linux-kernel - [PATCH 5.9 129/152] drm/nouveau: fix relocations applying logic and a double-free

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Date:   Tue,  1 Dec 2020 09:54:04 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Daniel Vetter <daniel.vetter@...ll.ch>,
        Ben Skeggs <bskeggs@...hat.com>, nouveau@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org, Matti Hamalainen <ccr@...p.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.9 129/152] drm/nouveau: fix relocations applying logic and a double-free

From: Matti Hamalainen <ccr@...p.org>

[ Upstream commit 2be65641642ef423f82162c3a5f28c754d1637d2 ]

Commit 03e0d26fcf79 ("drm/nouveau: slowpath for pushbuf ioctl") included
a logic-bug which results in the relocations not actually getting
applied at all as the call to nouveau_gem_pushbuf_reloc_apply() is
never reached. This causes a regression with graphical corruption,
triggered when relocations need to be done (for example after a
suspend/resume cycle.)

Fix by setting *apply_relocs value only if there were more than 0
relocations.

Additionally, the never reached code had a leftover u_free() call,
which, after fixing the logic, now got called and resulted in a
double-free. Fix by removing one u_free(), moving the other
and adding check for errors.

Cc: Daniel Vetter <daniel.vetter@...ll.ch>
Cc: Ben Skeggs <bskeggs@...hat.com>
Cc: nouveau@...ts.freedesktop.org
Cc: dri-devel@...ts.freedesktop.org
Signed-off-by: Matti Hamalainen <ccr@...p.org>
Fixes: 03e0d26fcf79 ("drm/nouveau: slowpath for pushbuf ioctl")
Signed-off-by: Daniel Vetter <daniel.vetter@...ll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120152338.1203257-1-ccr@tnsp.org
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/nouveau/nouveau_gem.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 124d3dcc5c590..98e99aa8a547e 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -570,8 +570,10 @@ nouveau_gem_pushbuf_validate(struct nouveau_channel *chan,
 			NV_PRINTK(err, cli, "validating bo list\n");
 		validate_fini(op, chan, NULL, NULL);
 		return ret;
+	} else if (ret > 0) {
+		*apply_relocs = true;
 	}
-	*apply_relocs = ret;
+
 	return 0;
 }
 
@@ -674,7 +676,6 @@ nouveau_gem_pushbuf_reloc_apply(struct nouveau_cli *cli,
 		nouveau_bo_wr32(nvbo, r->reloc_bo_offset >> 2, data);
 	}
 
-	u_free(reloc);
 	return ret;
 }
 
@@ -884,9 +885,10 @@ out:
 				break;
 			}
 		}
-		u_free(reloc);
 	}
 out_prevalid:
+	if (!IS_ERR(reloc))
+		u_free(reloc);
 	u_free(bo);
 	u_free(push);
 
-- 
2.27.0