From: Ketil Johnsen Date: Wed, 22 Oct 2025 10:32:41 +0000 (+0200) Subject: drm/panthor: Fix race with suspend during unplug X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=08be57e6e8aa20ea5a6dd2552e38ac168d6a9b11;p=thirdparty%2Fkernel%2Flinux.git drm/panthor: Fix race with suspend during unplug There is a race between panthor_device_unplug() and panthor_device_suspend() which can lead to IRQ handlers running on a powered down GPU. This is how it can happen: - unplug routine calls drm_dev_unplug() - panthor_device_suspend() can now execute, and will skip a lot of important work because the device is currently marked as unplugged. - IRQs will remain active in this case and IRQ handlers can therefore try to access a powered down GPU. The fix is simply to take the PM ref in panthor_device_unplug() a little bit earlier, before drm_dev_unplug(). Signed-off-by: Ketil Johnsen Fixes: 5fe909cae118a ("drm/panthor: Add the device logical block") Reviewed-by: Boris Brezillon Reviewed-by: Liviu Dudau Reviewed-by: Steven Price Link: https://patch.msgid.link/20251022103242.1083311-1-ketil.johnsen@arm.com Signed-off-by: Liviu Dudau --- diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c index f3ae93153b6e8..83adacaa5760d 100644 --- a/drivers/gpu/drm/panthor/panthor_device.c +++ b/drivers/gpu/drm/panthor/panthor_device.c @@ -84,6 +84,8 @@ void panthor_device_unplug(struct panthor_device *ptdev) return; } + drm_WARN_ON(&ptdev->base, pm_runtime_get_sync(ptdev->base.dev) < 0); + /* Call drm_dev_unplug() so any access to HW blocks happening after * that point get rejected. */ @@ -94,8 +96,6 @@ void panthor_device_unplug(struct panthor_device *ptdev) */ mutex_unlock(&ptdev->unplug.lock); - drm_WARN_ON(&ptdev->base, pm_runtime_get_sync(ptdev->base.dev) < 0); - /* Now, try to cleanly shutdown the GPU before the device resources * get reclaimed. */