Op 15-12-15 om 02:29 schreef Dmitry Torokhov: > Userspace can close the sync device while there are still active fence > points, in which case kernel produces the following warning: > > [ 43.853176] ------------[ cut here ]------------ > [ 43.857834] WARNING: CPU: 0 PID: 892 at /mnt/host/source/src/third_party/kernel/v3.18/drivers/staging/android/sync.c:439 android_fence_release+0x88/0x104() > [ 43.871741] CPU: 0 PID: 892 Comm: Binder_5 Tainted: G U 3.18.0-07661-g0550ce9 #1 > [ 43.880176] Hardware name: Google Tegra210 Smaug Rev 1+ (DT) > [ 43.885834] Call trace: > [ 43.888294] [<ffffffc000207464>] dump_backtrace+0x0/0x10c > [ 43.893697] [<ffffffc000207580>] show_stack+0x10/0x1c > [ 43.898756] [<ffffffc000ab1258>] dump_stack+0x74/0xb8 > [ 43.903814] [<ffffffc00021d414>] warn_slowpath_common+0x84/0xb0 > [ 43.909736] [<ffffffc00021d530>] warn_slowpath_null+0x14/0x20 > [ 43.915482] [<ffffffc00088aefc>] android_fence_release+0x84/0x104 > [ 43.921582] [<ffffffc000671cc4>] fence_release+0x104/0x134 > [ 43.927066] [<ffffffc00088b0cc>] sync_fence_free+0x74/0x9c > [ 43.932552] [<ffffffc00088b128>] sync_fence_release+0x34/0x48 > [ 43.938304] [<ffffffc000317bbc>] __fput+0x100/0x1b8 > [ 43.943185] [<ffffffc000317cc8>] ____fput+0x8/0x14 > [ 43.947982] [<ffffffc000237f38>] task_work_run+0xb0/0xe4 > [ 43.953297] [<ffffffc000207074>] do_notify_resume+0x44/0x5c > [ 43.958867] ---[ end trace 5a2aa4027cc5d171 ]--- > > Let's fix it by introducing a new optional callback (disable_signaling) > to fence operations so that drivers can do proper clean ups when we > remove last callback for given fence. > > Reviewed-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx> > Signed-off-by: Dmitry Torokhov <dtor@xxxxxxxxxxxx> > NACK! There's no way to do this race free. The driver should hold a refcount until fence is signaled. -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
