All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	christian.koenig@amd.com
Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Subject: [RFC PATCH] drm/ttm: Fix swapping dereferences of freed memory
Date: Thu, 27 May 2021 16:19:23 +0200	[thread overview]
Message-ID: <20210527141923.1962350-1-thomas.hellstrom@linux.intel.com> (raw)

The swapping code was dereference bo->ttm pointers without having the
dma-resv lock held. Also it might try to swap out unpopulated bos.

Fix this by moving the bo->ttm dereference until we have the reservation
lock. Check that the ttm_tt is populated after the swap_notify callback.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c     | 16 +++++++++++++++-
 drivers/gpu/drm/ttm/ttm_device.c |  8 +++-----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 9f53506a82fc..86213d37657b 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1163,6 +1163,16 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
 	if (!ttm_bo_evict_swapout_allowable(bo, ctx, &place, &locked, NULL))
 		return -EBUSY;
 
+	dma_resv_assert_held(bo->base.resv);
+
+	if (!bo->ttm ||
+	    bo->ttm->page_flags & TTM_PAGE_FLAG_SG ||
+	    bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED) {
+		if (locked)
+			dma_resv_unlock(bo->base.resv);
+		return -EBUSY;
+	}
+
 	if (!ttm_bo_get_unless_zero(bo)) {
 		if (locked)
 			dma_resv_unlock(bo->base.resv);
@@ -1215,7 +1225,8 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
 	if (bo->bdev->funcs->swap_notify)
 		bo->bdev->funcs->swap_notify(bo);
 
-	ret = ttm_tt_swapout(bo->bdev, bo->ttm, gfp_flags);
+	if (ttm_tt_is_populated(bo->ttm))
+		ret = ttm_tt_swapout(bo->bdev, bo->ttm, gfp_flags);
 out:
 
 	/*
@@ -1225,6 +1236,9 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
 	if (locked)
 		dma_resv_unlock(bo->base.resv);
 	ttm_bo_put(bo);
+
+	/* Don't break locking rules. */
+	WARN_ON(ret == -EBUSY);
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
index 460953dcad11..eaa7487ae404 100644
--- a/drivers/gpu/drm/ttm/ttm_device.c
+++ b/drivers/gpu/drm/ttm/ttm_device.c
@@ -143,14 +143,12 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
 
 		for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
 			list_for_each_entry(bo, &man->lru[j], lru) {
-				uint32_t num_pages;
+				pgoff_t num_pages;
 
-				if (!bo->ttm ||
-				    bo->ttm->page_flags & TTM_PAGE_FLAG_SG ||
-				    bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)
+				if (!READ_ONCE(bo->ttm))
 					continue;
 
-				num_pages = bo->ttm->num_pages;
+				num_pages = bo->base.size >> PAGE_SHIFT;
 				ret = ttm_bo_swapout(bo, ctx, gfp_flags);
 				/* ttm_bo_swapout has dropped the lru_lock */
 				if (!ret)
-- 
2.31.1


WARNING: multiple messages have this Message-ID (diff)
From: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	christian.koenig@amd.com
Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Subject: [Intel-gfx] [RFC PATCH] drm/ttm: Fix swapping dereferences of freed memory
Date: Thu, 27 May 2021 16:19:23 +0200	[thread overview]
Message-ID: <20210527141923.1962350-1-thomas.hellstrom@linux.intel.com> (raw)

The swapping code was dereference bo->ttm pointers without having the
dma-resv lock held. Also it might try to swap out unpopulated bos.

Fix this by moving the bo->ttm dereference until we have the reservation
lock. Check that the ttm_tt is populated after the swap_notify callback.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/ttm/ttm_bo.c     | 16 +++++++++++++++-
 drivers/gpu/drm/ttm/ttm_device.c |  8 +++-----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index 9f53506a82fc..86213d37657b 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -1163,6 +1163,16 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
 	if (!ttm_bo_evict_swapout_allowable(bo, ctx, &place, &locked, NULL))
 		return -EBUSY;
 
+	dma_resv_assert_held(bo->base.resv);
+
+	if (!bo->ttm ||
+	    bo->ttm->page_flags & TTM_PAGE_FLAG_SG ||
+	    bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED) {
+		if (locked)
+			dma_resv_unlock(bo->base.resv);
+		return -EBUSY;
+	}
+
 	if (!ttm_bo_get_unless_zero(bo)) {
 		if (locked)
 			dma_resv_unlock(bo->base.resv);
@@ -1215,7 +1225,8 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
 	if (bo->bdev->funcs->swap_notify)
 		bo->bdev->funcs->swap_notify(bo);
 
-	ret = ttm_tt_swapout(bo->bdev, bo->ttm, gfp_flags);
+	if (ttm_tt_is_populated(bo->ttm))
+		ret = ttm_tt_swapout(bo->bdev, bo->ttm, gfp_flags);
 out:
 
 	/*
@@ -1225,6 +1236,9 @@ int ttm_bo_swapout(struct ttm_buffer_object *bo, struct ttm_operation_ctx *ctx,
 	if (locked)
 		dma_resv_unlock(bo->base.resv);
 	ttm_bo_put(bo);
+
+	/* Don't break locking rules. */
+	WARN_ON(ret == -EBUSY);
 	return ret;
 }
 
diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
index 460953dcad11..eaa7487ae404 100644
--- a/drivers/gpu/drm/ttm/ttm_device.c
+++ b/drivers/gpu/drm/ttm/ttm_device.c
@@ -143,14 +143,12 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
 
 		for (j = 0; j < TTM_MAX_BO_PRIORITY; ++j) {
 			list_for_each_entry(bo, &man->lru[j], lru) {
-				uint32_t num_pages;
+				pgoff_t num_pages;
 
-				if (!bo->ttm ||
-				    bo->ttm->page_flags & TTM_PAGE_FLAG_SG ||
-				    bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)
+				if (!READ_ONCE(bo->ttm))
 					continue;
 
-				num_pages = bo->ttm->num_pages;
+				num_pages = bo->base.size >> PAGE_SHIFT;
 				ret = ttm_bo_swapout(bo, ctx, gfp_flags);
 				/* ttm_bo_swapout has dropped the lru_lock */
 				if (!ret)
-- 
2.31.1

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

             reply	other threads:[~2021-05-27 14:19 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-27 14:19 Thomas Hellström [this message]
2021-05-27 14:19 ` [Intel-gfx] [RFC PATCH] drm/ttm: Fix swapping dereferences of freed memory Thomas Hellström
2021-05-27 14:54 ` Christian König
2021-05-27 14:54   ` [Intel-gfx] " Christian König
2021-05-27 15:01   ` Thomas Hellström
2021-05-27 15:01     ` [Intel-gfx] " Thomas Hellström
2021-05-27 15:05     ` Thomas Hellström
2021-05-27 15:05       ` [Intel-gfx] " Thomas Hellström
2021-05-27 15:32       ` Christian König
2021-05-27 15:32         ` [Intel-gfx] " Christian König
2021-05-27 15:51         ` Thomas Hellström
2021-05-27 15:51           ` [Intel-gfx] " Thomas Hellström
2021-05-28  7:16           ` Christian König
2021-05-28  7:16             ` [Intel-gfx] " Christian König
2021-05-28  7:33             ` Thomas Hellström
2021-05-28  7:33               ` [Intel-gfx] " Thomas Hellström
2021-05-28 14:10               ` Christian König
2021-05-28 14:10                 ` [Intel-gfx] " Christian König
2021-05-28 14:17                 ` Thomas Hellström
2021-05-28 14:17                   ` [Intel-gfx] " Thomas Hellström
2021-05-28 14:21                   ` Christian König
2021-05-28 14:21                     ` [Intel-gfx] " Christian König
2021-05-27 15:17     ` Christian König
2021-05-27 15:17       ` [Intel-gfx] " Christian König
2021-05-27 19:58 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for " Patchwork

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210527141923.1962350-1-thomas.hellstrom@linux.intel.com \
    --to=thomas.hellstrom@linux.intel.com \
    --cc=christian.koenig@amd.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=intel-gfx@lists.freedesktop.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.