Messages in this thread Patch in this message | | | Date | Mon, 1 Nov 2021 10:50:07 +0300 | Subject | Re: Need help in debugging "memory leak in em28xx_init_dev" | From | Pavel Skripkin <> |
| |
On 11/1/21 06:02, Dongliang Mu wrote: > Hi all, > > My local syzkaller instance found one bug named "memory leak in > em28xx_init_dev" in 5.14-rc5. Kernel configuration and PoC file are > attached(I don't check if the latest kernel is vulnerable, but it > should be). The trace from memleak is as follows: > > backtrace: > [<ffffffff842cc66d>] kmalloc include/linux/slab.h:591 [inline] > [<ffffffff842cc66d>] kzalloc include/linux/slab.h:721 [inline] > [<ffffffff842cc66d>] em28xx_media_device_init > drivers/media/usb/em28xx/em28xx-cards.c:3444 [inline] > [<ffffffff842cc66d>] em28xx_init_dev.isra.0+0x366/0x9bf > drivers/media/usb/em28xx/em28xx-cards.c:3624 > [<ffffffff842cd1bd>] em28xx_usb_probe.cold+0x4f7/0xf95 > drivers/media/usb/em28xx/em28xx-cards.c:3979 > [<ffffffff82bf0815>] usb_probe_interface+0x185/0x350 > drivers/usb/core/driver.c:396 >
Looks like missing clean up on error handling path.
->probe() em28xx_init_dev() em28xx_media_device_init() <- dev->media_dev allocated *error somewhere in em28xx_init_dev()*
And then nothing unwinds em28xx_media_device_init() call, since disconnect won't be called in case of failure in ->probe()
Just build tested, but, I guess, something like this should work.
With regards, Pavel Skripkin
diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c index c1e0dccb7408..f22e5ca2d1b3 100644 --- a/drivers/media/usb/em28xx/em28xx-cards.c +++ b/drivers/media/usb/em28xx/em28xx-cards.c @@ -3626,7 +3626,7 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev, if (dev->is_audio_only) { retval = em28xx_audio_setup(dev); if (retval) - return -ENODEV; + goto deinit_media; em28xx_init_extension(dev); return 0; @@ -3645,7 +3645,7 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev, dev_err(&dev->intf->dev, "%s: em28xx_i2c_register bus 0 - error [%d]!\n", __func__, retval); - return retval; + goto deinit_media; } /* register i2c bus 1 */ @@ -3663,7 +3663,7 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev, em28xx_i2c_unregister(dev, 0); - return retval; + goto deinit_media; } } @@ -3671,6 +3671,10 @@ static int em28xx_init_dev(struct em28xx *dev, struct usb_device *udev, em28xx_card_setup(dev); return 0; + +deinit_media: + em28xx_unregister_media_device(dev); + return retval; } static int em28xx_duplicate_dev(struct em28xx *dev) | |