+ do_acct_process-dont-take-tty_mutex.patch added to -mm tree

[akpm@xxxxxxxx]

The patch titled
     do_acct_process(): don't take tty_mutex
has been added to the -mm tree.  Its filename is
     do_acct_process-dont-take-tty_mutex.patch

See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this

------------------------------------------------------
Subject: do_acct_process(): don't take tty_mutex
From: Oleg Nesterov <oleg@xxxxxxxxxx>

No need to take the global tty_mutex, signal->tty->driver can't go away while
we are holding ->siglock.

Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---

 kernel/acct.c |    7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff -puN kernel/acct.c~do_acct_process-dont-take-tty_mutex kernel/acct.c
--- a/kernel/acct.c~do_acct_process-dont-take-tty_mutex
+++ a/kernel/acct.c
@@ -484,12 +484,9 @@ static void do_acct_process(struct file 
 	ac.ac_ppid = current->parent->tgid;
 #endif
 
-	mutex_lock(&tty_mutex);
-	tty = get_current_tty();
-	ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
-	mutex_unlock(&tty_mutex);
-
 	spin_lock_irq(&current->sighand->siglock);
+	tty = current->signal->tty;
+	ac.ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0;
 	ac.ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime)));
 	ac.ac_stime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_stime)));
 	ac.ac_flag = pacct->ac_flag;
_

Patches currently in -mm which might be from oleg@xxxxxxxxxx are

tty-signal-tty-locking.patch
do_task_stat-dont-take-tty_mutex.patch
do_acct_process-dont-take-tty_mutex.patch
trivial-make-set_special_pids-static.patch
sys_unshare-remove-a-broken-clone_sighand-code.patch
pidhash-temporary-debug-checks.patch

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