+ proc-fix-type-confusion-in-pde_set_flags.patch added to mm-hotfixes-unstable branch

+ proc-fix-type-confusion-in-pde_set_flags.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: proc: fix type confusion in pde_set_flags()
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     proc-fix-type-confusion-in-pde_set_flags.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/proc-fix-type-confusion-in-pde_set_flags.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: wangzijie <wangzijie1@honor.com>
Subject: proc: fix type confusion in pde_set_flags()
Date: Thu, 4 Sep 2025 21:57:15 +0800

Commit 2ce3d282bd50 ("proc: fix missing pde_set_flags() for net proc
files") missed a key part in the definition of proc_dir_entry:

union {
	const struct proc_ops *proc_ops;
	const struct file_operations *proc_dir_ops;
};

So dereference of ->proc_ops assumes it is a proc_ops structure results in
type confusion and make NULL check for 'proc_ops' not work for proc dir.

Add !S_ISDIR(dp->mode) test before calling pde_set_flags() to fix it.

Link: https://lkml.kernel.org/r/20250904135715.3972782-1-wangzijie1@honor.com
Fixes: 2ce3d282bd50 ("proc: fix missing pde_set_flags() for net proc files")
Signed-off-by: wangzijie <wangzijie1@honor.com>
Reported-by: Brad Spengler <spender@grsecurity.net>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Stefano Brivio <sbrivio@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/proc/generic.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/proc/generic.c~proc-fix-type-confusion-in-pde_set_flags
+++ a/fs/proc/generic.c
@@ -393,7 +393,8 @@ struct proc_dir_entry *proc_register(str
 	if (proc_alloc_inum(&dp->low_ino))
 		goto out_free_entry;
 
-	pde_set_flags(dp);
+	if (!S_ISDIR(dp->mode))
+		pde_set_flags(dp);
 
 	write_lock(&proc_subdir_lock);
 	dp->parent = dir;
_

Patches currently in -mm which might be from wangzijie1@honor.com are

proc-fix-type-confusion-in-pde_set_flags.patch