Calling kobject_put() after a failed kobject_init_and_add() seemed wrong, and it also appears to be missing a kfree(), so I didn't want to mess it up any further. ttm_pool_kobj_release will do that, so no need kfree() here. I will fix this warning today. Thanks. Thanks Roger(Hongbo.He) -----Original Message----- From: arndbergmann@xxxxxxxxx [mailto:arndbergmann@xxxxxxxxx] On Behalf Of Arnd Bergmann Sent: Thursday, January 11, 2018 12:18 AM To: Koenig, Christian <Christian.Koenig@xxxxxxx> Cc: kernelci.org bot <bot@xxxxxxxxxxxx>; Kernel Build Reports Mailman List <kernel-build-reports@xxxxxxxxxxxxxxxx>; Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>; Thomas Hellstrom <thellstrom@xxxxxxxxxx>; Dave Airlie <airlied@xxxxxxxxxx>; He, Roger <Hongbo.He@xxxxxxx>; Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxx>; Francisco Jerez <currojerez@xxxxxxxxxx>; Viresh Kumar <vireshk@xxxxxxxxxx>; Shiraz Hashim <shiraz.linux.kernel@xxxxxxxxx>; Linus Walleij <linus.walleij@xxxxxxxxxx>; dri-devel <dri-devel@xxxxxxxxxxxxxxxxxxxxx> Subject: Re: next/master build: 198 builds: 1 failed, 197 passed, 1 error, 148 warnings (next-20180110) On Wed, Jan 10, 2018 at 4:54 PM, Christian König <christian.koenig@xxxxxxx> wrote: > Hi Arnd, > > Am 10.01.2018 um 16:45 schrieb Arnd Bergmann: >>> >>> 14 drivers/gpu/drm/ttm/ttm_page_alloc_dma.c:1186:2: warning: >>> ignoring return value of 'register_shrinker', declared with >>> attribute warn_unused_result [-Wunused-result] >>> 14 drivers/gpu/drm/ttm/ttm_page_alloc.c:485:2: warning: ignoring >>> return value of 'register_shrinker', declared with attribute >>> warn_unused_result [-Wunused-result] >> >> ttm and kvm are now the last user of register_shrinker that doesn't >> propagate the return code to its caller, all other callers got fixed >> in one way or another. >> >> I tried to fix this one too, but couldn't come up with a proper way >> of unwinding both >> kobject_init_and_add() and ttm_pool_mm_shrink_init(): >> >> ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type, >> &glob->kobj, "pool"); >> if (unlikely(ret != 0)) { >> kobject_put(&_manager->kobj); >> _manager = NULL; >> return ret; >> } >> >> ttm_pool_mm_shrink_init(_manager); >> >> Calling kobject_put() after a failed kobject_init_and_add() seemed >> wrong, and it also appears to be missing a kfree(), so I didn't want >> to mess it up any further. Added a few people to Cc that touched this >> file most, maybe one of them can have a look, or they already have a >> patch waiting to get merged. > > > That isn't urgent, isn't it? So I would say I put it on my TODO list > and I'm going to take care of it no later than 4.17. > > Otherwise Roger or me could take a look tomorrow. My understanding is that the warning will be in 4.16, so the fix should be as well, if only to get a clean build again. There were around a dozen such warnings when the warn_unused_result got added, but the others are all fixed in linux-next. This is how the flag got added: commit 64067c5cbfa24a2202b92e8fda7323610cad3043 Author: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Date: Fri Jan 5 13:25:45 2018 +1100 mm,vmscan: mark register_shrinker() as __must_check There are users not checking for register_shrinker() failure. Continuing with ignoring failure can lead to later oops at unregister_shrinker(). Link: http://lkml.kernel.org/r/1511265757-15563-1-git-send-email-penguin-kernel@xxxxxxxxxxxxxxxxxxx Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Arnd _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
