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[91.175.163.178]) by smtp.gmail.com with ESMTPSA id vu8-20020a170907a64800b00a1d5c52d628sm9007847ejc.3.2023.12.14.01.04.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Dec 2023 01:04:06 -0800 (PST) From: Alban Browaeys Cc: Alban Browaeys , Qiang Yu , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , dri-devel@lists.freedesktop.org, lima@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH] RFC: drm/lima: fix calling drm_mm_init with an empty range Date: Thu, 14 Dec 2023 10:12:11 +0100 Message-Id: <20231214091215.2435-1-alban.browaeys@gmail.com> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" For the empty_vm initialization the range is empty which is not supported by drm_mm_init. With CONFIG_DRM_DEBUG_MM set, I get: ------------[ cut here ]------------ kernel BUG at drivers/gpu/drm/drm_mm.c:965! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM Modules linked in: lima(+) drm_shmem_helper gpu_sched s5p_jpeg s5p_g2d videobuf2_dma_contig videobuf2_memops v4l2_mem2mem videobuf2_v4l2 videobuf2_common s5p_cec tun fuse configfs auth_rpcgss sunrpc ip_tables x_tables autofs4 btrfs lzo_compress zlib_deflate raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor xor_neon raid6_pq libcrc32c raid1 raid0 linear md_mod dm_mirror dm_region_hash dm_log hid_logitech_hidpp hid_logitech_dj CPU: 0 PID: 1033 Comm: systemd-udevd Not tainted 6.4.0-rc1-debug+ #230 Hardware name: Samsung Exynos (Flattened Device Tree) PC is at drm_mm_init+0x94/0x98 LR is at 0x0 Flags: nZCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment none drm_mm_init from lima_vm_create+0xcc/0x108 [lima] lima_vm_create [lima] from lima_device_init+0xd8/0x4a0 [lima] lima_device_init [lima] from lima_pdev_probe.part.0+0x6c/0x158 [lima] lima_pdev_probe.part.0 [lima] from platform_probe+0x64/0xc0 platform_probe from call_driver_probe+0x2c/0x110 The drm_mm.c line 965 is: drivers/gpu/drm/drm_mm.c void drm_mm_init(struct drm_mm *mm, u64 start, u64 size) { DRM_MM_BUG_ON(start + size <=3D start); lima_vm_create is called with va_start and va_end both unset in lima_device_init line 371: ldev->empty_vm =3D lima_vm_create(ldev); Signed-off-by: Alban Browaeys --- drivers/gpu/drm/lima/lima_device.c | 2 +- drivers/gpu/drm/lima/lima_drv.c | 2 +- drivers/gpu/drm/lima/lima_vm.c | 10 +++++++--- drivers/gpu/drm/lima/lima_vm.h | 3 ++- 4 files changed, 11 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/lima/lima_device.c b/drivers/gpu/drm/lima/lima= _device.c index 02cef0cea657..bd3afff0f44a 100644 --- a/drivers/gpu/drm/lima/lima_device.c +++ b/drivers/gpu/drm/lima/lima_device.c @@ -368,7 +368,7 @@ int lima_device_init(struct lima_device *ldev) if (err) goto err_out0; =20 - ldev->empty_vm =3D lima_vm_create(ldev); + ldev->empty_vm =3D lima_vm_create(ldev, false); if (!ldev->empty_vm) { err =3D -ENOMEM; goto err_out1; diff --git a/drivers/gpu/drm/lima/lima_drv.c b/drivers/gpu/drm/lima/lima_dr= v.c index 10fd9154cc46..ca09142e0ac1 100644 --- a/drivers/gpu/drm/lima/lima_drv.c +++ b/drivers/gpu/drm/lima/lima_drv.c @@ -219,7 +219,7 @@ static int lima_drm_driver_open(struct drm_device *dev,= struct drm_file *file) if (!priv) return -ENOMEM; =20 - priv->vm =3D lima_vm_create(ldev); + priv->vm =3D lima_vm_create(ldev, true); if (!priv->vm) { err =3D -ENOMEM; goto err_out0; diff --git a/drivers/gpu/drm/lima/lima_vm.c b/drivers/gpu/drm/lima/lima_vm.c index 2b2739adc7f5..7f9775eefd78 100644 --- a/drivers/gpu/drm/lima/lima_vm.c +++ b/drivers/gpu/drm/lima/lima_vm.c @@ -197,7 +197,7 @@ u32 lima_vm_get_va(struct lima_vm *vm, struct lima_bo *= bo) return ret; } =20 -struct lima_vm *lima_vm_create(struct lima_device *dev) +struct lima_vm *lima_vm_create(struct lima_device *dev, bool has_drm_mm) { struct lima_vm *vm; =20 @@ -221,7 +221,10 @@ struct lima_vm *lima_vm_create(struct lima_device *dev) goto err_out1; } =20 - drm_mm_init(&vm->mm, dev->va_start, dev->va_end - dev->va_start); + if (has_drm_mm) { + vm->has_drm_mm =3D true; + drm_mm_init(&vm->mm, dev->va_start, dev->va_end - dev->va_start); + } =20 return vm; =20 @@ -237,7 +240,8 @@ void lima_vm_release(struct kref *kref) struct lima_vm *vm =3D container_of(kref, struct lima_vm, refcount); int i; =20 - drm_mm_takedown(&vm->mm); + if (vm->has_drm_mm) + drm_mm_takedown(&vm->mm); =20 for (i =3D 0; i < LIMA_VM_NUM_BT; i++) { if (vm->bts[i].cpu) diff --git a/drivers/gpu/drm/lima/lima_vm.h b/drivers/gpu/drm/lima/lima_vm.h index 3a7c74822d8b..e7443f410d6d 100644 --- a/drivers/gpu/drm/lima/lima_vm.h +++ b/drivers/gpu/drm/lima/lima_vm.h @@ -30,6 +30,7 @@ struct lima_vm { struct mutex lock; struct kref refcount; =20 + bool has_drm_mm; struct drm_mm mm; =20 struct lima_device *dev; @@ -43,7 +44,7 @@ void lima_vm_bo_del(struct lima_vm *vm, struct lima_bo *b= o); =20 u32 lima_vm_get_va(struct lima_vm *vm, struct lima_bo *bo); =20 -struct lima_vm *lima_vm_create(struct lima_device *dev); +struct lima_vm *lima_vm_create(struct lima_device *dev, bool has_drm_mm); void lima_vm_release(struct kref *kref); =20 static inline struct lima_vm *lima_vm_get(struct lima_vm *vm) --=20 2.39.2