Merge tag 'vfs-6.15-rc1.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:

 - Add a new maintainer for configfs

 - Fix exportfs module description

 - Place flexible array memeber at the end of an internal struct in the
   mount code

 - Add new maintainer for netfslib as Jeff Layton is stepping down as
   current co-maintainer

 - Fix error handling in cachefiles_get_directory()

 - Cleanup do_notify_pidfd()

 - Fix syscall number definitions in pidfd selftests

 - Fix racy usage of fs_struct->in exec during multi-threaded exec

 - Ensure correct exit code is reported when pidfs_exit() is called from
   release_task() for a delayed thread-group leader exit

 - Fix conflicting iomap flag definitions

* tag 'vfs-6.15-rc1.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  iomap: Fix conflicting values of iomap flags
  fs: namespace: Avoid -Wflex-array-member-not-at-end warning
  MAINTAINERS: configfs: add Andreas Hindborg as maintainer
  exportfs: add module description
  exit: fix the usage of delay_group_leader->exit_code in do_notify_parent() and pidfs_exit()
  netfs: add Paulo as maintainer and remove myself as Reviewer
  cachefiles: Fix oops in vfs_mkdir from cachefiles_get_directory
  exec: fix the racy usage of fs_struct->in_exec
  selftests/pidfd: fixes syscall number defines
  pidfs: cleanup the usage of do_notify_pidfd()

4 files changed, 17 insertions, 10 deletions

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 83a60126de0f..14d0cc894000 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -128,10 +128,11 @@ retry:
 		ret = security_path_mkdir(&path, subdir, 0700);
 		if (ret < 0)
 			goto mkdir_error;
-		subdir = ERR_PTR(cachefiles_inject_write_error());
-		if (!IS_ERR(subdir))
+		ret = cachefiles_inject_write_error();
+		if (ret == 0)
 			subdir = vfs_mkdir(&nop_mnt_idmap, d_inode(dir), subdir, 0700);
-		ret = PTR_ERR(subdir);
+		else
+			subdir = ERR_PTR(ret);
 		if (IS_ERR(subdir)) {
 			trace_cachefiles_vfs_error(NULL, d_inode(dir), ret,
 						   cachefiles_trace_mkdir_error);
diff --git a/fs/exec.c b/fs/exec.c
index f45859ad13ac..5d1c0d2dc403 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1227,13 +1227,12 @@ int begin_new_exec(struct linux_binprm * bprm)
 	 */
 	bprm->point_of_no_return = true;
 
-	/*
-	 * Make this the only thread in the thread group.
-	 */
+	/* Make this the only thread in the thread group */
 	retval = de_thread(me);
 	if (retval)
 		goto out;
-
+	/* see the comment in check_unsafe_exec() */
+	current->fs->in_exec = 0;
 	/*
 	 * Cancel any io_uring activity across execve
 	 */
@@ -1495,6 +1494,8 @@ static void free_bprm(struct linux_binprm *bprm)
 	}
 	free_arg_pages(bprm);
 	if (bprm->cred) {
+		/* in case exec fails before de_thread() succeeds */
+		current->fs->in_exec = 0;
 		mutex_unlock(&current->signal->cred_guard_mutex);
 		abort_creds(bprm->cred);
 	}
@@ -1616,6 +1617,10 @@ static void check_unsafe_exec(struct linux_binprm *bprm)
 	 * suid exec because the differently privileged task
 	 * will be able to manipulate the current directory, etc.
 	 * It would be nice to force an unshare instead...
+	 *
+	 * Otherwise we set fs->in_exec = 1 to deny clone(CLONE_FS)
+	 * from another sub-thread until de_thread() succeeds, this
+	 * state is protected by cred_guard_mutex we hold.
 	 */
 	n_fs = 1;
 	spin_lock(&p->fs->lock);
@@ -1860,7 +1865,6 @@ static int bprm_execve(struct linux_binprm *bprm)
 
 	sched_mm_cid_after_execve(current);
 	/* execve succeeded */
-	current->fs->in_exec = 0;
 	current->in_execve = 0;
 	rseq_execve(current);
 	user_events_execve(current);
@@ -1879,7 +1883,6 @@ out:
 		force_fatal_sig(SIGSEGV);
 
 	sched_mm_cid_after_execve(current);
-	current->fs->in_exec = 0;
 	current->in_execve = 0;
 
 	return retval;
diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
index b5845c4846b8..128dd092916b 100644
--- a/fs/exportfs/expfs.c
+++ b/fs/exportfs/expfs.c
@@ -608,4 +608,5 @@ struct dentry *exportfs_decode_fh(struct vfsmount *mnt, struct fid *fid,
 }
 EXPORT_SYMBOL_GPL(exportfs_decode_fh);
 
+MODULE_DESCRIPTION("Code mapping from inodes to file handles");
 MODULE_LICENSE("GPL");
diff --git a/fs/namespace.c b/fs/namespace.c
index 6100e5b962a6..16292ff760c9 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -5326,8 +5326,10 @@ struct kstatmount {
 	struct mnt_idmap *idmap;
 	u64 mask;
 	struct path root;
-	struct statmount sm;
 	struct seq_file seq;
+
+	/* Must be last --ends in a flexible-array member. */
+	struct statmount sm;
 };
 
 static u64 mnt_to_attr_flags(struct vfsmount *mnt)