From d85b399b64e85a311c09205c675d4ae1c5af6246 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 8 Jun 2018 01:17:11 -0400
Subject: [PATCH] fix proc_fill_cache() in case of d_alloc_parallel() failure
If d_alloc_parallel() returns ERR_PTR(...), we don't want to dput()
that. Small reorganization allows to have all error-in-lookup
cases rejoin the main codepath after dput(child), avoiding the
entire problem.
Spotted-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Fixes: 0168b9e38c42 "procfs: switch instantiate_t to d_splice_alias()"
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/proc/base.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index de22c2002b38..6f927340db0a 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1891,19 +1891,19 @@ bool proc_fill_cache(struct file *file, struct dir_context *ctx,
struct dentry *res;
res = instantiate(child, task, ptr);
d_lookup_done(child);
- if (IS_ERR(res))
- goto end_instantiate;
if (unlikely(res)) {
dput(child);
child = res;
+ if (IS_ERR(child))
+ goto end_instantiate;
}
}
}
inode = d_inode(child);
ino = inode->i_ino;
type = inode->i_mode >> 12;
-end_instantiate:
dput(child);
+end_instantiate:
return dir_emit(ctx, name, len, ino, type);
}