Re: [mesa v2 5/9] nouveau: fix screen creation failure paths

[Ben Skeggs <skeggsb-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

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On 12/07/2015 01:40 PM, Ilia Mirkin wrote:
> This all seems very roundabout... Can't we do this in a somewhat
> consistent way with the device being cleaned up in one place or
> another but not both?
That would be lovely, but not possible.  It has to be cleaned up by the
pipe screen destroy() function, as that's the normal exit path.  If the
pipe driver creation path fails before it's got a struct, then the
winsys will have to clean up after itself instead.

> 
> On Thu, Nov 26, 2015 at 8:04 PM, Ben Skeggs <skeggsb-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> From: Ben Skeggs <bskeggs-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>>
>> The winsys layer would attempt to cleanup the nouveau_device if screen
>> init failed, however, in most paths the pipe driver would have already
>> destroyed it, resulting in accesses to freed memory etc.
>>
>> This commit fixes the problem by allowing the winsys to detect whether
>> the pipe driver's destroy function needs to be called or not.
>>
>> Signed-off-by: Ben Skeggs <bskeggs-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
>> ---
>>  src/gallium/drivers/nouveau/nouveau_screen.c        |  8 ++++++--
>>  src/gallium/drivers/nouveau/nv30/nv30_screen.c      | 19 ++++++++++---------
>>  src/gallium/drivers/nouveau/nv50/nv50_screen.c      |  6 +++---
>>  src/gallium/drivers/nouveau/nvc0/nvc0_screen.c      |  9 ++++-----
>>  src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c | 16 ++++++++++------
>>  5 files changed, 33 insertions(+), 25 deletions(-)
>>
>> diff --git a/src/gallium/drivers/nouveau/nouveau_screen.c b/src/gallium/drivers/nouveau/nouveau_screen.c
>> index a012579..3cdcc20 100644
>> --- a/src/gallium/drivers/nouveau/nouveau_screen.c
>> +++ b/src/gallium/drivers/nouveau/nouveau_screen.c
>> @@ -147,6 +147,12 @@ nouveau_screen_init(struct nouveau_screen *screen, struct nouveau_device *dev)
>>     if (nv_dbg)
>>        nouveau_mesa_debug = atoi(nv_dbg);
>>
>> +   /* These must be set before any failure is possible, as the cleanup
>> +    * paths assume they're responsible for deleting them.
>> +    */
>> +   screen->drm = nouveau_drm(&dev->object);
>> +   screen->device = dev;
>> +
>>     /*
>>      * this is initialized to 1 in nouveau_drm_screen_create after screen
>>      * is fully constructed and added to the global screen list.
>> @@ -175,8 +181,6 @@ nouveau_screen_init(struct nouveau_screen *screen, struct nouveau_device *dev)
>>                              data, size, &screen->channel);
>>     if (ret)
>>        return ret;
>> -   screen->drm = nouveau_drm(&dev->object);
>> -   screen->device = dev;
>>
>>     ret = nouveau_client_new(screen->device, &screen->client);
>>     if (ret)
>> diff --git a/src/gallium/drivers/nouveau/nv30/nv30_screen.c b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
>> index ea29811..854f70c 100644
>> --- a/src/gallium/drivers/nouveau/nv30/nv30_screen.c
>> +++ b/src/gallium/drivers/nouveau/nv30/nv30_screen.c
>> @@ -413,23 +413,20 @@ nv30_screen_destroy(struct pipe_screen *pscreen)
>>  #define FAIL_SCREEN_INIT(str, err)                    \
>>     do {                                               \
>>        NOUVEAU_ERR(str, err);                          \
>> -      nv30_screen_destroy(pscreen);                   \
>> -      return NULL;                                    \
>> +      screen->base.base.context_create = NULL;        \
>> +      return &screen->base;                           \
>>     } while(0)
>>
>>  struct nouveau_screen *
>>  nv30_screen_create(struct nouveau_device *dev)
>>  {
>> -   struct nv30_screen *screen = CALLOC_STRUCT(nv30_screen);
>> +   struct nv30_screen *screen;
>>     struct pipe_screen *pscreen;
>>     struct nouveau_pushbuf *push;
>>     struct nv04_fifo *fifo;
>>     unsigned oclass = 0;
>>     int ret, i;
>>
>> -   if (!screen)
>> -      return NULL;
>> -
>>     switch (dev->chipset & 0xf0) {
>>     case 0x30:
>>        if (RANKINE_0397_CHIPSET & (1 << (dev->chipset & 0x0f)))
>> @@ -458,10 +455,16 @@ nv30_screen_create(struct nouveau_device *dev)
>>
>>     if (!oclass) {
>>        NOUVEAU_ERR("unknown 3d class for 0x%02x\n", dev->chipset);
>> -      FREE(screen);
>>        return NULL;
>>     }
>>
>> +   screen = CALLOC_STRUCT(nv30_screen);
>> +   if (!screen)
>> +      return NULL;
>> +
>> +   pscreen = &screen->base.base;
>> +   pscreen->destroy = nv30_screen_destroy;
>> +
>>     /*
>>      * Some modern apps try to use msaa without keeping in mind the
>>      * restrictions on videomem of older cards. Resulting in dmesg saying:
>> @@ -479,8 +482,6 @@ nv30_screen_create(struct nouveau_device *dev)
>>     if (screen->max_sample_count > 4)
>>        screen->max_sample_count = 4;
>>
>> -   pscreen = &screen->base.base;
>> -   pscreen->destroy = nv30_screen_destroy;
>>     pscreen->get_param = nv30_screen_get_param;
>>     pscreen->get_paramf = nv30_screen_get_paramf;
>>     pscreen->get_shader_param = nv30_screen_get_shader_param;
>> diff --git a/src/gallium/drivers/nouveau/nv50/nv50_screen.c b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>> index 82b9e93..46c812b 100644
>> --- a/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>> +++ b/src/gallium/drivers/nouveau/nv50/nv50_screen.c
>> @@ -762,6 +762,7 @@ nv50_screen_create(struct nouveau_device *dev)
>>     if (!screen)
>>        return NULL;
>>     pscreen = &screen->base.base;
>> +   pscreen->destroy = nv50_screen_destroy;
>>
>>     ret = nouveau_screen_init(&screen->base, dev);
>>     if (ret) {
>> @@ -782,7 +783,6 @@ nv50_screen_create(struct nouveau_device *dev)
>>
>>     chan = screen->base.channel;
>>
>> -   pscreen->destroy = nv50_screen_destroy;
>>     pscreen->context_create = nv50_create;
>>     pscreen->is_format_supported = nv50_screen_is_format_supported;
>>     pscreen->get_param = nv50_screen_get_param;
>> @@ -964,8 +964,8 @@ nv50_screen_create(struct nouveau_device *dev)
>>     return &screen->base;
>>
>>  fail:
>> -   nv50_screen_destroy(pscreen);
>> -   return NULL;
>> +   screen->base.base.context_create = NULL;
>> +   return &screen->base;
>>  }
>>
>>  int
>> diff --git a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>> index e45031a..4897ebe 100644
>> --- a/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>> +++ b/src/gallium/drivers/nouveau/nvc0/nvc0_screen.c
>> @@ -617,8 +617,7 @@ nvc0_screen_resize_tls_area(struct nvc0_screen *screen,
>>  #define FAIL_SCREEN_INIT(str, err)                    \
>>     do {                                               \
>>        NOUVEAU_ERR(str, err);                          \
>> -      nvc0_screen_destroy(pscreen);                   \
>> -      return NULL;                                    \
>> +      goto fail;                                      \
>>     } while(0)
>>
>>  struct nouveau_screen *
>> @@ -650,6 +649,7 @@ nvc0_screen_create(struct nouveau_device *dev)
>>     if (!screen)
>>        return NULL;
>>     pscreen = &screen->base.base;
>> +   pscreen->destroy = nvc0_screen_destroy;
>>
>>     ret = nouveau_screen_init(&screen->base, dev);
>>     if (ret) {
>> @@ -672,7 +672,6 @@ nvc0_screen_create(struct nouveau_device *dev)
>>        screen->base.vidmem_bindings = 0;
>>     }
>>
>> -   pscreen->destroy = nvc0_screen_destroy;
>>     pscreen->context_create = nvc0_create;
>>     pscreen->is_format_supported = nvc0_screen_is_format_supported;
>>     pscreen->get_param = nvc0_screen_get_param;
>> @@ -1065,8 +1064,8 @@ nvc0_screen_create(struct nouveau_device *dev)
>>     return &screen->base;
>>
>>  fail:
>> -   nvc0_screen_destroy(pscreen);
>> -   return NULL;
>> +   screen->base.base.context_create = NULL;
>> +   return &screen->base;
>>  }
>>
>>  int
>> diff --git a/src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c b/src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c
>> index e117dfc..456530d 100644
>> --- a/src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c
>> +++ b/src/gallium/winsys/nouveau/drm/nouveau_drm_winsys.c
>> @@ -59,7 +59,7 @@ nouveau_drm_screen_create(int fd)
>>  {
>>         struct nouveau_device *dev = NULL;
>>         struct nouveau_screen *(*init)(struct nouveau_device *);
>> -       struct nouveau_screen *screen;
>> +       struct nouveau_screen *screen = NULL;
>>         int ret, dupfd = -1;
>>
>>         pipe_mutex_lock(nouveau_screen_mutex);
>> @@ -117,7 +117,7 @@ nouveau_drm_screen_create(int fd)
>>         }
>>
>>         screen = init(dev);
>> -       if (!screen)
>> +       if (!screen || !screen->base.context_create)
>>                 goto err;
>>
>>         /* Use dupfd in hash table, to avoid errors if the original fd gets
>> @@ -130,10 +130,14 @@ nouveau_drm_screen_create(int fd)
>>         return &screen->base;
>>
>>  err:
>> -       if (dev)
>> -               nouveau_device_del(&dev);
>> -       else if (dupfd >= 0)
>> -               close(dupfd);
>> +       if (screen) {
>> +               screen->base.destroy(&screen->base);
>> +       } else {
>> +               if (dev)
>> +                       nouveau_device_del(&dev);
>> +               else if (dupfd >= 0)
>> +                       close(dupfd);
>> +       }
>>         pipe_mutex_unlock(nouveau_screen_mutex);
>>         return NULL;
>>  }
>> --
>> 2.6.3
>>
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>> Nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
>> http://lists.freedesktop.org/mailman/listinfo/nouveau


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