On Fri, Dec 08, 2017 at 12:03:07AM +0100, Vasyl Gomonovych wrote: > p could be NULL and passing into PTR_ERR
What makes you think this is correct? To quote the documentation: The next function to implement is called, amazingly, next(); its job is to move the iterator forward to the next position in the sequence. The example module can simply increment the position by one; more useful modules will do what is needed to step through some data structure. The next() function returns a new iterator, or NULL if the sequence is complete. Here's the example version: So if it returns NULL, we want to set err to 0 and break. Which is, um, exactly what the code does. Did you test this at all? > Signed-off-by: Vasyl Gomonovych <[email protected]> > --- > fs/seq_file.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/seq_file.c b/fs/seq_file.c > index 4be761c..8b700b9 100644 > --- a/fs/seq_file.c > +++ b/fs/seq_file.c > @@ -262,8 +262,8 @@ ssize_t seq_read(struct file *file, char __user *buf, > size_t size, loff_t *ppos) > size_t offs = m->count; > loff_t next = pos; > p = m->op->next(m, p, &next); > - if (!p || IS_ERR(p)) { > - err = PTR_ERR(p); > + if (IS_ERR(p)) { > + err = (!p ? -EFAULT : PTR_ERR(p)); > break; > } > err = m->op->show(m, p); > -- > 1.9.1 >
