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Fri, 12 Jun 2026 18:10:50 +0000 (GMT) Received: from Mac.ibm.com (unknown [9.61.255.20]) by smtpav04.dal12v.mail.ibm.com (Postfix) with ESMTP; Fri, 12 Jun 2026 18:10:50 +0000 (GMT) From: Omar Elghoul To: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: oelghoul@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, schnelle@linux.ibm.com, mjrosato@linux.ibm.com, alifm@linux.ibm.com, farman@linux.ibm.com, gbayer@linux.ibm.com, alex@shazbot.org, stable@vger.kernel.org Subject: [PATCH v4 1/4] s390/pci: Hold fmb_lock when enabling or disabling PCI devices Date: Fri, 12 Jun 2026 14:10:45 -0400 Message-ID: <20260612181048.91548-2-oelghoul@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260612181048.91548-1-oelghoul@linux.ibm.com> References: <20260612181048.91548-1-oelghoul@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjEyMDE2OSBTYWx0ZWRfX1Nw0ETzbzYWi 1rNHTweYvLcVOqCW1mmmtSaOenUUoBc6ybv8GAnFyXHaswiw/n1s6x8b9hnUOG/51Z2Ld+UN3mp 5OJl3XM5Ae77KP8sW9Snx04zXXxWTfiWK5zpBgJytVKOdsMuK2ojTQsdBb086jStVTcSoc3V7xF XAioE8AgapJ5aBMX+ZFppdLC16XX8jYgARuR+zProjNAhfQaVvGwFJfPMPAu/qTKQ73UyGzz/y+ ooHlpcAa45FueIpkFsnWuuSQra8xDdo1zBjezQe0vbF1Wo2LZ2MPSmVBtmfFRXbSqVGs3boprS1 PYiSUzdyRHQ2RLHRXNwTVvZT/OO0uoumL9TGAtjVpaLamGNE1670yIBRU2z1bO4BAUn1dIhG/lO bp3JGofgkDZFbag9KntPMvvKIdO8CMtD2u3zlZOfFR4tj8bsa45JoKoHFNW3pKfi7vDrmBBLLl6 93Wk5osjGbcIqfL5PAQ== X-Authority-Analysis: v=2.4 cv=dr7rzVg4 c=1 sm=1 tr=0 ts=6a2c4bb0 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=5NbLduwtq9nBFWGw9KEA:9 X-Proofpoint-ORIG-GUID: 3uppq2iq8Ear7LSsHeAe1AfEfmO7DKoK X-Proofpoint-GUID: 3uppq2iq8Ear7LSsHeAe1AfEfmO7DKoK X-Proofpoint-Spam-Info: AW1haW4tMjYwNjEyMDE2OSBTYWx0ZWRfX7ZP/MnTOB8HX 1ERIt6CMLpyGuja0wiEjjTLU3z5uDsvLpOyVhvPRLri0msepn38r4LXwYtfothJpldRMJRI0EDT mBTLV3rYe0mqjbUJXvRnYVmo+y72Xas= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-12_02,2026-06-12_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 adultscore=0 suspectscore=0 priorityscore=1501 phishscore=0 clxscore=1015 bulkscore=0 impostorscore=0 lowpriorityscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606040000 definitions=main-2606120169 Ensure that fmb_lock is held by pcibios_enable_device() and pcibios_disable_device() when calling zpci_fmb_enable_device() or zpci_fmb_disable_device(), respectively. Additionally, assert that the fmb_lock is held within the latter two functions to prevent future race conditions regarding new callers. Fixes: af0a8a8453f7 ("s390/pci: implement pcibios_add_device") Fixes: 944239c59e93 ("s390/pci: implement pcibios_release_device") Cc: stable@vger.kernel.org Signed-off-by: Omar Elghoul Reviewed-by: Niklas Schnelle --- arch/s390/pci/pci.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c index 39bd2adfc240..2910d4038d39 100644 --- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -173,6 +173,8 @@ int zpci_fmb_enable_device(struct zpci_dev *zdev) unsigned long flags; u8 cc, status; + lockdep_assert_held(&zdev->fmb_lock); + if (zdev->fmb || sizeof(*zdev->fmb) < zdev->fmb_length) return -EINVAL; @@ -211,6 +213,8 @@ int zpci_fmb_disable_device(struct zpci_dev *zdev) struct zpci_fib fib = {0}; u8 cc, status; + lockdep_assert_held(&zdev->fmb_lock); + if (!zdev->fmb) return -EINVAL; @@ -639,7 +643,9 @@ int pcibios_enable_device(struct pci_dev *pdev, int mask) struct zpci_dev *zdev = to_zpci(pdev); zpci_debug_init_device(zdev, dev_name(&pdev->dev)); + mutex_lock(&zdev->fmb_lock); zpci_fmb_enable_device(zdev); + mutex_unlock(&zdev->fmb_lock); return pci_enable_resources(pdev, mask); } @@ -648,7 +654,9 @@ void pcibios_disable_device(struct pci_dev *pdev) { struct zpci_dev *zdev = to_zpci(pdev); + mutex_lock(&zdev->fmb_lock); zpci_fmb_disable_device(zdev); + mutex_unlock(&zdev->fmb_lock); zpci_debug_exit_device(zdev); } -- 2.54.0