Return-path: Received: from mail-pf0-f173.google.com ([209.85.192.173]:45978 "EHLO mail-pf0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751171AbdJDX1y (ORCPT ); Wed, 4 Oct 2017 19:27:54 -0400 Received: by mail-pf0-f173.google.com with SMTP id z84so7040624pfi.2 for ; Wed, 04 Oct 2017 16:27:53 -0700 (PDT) From: Kees Cook To: Thomas Gleixner Cc: Kees Cook , John Stultz , Stephen Boyd , Andrew Morton , Arnd Bergmann , Benjamin Herrenschmidt , Chris Metcalf , Geert Uytterhoeven , Greg Kroah-Hartman , Guenter Roeck , Harish Patil , Heiko Carstens , "James E.J. Bottomley" , Julian Wiedmann , Kalle Valo , Lai Jiangshan , Len Brown , Manish Chopra , Mark Gross , "Martin K. Petersen" , Martin Schwidefsky , Michael Ellerman , Michael Reed , netdev@vger.kernel.org, Oleg Nesterov , Paul Mackerras , Pavel Machek , Petr Mladek , "Rafael J. Wysocki" , Ralf Baechle , Sebastian Reichel , Stefan Richter , Sudip Mukherjee , Tejun Heo , Ursula Braun , Viresh Kumar , Wim Van Sebroeck , linux1394-devel@lists.sourceforge.net, linux-mips@linux-mips.org, linux-pm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, linux-watchdog@vger.kernel.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 01/13] timer: Convert schedule_timeout() to use from_timer() Date: Wed, 4 Oct 2017 16:26:55 -0700 Message-Id: <1507159627-127660-2-git-send-email-keescook@chromium.org> (sfid-20171005_013328_334260_996E3357) In-Reply-To: <1507159627-127660-1-git-send-email-keescook@chromium.org> References: <1507159627-127660-1-git-send-email-keescook@chromium.org> Sender: linux-wireless-owner@vger.kernel.org List-ID: In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new from_timer() helper and passing the timer pointer explicitly. Since this special timer is on the stack, it needs to have a wrapper structure to carry state once .data is eliminated. Cc: John Stultz Cc: Thomas Gleixner Cc: Stephen Boyd Signed-off-by: Kees Cook --- include/linux/timer.h | 8 ++++++++ kernel/time/timer.c | 26 +++++++++++++++++++------- 2 files changed, 27 insertions(+), 7 deletions(-) diff --git a/include/linux/timer.h b/include/linux/timer.h index 6383c528b148..5ef5c9e41a09 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -179,6 +179,14 @@ static inline void timer_setup(struct timer_list *timer, (TIMER_DATA_TYPE)timer, flags); } +static inline void timer_setup_on_stack(struct timer_list *timer, + void (*callback)(struct timer_list *), + unsigned int flags) +{ + __setup_timer_on_stack(timer, (TIMER_FUNC_TYPE)callback, + (TIMER_DATA_TYPE)timer, flags); +} + #define from_timer(var, callback_timer, timer_fieldname) \ container_of(callback_timer, typeof(*var), timer_fieldname) diff --git a/kernel/time/timer.c b/kernel/time/timer.c index f2674a056c26..38613ced2324 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1668,9 +1668,20 @@ void run_local_timers(void) raise_softirq(TIMER_SOFTIRQ); } -static void process_timeout(unsigned long __data) +/* + * Since schedule_timeout()'s timer is defined on the stack, it must store + * the target task on the stack as well. + */ +struct process_timer { + struct timer_list timer; + struct task_struct *task; +}; + +static void process_timeout(struct timer_list *t) { - wake_up_process((struct task_struct *)__data); + struct process_timer *timeout = from_timer(timeout, t, timer); + + wake_up_process(timeout->task); } /** @@ -1704,7 +1715,7 @@ static void process_timeout(unsigned long __data) */ signed long __sched schedule_timeout(signed long timeout) { - struct timer_list timer; + struct process_timer timer; unsigned long expire; switch (timeout) @@ -1738,13 +1749,14 @@ signed long __sched schedule_timeout(signed long timeout) expire = timeout + jiffies; - setup_timer_on_stack(&timer, process_timeout, (unsigned long)current); - __mod_timer(&timer, expire, false); + timer.task = current; + timer_setup_on_stack(&timer.timer, process_timeout, 0); + __mod_timer(&timer.timer, expire, false); schedule(); - del_singleshot_timer_sync(&timer); + del_singleshot_timer_sync(&timer.timer); /* Remove the timer from the object tracker */ - destroy_timer_on_stack(&timer); + destroy_timer_on_stack(&timer.timer); timeout = expire - jiffies; -- 2.7.4