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From: Lukas Wunner <lukas@wunner.de>
To: intel-gfx@lists.freedesktop.org
Cc: gustav.fagerlind@gmail.com, "Li, Weinan Z" <weinan.z.li@intel.com>
Subject: [PATCH 0/1] drm/i915: Fix races on fbdev [RESEND FOR CI]
Date: Mon, 15 Feb 2016 18:13:27 +0100	[thread overview]
Message-ID: <cover.1455555027.git.lukas@wunner.de> (raw)
In-Reply-To: <20160215163251.GR11240@phenom.ffwll.local>

Originally submitted inline with <20160205145831.GA14084@wunner.de>,
hereby resubmitted standalone for CI as requested by Daniel with
<20160215163251.GR11240@phenom.ffwll.local>.

Above-mentioned message contained the following important note:

> However AFAICT a corner case remains where we're still vulnerable to races:
> async_schedule() runs synchronously "if we're out of memory or if there's
> too much work pending already" (see __async_schedule() in kernel/async.c).
> In this case no entry is added to the pending list and
> async_synchronize_full() might theoretically return before the synchronously
> executed function has finished.
>
> The existing call to async_synchronize_full() in intel_fbdev_fini()
> seems to be susceptible to the same race condition, but it's probably
> very hard to trigger it. (Unload the module before the fbdev is fully
> initialized.)
>
> To make it bullet proof we could declare a completion in intel_fbdev.c
> and wait for that instead. Opinions?


Lukas Wunner (1):
  drm/i915: Fix races on fbdev

 drivers/gpu/drm/i915/i915_dma.c    | 8 +++-----
 drivers/gpu/drm/i915/intel_fbdev.c | 4 ++++
 2 files changed, 7 insertions(+), 5 deletions(-)

-- 
1.8.5.2 (Apple Git-48)

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  reply	other threads:[~2016-02-15 17:13 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-04  9:21 [PATCH] drm/i915: Protect fbdev across slow or failed initialisation Li, Weinan Z
2016-02-05  0:27 ` Lukas Wunner
2016-02-05 11:09   ` Chris Wilson
2016-02-05 14:58     ` Lukas Wunner
2016-02-15 16:32       ` Daniel Vetter
2016-02-15 17:13         ` Lukas Wunner [this message]
2016-02-15 17:13           ` [PATCH 1/1] drm/i915: Fix races on fbdev Lukas Wunner

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