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From:   Qianli Zhao <zhaoqianligood@gmail.com>
To:     tglx@linutronix.de, john.stultz@linaro.org, sboyd@kernel.org
Cc:     linux-kernel@vger.kernel.org, zhaoqianli@xiaomi.com
Subject: [PATCH v2] timer: Mask illegal set of flags in do_init_timer()
Date:   Thu, 13 Aug 2020 23:03:14 +0800
Message-Id: <9d79a8aa4eb56713af7379f99f062dedabcde140.1597326756.git.zhaoqianli@xiaomi.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Qianli Zhao <zhaoqianli@xiaomi.com>

do_init_timer() can specify flags of timer_list,
only TIMER_DEFFERABLE, TIMER_PINNED, TIMER_IRQSAFE are legal
do a sanity check, mask and warning illegal set of flags

Signed-off-by: Qianli Zhao <zhaoqianli@xiaomi.com>
---
V2:
- update changelog
- mask and warning illegal set
---
 include/linux/timer.h | 1 +
 kernel/time/timer.c   | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/include/linux/timer.h b/include/linux/timer.h
index 07910ae..d10bc7e 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -67,6 +67,7 @@ struct timer_list {
 #define TIMER_DEFERRABLE	0x00080000
 #define TIMER_PINNED		0x00100000
 #define TIMER_IRQSAFE		0x00200000
+#define TIMER_INIT_FLAGS	(TIMER_DEFERRABLE | TIMER_PINNED | TIMER_IRQSAFE)
 #define TIMER_ARRAYSHIFT	22
 #define TIMER_ARRAYMASK		0xFFC00000
 
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 026ac01..f7398ab 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -789,6 +789,8 @@ static void do_init_timer(struct timer_list *timer,
 {
 	timer->entry.pprev = NULL;
 	timer->function = func;
+	if (WARN_ON(flags & ~TIMER_INIT_FLAGS))
+		flags &= TIMER_INIT_FLAGS;
 	timer->flags = flags | raw_smp_processor_id();
 	lockdep_init_map(&timer->lockdep_map, name, key, 0);
 }
-- 
2.7.4