[PATCH] Fix sighand->siglock usage in kernel/acct.c

IRQs must be disabled before taking ->siglock.

Noticed by lockdep.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/kernel/acct.c b/kernel/acct.c
index f18e0b8df3e1d036e6276befb3e707c4610944de..2a7c933651c7c03b0777fcecdc1ea3e06fed259b 100644 (file)
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -488,7 +488,7 @@ static void do_acct_process(struct file *file)
                old_encode_dev(tty_devnum(current->signal->tty)) : 0;
        read_unlock(&tasklist_lock);
 
-       spin_lock(&current->sighand->siglock);
+       spin_lock_irq(&current->sighand->siglock);
        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;
@@ -496,7 +496,7 @@ static void do_acct_process(struct file *file)
        ac.ac_minflt = encode_comp_t(pacct->ac_minflt);
        ac.ac_majflt = encode_comp_t(pacct->ac_majflt);
        ac.ac_exitcode = pacct->ac_exitcode;
-       spin_unlock(&current->sighand->siglock);
+       spin_unlock_irq(&current->sighand->siglock);
        ac.ac_io = encode_comp_t(0 /* current->io_usage */);    /* %% */
        ac.ac_rw = encode_comp_t(ac.ac_io / 1024);
        ac.ac_swaps = encode_comp_t(0);