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authorLinus Torvalds <torvalds@linux-foundation.org>2023-01-19 23:32:07 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2023-01-19 23:32:07 +0300
commitd368967cb1039b5c4cccb62b5a4b9468c50cd143 (patch)
treefa8ad271bd843d85567ec1e93cb19398c2750c90 /drivers/tty
parenta03df4ec37291de74987e4fbfbbcaebb5a8f9a2e (diff)
parent21493c6e96e550509ead696ecca9f0d7196ee91c (diff)
downloadlinux-d368967cb1039b5c4cccb62b5a4b9468c50cd143.tar.xz
Merge tag 'printk-for-6.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk fixes from Petr Mladek: - Prevent a potential deadlock when configuring kgdb console - Fix a kernel doc warning * tag 'printk-for-6.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: kernel/printk/printk.c: Fix W=1 kernel-doc warning tty: serial: kgdboc: fix mutex locking order for configure_kgdboc()
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/kgdboc.c20
-rw-r--r--drivers/tty/serial/serial_core.c5
2 files changed, 10 insertions, 15 deletions
diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
index a3ed9b34e2ab..7ce7bb164005 100644
--- a/drivers/tty/serial/kgdboc.c
+++ b/drivers/tty/serial/kgdboc.c
@@ -171,6 +171,7 @@ static int configure_kgdboc(void)
int err = -ENODEV;
char *cptr = config;
struct console *cons;
+ int cookie;
if (!strlen(config) || isspace(config[0])) {
err = 0;
@@ -189,20 +190,9 @@ static int configure_kgdboc(void)
if (kgdboc_register_kbd(&cptr))
goto do_register;
- /*
- * tty_find_polling_driver() can call uart_set_options()
- * (via poll_init) to configure the uart. Take the console_list_lock
- * in order to synchronize against register_console(), which can also
- * configure the uart via uart_set_options(). This also allows safe
- * traversal of the console list.
- */
- console_list_lock();
-
p = tty_find_polling_driver(cptr, &tty_line);
- if (!p) {
- console_list_unlock();
+ if (!p)
goto noconfig;
- }
/*
* Take console_lock to serialize device() callback with
@@ -211,7 +201,8 @@ static int configure_kgdboc(void)
*/
console_lock();
- for_each_console(cons) {
+ cookie = console_srcu_read_lock();
+ for_each_console_srcu(cons) {
int idx;
if (cons->device && cons->device(cons, &idx) == p &&
idx == tty_line) {
@@ -219,11 +210,10 @@ static int configure_kgdboc(void)
break;
}
}
+ console_srcu_read_unlock(cookie);
console_unlock();
- console_list_unlock();
-
kgdb_tty_driver = p;
kgdb_tty_line = tty_line;
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index b9fbbee598b8..ec874f3a567c 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -2212,6 +2212,9 @@ EXPORT_SYMBOL_GPL(uart_parse_options);
* @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
* @bits: number of data bits
* @flow: flow control character - 'r' (rts)
+ *
+ * Locking: Caller must hold console_list_lock in order to serialize
+ * early initialization of the serial-console lock.
*/
int
uart_set_options(struct uart_port *port, struct console *co,
@@ -2619,7 +2622,9 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options)
if (!ret && options) {
uart_parse_options(options, &baud, &parity, &bits, &flow);
+ console_list_lock();
ret = uart_set_options(port, NULL, baud, parity, bits, flow);
+ console_list_unlock();
}
out:
mutex_unlock(&tport->mutex);