drm/nouveau: fix relocations applying logic and a double-free

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@ffwll.ch>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: nouveau@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Matti Hamalainen <ccr@tnsp.org>
Fixes: 03e0d26fcf79 ("drm/nouveau: slowpath for pushbuf ioctl")
References: https://gitlab.freedesktop.org/drm/nouveau/-/issues/11
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120152338.1203257-1-ccr@tnsp.org

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 549bc67..c205138 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -558,8 +558,10 @@ 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;
 }
 
@@ -662,7 +664,6 @@ nouveau_gem_pushbuf_reloc_apply(struct nouveau_cli *cli,
                nouveau_bo_wr32(nvbo, r->reloc_bo_offset >> 2, data);
        }
 
-       u_free(reloc);
        return ret;
 }
 
@@ -872,9 +873,10 @@ out:
                                break;
                        }
                }
-               u_free(reloc);
        }
 out_prevalid:
+       if (!IS_ERR(reloc))
+               u_free(reloc);
        u_free(bo);
        u_free(push);