On 12/6/23 22:38, Stephen Rothwell wrote:
Hi all,
After merging the cgroup tree, today's linux-next build (x86_64
allmodconfig) failed like this:
In file included from <command-line>:
kernel/cgroup/cgroup.c: In function 'cgroup_free_root':
include/linux/compiler_types.h:435:45: error: call to '__compiletime_assert_1792' declared with attribute error: BUILD_BUG_ON failed: !__is_kvfree_rcu_offset(offsetof(typeof(*(root)), rcu))
435 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
include/linux/compiler_types.h:416:25: note: in definition of macro '__compiletime_assert'
416 | prefix ## suffix(); \
| ^~~~~~
include/linux/compiler_types.h:435:9: note: in expansion of macro '_compiletime_assert'
435 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:50:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
| ^~~~~~~~~~~~~~~~
include/linux/rcupdate.h:985:17: note: in expansion of macro 'BUILD_BUG_ON'
985 | BUILD_BUG_ON(!__is_kvfree_rcu_offset(offsetof(typeof(*(ptr)), rhf))); \
#define __is_kvfree_rcu_offset(offset) ((offset) < 4096)
It looks like commit 77070eeb8821 ("cgroup: Avoid false cacheline
sharing of read mostly rstat_cpu") has caused the offset of rcu to
exceed the 4096 limit under such configuration. After I move the rcu
field up, the compilation error was gone. So any change that makes the
cgroup structure larger is likely to cause this problem again. The
simple fix is just to move the rcu field up. I will send a patch to do that.
Cheers,
Longman
| ^~~~~~~~~~~~
include/linux/rcupdate.h:957:29: note: in expansion of macro 'kvfree_rcu_arg_2'
957 | #define kfree_rcu(ptr, rhf) kvfree_rcu_arg_2(ptr, rhf)
| ^~~~~~~~~~~~~~~~
kernel/cgroup/cgroup.c:1318:9: note: in expansion of macro 'kfree_rcu'
1318 | kfree_rcu(root, rcu);
| ^~~~~~~~~
In function 'cgroup_free_root',
inlined from 'cgroup_destroy_root' at kernel/cgroup/cgroup.c:1363:2:
include/linux/compiler_types.h:435:45: error: call to '__compiletime_assert_1792' declared with attribute error: BUILD_BUG_ON failed: !__is_kvfree_rcu_offset(offsetof(typeof(*(root)), rcu))
435 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
include/linux/compiler_types.h:416:25: note: in definition of macro '__compiletime_assert'
416 | prefix ## suffix(); \
| ^~~~~~
include/linux/compiler_types.h:435:9: note: in expansion of macro '_compiletime_assert'
435 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:50:9: note: in expansion of macro 'BUILD_BUG_ON_MSG'
50 | BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
| ^~~~~~~~~~~~~~~~
include/linux/rcupdate.h:985:17: note: in expansion of macro 'BUILD_BUG_ON'
985 | BUILD_BUG_ON(!__is_kvfree_rcu_offset(offsetof(typeof(*(ptr)), rhf))); \
| ^~~~~~~~~~~~
include/linux/rcupdate.h:957:29: note: in expansion of macro 'kvfree_rcu_arg_2'
957 | #define kfree_rcu(ptr, rhf) kvfree_rcu_arg_2(ptr, rhf)
| ^~~~~~~~~~~~~~~~
kernel/cgroup/cgroup.c:1318:9: note: in expansion of macro 'kfree_rcu'
1318 | kfree_rcu(root, rcu);
| ^~~~~~~~~
Possibly caused by commit
77070eeb8821 ("cgroup: Avoid false cacheline sharing of read mostly rstat_cpu")
I have used the cgroup tree from next-20231206 for today.
