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authorArnd Bergmann <arnd@arndb.de>2010-06-01 22:53:06 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-10 13:47:43 -0700
commit60af22d2ed490554cc92c8d0fed0b5b9cf687568 (patch)
tree6c9d1b2d9b5c409dc6a38f26ed5b7ec0f37a041a /drivers/char/selection.c
parentbe1bc2889a4db4961ef69f47fb471ecae9f23ade (diff)
tty: reorder ldisc locking
We need to release the BTM in paste_selection() when sleeping in tty_ldisc_ref_wait to avoid deadlocks with tty_ldisc_enable. In tty_set_ldisc, we now always grab the BTM before taking the ldisc_mutex in order to avoid AB-BA deadlocks between the two. tty_ldisc_halt potentially blocks on a workqueue function that takes the BTM, so we must release the BTM before calling it. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/char/selection.c')
-rw-r--r--drivers/char/selection.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/char/selection.c b/drivers/char/selection.c
index 85211a3a5811..75889cd9375f 100644
--- a/drivers/char/selection.c
+++ b/drivers/char/selection.c
@@ -319,8 +319,13 @@ int paste_selection(struct tty_struct *tty)
poke_blanked_console();
release_console_sem();
- ld = tty_ldisc_ref_wait(tty);
-
+ ld = tty_ldisc_ref(tty);
+ if (!ld) {
+ tty_unlock();
+ ld = tty_ldisc_ref_wait(tty);
+ tty_lock();
+ }
+
add_wait_queue(&vc->paste_wait, &wait);
while (sel_buffer && sel_buffer_lth > pasted) {
set_current_state(TASK_INTERRUPTIBLE);