diff options
| author | Jonathan Gray <jsg@cvs.openbsd.org> | 2018-01-09 13:48:37 +0000 |
|---|---|---|
| committer | Jonathan Gray <jsg@cvs.openbsd.org> | 2018-01-09 13:48:37 +0000 |
| commit | 762f64c401e8c81020cf5fe93c9d3eb6666f5d9f (patch) | |
| tree | 0f4b5272d900f2626edc764e98bf37e03a2a16bd /sys/dev/pci | |
| parent | 5151fb35ae04d7b5f666d1a8d1fc477dab57194d (diff) | |
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@
Diffstat (limited to 'sys/dev/pci')
| -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); |