Thread (2 messages) flat view 2 messages, 2 authors, 3d ago
WARM3d

[PATCH] media: exynos4-is: Fix a race between s_stream(0) and the interrupt handler

From: Ginger Li <hidden>
Date: 2026-09-23 08:37:52
Also in: linux-media, linux-samsung-soc, lkml
Subsystem: media input infrastructure (v4l/dvb), samsung s5p/exynos4 soc series camera subsystem drivers, the rest · Maintainers: Mauro Carvalho Chehab, Sylwester Nawrocki, Linus Torvalds

fimc_lite_subdev_s_stream(on = 0) sets ST_FLITE_OFF outside of the
fimc->slock protected region and only then stops the capture in the hardware.
flite_irq_handler() runs under fimc->slock and clears ST_FLITE_OFF, so an
interrupt can be handled in between: the handler finds ST_FLITE_OFF already
set, clears it and wakes up fimc->irq_queue before the capture has actually
been stopped.  The wait_event_timeout() right after it then returns
immediately and the driver continues as if the capture had stopped.

Set ST_FLITE_OFF in the same critical section that stops the capture, as
fimc_lite_stop_capture() already does.

Fixes: 6319d6a ("[media] fimc-lite: Add ISP FIFO output support")
Signed-off-by: Ginger Li <redacted>
---
 drivers/media/platform/samsung/exynos4-is/fimc-lite.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/media/platform/samsung/exynos4-is/fimc-lite.c b/drivers/media/platform/samsung/exynos4-is/fimc-lite.c
--- a/drivers/media/platform/samsung/exynos4-is/fimc-lite.c
+++ b/drivers/media/platform/samsung/exynos4-is/fimc-lite.c
@@ -1209,9 +1209,8 @@ static int fimc_lite_subdev_s_stream(struct v4l2_subde
 			spin_unlock_irqrestore(&fimc->slock, flags);
 		}
 	} else {
-		set_bit(ST_FLITE_OFF, &fimc->state);
-
 		spin_lock_irqsave(&fimc->slock, flags);
+		set_bit(ST_FLITE_OFF, &fimc->state);
 		flite_hw_capture_stop(fimc);
 		spin_unlock_irqrestore(&fimc->slock, flags);
 
-- 
2.43.0

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