| Message ID | 1468242606-10826-1-git-send-email-jlayton@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h index 5b5a80cc5926..c818772d9f9d 100644 --- a/include/linux/posix_acl.h +++ b/include/linux/posix_acl.h @@ -43,10 +43,8 @@ struct posix_acl_entry { }; struct posix_acl { - union { - atomic_t a_refcount; - struct rcu_head a_rcu; - }; + atomic_t a_refcount; + struct rcu_head a_rcu; unsigned int a_count; struct posix_acl_entry a_entries[0]; };
Currently the two are unioned together, but I don't think that's safe. It looks like get_cached_acl could race with the last put in posix_acl_release. get_cached_acl calls atomic_inc_not_zero on a_refcount, but that field could have already been clobbered by call_rcu, and may no longer be zero. Fix this by de-unioning the two fields. Fixes: b8a7a3a66747 (posix_acl: Inode acl caching fixes) Signed-off-by: Jeff Layton <jlayton@redhat.com> --- include/linux/posix_acl.h | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) This appears to be a regression from v4.6, so I think we do want this in v4.7.