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Mon, 17 Aug 2026 07:49:02 +0000 (GMT) Received: from ltc.linux.ibm.com (unknown [9.5.196.140]) by smtpav05.wdc07v.mail.ibm.com (Postfix) with ESMTP; Mon, 17 Aug 2026 07:49:02 +0000 (GMT) Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Mon, 17 Aug 2026 09:49:01 +0200 From: Harald Freudenberger To: sashiko-reviews@lists.linux.dev Cc: Alexander Gordeev , Christian Borntraeger , Vasily Gorbik , linux-s390@vger.kernel.org, Heiko Carstens Subject: Re: [PATCH v4 3/3] s390/crypto: Fix use of mutex in atomic context Reply-To: freude@linux.ibm.com Mail-Reply-To: freude@linux.ibm.com In-Reply-To: <20260814124606.4B0F31F000E9@smtp.kernel.org> References: <20260814123711.61145-1-freude@linux.ibm.com> <20260814123711.61145-4-freude@linux.ibm.com> <20260814124606.4B0F31F000E9@smtp.kernel.org> Message-ID: <0c9e1e8fb696f01e65e0577f5bedb874@linux.ibm.com> X-Sender: freude@linux.ibm.com Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: gJZFB3LdexlGS-gH91mlVZED5WsdIeWY X-Proofpoint-ORIG-GUID: gJZFB3LdexlGS-gH91mlVZED5WsdIeWY X-Proofpoint-Spam-Info: AW1haW4tMjYwODE3MDA1NSBTYWx0ZWRfX5y1LRlM9H5M+ UdvEeOMcewNm1DAnsR7VE8/g9zKr6wn1CYrmXFhqe5sL7x1ITBi4irMuRjogOlppJ1By/WZwfJK bORorsHL1udTRK1LTzB4uPFyTuzhxrA= X-Authority-Analysis: v=2.4 cv=WtQb99fv c=1 sm=1 tr=0 ts=6a82bcf1 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=kj9zAlcOel0A:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=NQAhLJwWZoJv7Md_NhgA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODE3MDA1NSBTYWx0ZWRfXzMm5VIck28RW ZuerxscC0nvfyj0CeEf2ChZsvlRitAcvrbJqCcJu2WbK+a86dUejMoxIOPX6RGsezWEZl22nLv4 IO+Rp1Ojy/cNzpYWGgUs0LK52Zhadieso7Ftihy4cnNbZGq5yyX60gA9n7TbJw/Sn+AWelGaDll qdRqwSJx6452BJN7Kbuc78aitggfvsYwguWVvvlpPjKgoxdw76UHDflFOgU3+zrmuuiZjtqDhAO Sjooiah/Wu45csceqRCVMb8txySHgHEiG8HzFCLDlcKBhbgYX/2/C9CPthwY8x7qrH9LIoz47jK gfsK7l44UcVpxCSleyursS0OkttOZWlzp+DE4ELa8UB6gRiBCyC407JREIRkIvbff6gYPI2IQEw qzxuYLcr41ME815jGDA3MnB4jvBIdK22LjqO3MBvHlgTpHgauGOpWq+IQ1/J3aZRRAncBw3XVCB CzpoDaa0FXDVAyclRnw== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-16_06,2026-08-12_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 spamscore=0 malwarescore=0 suspectscore=0 phishscore=0 lowpriorityscore=0 clxscore=1015 adultscore=0 priorityscore=1501 impostorscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608170055 On 2026-08-14 14:46, sashiko-bot@kernel.org wrote: > Thank you for your contribution! Sashiko AI review found 1 potential > issue(s) to consider: > > Pre-existing issues: > - [High] The patch completely misses the exact same preexisting > invalid mutex usage in atomic context in the Protected AES (PAES) CTR > implementation (`paes_s390.c`). > -- > > --- Patch [3]: [PATCH v4 3/3] s390/crypto: Fix use of mutex in atomic > context --- > commit 709721b3784d3a0026753ef3b28100620270373d > Author: Harald Freudenberger > > s390/crypto: Fix use of mutex in atomic context > > This commit replaces a mutex with a binary semaphore in the s390 AES > CTR > implementation. This prevents unsafe locking when the crypto routines > are > called from atomic or interrupt contexts. > >> diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c >> index 10561aa687c78..bd9815988c813 100644 >> --- a/arch/s390/crypto/aes_s390.c >> +++ b/arch/s390/crypto/aes_s390.c > [ ... ] >> @@ -569,12 +569,13 @@ static int ctr_aes_crypt(struct skcipher_request >> *req) >> u8 buf[AES_BLOCK_SIZE], *ctrptr; >> struct skcipher_walk walk; >> unsigned int n, nbytes; >> - int ret, locked; >> + bool locked; >> + int ret; >> >> if (unlikely(!sctx->fc)) >> return fallback_skcipher_crypt(sctx, req, 0); >> >> - locked = mutex_trylock(&ctrblk_lock); >> + locked = down_trylock(&ctrblk_sem) == 0; > > [Severity: High] > This is a pre-existing issue, but it appears the exact same pattern > exists in > the Protected AES (PAES) CTR implementation which wasn't updated here. > > Looking at ctr_paes_do_crypt() in arch/s390/crypto/paes_s390.c: > > locked = mutex_trylock(&ctrblk_lock); > > Since the skcipher API can be invoked from atomic or interrupt contexts > (like > network softirqs), does the PAES implementation also risk an atomic > context > locking violation? Should arch/s390/crypto/paes_s390.c receive a > similar > conversion to a binary semaphore? This is addressed in another patch series for paes_s390.c