From: Christoph Hellwig <hch@infradead.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>,
Ralph Campbell <rcampbell@nvidia.com>,
John Hubbard <jhubbard@nvidia.com>,
Felix.Kuehling@amd.com, linux-rdma@vger.kernel.org,
linux-mm@kvack.org, Andrea Arcangeli <aarcange@redhat.com>,
dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org,
Ben Skeggs <bskeggs@redhat.com>,
Jason Gunthorpe <jgg@mellanox.com>,
Souptick Joarder <jrdr.linux@gmail.com>,
Ira Weiny <ira.weiny@intel.com>,
Philip Yang <Philip.Yang@amd.com>
Subject: Re: [PATCH v3 hmm 09/12] mm/hmm: Poison hmm_range during unregister
Date: Sat, 15 Jun 2019 07:17:26 -0700 [thread overview]
Message-ID: <20190615141726.GI17724@infradead.org> (raw)
In-Reply-To: <20190614004450.20252-10-jgg@ziepe.ca>
> - /* Sanity check this really should not happen. */
> - if (hmm == NULL || range->end <= range->start)
> - return;
> -
> mutex_lock(&hmm->lock);
> list_del_rcu(&range->list);
> mutex_unlock(&hmm->lock);
>
> /* Drop reference taken by hmm_range_register() */
> - range->valid = false;
> mmput(hmm->mm);
> hmm_put(hmm);
> - range->hmm = NULL;
> +
> + /*
> + * The range is now invalid and the ref on the hmm is dropped, so
> + * poison the pointer. Leave other fields in place, for the caller's
> + * use.
> + */
> + range->valid = false;
> + memset(&range->hmm, POISON_INUSE, sizeof(range->hmm));
Formatting seems to be messed up. But again I don't see the value
in the poisoning, just let normal linked list debugging do its work.
The other cleanups looks fine to me.
next prev parent reply other threads:[~2019-06-15 14:17 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-14 0:44 [PATCH v3 hmm 00/12] mm/hmm: Various revisions from a locking/code review Jason Gunthorpe
2019-06-14 0:44 ` [PATCH v3 hmm 01/12] mm/hmm: fix use after free with struct hmm in the mmu notifiers Jason Gunthorpe
2019-06-15 13:56 ` Christoph Hellwig
2019-06-14 0:44 ` [PATCH v3 hmm 02/12] mm/hmm: Use hmm_mirror not mm as an argument for hmm_range_register Jason Gunthorpe
2019-06-15 13:59 ` Christoph Hellwig
2019-06-18 13:05 ` Jason Gunthorpe
2019-06-19 8:14 ` Christoph Hellwig
2019-06-14 0:44 ` [PATCH v3 hmm 03/12] mm/hmm: Hold a mmgrab from hmm to mm Jason Gunthorpe
2019-06-15 13:59 ` Christoph Hellwig
2019-06-14 0:44 ` [PATCH v3 hmm 04/12] mm/hmm: Simplify hmm_get_or_create and make it reliable Jason Gunthorpe
2019-06-15 14:12 ` Christoph Hellwig
2019-06-18 0:36 ` Jason Gunthorpe
2019-06-18 18:55 ` Jason Gunthorpe
2019-06-14 0:44 ` [PATCH v3 hmm 05/12] mm/hmm: Remove duplicate condition test before wait_event_timeout Jason Gunthorpe
2019-06-15 14:12 ` Christoph Hellwig
2019-06-14 0:44 ` [PATCH v3 hmm 06/12] mm/hmm: Hold on to the mmget for the lifetime of the range Jason Gunthorpe
2019-06-15 14:14 ` Christoph Hellwig
2019-06-18 15:11 ` Jason Gunthorpe
2019-06-19 8:18 ` Christoph Hellwig
2019-06-19 11:34 ` Jason Gunthorpe
2019-06-19 11:54 ` Christoph Hellwig
2019-06-14 0:44 ` [PATCH v3 hmm 07/12] mm/hmm: Use lockdep instead of comments Jason Gunthorpe
2019-06-15 14:14 ` Christoph Hellwig
2019-06-14 0:44 ` [PATCH v3 hmm 08/12] mm/hmm: Remove racy protection against double-unregistration Jason Gunthorpe
2019-06-15 14:16 ` Christoph Hellwig
2019-06-18 13:13 ` Jason Gunthorpe
2019-06-18 13:27 ` Christoph Hellwig
2019-06-18 18:57 ` Jason Gunthorpe
2019-06-19 8:19 ` Christoph Hellwig
2019-06-14 0:44 ` [PATCH v3 hmm 09/12] mm/hmm: Poison hmm_range during unregister Jason Gunthorpe
2019-06-15 14:17 ` Christoph Hellwig [this message]
2019-06-18 18:04 ` Jason Gunthorpe
2019-06-14 0:44 ` [PATCH v3 hmm 10/12] mm/hmm: Do not use list*_rcu() for hmm->ranges Jason Gunthorpe
2019-06-15 14:18 ` Christoph Hellwig
2019-06-18 0:38 ` Jason Gunthorpe
2019-06-14 0:44 ` [PATCH v3 hmm 11/12] mm/hmm: Remove confusing comment and logic from hmm_release Jason Gunthorpe
2019-06-15 14:21 ` Christoph Hellwig
2019-06-18 0:45 ` Jason Gunthorpe
2019-06-18 5:37 ` Christoph Hellwig
2019-06-19 0:53 ` Kuehling, Felix
2019-06-19 8:07 ` Christoph Hellwig
2019-06-19 11:56 ` Jason Gunthorpe
2019-06-19 12:03 ` Christoph Hellwig
2019-06-14 0:44 ` [PATCH v3 hmm 12/12] mm/hmm: Fix error flows in hmm_invalidate_range_start Jason Gunthorpe
2019-06-15 14:25 ` Christoph Hellwig
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