Re: [PATCH] drm/mgag200: fix memory leak

From: Dave Airlie <airlied@gmail.com>
To: Ingo Molnar <mingo@kernel.org>, architt@codeaurora.org
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
	David Airlie <airlied@linux.ie>,
	Daniel Vetter <daniel.vetter@ffwll.ch>,
	LKML <linux-kernel@vger.kernel.org>,
	dri-devel <dri-devel@lists.freedesktop.org>,
	Archit Taneja <archit@ti.com>
Subject: Re: [PATCH] drm/mgag200: fix memory leak
Date: Mon, 14 Sep 2015 20:05:37 +1000	[thread overview]
Message-ID: <CAPM=9tyRJ-vWqxTMHeUXDm7+2RH8gtPwvx-rRsSOweB4CLw96w@mail.gmail.com> (raw)
In-Reply-To: <CAPM=9tzwUOKzJwvH1CO2u7YDCUoai3XxAdWZzA2_c44e4XfEEA@mail.gmail.com>

(this time with correct email address).

On 14 September 2015 at 20:04, Dave Airlie <airlied@gmail.com> wrote:
>>
>>> If drm_fb_helper_alloc_fbi() fails then we were directly returning
>>> without freeing sysram. Also if drm_fb_helper_alloc_fbi() succeeds but
>>> mgag200_framebuffer_init() fails then we were not releasing sysram and
>>> we were not releasing fbi helper also.
>>>
>>> Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
>>> ---
>>>  drivers/gpu/drm/mgag200/mgag200_fb.c | 15 ++++++++++++---
>>>  1 file changed, 12 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/mgag200/mgag200_fb.c b/drivers/gpu/drm/mgag200/mgag200_fb.c
>>> index 87de15e..5fe476a 100644
>>> --- a/drivers/gpu/drm/mgag200/mgag200_fb.c
>>> +++ b/drivers/gpu/drm/mgag200/mgag200_fb.c
>>> @@ -189,14 +189,16 @@ static int mgag200fb_create(struct drm_fb_helper *helper,
>>>               return -ENOMEM;
>>>
>>>       info = drm_fb_helper_alloc_fbi(helper);
>>> -     if (IS_ERR(info))
>>> -             return PTR_ERR(info);
>>> +     if (IS_ERR(info)) {
>>> +             ret = PTR_ERR(info);
>>> +             goto err_alloc_fbi;
>>> +     }
>>>
>>>       info->par = mfbdev;
>>>
>>>       ret = mgag200_framebuffer_init(dev, &mfbdev->mfb, &mode_cmd, gobj);
>>>       if (ret)
>>> -             return ret;
>>> +             goto err_framebuffer_init;
>>>
>>>       mfbdev->sysram = sysram;
>>>       mfbdev->size = size;
>>> @@ -226,6 +228,13 @@ static int mgag200fb_create(struct drm_fb_helper *helper,
>>>       DRM_DEBUG_KMS("allocated %dx%d\n",
>>>                     fb->width, fb->height);
>>>       return 0;
>>> +
>>> +err_framebuffer_init:
>>> +     drm_fb_helper_release_fbi(helper);
>>> +
>>> +err_alloc_fbi:
>>> +     vfree(sysram);
>>> +     return ret;
>>>  }
>>>
>>>  static int mga_fbdev_destroy(struct drm_device *dev,
>>
>> There's a new regression: v4.3-rc1 crashes on bootup on non-supported hardware, if
>> CONFIG_DRM_MGAG200=y (built into the kernel).
>
> Archit, I'm guessing this is some fallout from the fbdev changes.
>
> There is no reason we should need CONFIG_FB_LITTLE_ENDIAN I don't think.
>
> Dave.
>
>>
>> [   10.191561] bus: 'i2c': add device i2c-0
>> [   10.227367] mgadrmfb: enable CONFIG_FB_LITTLE_ENDIAN to support this framebuffer
>> [   10.235781] [drm:mgag200_modeset_init] *ERROR* mga_fbdev_init failed
>> [   10.242992] mgag200 0000:0b:00.0: Fatal error during modeset init: -22
>> [   10.250456] kfree_debugcheck: out of range ptr 6b6b6b6b6b6b6b6bh.
>> [   10.257378] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
>> [   10.264730] Modules linked in:
>> [   10.268319] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.3.0-rc1-01643-g6013d75-dirty #15
>> [   10.277498] Hardware name: Intel Corporation S2600GZ/S2600GZ, BIOS SE5C600.86B.02.02.0002.122320131210 12/23/2013
>> [   10.289111] task: ffff88017fb6c040 ti: ffff88017fb70000 task.ti: ffff88017fb70000
>> [   10.297611] RIP: 0010:[<ffffffffa493d1a7>]  [<ffffffffa493d1a7>] kfree_debugcheck+0x20/0x25
>> [   10.307170] RSP: 0000:ffff88017fb73b28  EFLAGS: 00010086
>> [   10.313213] RAX: 0000000000000035 RBX: 6b6b6b6b6b6b6b6b RCX: 0000000000000000
>> [   10.321297] RDX: ffffffffa489ac8f RSI: ffffffffa489b27b RDI: ffffffffa489b11e
>> [   10.329381] RBP: ffff88017fb73b30 R08: 0000000000000001 R09: 0000000000000000
>> [   10.337466] R10: ffffffffa537dec0 R11: 0000000000000000 R12: 0000000000000001
>> [   10.345549] R13: ffffffffa4c2c22a R14: 0000000000000202 R15: ffff8807ee3f1018
>> [   10.353632] FS:  0000000000000000(0000) GS:ffff88081b200000(0000) knlGS:0000000000000000
>> [   10.362812] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [   10.369330] CR2: 0000000000000000 CR3: 00000000258c0000 CR4: 00000000001406f0
>> [   10.377415] Stack:
>> [   10.379761]  6b6b6b6b6b6b6b6b ffff88017fb73b70 ffffffffa493e421 ffff8807ee784ea0
>> [   10.388499]  ffff8807ee784e18 0000000000000001 ffff8807ee361060 00000000ffffffea
>> [   10.397238]  ffff8807ee3f1018 ffff88017fb73b98 ffffffffa4c2c22a ffff8807ee784e18
>> [   10.405968] Call Trace:
>> [   10.408804]  [<ffffffffa493e421>] kfree+0x5a/0x195
>> [   10.414256]  [<ffffffffa4c2c22a>] drm_fb_helper_crtc_free+0x28/0x75
>> [   10.421368]  [<ffffffffa4c2cbbd>] drm_fb_helper_fini+0x6b/0x6e
>> [   10.427996]  [<ffffffffa4ce522d>] mgag200_fbdev_fini+0x8a/0xb9
>> [   10.434621]  [<ffffffffa4ce0a17>] mgag200_driver_unload+0x23/0x43
>> [   10.441539]  [<ffffffffa4ce0ee1>] mgag200_driver_load+0x4aa/0x4bc
>> [   10.448458]  [<ffffffffa4c3537c>] drm_dev_register+0x6a/0xab
>> [   10.454889]  [<ffffffffa4c36e42>] drm_get_pci_dev+0xe8/0x1ab
>> [   10.461322]  [<ffffffffa4ce4b73>] mga_pci_probe+0xa1/0xaa
>> [   10.467465]  [<ffffffffa4b785ba>] pci_device_probe+0x7e/0xe8
>> ...
>>
>> Thanks,
>>
>>         Ingo
>> --
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