On Tue, Apr 18, 2023 at 09:47:33PM +0530, Harshit Mogalapalli wrote:
Hi Greg,
On 18/04/23 8:17 pm, Naresh Kamboju wrote:
On Tue, 18 Apr 2023 at 18:07, Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
This is the start of the stable review cycle for the 5.15.108 release. There are 91 patches in this series, all will be posted as a response to this one. If anyone has any issues with these being applied, please let me know.
Responses should be made by Thu, 20 Apr 2023 12:02:44 +0000. Anything received after that time might be too late.
The whole patch series can be found in one patch at: https://www.kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.15.108-rc... or in the git tree and branch at: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.15.y and the diffstat can be found below.
thanks,
greg k-h
Following patch causing build break on stable-rc 5.15
Waiman Long longman@redhat.com cgroup/cpuset: Add cpuset_can_fork() and cpuset_cancel_fork() methods
cgroup/cpuset: Add cpuset_can_fork() and cpuset_cancel_fork() methods commit eee87853794187f6adbe19533ed79c8b44b36a91 upstream.
Reported-by: Linux Kernel Functional Testing lkft@linaro.org
Build error: kernel/cgroup/cpuset.c: In function 'cpuset_can_fork': kernel/cgroup/cpuset.c:2979:30: error: 'cgroup_mutex' undeclared (first use in this function); did you mean 'cgroup_put'? 2979 | lockdep_assert_held(&cgroup_mutex); | ^~~~~~~~~~~~ include/linux/lockdep.h:415:61: note: in definition of macro 'lockdep_assert_held' 415 | #define lockdep_assert_held(l) do { (void)(l); } while (0) | ^ kernel/cgroup/cpuset.c:2979:30: note: each undeclared identifier is reported only once for each function it appears in 2979 | lockdep_assert_held(&cgroup_mutex); | ^~~~~~~~~~~~ include/linux/lockdep.h:415:61: note: in definition of macro 'lockdep_assert_held' 415 | #define lockdep_assert_held(l) do { (void)(l); } while (0) | ^ make[3]: *** [scripts/Makefile.build:289: kernel/cgroup/cpuset.o] Error 1
We observed same build error.(5.15.108-rc1), and investigated about this.
Please see the below findings.
With defconfig --> build breaks. With allmodconfig --> build succeeds.
From the above we know that this is something related to CONFIG.
In 5.15.y --> cgroup_mutex is defined like this in include/linux/cgroup.h
#ifdef CONFIG_PROVE_RCU extern struct mutex cgroup_mutex;
In 6.2.y --> include/linux/cgroup.h
extern struct mutex cgroup_mutex;
-- We don't have that ifdef in 6.2.y.
Tom Saeger identified that the below commit moves it out of ifdef.
commit 354ed597442952fb680c9cafc7e4eb8a76f9514c Author: Yu Zhao yuzhao@google.com Date: Sun Sep 18 02:00:07 2022 -0600
mm: multi-gen LRU: kill switchGiven that we don't have this commit in 5.15.y and 5.10.y we are seeing this build problem.
on allmodconfig:
~/linux$ grep "CONFIG_PROVE_RCU" .config CONFIG_PROVE_RCU=y CONFIG_PROVE_RCU_LIST=y
on defconfig: ~/linux$ grep "CONFIG_PROVE_RCU" .config -- No match
This explains the failure on defconfig and a build success on allmodconfig.
Thanks, Harshit
FWIW - partially backporting (location of cgroup_mutex extern) from: 354ed5974429 ("mm: multi-gen LRU: kill switch")
fixes x86_64 build for me.
Regards,
--Tom
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 45cdb12243e3..460ba084888a 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -433,6 +433,8 @@ static inline void cgroup_put(struct cgroup *cgrp) css_put(&cgrp->self); }
+extern struct mutex cgroup_mutex; + /** * task_css_set_check - obtain a task's css_set with extra access conditions * @task: the task to obtain css_set for @@ -447,7 +449,6 @@ static inline void cgroup_put(struct cgroup *cgrp) * as locks used during the cgroup_subsys::attach() methods. */ #ifdef CONFIG_PROVE_RCU -extern struct mutex cgroup_mutex; extern spinlock_t css_set_lock; #define task_css_set_check(task, __c) \ rcu_dereference_check((task)->cgroups, \ diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h index d8fcc139ac05..28c32a01da7d 100644 --- a/kernel/cgroup/cgroup-internal.h +++ b/kernel/cgroup/cgroup-internal.h @@ -165,7 +165,6 @@ struct cgroup_mgctx { #define DEFINE_CGROUP_MGCTX(name) \ struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
-extern struct mutex cgroup_mutex; extern spinlock_t css_set_lock; extern struct cgroup_subsys *cgroup_subsys[]; extern struct list_head cgroup_roots;