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authorIvan Delalande <colona@arista.com>2018-12-13 15:20:52 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-12-29 13:40:16 +0100
commit4d5741aa2aaa1fb41abeeb46b0699299eea82d49 (patch)
treeaf42fa58d76cec152a7b918e05971eba2ccde9ad
parent6c976b42dc1540cf7cd0fc013928adf53b4f8791 (diff)
proc/sysctl: don't return ENOMEM on lookup when a table is unregistering
commit ea5751ccd665a2fd1b24f9af81f6167f0718c5f6 upstream. proc_sys_lookup can fail with ENOMEM instead of ENOENT when the corresponding sysctl table is being unregistered. In our case we see this upon opening /proc/sys/net/*/conf files while network interfaces are being deleted, which confuses our configuration daemon. The problem was successfully reproduced and this fix tested on v4.9.122 and v4.20-rc6. v2: return ERR_PTRs in all cases when proc_sys_make_inode fails instead of mixing them with NULL. Thanks Al Viro for the feedback. Fixes: ace0c791e6c3 ("proc/sysctl: Don't grab i_lock under sysctl_lock.") Cc: stable@vger.kernel.org Signed-off-by: Ivan Delalande <colona@arista.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/proc/proc_sysctl.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 46cd2e1b055b..1999e85840d5 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -466,7 +466,7 @@ static struct inode *proc_sys_make_inode(struct super_block *sb,
inode = new_inode(sb);
if (!inode)
- goto out;
+ return ERR_PTR(-ENOMEM);
inode->i_ino = get_next_ino();
@@ -476,8 +476,7 @@ static struct inode *proc_sys_make_inode(struct super_block *sb,
if (unlikely(head->unregistering)) {
spin_unlock(&sysctl_lock);
iput(inode);
- inode = NULL;
- goto out;
+ return ERR_PTR(-ENOENT);
}
ei->sysctl = head;
ei->sysctl_entry = table;
@@ -502,7 +501,6 @@ static struct inode *proc_sys_make_inode(struct super_block *sb,
if (root->set_ownership)
root->set_ownership(head, table, &inode->i_uid, &inode->i_gid);
-out:
return inode;
}
@@ -551,10 +549,11 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
goto out;
}
- err = ERR_PTR(-ENOMEM);
inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
- if (!inode)
+ if (IS_ERR(inode)) {
+ err = ERR_CAST(inode);
goto out;
+ }
err = NULL;
d_set_d_op(dentry, &proc_sys_dentry_operations);
@@ -687,7 +686,7 @@ static bool proc_sys_fill_cache(struct file *file,
return false;
if (d_in_lookup(child)) {
inode = proc_sys_make_inode(dir->d_sb, head, table);
- if (!inode) {
+ if (IS_ERR(inode)) {
d_lookup_done(child);
dput(child);
return false;