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From: Al Viro <viro@zeniv.linux.org.uk>
To: linux-fsdevel@vger.kernel.org
Cc: Christian Brauner <brauner@kernel.org>,
	Christoph Hellwig <hch@lst.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Namjae Jeon <linkinjeon@kernel.org>,
	David Sterba <dsterba@suse.com>,
	David Howells <dhowells@redhat.com>,
	Miklos Szeredi <miklos@szeredi.hu>,
	Amir Goldstein <amir73il@gmail.com>,
	Trond Myklebust <trond.myklebust@hammerspace.com>,
	Bob Peterson <rpeterso@redhat.com>,
	Steve French <sfrench@samba.org>,
	Luis Chamberlain <mcgrof@kernel.org>
Subject: [PATCH 06/15] procfs: move dropping pde and pid from ->evict_inode() to ->free_inode()
Date: Mon, 2 Oct 2023 03:32:31 +0100	[thread overview]
Message-ID: <20231002023231.GG3389589@ZenIV> (raw)
In-Reply-To: <20231002022846.GA3389589@ZenIV>

that keeps both around until struct inode is freed, making access
to them safe from rcu-pathwalk

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/proc/base.c  |  2 --
 fs/proc/inode.c | 19 ++++++++-----------
 2 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index ffd54617c354..8e93b11a0fed 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1881,8 +1881,6 @@ void proc_pid_evict_inode(struct proc_inode *ei)
 		hlist_del_init_rcu(&ei->sibling_inodes);
 		spin_unlock(&pid->lock);
 	}
-
-	put_pid(pid);
 }
 
 struct inode *proc_pid_make_inode(struct super_block *sb,
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 532dc9d240f7..c83e1a55da42 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -30,7 +30,6 @@
 
 static void proc_evict_inode(struct inode *inode)
 {
-	struct proc_dir_entry *de;
 	struct ctl_table_header *head;
 	struct proc_inode *ei = PROC_I(inode);
 
@@ -38,17 +37,8 @@ static void proc_evict_inode(struct inode *inode)
 	clear_inode(inode);
 
 	/* Stop tracking associated processes */
-	if (ei->pid) {
+	if (ei->pid)
 		proc_pid_evict_inode(ei);
-		ei->pid = NULL;
-	}
-
-	/* Let go of any associated proc directory entry */
-	de = ei->pde;
-	if (de) {
-		pde_put(de);
-		ei->pde = NULL;
-	}
 
 	head = ei->sysctl;
 	if (head) {
@@ -80,6 +70,13 @@ static struct inode *proc_alloc_inode(struct super_block *sb)
 
 static void proc_free_inode(struct inode *inode)
 {
+	struct proc_inode *ei = PROC_I(inode);
+
+	if (ei->pid)
+		put_pid(ei->pid);
+	/* Let go of any associated proc directory entry */
+	if (ei->pde)
+		pde_put(ei->pde);
 	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
 }
 
-- 
2.39.2


  parent reply	other threads:[~2023-10-02  2:32 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-02  2:28 [RFC][PATCHES] fixes in methods exposed to rcu pathwalk Al Viro
2023-10-02  2:28 ` Al Viro
2023-10-02  2:29   ` [PATCH 01/15] rcu pathwalk: prevent bogus hard errors from may_lookup() Al Viro
2023-10-02  2:30   ` [PATCH 02/15] exfat: move freeing sbi, upcase table and dropping nls into rcu-delayed helper Al Viro
2023-10-02 16:10     ` Linus Torvalds
2023-10-02 18:04       ` Al Viro
2023-10-02  2:30   ` [PATCH 03/15] affs: free affs_sb_info with kfree_rcu() Al Viro
2023-10-02  2:31   ` [PATCH 04/15] hfsplus: switch to rcu-delayed unloading of nls and freeing ->s_fs_info Al Viro
2023-10-02  6:49     ` Christoph Hellwig
2023-10-02  7:14       ` Al Viro
2023-10-02  7:21         ` Al Viro
2023-10-02 18:09           ` Al Viro
2023-10-04 19:04             ` Linus Torvalds
2023-10-04 19:06               ` Linus Torvalds
2023-10-02  2:31   ` [PATCH 05/15] cifs_get_link(): bail out in unsafe case Al Viro
2023-10-02  2:32   ` Al Viro [this message]
2023-10-02  2:33   ` [PATCH 07/15] procfs: make freeing proc_fs_info rcu-delayed Al Viro
2023-10-02  2:33   ` [PATCH 08/15] gfs2: fix an oops in gfs2_permission() Al Viro
2023-10-02 11:46     ` Bob Peterson
2023-10-02 12:59       ` Al Viro
2023-10-02 14:16         ` Al Viro
2023-10-03 14:46           ` Andreas Grünbacher
2023-10-02  2:34   ` [PATCH 09/15] nfs: make nfs_set_verifier() safe for use in RCU pathwalk Al Viro
2023-10-02  2:34   ` [PATCH 10/15] nfs: fix UAF on pathwalk running into umount Al Viro
2023-10-02  2:35   ` [PATCH 11/15] fuse: fix UAF in rcu pathwalks Al Viro
2023-10-02  2:35   ` [PATCH 12/15] afs: fix __afs_break_callback() / afs_drop_open_mmap() race Al Viro
2023-10-02  2:36   ` [PATCH 13/15] overlayfs: move freeing ovl_entry past rcu delay Al Viro
2023-10-02  2:36     ` [PATCH 14/15] ovl_dentry_revalidate_common(): fetch inode once Al Viro
2023-10-02  2:37       ` [PATCH 15/15] overlayfs: make use of ->layers safe in rcu pathwalk Al Viro
2023-10-02  6:40         ` Amir Goldstein
2023-10-02  7:23           ` Al Viro
2023-10-02  8:53             ` Amir Goldstein
2023-10-03 20:47               ` Al Viro
2023-10-02  5:47       ` [PATCH 14/15] ovl_dentry_revalidate_common(): fetch inode once Amir Goldstein
2023-10-02  5:56         ` Amir Goldstein
2023-10-02 14:47           ` Amir Goldstein
2023-10-02  5:51     ` [PATCH 13/15] overlayfs: move freeing ovl_entry past rcu delay Amir Goldstein
2023-10-02  2:52   ` [RFC][PATCHES] fixes in methods exposed to rcu pathwalk Al Viro

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