From: Dave Airlie airlied@redhat.com
Lookup the context first to see if its valid before trying to remove it.
Saw this WARNING a few times while fuzzing the kernel with Trinity in a qemu virtual machine:
[ 22.883257] idr_remove called for id=4096 which is not allocated. [ 22.884487] Pid: 2303, comm: trinity-child1 Not tainted 3.8.0+ #87 [ 22.885601] Call Trace: [ 22.886080] [<ffffffff8134b111>] idr_remove+0x131/0x1f0 [ 22.887107] [<ffffffff8143c678>] drm_ctxbitmap_free+0x38/0x50 [ 22.888158] [<ffffffff8143cbd3>] drm_rmctx+0x63/0x100 [ 22.889091] [<ffffffff8143d710>] drm_ioctl+0x3d0/0x4d0 [ 22.890034] [<ffffffff8143cb70>] ? drm_newctx+0xb0/0xb0 [ 22.890970] [<ffffffff812fb640>] ? avc_has_perm_flags+0x1d0/0x2a0 [ 22.892127] [<ffffffff812fb498>] ? avc_has_perm_flags+0x28/0x2a0 [ 22.893218] [<ffffffff810f5b18>] ? trace_hardirqs_off_caller+0x28/0xd0 [ 22.894401] [<ffffffff810f5bcd>] ? trace_hardirqs_off+0xd/0x10 [ 22.895461] [<ffffffff811b5ff2>] do_vfs_ioctl+0x532/0x580 [ 22.896447] [<ffffffff812fc7d3>] ? file_has_perm+0x83/0xa0 [ 22.897453] [<ffffffff811b609d>] sys_ioctl+0x5d/0xa0 [ 22.898429] [<ffffffff813571de>] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 22.899629] [<ffffffff81ca07e9>] system_call_fastpath+0x16/0x1b
Reported-by: Tommi Rantala tt.rantala@gmail.com Signed-off-by: Dave Airlie airlied@redhat.com --- drivers/gpu/drm/drm_context.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/drm_context.c b/drivers/gpu/drm/drm_context.c index 45adf97..a186563 100644 --- a/drivers/gpu/drm/drm_context.c +++ b/drivers/gpu/drm/drm_context.c @@ -438,6 +438,13 @@ int drm_rmctx(struct drm_device *dev, void *data,
DRM_DEBUG("%d\n", ctx->handle); if (ctx->handle != DRM_KERNEL_CONTEXT) { + struct drm_local_map *map; + mutex_lock(&dev->struct_mutex); + map = idr_find(&dev->ctx_idr, ctx->handle); + mutex_unlock(&dev->struct_mutex); + + if (!map) + return -EINVAL; if (dev->driver->context_dtor) dev->driver->context_dtor(dev, ctx->handle); drm_ctxbitmap_free(dev, ctx->handle);