From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:49614 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753449AbeFITva (ORCPT ); Sat, 9 Jun 2018 15:51:30 -0400 From: Chunyu Hu To: viro@zeniv.linux.org.uk, hch@lst.de Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] proc: add proc_seq_release Date: Sun, 10 Jun 2018 03:51:24 +0800 Message-Id: <1528573884-9133-1-git-send-email-chuhu@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: kmemleak reported some memory leak on reading proc files. After adding some debug lines, find that proc_seq_fops is using seq_release as release handler, which won't handle the free of 'private' field of seq_file, while in fact the open handler proc_seq_open could create the private data with __seq_open_private when state_size is greater than zero. So after reading files created with proc_create_seq_private, such as /proc/timer_list and /proc/vmallocinfo, the private mem of a seq_file is not freed. Fix it by adding the paired proc_seq_release as the default release handler of proc_seq_ops instead of seq_release. Fixes: 44414d82cfe0 ("proc: introduce proc_create_seq_private") CC: Christoph Hellwig Signed-off-by: Chunyu Hu --- fs/proc/generic.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/fs/proc/generic.c b/fs/proc/generic.c index 7b4d971..021acc5 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -564,11 +564,20 @@ static int proc_seq_open(struct inode *inode, struct file *file) return seq_open(file, de->seq_ops); } +static int proc_seq_release(struct inode *inode, struct file *file) +{ + struct proc_dir_entry *de = PDE(inode); + + if (de->state_size) + return seq_release_private(inode, file); + return seq_release(inode, file); +} + static const struct file_operations proc_seq_fops = { .open = proc_seq_open, .read = seq_read, .llseek = seq_lseek, - .release = seq_release, + .release = proc_seq_release, }; struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode, -- 1.8.3.1