From b0940003f25dd3d2c54c4879809a432a35197f54 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Wed, 6 Feb 2008 01:37:04 -0800 Subject: [PATCH] vt: bitlock fix vt is missing a memory barrier to close the critical section. Use a real spinlock for this. Signed-off-by: Nick Piggin Cc: "Antonino A. Daplas" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/vt.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/char/vt.c b/drivers/char/vt.c index 7a5badfb7d84..367be9175061 100644 --- a/drivers/char/vt.c +++ b/drivers/char/vt.c @@ -2400,13 +2400,15 @@ static void vt_console_print(struct console *co, const char *b, unsigned count) { struct vc_data *vc = vc_cons[fg_console].d; unsigned char c; - static unsigned long printing; + static DEFINE_SPINLOCK(printing_lock); const ushort *start; ushort cnt = 0; ushort myx; /* console busy or not yet initialized */ - if (!printable || test_and_set_bit(0, &printing)) + if (!printable) + return; + if (!spin_trylock(&printing_lock)) return; if (kmsg_redirect && vc_cons_allocated(kmsg_redirect - 1)) @@ -2481,7 +2483,7 @@ static void vt_console_print(struct console *co, const char *b, unsigned count) notify_update(vc); quit: - clear_bit(0, &printing); + spin_unlock(&printing_lock); } static struct tty_driver *vt_console_device(struct console *c, int *index)