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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


  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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