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@xxxxxxxxxxxxxxxxxxx> 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-rc1.gz > > > 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@xxxxxxxxxx> > > > 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@xxxxxxxxxx> > > > > 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@xxxxxxxxxx> > Date: Sun Sep 18 02:00:07 2022 -0600 > > mm: multi-gen LRU: kill switch > > Given 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;
