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Diffstat (limited to 'fs/proc/consoles.c')
-rw-r--r--fs/proc/consoles.c21
1 files changed, 18 insertions, 3 deletions
diff --git a/fs/proc/consoles.c b/fs/proc/consoles.c
index dfe6ce3505ce..e0758fe7936d 100644
--- a/fs/proc/consoles.c
+++ b/fs/proc/consoles.c
@@ -33,7 +33,16 @@ static int show_console_dev(struct seq_file *m, void *v)
if (con->device) {
const struct tty_driver *driver;
int index;
+
+ /*
+ * Take console_lock to serialize device() callback with
+ * other console operations. For example, fg_console is
+ * modified under console_lock when switching vt.
+ */
+ console_lock();
driver = con->device(con, &index);
+ console_unlock();
+
if (driver) {
dev = MKDEV(driver->major, driver->minor_start);
dev += index;
@@ -63,7 +72,12 @@ static void *c_start(struct seq_file *m, loff_t *pos)
struct console *con;
loff_t off = 0;
- console_lock();
+ /*
+ * Hold the console_list_lock to guarantee safe traversal of the
+ * console list. SRCU cannot be used because there is no
+ * place to store the SRCU cookie.
+ */
+ console_list_lock();
for_each_console(con)
if (off++ == *pos)
break;
@@ -74,13 +88,14 @@ static void *c_start(struct seq_file *m, loff_t *pos)
static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
struct console *con = v;
+
++*pos;
- return con->next;
+ return hlist_entry_safe(con->node.next, struct console, node);
}
static void c_stop(struct seq_file *m, void *v)
{
- console_unlock();
+ console_list_unlock();
}
static const struct seq_operations consoles_op = {