Thread (18 messages) 18 messages, 4 authors, 2017-11-25

Re: [PATCH] crypto: AF_ALG - remove locking in async callback

From: Romain Izard <hidden>
Date: 2017-10-30 17:15:53
Also in: linux-arm-kernel

2017-10-29 21:39 GMT+01:00 Stephan Müller [off-list ref]:
Am Mittwoch, 25. Oktober 2017, 17:26:31 CET schrieb Romain Izard:

Hi Romain,

the patch below should cover the issue you see. Would you mind testing it?

Thanks
Stephan

---8<---

The code paths protected by the socket-lock do not use or modify the
socket in a non-atomic fashion. The actions pertaining the socket do not
even need to be handled as an atomic operation. Thus, the socket-lock
can be safely ignored.

This fixes a bug regarding scheduling in atomic as the callback function
may be invoked in interrupt context.

Fixes: 2d97591ef43d0 ("crypto: af_alg - consolidation of duplicate code")
Reported-by: Romain Izard <redacted>
Signed-off-by: Stephan Mueller <redacted>
Tested-by: Romain Izard <redacted>

The issue observed with atmel-aes is not reproduced anymore.
quoted hunk ↗ jump to hunk
---
 crypto/af_alg.c | 4 ----
 1 file changed, 4 deletions(-)
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 337cf382718e..a41f08642eee 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1063,8 +1063,6 @@ void af_alg_async_cb(struct crypto_async_request *_req, int err)
        struct kiocb *iocb = areq->iocb;
        unsigned int resultlen;

-       lock_sock(sk);
-
        /* Buffer size written by crypto operation. */
        resultlen = areq->outlen;
@@ -1073,8 +1071,6 @@ void af_alg_async_cb(struct crypto_async_request *_req, int err)
        __sock_put(sk);

        iocb->ki_complete(iocb, err ? err : resultlen, 0);
-
-       release_sock(sk);
 }
 EXPORT_SYMBOL_GPL(af_alg_async_cb);

--
2.13.6
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