From 7055197705709c59b8ab77e6a5c7d46d61edd96e Mon Sep 17 00:00:00 2001
From: Alexey Dobriyan <adobriyan@gmail.com>
Date: Mon, 9 May 2022 18:29:19 -0700
Subject: [PATCH] proc: fix dentry/inode overinstantiating under /proc/${pid}/net
Git-commit: 7055197705709c59b8ab77e6a5c7d46d61edd96e
Patch-mainline: v5.19-rc1
References: git-fixes
When a process exits, /proc/${pid}, and /proc/${pid}/net dentries are
flushed. However some leaf dentries like /proc/${pid}/net/arp_cache
aren't. That's because respective PDEs have proc_misc_d_revalidate() hook
which returns 1 and leaves dentries/inodes in the LRU.
Force revalidation/lookup on everything under /proc/${pid}/net by
inheriting proc_net_dentry_ops.
[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/YjdVHgildbWO7diJ@localhost.localdomain
Fixes: c6c75deda813 ("proc: fix lookup in /proc/net subdirectories after setns(2)")
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reported-by: hui li <juanfengpy@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
fs/proc/generic.c | 3 +++
fs/proc/proc_net.c | 3 +++
2 files changed, 6 insertions(+)
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index f2132407e133..587b91d9d998 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -448,6 +448,9 @@ static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
proc_set_user(ent, (*parent)->uid, (*parent)->gid);
ent->proc_dops = &proc_misc_dentry_ops;
+ /* Revalidate everything under /proc/${pid}/net */
+ if ((*parent)->proc_dops == &proc_net_dentry_ops)
+ pde_force_lookup(ent);
out:
return ent;
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
index e1cfeda397f3..913e5acefbb6 100644
--- a/fs/proc/proc_net.c
+++ b/fs/proc/proc_net.c
@@ -376,6 +376,9 @@ static __net_init int proc_net_ns_init(struct net *net)
proc_set_user(netd, uid, gid);
+ /* Seed dentry revalidation for /proc/${pid}/net */
+ pde_force_lookup(netd);
+
err = -EEXIST;
net_statd = proc_net_mkdir(net, "stat", netd);
if (!net_statd)
--
2.35.3