seq_tab_next() should increase position index

vaverin · davem330 · commit 70a87287c821 · 2020-01-24T11:42:18.000+01:00
if seq_file .next fuction does not change position index, read after some lseek can generate unexpected output. https://bugzilla.kernel.org/show_bug.cgi?id=206283 Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_debugfs.c
@@ -70,8 +70,7 @@ static void *seq_tab_start(struct seq_file *seq, loff_t *pos)
 static void *seq_tab_next(struct seq_file *seq, void *v, loff_t *pos)
 {
 	v = seq_tab_get_idx(seq->private, *pos + 1);
-	if (v)
-		++*pos;
+	++(*pos);
 	return v;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -70,8 +70,7 @@ static void seq_tab_start(struct seq_file seq, loff_t *pos)`
`70`	`70`	`static void seq_tab_next(struct seq_file seq, void v, loff_t pos)`
`71`	`71`	`{`
`72`	`72`	`v = seq_tab_get_idx(seq->private, *pos + 1);`
`73`		`- if (v)`
`74`		`- ++*pos;`
	`73`	`+ ++(*pos);`
`75`	`74`	`return v;`
`76`	`75`	`}`
`77`	`76`