Linaro-mm-sig February 2020

linaro-mm-sig@lists.linaro.org

10 participants
26 discussions

[PATCH v2 3/4] drm/virtio: move mapping teardown to virtio_gpu_cleanup_object()

by Gerd Hoffmann

Stop sending DETACH_BACKING commands, that will happening anyway when releasing resources via UNREF. Handle guest-side cleanup in virtio_gpu_cleanup_object(), called when the host finished processing the UNREF command. Signed-off-by: Gerd Hoffmann <kraxel(a)redhat.com> --- drivers/gpu/drm/virtio/virtgpu_drv.h | 2 -- drivers/gpu/drm/virtio/virtgpu_object.c | 14 ++++++-- drivers/gpu/drm/virtio/virtgpu_vq.c | 46 ------------------------- 3 files changed, 12 insertions(+), 50 deletions(-) diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h index 1bc13f6b161b..d37ddd7644f6 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drv.h +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h @@ -281,8 +281,6 @@ void virtio_gpu_cmd_set_scanout(struct virtio_gpu_device *vgdev, int virtio_gpu_object_attach(struct virtio_gpu_device *vgdev, struct virtio_gpu_object *obj, struct virtio_gpu_fence *fence); -void virtio_gpu_object_detach(struct virtio_gpu_device *vgdev, - struct virtio_gpu_object *obj); int virtio_gpu_attach_status_page(struct virtio_gpu_device *vgdev); int virtio_gpu_detach_status_page(struct virtio_gpu_device *vgdev); void virtio_gpu_cursor_ping(struct virtio_gpu_device *vgdev, diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c index 28a161af7503..bce2b3d843fe 100644 --- a/drivers/gpu/drm/virtio/virtgpu_object.c +++ b/drivers/gpu/drm/virtio/virtgpu_object.c @@ -23,6 +23,7 @@ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ +#include <linux/dma-mapping.h> #include <linux/moduleparam.h> #include "virtgpu_drv.h" @@ -65,6 +66,17 @@ void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo) { struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private; + if (bo->pages) { + if (bo->mapped) { + dma_unmap_sg(vgdev->vdev->dev.parent, + bo->pages->sgl, bo->mapped, + DMA_TO_DEVICE); + bo->mapped = 0; + } + sg_free_table(bo->pages); + bo->pages = NULL; + drm_gem_shmem_unpin(&bo->base.base); + } virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle); drm_gem_shmem_free_object(&bo->base.base); } @@ -74,8 +86,6 @@ static void virtio_gpu_free_object(struct drm_gem_object *obj) struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj); struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private; - if (bo->pages) - virtio_gpu_object_detach(vgdev, bo); if (bo->created) { virtio_gpu_cmd_unref_resource(vgdev, bo); /* completion handler calls virtio_gpu_cleanup_object() */ diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c index 4e22c3914f94..87c439156151 100644 --- a/drivers/gpu/drm/virtio/virtgpu_vq.c +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c @@ -545,22 +545,6 @@ void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev, virtio_gpu_queue_ctrl_buffer(vgdev, vbuf); } -static void virtio_gpu_cmd_resource_inval_backing(struct virtio_gpu_device *vgdev, - uint32_t resource_id, - struct virtio_gpu_fence *fence) -{ - struct virtio_gpu_resource_detach_backing *cmd_p; - struct virtio_gpu_vbuffer *vbuf; - - cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p)); - memset(cmd_p, 0, sizeof(*cmd_p)); - - cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_DETACH_BACKING); - cmd_p->resource_id = cpu_to_le32(resource_id); - - virtio_gpu_queue_fenced_ctrl_buffer(vgdev, vbuf, fence); -} - void virtio_gpu_cmd_set_scanout(struct virtio_gpu_device *vgdev, uint32_t scanout_id, uint32_t resource_id, uint32_t width, uint32_t height, @@ -1155,36 +1139,6 @@ int virtio_gpu_object_attach(struct virtio_gpu_device *vgdev, return 0; } -void virtio_gpu_object_detach(struct virtio_gpu_device *vgdev, - struct virtio_gpu_object *obj) -{ - bool use_dma_api = !virtio_has_iommu_quirk(vgdev->vdev); - - if (WARN_ON_ONCE(!obj->pages)) - return; - - if (use_dma_api && obj->mapped) { - struct virtio_gpu_fence *fence = virtio_gpu_fence_alloc(vgdev); - /* detach backing and wait for the host process it ... */ - virtio_gpu_cmd_resource_inval_backing(vgdev, obj->hw_res_handle, fence); - dma_fence_wait(&fence->f, true); - dma_fence_put(&fence->f); - - /* ... then tear down iommu mappings */ - dma_unmap_sg(vgdev->vdev->dev.parent, - obj->pages->sgl, obj->mapped, - DMA_TO_DEVICE); - obj->mapped = 0; - } else { - virtio_gpu_cmd_resource_inval_backing(vgdev, obj->hw_res_handle, NULL); - } - - sg_free_table(obj->pages); - obj->pages = NULL; - - drm_gem_shmem_unpin(&obj->base.base); -} - void virtio_gpu_cursor_ping(struct virtio_gpu_device *vgdev, struct virtio_gpu_output *output) { -- 2.18.1

4 years, 10 months

[PATCH 3/4] drm/virtio: move mapping teardown to virtio_gpu_cleanup_object()

by Gerd Hoffmann

Stop sending DETACH_BACKING commands, that will happening anyway when releasing resources via UNREF. Handle guest-side cleanup in virtio_gpu_cleanup_object(), called when the host finished processing the UNREF command. Signed-off-by: Gerd Hoffmann <kraxel(a)redhat.com> --- drivers/gpu/drm/virtio/virtgpu_drv.h | 2 -- drivers/gpu/drm/virtio/virtgpu_object.c | 14 ++++++-- drivers/gpu/drm/virtio/virtgpu_vq.c | 46 ------------------------- 3 files changed, 12 insertions(+), 50 deletions(-) diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h index 372dd248cf02..15fb3c12f22f 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drv.h +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h @@ -280,8 +280,6 @@ void virtio_gpu_cmd_set_scanout(struct virtio_gpu_device *vgdev, int virtio_gpu_object_attach(struct virtio_gpu_device *vgdev, struct virtio_gpu_object *obj, struct virtio_gpu_fence *fence); -void virtio_gpu_object_detach(struct virtio_gpu_device *vgdev, - struct virtio_gpu_object *obj); int virtio_gpu_attach_status_page(struct virtio_gpu_device *vgdev); int virtio_gpu_detach_status_page(struct virtio_gpu_device *vgdev); void virtio_gpu_cursor_ping(struct virtio_gpu_device *vgdev, diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c index 28a161af7503..bce2b3d843fe 100644 --- a/drivers/gpu/drm/virtio/virtgpu_object.c +++ b/drivers/gpu/drm/virtio/virtgpu_object.c @@ -23,6 +23,7 @@ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ +#include <linux/dma-mapping.h> #include <linux/moduleparam.h> #include "virtgpu_drv.h" @@ -65,6 +66,17 @@ void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo) { struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private; + if (bo->pages) { + if (bo->mapped) { + dma_unmap_sg(vgdev->vdev->dev.parent, + bo->pages->sgl, bo->mapped, + DMA_TO_DEVICE); + bo->mapped = 0; + } + sg_free_table(bo->pages); + bo->pages = NULL; + drm_gem_shmem_unpin(&bo->base.base); + } virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle); drm_gem_shmem_free_object(&bo->base.base); } @@ -74,8 +86,6 @@ static void virtio_gpu_free_object(struct drm_gem_object *obj) struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj); struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private; - if (bo->pages) - virtio_gpu_object_detach(vgdev, bo); if (bo->created) { virtio_gpu_cmd_unref_resource(vgdev, bo); /* completion handler calls virtio_gpu_cleanup_object() */ diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c index 6e8097e4c214..e258186bedb2 100644 --- a/drivers/gpu/drm/virtio/virtgpu_vq.c +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c @@ -538,22 +538,6 @@ void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev, virtio_gpu_queue_ctrl_buffer(vgdev, vbuf); } -static void virtio_gpu_cmd_resource_inval_backing(struct virtio_gpu_device *vgdev, - uint32_t resource_id, - struct virtio_gpu_fence *fence) -{ - struct virtio_gpu_resource_detach_backing *cmd_p; - struct virtio_gpu_vbuffer *vbuf; - - cmd_p = virtio_gpu_alloc_cmd(vgdev, &vbuf, sizeof(*cmd_p)); - memset(cmd_p, 0, sizeof(*cmd_p)); - - cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_DETACH_BACKING); - cmd_p->resource_id = cpu_to_le32(resource_id); - - virtio_gpu_queue_fenced_ctrl_buffer(vgdev, vbuf, &cmd_p->hdr, fence); -} - void virtio_gpu_cmd_set_scanout(struct virtio_gpu_device *vgdev, uint32_t scanout_id, uint32_t resource_id, uint32_t width, uint32_t height, @@ -1148,36 +1132,6 @@ int virtio_gpu_object_attach(struct virtio_gpu_device *vgdev, return 0; } -void virtio_gpu_object_detach(struct virtio_gpu_device *vgdev, - struct virtio_gpu_object *obj) -{ - bool use_dma_api = !virtio_has_iommu_quirk(vgdev->vdev); - - if (WARN_ON_ONCE(!obj->pages)) - return; - - if (use_dma_api && obj->mapped) { - struct virtio_gpu_fence *fence = virtio_gpu_fence_alloc(vgdev); - /* detach backing and wait for the host process it ... */ - virtio_gpu_cmd_resource_inval_backing(vgdev, obj->hw_res_handle, fence); - dma_fence_wait(&fence->f, true); - dma_fence_put(&fence->f); - - /* ... then tear down iommu mappings */ - dma_unmap_sg(vgdev->vdev->dev.parent, - obj->pages->sgl, obj->mapped, - DMA_TO_DEVICE); - obj->mapped = 0; - } else { - virtio_gpu_cmd_resource_inval_backing(vgdev, obj->hw_res_handle, NULL); - } - - sg_free_table(obj->pages); - obj->pages = NULL; - - drm_gem_shmem_unpin(&obj->base.base); -} - void virtio_gpu_cursor_ping(struct virtio_gpu_device *vgdev, struct virtio_gpu_output *output) { -- 2.18.1

4 years, 10 months

Re: [Linaro-mm-sig] [PATCH -next] drm/panfrost: Remove set but not used variable 'bo'

by Steven Price

On Mon, Feb 03, 2020 at 03:27:24PM +0000, YueHaibing wrote: > Fixes gcc '-Wunused-but-set-variable' warning: > > drivers/gpu/drm/panfrost/panfrost_job.c: In function 'panfrost_job_cleanup': > drivers/gpu/drm/panfrost/panfrost_job.c:278:31: warning: > variable 'bo' set but not used [-Wunused-but-set-variable] > > commit bdefca2d8dc0 ("drm/panfrost: Add the panfrost_gem_mapping concept") > involved this unused variable. > > Reported-by: Hulk Robot <hulkci(a)huawei.com> > Signed-off-by: YueHaibing <yuehaibing(a)huawei.com> I'm not sure how I didn't spot that before! Thanks for fixing it. Note commit bdefca2d8dc0 is actually in v5.5 and not (yet) in drm-misc-next. Reviewed-by: Steven Price <steven.price(a)arm.com> > --- > drivers/gpu/drm/panfrost/panfrost_job.c | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c > index 7c36ec675b73..ccb8546a9342 100644 > --- a/drivers/gpu/drm/panfrost/panfrost_job.c > +++ b/drivers/gpu/drm/panfrost/panfrost_job.c > @@ -275,12 +275,8 @@ static void panfrost_job_cleanup(struct kref *ref) > } > > if (job->bos) { > - struct panfrost_gem_object *bo; > - > - for (i = 0; i < job->bo_count; i++) { > - bo = to_panfrost_bo(job->bos[i]); > + for (i = 0; i < job->bo_count; i++) > drm_gem_object_put_unlocked(job->bos[i]); > - } > > kvfree(job->bos); > } > > >

4 years, 10 months

Re: [Linaro-mm-sig] KASAN: use-after-free Read in vgem_gem_dumb_create

by Daniel Vetter

On Fri, Jan 31, 2020 at 11:28 PM syzbot <syzbot+0dc4444774d419e916c8(a)syzkaller.appspotmail.com> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: 39bed42d Merge tag 'for-linus-hmm' of git://git.kernel.org.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=179465bee00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=2646535f8818ae25 > dashboard link: https://syzkaller.appspot.com/bug?extid=0dc4444774d419e916c8 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16251279e00000 > > The bug was bisected to: > > commit 7611750784664db46d0db95631e322aeb263dde7 > Author: Alex Deucher <alexander.deucher(a)amd.com> > Date: Wed Jun 21 16:31:41 2017 +0000 > > drm/amdgpu: use kernel is_power_of_2 rather than local version > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=11628df1e00000 > final crash: https://syzkaller.appspot.com/x/report.txt?x=13628df1e00000 > console output: https://syzkaller.appspot.com/x/log.txt?x=15628df1e00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+0dc4444774d419e916c8(a)syzkaller.appspotmail.com > Fixes: 761175078466 ("drm/amdgpu: use kernel is_power_of_2 rather than local version") Aside: This bisect line is complete nonsense ... I'm kinda at the point where I'm assuming that syzbot bisect results are garbage, which is maybe not what we want. I guess much stricter filtering for noise is needed, dunno. -Danile > > ================================================================== > BUG: KASAN: use-after-free in vgem_gem_dumb_create+0x238/0x250 drivers/gpu/drm/vgem/vgem_drv.c:221 > Read of size 8 at addr ffff88809fa67908 by task syz-executor.0/14871 > > CPU: 0 PID: 14871 Comm: syz-executor.0 Not tainted 5.5.0-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x197/0x210 lib/dump_stack.c:118 > print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 > __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506 > kasan_report+0x12/0x20 mm/kasan/common.c:639 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 > vgem_gem_dumb_create+0x238/0x250 drivers/gpu/drm/vgem/vgem_drv.c:221 > drm_mode_create_dumb+0x282/0x310 drivers/gpu/drm/drm_dumb_buffers.c:94 > drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:100 > drm_ioctl_kernel+0x244/0x300 drivers/gpu/drm/drm_ioctl.c:786 > drm_ioctl+0x54e/0xa60 drivers/gpu/drm/drm_ioctl.c:886 > vfs_ioctl fs/ioctl.c:47 [inline] > ksys_ioctl+0x123/0x180 fs/ioctl.c:747 > __do_sys_ioctl fs/ioctl.c:756 [inline] > __se_sys_ioctl fs/ioctl.c:754 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 > do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x45b349 > Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f871af46c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007f871af476d4 RCX: 000000000045b349 > RDX: 0000000020000180 RSI: 00000000c02064b2 RDI: 0000000000000003 > RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 0000000000000285 R14: 00000000004d14d0 R15: 000000000075bf2c > > Allocated by task 14871: > save_stack+0x23/0x90 mm/kasan/common.c:72 > set_track mm/kasan/common.c:80 [inline] > __kasan_kmalloc mm/kasan/common.c:513 [inline] > __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486 > kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527 > kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551 > kmalloc include/linux/slab.h:556 [inline] > kzalloc include/linux/slab.h:670 [inline] > __vgem_gem_create+0x49/0x100 drivers/gpu/drm/vgem/vgem_drv.c:165 > vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:194 [inline] > vgem_gem_dumb_create+0xd7/0x250 drivers/gpu/drm/vgem/vgem_drv.c:217 > drm_mode_create_dumb+0x282/0x310 drivers/gpu/drm/drm_dumb_buffers.c:94 > drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:100 > drm_ioctl_kernel+0x244/0x300 drivers/gpu/drm/drm_ioctl.c:786 > drm_ioctl+0x54e/0xa60 drivers/gpu/drm/drm_ioctl.c:886 > vfs_ioctl fs/ioctl.c:47 [inline] > ksys_ioctl+0x123/0x180 fs/ioctl.c:747 > __do_sys_ioctl fs/ioctl.c:756 [inline] > __se_sys_ioctl fs/ioctl.c:754 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 > do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 14871: > save_stack+0x23/0x90 mm/kasan/common.c:72 > set_track mm/kasan/common.c:80 [inline] > kasan_set_free_info mm/kasan/common.c:335 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474 > kasan_slab_free+0xe/0x10 mm/kasan/common.c:483 > __cache_free mm/slab.c:3426 [inline] > kfree+0x10a/0x2c0 mm/slab.c:3757 > vgem_gem_free_object+0xbe/0xe0 drivers/gpu/drm/vgem/vgem_drv.c:68 > drm_gem_object_free+0x100/0x220 drivers/gpu/drm/drm_gem.c:983 > kref_put include/linux/kref.h:65 [inline] > drm_gem_object_put_unlocked drivers/gpu/drm/drm_gem.c:1017 [inline] > drm_gem_object_put_unlocked+0x196/0x1c0 drivers/gpu/drm/drm_gem.c:1002 > vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:199 [inline] > vgem_gem_dumb_create+0x115/0x250 drivers/gpu/drm/vgem/vgem_drv.c:217 > drm_mode_create_dumb+0x282/0x310 drivers/gpu/drm/drm_dumb_buffers.c:94 > drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:100 > drm_ioctl_kernel+0x244/0x300 drivers/gpu/drm/drm_ioctl.c:786 > drm_ioctl+0x54e/0xa60 drivers/gpu/drm/drm_ioctl.c:886 > vfs_ioctl fs/ioctl.c:47 [inline] > ksys_ioctl+0x123/0x180 fs/ioctl.c:747 > __do_sys_ioctl fs/ioctl.c:756 [inline] > __se_sys_ioctl fs/ioctl.c:754 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 > do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff88809fa67800 > which belongs to the cache kmalloc-1k of size 1024 > The buggy address is located 264 bytes inside of > 1024-byte region [ffff88809fa67800, ffff88809fa67c00) > The buggy address belongs to the page: > page:ffffea00027e99c0 refcount:1 mapcount:0 mapping:ffff8880aa400c40 index:0x0 > raw: 00fffe0000000200 ffffea0002293548 ffffea00023e1f08 ffff8880aa400c40 > raw: 0000000000000000 ffff88809fa67000 0000000100000002 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff88809fa67800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88809fa67880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > >ffff88809fa67900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff88809fa67980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88809fa67a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller(a)googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch

4 years, 10 months

Re: [Linaro-mm-sig] KASAN: use-after-free Read in vgem_gem_dumb_create

by Hillf Danton

Fri, 31 Jan 2020 14:28:10 -0800 (PST) > syzbot found the following crash on: > > HEAD commit: 39bed42d Merge tag 'for-linus-hmm' of git://git.kernel.org.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=179465bee00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=2646535f8818ae25 > dashboard link: https://syzkaller.appspot.com/bug?extid=0dc4444774d419e916c8 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16251279e00000 > > The bug was bisected to: > > commit 7611750784664db46d0db95631e322aeb263dde7 > Author: Alex Deucher <alexander.deucher(a)amd.com> > Date: Wed Jun 21 16:31:41 2017 +0000 > > drm/amdgpu: use kernel is_power_of_2 rather than local version > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=11628df1e00000 > final crash: https://syzkaller.appspot.com/x/report.txt?x=13628df1e00000 > console output: https://syzkaller.appspot.com/x/log.txt?x=15628df1e00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+0dc4444774d419e916c8(a)syzkaller.appspotmail.com > Fixes: 761175078466 ("drm/amdgpu: use kernel is_power_of_2 rather than local version") > > ================================================================== > BUG: KASAN: use-after-free in vgem_gem_dumb_create+0x238/0x250 drivers/gpu/drm/vgem/vgem_drv.c:221 > Read of size 8 at addr ffff88809fa67908 by task syz-executor.0/14871 > > CPU: 0 PID: 14871 Comm: syz-executor.0 Not tainted 5.5.0-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x197/0x210 lib/dump_stack.c:118 > print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374 > __kasan_report.cold+0x1b/0x32 mm/kasan/report.c:506 > kasan_report+0x12/0x20 mm/kasan/common.c:639 > __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135 > vgem_gem_dumb_create+0x238/0x250 drivers/gpu/drm/vgem/vgem_drv.c:221 > drm_mode_create_dumb+0x282/0x310 drivers/gpu/drm/drm_dumb_buffers.c:94 > drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:100 > drm_ioctl_kernel+0x244/0x300 drivers/gpu/drm/drm_ioctl.c:786 > drm_ioctl+0x54e/0xa60 drivers/gpu/drm/drm_ioctl.c:886 > vfs_ioctl fs/ioctl.c:47 [inline] > ksys_ioctl+0x123/0x180 fs/ioctl.c:747 > __do_sys_ioctl fs/ioctl.c:756 [inline] > __se_sys_ioctl fs/ioctl.c:754 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 > do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x45b349 > Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f871af46c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 00007f871af476d4 RCX: 000000000045b349 > RDX: 0000000020000180 RSI: 00000000c02064b2 RDI: 0000000000000003 > RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 0000000000000285 R14: 00000000004d14d0 R15: 000000000075bf2c > > Allocated by task 14871: > save_stack+0x23/0x90 mm/kasan/common.c:72 > set_track mm/kasan/common.c:80 [inline] > __kasan_kmalloc mm/kasan/common.c:513 [inline] > __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:486 > kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527 > kmem_cache_alloc_trace+0x158/0x790 mm/slab.c:3551 > kmalloc include/linux/slab.h:556 [inline] > kzalloc include/linux/slab.h:670 [inline] > __vgem_gem_create+0x49/0x100 drivers/gpu/drm/vgem/vgem_drv.c:165 > vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:194 [inline] > vgem_gem_dumb_create+0xd7/0x250 drivers/gpu/drm/vgem/vgem_drv.c:217 > drm_mode_create_dumb+0x282/0x310 drivers/gpu/drm/drm_dumb_buffers.c:94 > drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:100 > drm_ioctl_kernel+0x244/0x300 drivers/gpu/drm/drm_ioctl.c:786 > drm_ioctl+0x54e/0xa60 drivers/gpu/drm/drm_ioctl.c:886 > vfs_ioctl fs/ioctl.c:47 [inline] > ksys_ioctl+0x123/0x180 fs/ioctl.c:747 > __do_sys_ioctl fs/ioctl.c:756 [inline] > __se_sys_ioctl fs/ioctl.c:754 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 > do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 14871: > save_stack+0x23/0x90 mm/kasan/common.c:72 > set_track mm/kasan/common.c:80 [inline] > kasan_set_free_info mm/kasan/common.c:335 [inline] > __kasan_slab_free+0x102/0x150 mm/kasan/common.c:474 > kasan_slab_free+0xe/0x10 mm/kasan/common.c:483 > __cache_free mm/slab.c:3426 [inline] > kfree+0x10a/0x2c0 mm/slab.c:3757 > vgem_gem_free_object+0xbe/0xe0 drivers/gpu/drm/vgem/vgem_drv.c:68 > drm_gem_object_free+0x100/0x220 drivers/gpu/drm/drm_gem.c:983 > kref_put include/linux/kref.h:65 [inline] > drm_gem_object_put_unlocked drivers/gpu/drm/drm_gem.c:1017 [inline] > drm_gem_object_put_unlocked+0x196/0x1c0 drivers/gpu/drm/drm_gem.c:1002 > vgem_gem_create drivers/gpu/drm/vgem/vgem_drv.c:199 [inline] > vgem_gem_dumb_create+0x115/0x250 drivers/gpu/drm/vgem/vgem_drv.c:217 > drm_mode_create_dumb+0x282/0x310 drivers/gpu/drm/drm_dumb_buffers.c:94 > drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:100 > drm_ioctl_kernel+0x244/0x300 drivers/gpu/drm/drm_ioctl.c:786 > drm_ioctl+0x54e/0xa60 drivers/gpu/drm/drm_ioctl.c:886 > vfs_ioctl fs/ioctl.c:47 [inline] > ksys_ioctl+0x123/0x180 fs/ioctl.c:747 > __do_sys_ioctl fs/ioctl.c:756 [inline] > __se_sys_ioctl fs/ioctl.c:754 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 > do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff88809fa67800 > which belongs to the cache kmalloc-1k of size 1024 > The buggy address is located 264 bytes inside of > 1024-byte region [ffff88809fa67800, ffff88809fa67c00) > The buggy address belongs to the page: > page:ffffea00027e99c0 refcount:1 mapcount:0 mapping:ffff8880aa400c40 index:0x0 > raw: 00fffe0000000200 ffffea0002293548 ffffea00023e1f08 ffff8880aa400c40 > raw: 0000000000000000 ffff88809fa67000 0000000100000002 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff88809fa67800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88809fa67880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > >ffff88809fa67900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff88809fa67980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff88809fa67a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== Release obj in error path. --- a/drivers/gpu/drm/vgem/vgem_drv.c +++ b/drivers/gpu/drm/vgem/vgem_drv.c @@ -196,10 +196,10 @@ static struct drm_gem_object *vgem_gem_c return ERR_CAST(obj); ret = drm_gem_handle_create(file, &obj->base, handle); - drm_gem_object_put_unlocked(&obj->base); - if (ret) + if (ret) { + drm_gem_object_put_unlocked(&obj->base); return ERR_PTR(ret); - + } return &obj->base; }

4 years, 10 months

Re: [Linaro-mm-sig] KASAN: use-after-free Read in vgem_gem_dumb_create

by Dan Carpenter

I don't totally understand the stack trace but I do see a double free bug. drivers/gpu/drm/vgem/vgem_drv.c 186 static struct drm_gem_object *vgem_gem_create(struct drm_device *dev, 187 struct drm_file *file, 188 unsigned int *handle, 189 unsigned long size) 190 { 191 struct drm_vgem_gem_object *obj; 192 int ret; 193 194 obj = __vgem_gem_create(dev, size); obj->base.handle_count is zero. 195 if (IS_ERR(obj)) 196 return ERR_CAST(obj); 197 198 ret = drm_gem_handle_create(file, &obj->base, handle); We bump it +1 and then the error handling calls drm_gem_object_handle_put_unlocked(obj); which calls drm_gem_object_put_unlocked(); which frees obj. 199 drm_gem_object_put_unlocked(&obj->base); So this is a double free. Could someone check my thinking and send a patch? It's just a one liner. Otherwise I can send it on Monday. 200 if (ret) 201 return ERR_PTR(ret); 202 203 return &obj->base; 204 } regards, dan carpenter

4 years, 10 months

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Linaro-mm-sig February 2020