From: Dan Carpenter <dan.carpenter@oracle.com>
To: John Hubbard <jhubbard@nvidia.com>
Cc: akpm@linux-foundation.org, alex.bou9@gmail.com,
gustavoars@kernel.org, ira.weiny@intel.com, jrdr.linux@gmail.com,
linux-kernel@vger.kernel.org, madhuparnabhowmik10@gmail.com,
mporter@kernel.crashing.org, willy@infradead.org
Subject: Re: [PATCH] mm/gup: protect unpin_user_pages() against npages==-ERRNO
Date: Thu, 17 Sep 2020 10:40:54 +0300 [thread overview]
Message-ID: <20200917074054.GO18329@kadam> (raw)
In-Reply-To: <20200917065706.409079-1-jhubbard@nvidia.com>
On Wed, Sep 16, 2020 at 11:57:06PM -0700, John Hubbard wrote:
> As suggested by Dan Carpenter, fortify unpin_user_pages() just a bit,
> against a typical caller mistake: check if the npages arg is really a
> -ERRNO value, which would blow up the unpinning loop: WARN and return.
>
> If this new WARN_ON() fires, then the system *might* be leaking pages
> (by leaving them pinned), but probably not. More likely, gup/pup
> returned a hard -ERRNO error to the caller, who erroneously passed it
> here.
>
> Cc: Ira Weiny <ira.weiny@intel.com>
> Cc: Souptick Joarder <jrdr.linux@gmail.com>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> ---
>
> Hi Dan,
>
> Is is OK to use your signed-off-by here? Since you came up with this.
>
Yeah. That's fine.
regards,
dan carpenter
next prev parent reply other threads:[~2020-09-17 9:51 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-16 3:42 [linux-next PATCH] rapidio: Fix error handling path Souptick Joarder
2020-09-16 6:37 ` John Hubbard
2020-09-16 10:02 ` Dan Carpenter
2020-09-16 10:07 ` Dan Carpenter
2020-09-16 15:16 ` Ira Weiny
2020-09-16 15:27 ` Dan Carpenter
2020-09-17 6:57 ` [PATCH] mm/gup: protect unpin_user_pages() against npages==-ERRNO John Hubbard
2020-09-17 7:40 ` Dan Carpenter [this message]
2020-09-20 3:03 ` Souptick Joarder
2020-09-20 4:13 ` John Hubbard
2020-09-21 9:34 ` Dan Carpenter
2020-09-17 12:39 ` [linux-next PATCH] rapidio: Fix error handling path Dan Carpenter
2020-09-17 17:34 ` Ira Weiny
2020-09-17 17:47 ` John Hubbard
2020-09-18 2:21 ` Souptick Joarder
2020-09-18 6:33 ` John Hubbard
2020-09-18 2:25 ` Souptick Joarder
2020-09-18 6:15 ` Dan Carpenter
2020-09-16 15:20 ` Ira Weiny
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