From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Vetter <daniel.vetter@ffwll.ch>
Subject: [PATCH] drm/i915: Prevent oops on req->engine in
	rcu-protected peeking
Date: Fri,  5 Aug 2016 18:37:00 +0200
Message-ID: <1470415020-1769-1-git-send-email-daniel.vetter@ffwll.ch>
Mime-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: base64
Return-path: <intel-gfx-bounces@lists.freedesktop.org>
Received: from mail-wm0-x244.google.com (mail-wm0-x244.google.com
 [IPv6:2a00:1450:400c:c09::244])
 by gabe.freedesktop.org (Postfix) with ESMTPS id EED376E169
 for <intel-gfx@lists.freedesktop.org>; Fri,  5 Aug 2016 16:37:07 +0000 (UTC)
Received: by mail-wm0-x244.google.com with SMTP id o80so4489531wme.0
 for <intel-gfx@lists.freedesktop.org>; Fri, 05 Aug 2016 09:37:07 -0700 (PDT)
List-Unsubscribe: <https://lists.freedesktop.org/mailman/options/intel-gfx>,
 <mailto:intel-gfx-request@lists.freedesktop.org?subject=unsubscribe>
List-Archive: <https://lists.freedesktop.org/archives/intel-gfx>
List-Post: <mailto:intel-gfx@lists.freedesktop.org>
List-Help: <mailto:intel-gfx-request@lists.freedesktop.org?subject=help>
List-Subscribe: <https://lists.freedesktop.org/mailman/listinfo/intel-gfx>,
 <mailto:intel-gfx-request@lists.freedesktop.org?subject=subscribe>
Errors-To: intel-gfx-bounces@lists.freedesktop.org
Sender: "Intel-gfx" <intel-gfx-bounces@lists.freedesktop.org>
To: Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>, "Goel,
 Akash" <akash.goel@intel.com>
List-Id: intel-gfx@lists.freedesktop.org

V2hlbiBvbmx5IHJjdS1wcm90ZWN0ZWQgd2UgbWlnaHQgcGVlayBhdCBhIHJlaW5pdGlhbGl6aW5n
IHJlcXVlc3QuClByZXZlbnQgY2FybmFnZSBieSBtYWtpbmcgc3VyZSB3ZSBkb24ndCBhY2NpZGVu
dGFsbHkgY2hhc2UgYSBOVUxMCnBvaW50ZXIuCgpUaGUgcHJvcGVyIGZpeCBmb3IgdGhpcyBpcyB0
byBkcm9wIHRoZSBtZW1zZXQgKHdpdGgga3phbGxvYykgaW4gdGhlCnJlcXVlc3QgYWxsb2NhdGlv
biBmdW5jdGlvbiwgc2luY2UgdGhhdCBhdm9pZHMgYm90aCB0aGUgTlVMTCBjaGVjayBpbgp0aGVz
ZSBmYXN0cGF0aHMgYW5kIG1ha2VzIHJlcXVlc3QgYWxsb2NhdGlvbiBhIG5vdGNoIGxpZ2h0ZXIu
IEJ1dCBpdAphbHNvIG1lYW5zIHdlIG5lZWQgdG8gY2FyZWZ1bCBhdWRpdCBhbGwgdGhlIHBhdGhz
IHRvIG1ha2Ugc3VyZSBub3RoaW5nCmdldHMgdXBzZXQgYW5kIHJ1bnMgaW50byBnYXJiYWdlLiBB
bmQgdGhhdCdzIGEgYml0IG11Y2ggb24gYSBsYXRlIEZyaWRheQp3aXRoIEpvb25hcyBhbHJlYWR5
IG9uIHcvZS4gQWxzbywgdG9kYXkgaXMgZHJtLWludGVsLW5leHQgdGFnIGRheSwgYW5kCnRoaXMg
d2lsbCBiZSB0aGUgdGFnIGZvciB0aGUgZmlyc3QgNC45IHB1bGwgcmVxdWVzdC4KCkhlbmNlIHRo
aXMgZWFzaWVyIHRvIHJldmlldyBpbnRlcmltIGZpeCwgd2hpY2ggd2lsbCBiZSByZXBsYWNlZCBl
YXJseSBuZXh0CndlZWsgYnkgdGhlIHByb3BlciBmaXggQ2hyaXMgaXMgd29ya2luZyBvbi4KCkZp
eGVzOiAwZWFmZWM2ZDMyNDQgKCJkcm0vaTkxNTogRW5hYmxlIGxvY2tsZXNzIGxvb2t1cCBvZiBy
ZXF1ZXN0Li4uIikKQ2M6IENocmlzIFdpbHNvbiA8Y2hyaXNAY2hyaXMtd2lsc29uLmNvLnVrPgpD
YzogIkdvZWwsIEFrYXNoIiA8YWthc2guZ29lbEBpbnRlbC5jb20+CkNjOiBEYW5pZWwgVmV0dGVy
IDxkYW5pZWwudmV0dGVyQGZmd2xsLmNoPgpDYzogSm9vbmFzIExhaHRpbmVuIDxqb29uYXMubGFo
dGluZW5AbGludXguaW50ZWwuY29tPgpTaWduZWQtb2ZmLWJ5OiBEYW5pZWwgVmV0dGVyIDxkYW5p
ZWwudmV0dGVyQGZmd2xsLmNoPgotLS0KIGRyaXZlcnMvZ3B1L2RybS9pOTE1L2k5MTVfZ2VtX3Jl
cXVlc3QuaCB8IDI0ICsrKysrKysrKysrKysrKysrKysrKystLQogMSBmaWxlIGNoYW5nZWQsIDIy
IGluc2VydGlvbnMoKyksIDIgZGVsZXRpb25zKC0pCgpkaWZmIC0tZ2l0IGEvZHJpdmVycy9ncHUv
ZHJtL2k5MTUvaTkxNV9nZW1fcmVxdWVzdC5oIGIvZHJpdmVycy9ncHUvZHJtL2k5MTUvaTkxNV9n
ZW1fcmVxdWVzdC5oCmluZGV4IDYwMDJhZGM0MzUyMy4uZTU1NDkyYmEyMGVjIDEwMDY0NAotLS0g
YS9kcml2ZXJzL2dwdS9kcm0vaTkxNS9pOTE1X2dlbV9yZXF1ZXN0LmgKKysrIGIvZHJpdmVycy9n
cHUvZHJtL2k5MTUvaTkxNV9nZW1fcmVxdWVzdC5oCkBAIC0yNDQsNiArMjQ0LDI2IEBAIGk5MTVf
Z2VtX3JlcXVlc3Rfc3RhcnRlZChjb25zdCBzdHJ1Y3QgZHJtX2k5MTVfZ2VtX3JlcXVlc3QgKnJl
cSkKIH0KIAogc3RhdGljIGlubGluZSBib29sCitpOTE1X2dlbV9yZXF1ZXN0X2NvbXBsZXRlZF9y
Y3UoY29uc3Qgc3RydWN0IGRybV9pOTE1X2dlbV9yZXF1ZXN0ICpyZXEpCit7CisJc3RydWN0IGlu
dGVsX2VuZ2luZV9jcyAqZW5naW5lID0gUkVBRF9PTkNFKHJlcS0+ZW5naW5lKTsKKworCS8qIFdo
ZW4gd2UgcGVlayBhdCBhIHJlcXVlc3Qgc29sZWx5IHVuZGVyIHJjdSBwcm90ZWN0aW9uLCB3aXRo
b3V0CisJICogaG9kbGluZyBhIGZ1bGwgcmVmZXJlbmNlLCB0aGUgcmVxdWVzdCBtaWdodCBiZSBp
biB0aGUgcHJvY2VzcyBvZgorCSAqIGdldHRpbmcgZnJlZWQgYW5kIHJlYWxsb2NhdGVkLiBNYWtl
IHN1cmUgd2UgZG9uJ3Qgc3R1bWJsZSBvdmVyIGEgTlVMTAorCSAqIGVuZ2luZSBpbiB0aGF0IGNh
c2UuCisJICoKKwkgKiBJZiB3ZSBhcmUgaGl0dGluZyB0aGlzIHJhY2UgaXQgbWVhbnMgdGhhdCB0
aGUgb2xkIHJlcXVlc3QgaGFzIGJlZW4KKwkgKiByZWxlYXNlZCwgd2hpY2ggb25seSBoYXBwZW5z
IG9uY2UgaXQgaGFzIGNvbXBsZXRlZC4KKwkgKi8KKwlpZiAoIWVuZ2luZSkKKwkJcmV0dXJuIHRy
dWU7CisKKwlyZXR1cm4gaTkxNV9zZXFub19wYXNzZWQoaW50ZWxfZW5naW5lX2dldF9zZXFubyhl
bmdpbmUpLAorCQkJCSByZXEtPmZlbmNlLnNlcW5vKTsKK30KKworc3RhdGljIGlubGluZSBib29s
CiBpOTE1X2dlbV9yZXF1ZXN0X2NvbXBsZXRlZChjb25zdCBzdHJ1Y3QgZHJtX2k5MTVfZ2VtX3Jl
cXVlc3QgKnJlcSkKIHsKIAlyZXR1cm4gaTkxNV9zZXFub19wYXNzZWQoaW50ZWxfZW5naW5lX2dl
dF9zZXFubyhyZXEtPmVuZ2luZSksCkBAIC0zODQsNyArNDA0LDcgQEAgaTkxNV9nZW1fYWN0aXZl
X3BlZWtfcmN1KGNvbnN0IHN0cnVjdCBpOTE1X2dlbV9hY3RpdmUgKmFjdGl2ZSkKIAlzdHJ1Y3Qg
ZHJtX2k5MTVfZ2VtX3JlcXVlc3QgKnJlcXVlc3Q7CiAKIAlyZXF1ZXN0ID0gcmN1X2RlcmVmZXJl
bmNlKGFjdGl2ZS0+cmVxdWVzdCk7Ci0JaWYgKCFyZXF1ZXN0IHx8IGk5MTVfZ2VtX3JlcXVlc3Rf
Y29tcGxldGVkKHJlcXVlc3QpKQorCWlmICghcmVxdWVzdCB8fCBpOTE1X2dlbV9yZXF1ZXN0X2Nv
bXBsZXRlZF9yY3UocmVxdWVzdCkpCiAJCXJldHVybiBOVUxMOwogCiAJcmV0dXJuIHJlcXVlc3Q7
CkBAIC00NTksNyArNDc5LDcgQEAgX19pOTE1X2dlbV9hY3RpdmVfZ2V0X3JjdShjb25zdCBzdHJ1
Y3QgaTkxNV9nZW1fYWN0aXZlICphY3RpdmUpCiAJCXN0cnVjdCBkcm1faTkxNV9nZW1fcmVxdWVz
dCAqcmVxdWVzdDsKIAogCQlyZXF1ZXN0ID0gcmN1X2RlcmVmZXJlbmNlKGFjdGl2ZS0+cmVxdWVz
dCk7Ci0JCWlmICghcmVxdWVzdCB8fCBpOTE1X2dlbV9yZXF1ZXN0X2NvbXBsZXRlZChyZXF1ZXN0
KSkKKwkJaWYgKCFyZXF1ZXN0IHx8IGk5MTVfZ2VtX3JlcXVlc3RfY29tcGxldGVkX3JjdShyZXF1
ZXN0KSkKIAkJCXJldHVybiBOVUxMOwogCiAJCXJlcXVlc3QgPSBpOTE1X2dlbV9yZXF1ZXN0X2dl
dF9yY3UocmVxdWVzdCk7Ci0tIAoyLjguMQoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f
X19fX19fX19fX19fX19fX18KSW50ZWwtZ2Z4IG1haWxpbmcgbGlzdApJbnRlbC1nZnhAbGlzdHMu
ZnJlZWRlc2t0b3Aub3JnCmh0dHBzOi8vbGlzdHMuZnJlZWRlc2t0b3Aub3JnL21haWxtYW4vbGlz
dGluZm8vaW50ZWwtZ2Z4Cg==