diff options
| author |   jsg <jsg@openbsd.org> | 2018-01-09 13:48:36 +0000 |
|---|---|---|
| committer | jsg <jsg@openbsd.org> | 2018-01-09 13:48:36 +0000 |
| commit | 564211fc8324e1aa1b07f1b6aef22d3c83ada672 (patch) | |
| tree | ce38c98686dec488fc0068419198f5008a55447d | |
| parent | Do not truncate 64bit integers when pretty-printing types. (diff) | |
| download | wireguard-openbsd-564211fc8324e1aa1b07f1b6aef22d3c83ada672.tar.xz wireguard-openbsd-564211fc8324e1aa1b07f1b6aef22d3c83ada672.zip | |
Work around a problem with ww_mutexes in the drm modeset lock.
Screen blanks often result in a NULL dereference in __ww_mutex_lock with
lock->acquired being non zero and lock->ctx NULL. mpi@ also reported
it occuring when switching from Xorg to a virtual terminal.
ok mpi@
| -rw-r--r-- | sys/dev/pci/drm/linux_ww_mutex.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/sys/dev/pci/drm/linux_ww_mutex.h b/sys/dev/pci/drm/linux_ww_mutex.h index 69d50d4c669..fb1b26791f6 100644 --- a/sys/dev/pci/drm/linux_ww_mutex.h +++ b/sys/dev/pci/drm/linux_ww_mutex.h @@ -163,7 +163,8 @@ __ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx, bool slow, bo * the `younger` process gives up all it's * resources. */ - if (slow || ctx == NULL || ctx->stamp < lock->ctx->stamp) { + if (slow || ctx == NULL || + (lock->ctx != NULL && ctx->stamp < lock->ctx->stamp)) { int s = msleep(lock, &lock->lock, intr ? PCATCH : 0, ctx ? ctx->ww_class->name : "ww_mutex_lock", 0); |