diff options
author | Noralf Trønnes <noralf@tronnes.org> | 2018-10-01 22:45:36 +0300 |
---|---|---|
committer | Noralf Trønnes <noralf@tronnes.org> | 2018-10-02 14:03:34 +0300 |
commit | 4d4c2d89913e2d891bd6a34b12050a2576e60525 (patch) | |
tree | 5b1ead135c30e41f26979ebc70d02d55af8b7774 /drivers/gpu | |
parent | 12d43deb1ee639d01a2a8d2a7a4cc8ad31224475 (diff) | |
download | linux-4d4c2d89913e2d891bd6a34b12050a2576e60525.tar.xz |
drm/cma-helper: Fix crash in fbdev error path
Sergey Suloev reported a crash happening in drm_client_dev_hotplug()
when fbdev had failed to register.
[ 9.124598] vc4_hdmi 3f902000.hdmi: ASoC: Failed to create component debugfs directory
[ 9.147667] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi mapping ok
[ 9.155184] vc4_hdmi 3f902000.hdmi: ASoC: no DMI vendor name!
[ 9.166544] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4])
[ 9.173840] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops [vc4])
[ 9.181029] vc4-drm soc:gpu: bound 3f004000.txp (ops vc4_txp_ops [vc4])
[ 9.188519] vc4-drm soc:gpu: bound 3f400000.hvs (ops vc4_hvs_ops [vc4])
[ 9.195690] vc4-drm soc:gpu: bound 3f206000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 9.203523] vc4-drm soc:gpu: bound 3f207000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 9.215032] vc4-drm soc:gpu: bound 3f807000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 9.274785] vc4-drm soc:gpu: bound 3fc00000.v3d (ops vc4_v3d_ops [vc4])
[ 9.290246] [drm] Initialized vc4 0.0.0 20140616 for soc:gpu on minor 0
[ 9.297464] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[ 9.304600] [drm] Driver supports precise vblank timestamp query.
[ 9.382856] vc4-drm soc:gpu: [drm:drm_fb_helper_fbdev_setup [drm_kms_helper]] *ERROR* Failed to set fbdev configuration
[ 10.404937] Unable to handle kernel paging request at virtual address 00330a656369768a
[ 10.441620] [00330a656369768a] address between user and kernel address ranges
[ 10.449087] Internal error: Oops: 96000004 [#1] PREEMPT SMP
[ 10.454762] Modules linked in: brcmfmac vc4 drm_kms_helper cfg80211 drm rfkill smsc95xx brcmutil usbnet drm_panel_orientation_quirks raspberrypi_hwmon bcm2835_dma crc32_ce pwm_bcm2835 bcm2835_rng virt_dma rng_core i2c_bcm2835 ip_tables x_tables ipv6
[ 10.477296] CPU: 2 PID: 45 Comm: kworker/2:1 Not tainted 4.19.0-rc5 #3
[ 10.483934] Hardware name: Raspberry Pi 3 Model B Rev 1.2 (DT)
[ 10.489966] Workqueue: events output_poll_execute [drm_kms_helper]
[ 10.596515] Process kworker/2:1 (pid: 45, stack limit = 0x000000007e8924dc)
[ 10.603590] Call trace:
[ 10.606259] drm_client_dev_hotplug+0x5c/0xb0 [drm]
[ 10.611303] drm_kms_helper_hotplug_event+0x30/0x40 [drm_kms_helper]
[ 10.617849] output_poll_execute+0xc4/0x1e0 [drm_kms_helper]
[ 10.623616] process_one_work+0x1c8/0x318
[ 10.627695] worker_thread+0x48/0x428
[ 10.631420] kthread+0xf8/0x128
[ 10.634615] ret_from_fork+0x10/0x18
[ 10.638255] Code: 54000220 f9401261 aa1303e0 b4000141 (f9400c21)
[ 10.644456] ---[ end trace c75b4a4b0e141908 ]---
The reason for this is that drm_fbdev_cma_init() removes the drm_client
when fbdev registration fails, but it doesn't remove the client from the
drm_device client list. So the client list now has a pointer that points
into the unknown and we have a 'use after free' situation.
Split drm_client_new() into drm_client_init() and drm_client_add() to fix
removal in the error path.
Fixes: 894a677f4b3e ("drm/cma-helper: Use the generic fbdev emulation")
Reported-by: Sergey Suloev <ssuloev@orpaltech.com>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181001194536.57756-1-noralf@tronnes.org
Diffstat (limited to 'drivers/gpu')
-rw-r--r-- | drivers/gpu/drm/drm_client.c | 35 | ||||
-rw-r--r-- | drivers/gpu/drm/drm_fb_cma_helper.c | 4 | ||||
-rw-r--r-- | drivers/gpu/drm/drm_fb_helper.c | 4 |
3 files changed, 32 insertions, 11 deletions
diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c index baff50a4c234..df31c3815092 100644 --- a/drivers/gpu/drm/drm_client.c +++ b/drivers/gpu/drm/drm_client.c @@ -63,20 +63,21 @@ static void drm_client_close(struct drm_client_dev *client) EXPORT_SYMBOL(drm_client_close); /** - * drm_client_new - Create a DRM client + * drm_client_init - Initialise a DRM client * @dev: DRM device * @client: DRM client * @name: Client name * @funcs: DRM client functions (optional) * + * This initialises the client and opens a &drm_file. Use drm_client_add() to complete the process. * The caller needs to hold a reference on @dev before calling this function. * The client is freed when the &drm_device is unregistered. See drm_client_release(). * * Returns: * Zero on success or negative error code on failure. */ -int drm_client_new(struct drm_device *dev, struct drm_client_dev *client, - const char *name, const struct drm_client_funcs *funcs) +int drm_client_init(struct drm_device *dev, struct drm_client_dev *client, + const char *name, const struct drm_client_funcs *funcs) { int ret; @@ -95,10 +96,6 @@ int drm_client_new(struct drm_device *dev, struct drm_client_dev *client, if (ret) goto err_put_module; - mutex_lock(&dev->clientlist_mutex); - list_add(&client->list, &dev->clientlist); - mutex_unlock(&dev->clientlist_mutex); - drm_dev_get(dev); return 0; @@ -109,13 +106,33 @@ err_put_module: return ret; } -EXPORT_SYMBOL(drm_client_new); +EXPORT_SYMBOL(drm_client_init); + +/** + * drm_client_add - Add client to the device list + * @client: DRM client + * + * Add the client to the &drm_device client list to activate its callbacks. + * @client must be initialized by a call to drm_client_init(). After + * drm_client_add() it is no longer permissible to call drm_client_release() + * directly (outside the unregister callback), instead cleanup will happen + * automatically on driver unload. + */ +void drm_client_add(struct drm_client_dev *client) +{ + struct drm_device *dev = client->dev; + + mutex_lock(&dev->clientlist_mutex); + list_add(&client->list, &dev->clientlist); + mutex_unlock(&dev->clientlist_mutex); +} +EXPORT_SYMBOL(drm_client_add); /** * drm_client_release - Release DRM client resources * @client: DRM client * - * Releases resources by closing the &drm_file that was opened by drm_client_new(). + * Releases resources by closing the &drm_file that was opened by drm_client_init(). * It is called automatically if the &drm_client_funcs.unregister callback is _not_ set. * * This function should only be called from the unregister callback. An exception diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c index 9da36a6271d3..9ac1f2e0f064 100644 --- a/drivers/gpu/drm/drm_fb_cma_helper.c +++ b/drivers/gpu/drm/drm_fb_cma_helper.c @@ -160,7 +160,7 @@ struct drm_fbdev_cma *drm_fbdev_cma_init(struct drm_device *dev, fb_helper = &fbdev_cma->fb_helper; - ret = drm_client_new(dev, &fb_helper->client, "fbdev", NULL); + ret = drm_client_init(dev, &fb_helper->client, "fbdev", NULL); if (ret) goto err_free; @@ -169,6 +169,8 @@ struct drm_fbdev_cma *drm_fbdev_cma_init(struct drm_device *dev, if (ret) goto err_client_put; + drm_client_add(&fb_helper->client); + return fbdev_cma; err_client_put: diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 16ec93b75dbf..515a7aec57ac 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -3218,12 +3218,14 @@ int drm_fbdev_generic_setup(struct drm_device *dev, unsigned int preferred_bpp) if (!fb_helper) return -ENOMEM; - ret = drm_client_new(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs); + ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs); if (ret) { kfree(fb_helper); return ret; } + drm_client_add(&fb_helper->client); + fb_helper->preferred_bpp = preferred_bpp; drm_fbdev_client_hotplug(&fb_helper->client); |