Commit 877f919e authored by Chunyu Hu's avatar Chunyu Hu Committed by Al Viro

proc: add proc_seq_release

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: 44414d82 ("proc: introduce proc_create_seq_private")
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
CC: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarChunyu Hu <chuhu@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ce397d21
...@@ -564,11 +564,20 @@ static int proc_seq_open(struct inode *inode, struct file *file) ...@@ -564,11 +564,20 @@ static int proc_seq_open(struct inode *inode, struct file *file)
return seq_open(file, de->seq_ops); 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 = { static const struct file_operations proc_seq_fops = {
.open = proc_seq_open, .open = proc_seq_open,
.read = seq_read, .read = seq_read,
.llseek = seq_lseek, .llseek = seq_lseek,
.release = seq_release, .release = proc_seq_release,
}; };
struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode, struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
......
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