The console_lock is held throughout the start/show/stop procedure to print out device/driver information about all registered consoles. Since the console_lock is being used for multiple reasons, explicitly document these reasons. This will be useful when the console_lock is split into fine-grained locking. Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx> --- fs/proc/consoles.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/proc/consoles.c b/fs/proc/consoles.c index cf2e0788f9c7..32512b477605 100644 --- a/fs/proc/consoles.c +++ b/fs/proc/consoles.c @@ -63,6 +63,14 @@ static void *c_start(struct seq_file *m, loff_t *pos) struct console *con; loff_t off = 0; + /* + * Stop console printing because the device() callback may + * assume the console is not within its write() callback. + * + * Hold the console_lock to guarantee safe traversal of the + * console list. SRCU cannot be used because there is no + * place to store the SRCU cookie. + */ console_lock(); for_each_console(con) if (off++ == *pos) -- 2.30.2
