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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 <stefanha@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
zero-colors
Namhyung Kim 2016-10-19 10:23:40 +09:00 committed by Kees Cook
parent 7a0032f504
commit e9e360b08a
1 changed files with 5 additions and 2 deletions
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7
fs/pstore/inode.c
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@ -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);
}