -0700 > > While reimplementing cgroup_path(), 65dff759d2 ("cgroup: fix > cgroup_path() vs rename() race") introduced a bug where the path of a > non-root cgroup would have two slahses at the beginning, which is > caused by adding '/' before the name of the root cgroup which is an > empty string. > I guess I booted a wrong kernel when testing that patch... > $ grep systemd /proc/self/cgroup > 1:name=systemd://user/root/1 > > Fix it by special casing root cgroup. > I made a patch to fix it before the weekend, but didn't post it. It doesn't treat root-only cgroup specially. You can apply whichever you like better. > Signed-off-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> > Cc: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> > --- > Applying to cgroup/for-3.10. > > Thanks. > > kernel/cgroup.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > [PATCH] cgroup: make cgroup_path() not print double slashes While reimplementing cgroup_path(), 65dff759d2 ("cgroup: fix cgroup_path() vs rename() race") introduced a bug where the path of a non-root cgroup would have two slahses at the beginning, which is caused by treating the root cgroup which has the name '/' like non-root cgroups. Fix it by not adding '/' if it's the root cgroup. $ grep systemd /proc/self/cgroup 1:name=systemd://user/root/1 Signed-off-by: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> --- kernel/cgroup.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 06aeb42..2a28425 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1809,14 +1809,15 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen) goto out; memcpy(start, name, len); - if (!cgrp->parent) + cgrp = cgrp->parent; + if (!cgrp) break; + if (!cgrp->parent) + continue; if (--start < buf) goto out; *start = '/'; - - cgrp = cgrp->parent; } ret = 0; memmove(buf, start, buf + buflen - start); -- 1.8.0.2 ^ permalink raw reply related [flat|nested] 6+ messages in thread
[parent not found: <516B6FA9.9030301-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>]
* Re: [PATCH cgroup/for-3.10] cgroup: make cgroup_path() not print double slashes [not found] ` <516B6FA9.9030301-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> @ 2013-04-15 3:18 ` Tejun Heo 2013-04-15 3:18 ` Tejun Heo 1 sibling, 0 replies; 6+ messages in thread From: Tejun Heo @ 2013-04-15 3:18 UTC (permalink / raw) To: Li Zefan Cc: cgroups-u79uwXL29TY76Z2rM5mHXA, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA On Mon, Apr 15, 2013 at 11:10:33AM +0800, Li Zefan wrote: > On 2013/4/15 1:37, Tejun Heo wrote: > >>From 277f3d4be79aefe2071d9053a9c7c89c4e5dad30 Mon Sep 17 00:00:00 2001 > > From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> > > Date: Sun, 14 Apr 2013 10:32:19 -0700 > > > > While reimplementing cgroup_path(), 65dff759d2 ("cgroup: fix > > cgroup_path() vs rename() race") introduced a bug where the path of a > > non-root cgroup would have two slahses at the beginning, which is > > caused by adding '/' before the name of the root cgroup which is an > > empty string. > > > > I guess I booted a wrong kernel when testing that patch... > > > $ grep systemd /proc/self/cgroup > > 1:name=systemd://user/root/1 > > > > Fix it by special casing root cgroup. > > > > I made a patch to fix it before the weekend, but didn't post it. It doesn't > treat root-only cgroup specially. > > You can apply whichever you like better. Already applied the special case patch this morning. Neither seems much better than each other so I'll just leave it that way. Thanks! -- tejun ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH cgroup/for-3.10] cgroup: make cgroup_path() not print double slashes [not found] ` <516B6FA9.9030301-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> 2013-04-15 3:18 ` Tejun Heo @ 2013-04-15 3:18 ` Tejun Heo 1 sibling, 0 replies; 6+ messages in thread From: Tejun Heo @ 2013-04-15 3:18 UTC (permalink / raw) To: Li Zefan Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA, cgroups-u79uwXL29TY76Z2rM5mHXA On Mon, Apr 15, 2013 at 11:10:33AM +0800, Li Zefan wrote: > On 2013/4/15 1:37, Tejun Heo wrote: > >>From 277f3d4be79aefe2071d9053a9c7c89c4e5dad30 Mon Sep 17 00:00:00 2001 > > From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> > > Date: Sun, 14 Apr 2013 10:32:19 -0700 > > > > While reimplementing cgroup_path(), 65dff759d2 ("cgroup: fix > > cgroup_path() vs rename() race") introduced a bug where the path of a > > non-root cgroup would have two slahses at the beginning, which is > > caused by adding '/' before the name of the root cgroup which is an > > empty string. > > > > I guess I booted a wrong kernel when testing that patch... > > > $ grep systemd /proc/self/cgroup > > 1:name=systemd://user/root/1 > > > > Fix it by special casing root cgroup. > > > > I made a patch to fix it before the weekend, but didn't post it. It doesn't > treat root-only cgroup specially. > > You can apply whichever you like better. Already applied the special case patch this morning. Neither seems much better than each other so I'll just leave it that way. Thanks! -- tejun ^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH cgroup/for-3.10] cgroup: make cgroup_path() not print double slashes
@ 2013-04-14 17:37 Tejun Heo
0 siblings, 0 replies; 6+ messages in thread
From: Tejun Heo @ 2013-04-14 17:37 UTC (permalink / raw)
To: Li Zefan
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA
From 277f3d4be79aefe2071d9053a9c7c89c4e5dad30 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Date: Sun, 14 Apr 2013 10:32:19 -0700
While reimplementing cgroup_path(), 65dff759d2 ("cgroup: fix
cgroup_path() vs rename() race") introduced a bug where the path of a
non-root cgroup would have two slahses at the beginning, which is
caused by adding '/' before the name of the root cgroup which is an
empty string.
$ grep systemd /proc/self/cgroup
1:name=systemd://user/root/1
Fix it by special casing root cgroup.
Signed-off-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
---
Applying to cgroup/for-3.10.
Thanks.
kernel/cgroup.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 678a22c..faf55f5 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1811,11 +1811,17 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
int ret = -ENAMETOOLONG;
char *start;
+ if (!cgrp->parent) {
+ if (strlcpy(buf, "/", buflen) >= buflen)
+ return -ENAMETOOLONG;
+ return 0;
+ }
+
start = buf + buflen - 1;
*start = '\0';
rcu_read_lock();
- while (cgrp) {
+ do {
const char *name = cgroup_name(cgrp);
int len;
@@ -1824,15 +1830,12 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
goto out;
memcpy(start, name, len);
- if (!cgrp->parent)
- break;
-
if (--start < buf)
goto out;
*start = '/';
cgrp = cgrp->parent;
- }
+ } while (cgrp->parent);
ret = 0;
memmove(buf, start, buf + buflen - start);
out:
--
1.8.1.4
^ permalink raw reply related [flat|nested] 6+ messages in threadend of thread, other threads:[~2013-04-15 3:18 UTC | newest]
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2013-04-14 17:37 [PATCH cgroup/for-3.10] cgroup: make cgroup_path() not print double slashes Tejun Heo
[not found] ` <20130414173704.GB3050-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2013-04-14 17:48 ` [PATCH UPDATED " Tejun Heo
2013-04-15 3:10 ` [PATCH " Li Zefan
[not found] ` <516B6FA9.9030301-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2013-04-15 3:18 ` Tejun Heo
2013-04-15 3:18 ` Tejun Heo
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2013-04-14 17:37 Tejun Heo
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