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From:   Jia-Ju Bai <baijiaju1990@gmail.com>
To:     adobriyan@gmail.com, christian@brauner.io, ebiederm@xmission.com,
        akpm@linux-foundation.org, keescook@chromium.org,
        gladkov.alexey@gmail.com, walken@google.com,
        bernd.edlinger@hotmail.de, avagin@gmail.com, deller@gmx.de
Cc:     linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [PATCH] fs: proc: fix error return code of proc_map_files_readdir()
Date:   Tue,  9 Mar 2021 01:55:27 -0800
Message-Id: <20210309095527.27969-1-baijiaju1990@gmail.com>
Precedence: bulk

When get_task_mm() returns NULL to mm, no error return code of
proc_map_files_readdir() is assigned.
To fix this bug, ret is assigned with -ENOENT in this case.

Fixes: f0c3b5093add ("[readdir] convert procfs")
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 fs/proc/base.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index 3851bfcdba56..254cc6ac65fb 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2332,8 +2332,10 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
 		goto out_put_task;
 
 	mm = get_task_mm(task);
-	if (!mm)
+	if (!mm) {
+		ret = -ENOENT;
 		goto out_put_task;
+	}
 
 	ret = mmap_read_lock_killable(mm);
 	if (ret) {
-- 
2.17.1