From: Thomas Gleixner <tglx@linutronix.de> To: Bart Van Assche <Bart.VanAssche@wdc.com> Cc: "mingo@kernel.org" <mingo@kernel.org>, "peterz@infradead.org" <peterz@infradead.org>, "byungchul.park@lge.com" <byungchul.park@lge.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "amir73il@gmail.com" <amir73il@gmail.com>, "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>, "hch@infradead.org" <hch@infradead.org>, "linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>, "linux-mm@kvack.org" <linux-mm@kvack.org>, "oleg@redhat.com" <oleg@redhat.com>, "darrick.wong@oracle.com" <darrick.wong@oracle.com>, "johannes.berg@intel.com" <johannes.berg@intel.com>, "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>, "idryomov@gmail.com" <idryomov@gmail.com>, "tj@kernel.org" <tj@kernel.org>, "kernel-team@lge.com" <kernel-team@lge.com>, "david@fromorbit.com" <david@fromorbit.com> Subject: Re: [RESEND PATCH 1/3] completion: Add support for initializing completion with lockdep_map Date: Fri, 20 Oct 2017 08:34:36 +0200 (CEST) [thread overview] Message-ID: <alpine.DEB.2.20.1710200829340.3083@nanos> (raw) In-Reply-To: <1508455438.4542.4.camel@wdc.com> On Thu, 19 Oct 2017, Bart Van Assche wrote: > On Wed, 2017-10-18 at 18:38 +0900, Byungchul Park wrote: > > Sometimes, we want to initialize completions with sparate lockdep maps > > to assign lock classes under control. For example, the workqueue code > > manages lockdep maps, as it can classify lockdep maps properly. > > Provided a function for that purpose. > > > > Signed-off-by: Byungchul Park <byungchul.park@lge.com> > > --- > > include/linux/completion.h | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/include/linux/completion.h b/include/linux/completion.h > > index cae5400..182d56e 100644 > > --- a/include/linux/completion.h > > +++ b/include/linux/completion.h > > @@ -49,6 +49,13 @@ static inline void complete_release_commit(struct completion *x) > > lock_commit_crosslock((struct lockdep_map *)&x->map); > > } > > > > +#define init_completion_with_map(x, m) \ > > +do { \ > > + lockdep_init_map_crosslock((struct lockdep_map *)&(x)->map, \ > > + (m)->name, (m)->key, 0); \ > > + __init_completion(x); \ > > +} while (0) > > Are there any completion objects for which the cross-release checking is > useful? All of them by definition. > Are there any wait_for_completion() callers that hold a mutex or > other locking object? Yes, there are also cross completion dependencies. There have been such bugs and I expect more to be unearthed. I really have to ask what your motiviation is to fight the lockdep coverage of synchronization objects tooth and nail? Thanks, tglx
WARNING: multiple messages have this Message-ID (diff)
From: Thomas Gleixner <tglx@linutronix.de> To: Bart Van Assche <Bart.VanAssche@wdc.com> Cc: "mingo@kernel.org" <mingo@kernel.org>, "peterz@infradead.org" <peterz@infradead.org>, "byungchul.park@lge.com" <byungchul.park@lge.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "amir73il@gmail.com" <amir73il@gmail.com>, "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>, "hch@infradead.org" <hch@infradead.org>, "linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>, "linux-mm@kvack.org" <linux-mm@kvack.org>, "oleg@redhat.com" <oleg@redhat.com>, "darrick.wong@oracle.com" <darrick.wong@oracle.com>, "johannes.berg@intel.com" <johannes.berg@intel.com>, "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>, "idryomov@gmail.com" <idryomov@gmail.com>, "tj@kernel.org" <tj@kernel.org>, "kernel-team@lge.com" <kernel-team@lge.com>, "david@fromorbit.com" <david@fromorbit.com> Subject: Re: [RESEND PATCH 1/3] completion: Add support for initializing completion with lockdep_map Date: Fri, 20 Oct 2017 08:34:36 +0200 (CEST) [thread overview] Message-ID: <alpine.DEB.2.20.1710200829340.3083@nanos> (raw) In-Reply-To: <1508455438.4542.4.camel@wdc.com> On Thu, 19 Oct 2017, Bart Van Assche wrote: > On Wed, 2017-10-18 at 18:38 +0900, Byungchul Park wrote: > > Sometimes, we want to initialize completions with sparate lockdep maps > > to assign lock classes under control. For example, the workqueue code > > manages lockdep maps, as it can classify lockdep maps properly. > > Provided a function for that purpose. > > > > Signed-off-by: Byungchul Park <byungchul.park@lge.com> > > --- > > include/linux/completion.h | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/include/linux/completion.h b/include/linux/completion.h > > index cae5400..182d56e 100644 > > --- a/include/linux/completion.h > > +++ b/include/linux/completion.h > > @@ -49,6 +49,13 @@ static inline void complete_release_commit(struct completion *x) > > lock_commit_crosslock((struct lockdep_map *)&x->map); > > } > > > > +#define init_completion_with_map(x, m) \ > > +do { \ > > + lockdep_init_map_crosslock((struct lockdep_map *)&(x)->map, \ > > + (m)->name, (m)->key, 0); \ > > + __init_completion(x); \ > > +} while (0) > > Are there any completion objects for which the cross-release checking is > useful? All of them by definition. > Are there any wait_for_completion() callers that hold a mutex or > other locking object? Yes, there are also cross completion dependencies. There have been such bugs and I expect more to be unearthed. I really have to ask what your motiviation is to fight the lockdep coverage of synchronization objects tooth and nail? Thanks, tglx -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-10-20 6:34 UTC|newest] Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-10-18 9:38 Fix false positive by LOCKDEP_CROSSRELEASE Byungchul Park 2017-10-18 9:38 ` Byungchul Park 2017-10-18 9:38 ` [RESEND PATCH 1/3] completion: Add support for initializing completion with lockdep_map Byungchul Park 2017-10-18 9:38 ` Byungchul Park 2017-10-19 23:24 ` Bart Van Assche 2017-10-19 23:24 ` Bart Van Assche 2017-10-20 6:14 ` Byungchul Park 2017-10-20 6:14 ` Byungchul Park 2017-10-20 6:34 ` Thomas Gleixner [this message] 2017-10-20 6:34 ` Thomas Gleixner 2017-10-20 19:58 ` Bart Van Assche 2017-10-20 19:58 ` Bart Van Assche 2017-10-20 19:58 ` Bart Van Assche 2017-10-21 2:23 ` Byungchul Park 2017-10-21 2:23 ` Byungchul Park 2017-10-22 14:34 ` Bart Van Assche 2017-10-22 14:34 ` Bart Van Assche 2017-10-23 2:08 ` Byungchul Park 2017-10-23 2:08 ` Byungchul Park 2017-10-25 7:07 ` Bart Van Assche 2017-10-25 7:07 ` Bart Van Assche 2017-10-25 11:49 ` Byungchul Park 2017-10-25 11:49 ` Byungchul Park 2017-10-18 9:38 ` [RESEND PATCH 2/3] lockdep: Remove unnecessary acquisitions wrt workqueue flush Byungchul Park 2017-10-18 9:38 ` Byungchul Park 2017-10-18 9:38 ` [RESEND PATCH 3/3] lockdep: Assign a lock_class per gendisk used for wait_for_completion() Byungchul Park 2017-10-18 9:38 ` Byungchul Park 2017-10-18 9:59 ` Ingo Molnar 2017-10-18 9:59 ` Ingo Molnar 2017-10-19 1:57 ` Byungchul Park 2017-10-19 1:57 ` Byungchul Park 2017-10-18 14:29 ` Fix false positive by LOCKDEP_CROSSRELEASE Bart Van Assche 2017-10-18 14:29 ` Bart Van Assche 2017-10-19 1:57 ` Byungchul Park 2017-10-19 1:57 ` Byungchul Park 2017-10-19 14:52 ` Bart Van Assche 2017-10-19 14:52 ` Bart Van Assche 2017-10-19 14:52 ` Bart Van Assche
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