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 <hch@xxxxxx>
Signed-off-by: Chunyu Hu <chuhu@xxxxxxxxxx>
---
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
