diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2016-04-05 15:00:00 +0100 |
|---|---|---|
| committer | Jani Nikula <jani.nikula@intel.com> | 2016-04-18 12:35:49 +0300 |
| commit | db9f9203e27495b2d151b695504e286eec026e9b (patch) | |
| tree | 2c8d22c693031da6bda1ae7976c60f176cea4e7b /drivers/gpu | |
| parent | d43f3ebf12f59c57782ec652da65ef61c2662b40 (diff) | |
drm/i915/userptr: Hold mmref whilst calling get-user-pages
Holding a reference to the containing task_struct is not sufficient to
prevent the mm_struct from being reaped under memory pressure. If this
happens whilst we are calling get_user_pages(), explosions erupt -
sometimes an immediate GPF, sometimes page flag corruption. To prevent
the target mm from being reaped as we are reading from it, acquire a
reference before we begin.
Testcase: igt/gem_shrink/*userptr
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Michał Winiarski <michal.winiarski@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1459864801-28606-2-git-send-email-chris@chris-wilson.co.uk
(cherry picked from commit 40313f0cd0b711a7a5905e5182422799e157d8aa)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem_userptr.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c index 18ba8139e922..4d30b60defda 100644 --- a/drivers/gpu/drm/i915/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -501,19 +501,24 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work) if (pvec != NULL) { struct mm_struct *mm = obj->userptr.mm->mm; - down_read(&mm->mmap_sem); - while (pinned < npages) { - ret = get_user_pages_remote(work->task, mm, - obj->userptr.ptr + pinned * PAGE_SIZE, - npages - pinned, - !obj->userptr.read_only, 0, - pvec + pinned, NULL); - if (ret < 0) - break; - - pinned += ret; + ret = -EFAULT; + if (atomic_inc_not_zero(&mm->mm_users)) { + down_read(&mm->mmap_sem); + while (pinned < npages) { + ret = get_user_pages_remote + (work->task, mm, + obj->userptr.ptr + pinned * PAGE_SIZE, + npages - pinned, + !obj->userptr.read_only, 0, + pvec + pinned, NULL); + if (ret < 0) + break; + + pinned += ret; + } + up_read(&mm->mmap_sem); + mmput(mm); } - up_read(&mm->mmap_sem); } mutex_lock(&dev->struct_mutex); |