Reimplement RLIMIT_MEMLOCK on top of ucounts
The rlimit counter is tied to uid in the user_namespace. This allows
rlimit values to be specified in userns even if they are already
globally exceeded by the user. However, the value of the previous
user_namespaces cannot be exceeded.
Changelog
v11:
* Fix issue found by lkp robot.
v8:
* Fix issues found by lkp-tests project.
v7:
* Keep only ucounts for RLIMIT_MEMLOCK checks instead of struct cred.
v6:
* Fix bug in hugetlb_file_setup() detected by trinity.
Reported-by: kernel test robot <oliver.sang@intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://lkml.kernel.org/r/970d50c70c71bfd4496e0e8d2a0a32feebebb350.1619094428.git.legion@kernel.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/mm/shmem.c b/mm/shmem.c
index b2db4ed..7ee6d27 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2227,7 +2227,7 @@ static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
}
#endif
-int shmem_lock(struct file *file, int lock, struct user_struct *user)
+int shmem_lock(struct file *file, int lock, struct ucounts *ucounts)
{
struct inode *inode = file_inode(file);
struct shmem_inode_info *info = SHMEM_I(inode);
@@ -2239,13 +2239,13 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user)
* no serialization needed when called from shm_destroy().
*/
if (lock && !(info->flags & VM_LOCKED)) {
- if (!user_shm_lock(inode->i_size, user))
+ if (!user_shm_lock(inode->i_size, ucounts))
goto out_nomem;
info->flags |= VM_LOCKED;
mapping_set_unevictable(file->f_mapping);
}
- if (!lock && (info->flags & VM_LOCKED) && user) {
- user_shm_unlock(inode->i_size, user);
+ if (!lock && (info->flags & VM_LOCKED) && ucounts) {
+ user_shm_unlock(inode->i_size, ucounts);
info->flags &= ~VM_LOCKED;
mapping_clear_unevictable(file->f_mapping);
}
@@ -4093,7 +4093,7 @@ int shmem_unuse(unsigned int type, bool frontswap,
return 0;
}
-int shmem_lock(struct file *file, int lock, struct user_struct *user)
+int shmem_lock(struct file *file, int lock, struct ucounts *ucounts)
{
return 0;
}
