From e9e360b08a44098ec6f31de8e5a29a3ffaada828 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Wed, 19 Oct 2016 10:23:40 +0900 Subject: pstore: Protect unlink with read_mutex When update_ms is set, pstore_get_records() will be called when there's a new entry. But unlink can be called at the same time and might contend with the open-read-close loop. Depending on the implementation of platform driver, it may be safe or not. But I think it'd be better to protect those race in the first place. Cc: Stefan Hajnoczi Signed-off-by: Namhyung Kim Signed-off-by: Kees Cook --- fs/pstore/inode.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c index 0d6bbcf47d52..57c0646479f5 100644 --- a/fs/pstore/inode.c +++ b/fs/pstore/inode.c @@ -199,11 +199,14 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry) if (err) return err; - if (p->psi->erase) + if (p->psi->erase) { + mutex_lock(&p->psi->read_mutex); p->psi->erase(p->type, p->id, p->count, d_inode(dentry)->i_ctime, p->psi); - else + mutex_unlock(&p->psi->read_mutex); + } else { return -EPERM; + } return simple_unlink(dir, dentry); } -- cgit v1.2.3