Re: BUG: KASAN: use-after-free in amdgpu_job_free_cb

From: Johannes Hirte <johannes.hirte-rSzmJuYucINa7YElYzY8/Q@public.gmane.org>
To: "Grodzovsky, Andrey" <Andrey.Grodzovsky-5C7GfCeVMHo@public.gmane.org>
Cc: "Li, Sun peng (Leo)" <Sunpeng.Li-5C7GfCeVMHo@public.gmane.org>,
	"amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org"
	<amd-gfx-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>,
	"Deucher,
	Alexander" <Alexander.Deucher-5C7GfCeVMHo@public.gmane.org>,
	"Luís Mendes"
	<luis.p.mendes-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	"Wentland, Harry" <Harry.Wentland-5C7GfCeVMHo@public.gmane.org>,
	"Koenig,
	Christian" <Christian.Koenig-5C7GfCeVMHo@public.gmane.org>
Subject: Re: BUG: KASAN: use-after-free in amdgpu_job_free_cb
Date: Sun, 14 Jan 2018 21:34:16 +0100	[thread overview]
Message-ID: <20180114203416.GA14765@probook> (raw)
In-Reply-To: <BN6PR1201MB0115E7D6A5932AC3A932FA98EA150-6iU6OBHu2P+5DJ1TLF5OxWrFom/aUZj6nBOFsp37pqbUKgpGm//BTAC/G2K4zDHf@public.gmane.org>

On 2018 Jan 14, Grodzovsky, Andrey wrote:
> To be sure it was inserted at the correct place please send me output of git diff on your modified branch.
> 
> Thanks,
> Andrey
>

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index bb5fa895fb64..bc2050a5a5c6 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4802,7 +4802,7 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
         * synchronization events.
         */

-       if (lock_and_validation_needed) {
+       if (lock_and_validation_needed || state->legacy_cursor_update == true) {

                ret = do_aquire_global_lock(dev, state);
                if (ret)

If this matters, I've applied the patch on top of 4.15-rc7 with your 
"Fix: Save job's priority on it's creation instead of accessing it from s_entity later on." 
patch. This one is still not upstream, but without I see the other
use-after-free

-- 
Regards,
  Johannes

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