From: "Stephan Müller" <smueller@chronox.de> To: Herbert Xu <herbert@gondor.apana.org.au> Cc: Romain Izard <romain.izard.pro@gmail.com>, linux-crypto@vger.kernel.org, Cyrille Pitchen <cyrille.pitchen@microchip.com>, Tudor Ambarus <tudor.ambarus@microchip.com>, Nicolas Ferre <nicolas.ferre@microchip.com>, linux-arm-kernel <linux-arm-kernel@lists.infradead.org> Subject: Re: [PATCH] crypto: AF_ALG - remove locking in async callback Date: Tue, 07 Nov 2017 07:19:32 +0100 [thread overview] Message-ID: <4677171.2qOLUIFS1s@positron.chronox.de> (raw) In-Reply-To: <20171107052235.GA20803@gondor.apana.org.au> Am Dienstag, 7. November 2017, 06:22:35 CET schrieb Herbert Xu: Hi Herbert, > On Mon, Nov 06, 2017 at 05:06:09PM +0100, Stephan Mueller wrote: > > Am Freitag, 3. November 2017, 14:20:16 CET schrieb Herbert Xu: > > > Are you sure about that? In particular is the callback function still > > > sane without the socket lock if a concurrent recvmsg/sendmsg call is > > > made? > > > > I reviewed the code again and I cannot find a reason for keeping the lock. > > All we need to ensure is that the socket exists. This is ensured with the > > refcount of the socket released by __sock_put(). > > OK, I can't see why we need a lock there either. However, the call > to __sock_put looks suspicious. Why isn't this using sock_put? I simply ported the existing code from algif_aead over -- but I think you are right that sock_put is more appropriate. > > Also the sock_hold on the caller side looks buggy. Surely it needs > to be made before we even call the encrypt/decrypt functions rather > than after it returns EINPROGRESS at which point it may well be too > late? I would concur. The sock_hold would need to be moved from the EINPROGRESS conditional to before the AIO enc/dec operation is invoked. Where I am not fully sure is whether af_alg_async_cb is called in any case. I.e. when we invoke an AIO operation with a cipher that completes synchronously (e.g. AES-NI), is this callback triggered? Ciao Stephan
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From: smueller@chronox.de (Stephan Müller) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] crypto: AF_ALG - remove locking in async callback Date: Tue, 07 Nov 2017 07:19:32 +0100 [thread overview] Message-ID: <4677171.2qOLUIFS1s@positron.chronox.de> (raw) In-Reply-To: <20171107052235.GA20803@gondor.apana.org.au> Am Dienstag, 7. November 2017, 06:22:35 CET schrieb Herbert Xu: Hi Herbert, > On Mon, Nov 06, 2017 at 05:06:09PM +0100, Stephan Mueller wrote: > > Am Freitag, 3. November 2017, 14:20:16 CET schrieb Herbert Xu: > > > Are you sure about that? In particular is the callback function still > > > sane without the socket lock if a concurrent recvmsg/sendmsg call is > > > made? > > > > I reviewed the code again and I cannot find a reason for keeping the lock. > > All we need to ensure is that the socket exists. This is ensured with the > > refcount of the socket released by __sock_put(). > > OK, I can't see why we need a lock there either. However, the call > to __sock_put looks suspicious. Why isn't this using sock_put? I simply ported the existing code from algif_aead over -- but I think you are right that sock_put is more appropriate. > > Also the sock_hold on the caller side looks buggy. Surely it needs > to be made before we even call the encrypt/decrypt functions rather > than after it returns EINPROGRESS at which point it may well be too > late? I would concur. The sock_hold would need to be moved from the EINPROGRESS conditional to before the AIO enc/dec operation is invoked. Where I am not fully sure is whether af_alg_async_cb is called in any case. I.e. when we invoke an AIO operation with a cipher that completes synchronously (e.g. AES-NI), is this callback triggered? Ciao Stephan
next prev parent reply other threads:[~2017-11-07 6:19 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-10-25 15:26 "BUG: scheduling while atomic" in atmel-aes on Linux v4.14-rc6 Romain Izard 2017-10-25 15:26 ` Romain Izard 2017-10-25 15:59 ` Stephan Mueller 2017-10-25 15:59 ` Stephan Mueller 2017-10-29 20:39 ` [PATCH] crypto: AF_ALG - remove locking in async callback Stephan Müller 2017-10-29 20:39 ` Stephan Müller 2017-10-30 17:15 ` Romain Izard 2017-10-30 17:15 ` Romain Izard 2017-11-03 13:20 ` Herbert Xu 2017-11-03 13:20 ` Herbert Xu 2017-11-03 13:34 ` Stephan Mueller 2017-11-03 13:34 ` Stephan Mueller 2017-11-06 16:06 ` Stephan Mueller 2017-11-06 16:06 ` Stephan Mueller 2017-11-07 5:22 ` Herbert Xu 2017-11-07 5:22 ` Herbert Xu 2017-11-07 6:19 ` Stephan Müller [this message] 2017-11-07 6:19 ` Stephan Müller 2017-11-07 6:32 ` Herbert Xu 2017-11-07 6:32 ` Herbert Xu 2017-11-07 9:05 ` [PATCH v2] " Stephan Müller 2017-11-07 9:05 ` Stephan Müller 2017-11-10 11:10 ` Herbert Xu 2017-11-10 11:10 ` Herbert Xu 2017-11-10 12:20 ` [PATCH v3] " Stephan Müller 2017-11-10 12:20 ` Stephan Müller 2017-11-10 16:50 ` Romain Izard 2017-11-10 16:50 ` Romain Izard 2017-11-24 7:37 ` Herbert Xu 2017-11-24 7:37 ` Herbert Xu 2017-11-24 16:04 ` Stephan Mueller 2017-11-24 16:04 ` Stephan Mueller 2017-11-24 17:37 ` Jonathan Cameron 2017-11-24 17:37 ` Jonathan Cameron 2017-11-25 0:17 ` Herbert Xu 2017-11-25 0:17 ` Herbert Xu
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