From: Jason Gunthorpe <jgg@ziepe.ca>
To: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>,
Matthew Wilcox <willy@infradead.org>,
Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
Leon Romanovsky <leon@kernel.org>,
Christian Benvenuti <benve@cisco.com>,
Nelson Escobar <neescoba@cisco.com>,
Bernard Metzler <bmt@zurich.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Bjorn Topel <bjorn@kernel.org>,
Magnus Karlsson <magnus.karlsson@intel.com>,
Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
Jonathan Lemon <jonathan.lemon@gmail.com>,
"David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Christian Brauner <brauner@kernel.org>,
Richard Cochran <richardcochran@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
linux-fsdevel@vger.kernel.org, linux-perf-users@vger.kernel.org,
netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH] mm/gup: disallow GUP writing to file-backed mappings by default
Date: Mon, 24 Apr 2023 14:49:35 -0300 [thread overview]
Message-ID: <ZEbBLzy4SU8IZR68@ziepe.ca> (raw)
In-Reply-To: <14c6f0f3-0747-4800-8718-4f109f7321ea@lucifer.local>
On Sun, Apr 23, 2023 at 11:56:48PM +0100, Lorenzo Stoakes wrote:
> This warned upon check should in reality not occur, because it implies the
> GUP user is trying to do something broken and is _not_ explicitly telling
> GUP that it knows it's doing it and can live with the consequences. And on
> that basis, is worthy of a warning so we know we have to go put this flag
> in that place (and know it is a source of problematic GUP usage), or fix
> the caller.
It is fine for debugging, but we can't merge user triggerable
WARN_ONs..
Since the GUP caller has no idea if userspace might be maliciously
passing in a file VMA we can't throw warnings.
Jason
next prev parent reply other threads:[~2023-04-24 17:49 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-22 13:37 [PATCH] mm/gup: disallow GUP writing to file-backed mappings by default Lorenzo Stoakes
2023-04-23 0:46 ` Hillf Danton
2023-04-23 19:32 ` Simon Horman
2023-04-23 19:40 ` Lorenzo Stoakes
2023-04-23 20:02 ` Simon Horman
2023-04-23 22:29 ` Dave Chinner
2023-04-23 22:56 ` Lorenzo Stoakes
2023-04-24 17:49 ` Jason Gunthorpe [this message]
2023-04-24 3:41 ` Mika Penttilä
2023-04-24 6:51 ` Lorenzo Stoakes
2023-04-24 12:02 ` Kirill A. Shutemov
2023-04-24 12:31 ` Lorenzo Stoakes
2023-04-24 13:40 ` Kirill A. Shutemov
2023-04-24 17:59 ` Jason Gunthorpe
2023-04-24 16:09 ` Jan Kara
2023-04-24 16:22 ` Lorenzo Stoakes
2023-04-24 17:53 ` Jason Gunthorpe
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