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[143.89.191.9]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4356992201csm16245897f8f.2.2026.01.18.00.42.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 18 Jan 2026 00:42:36 -0800 (PST) From: Chengfeng Ye To: sathya.prakash@broadcom.com, sreekanth.reddy@broadcom.com, suganath-prabu.subramani@broadcom.com, Markus.Elfring@web.de Cc: James.Bottomley@HansenPartnership.com, martin.petersen@oracle.com, MPT-FusionLinux.pdl@broadcom.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Chengfeng Ye , Tomas Henzl Subject: [PATCH v2 RESEND] scsi: mpt3sas: Fix use-after-free race in event log access Date: Sun, 18 Jan 2026 08:41:35 +0000 Message-Id: <20260118084135.321976-1-dg573847474@gmail.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" A use-after-free race exists between ioctl operations accessing the event log and device removal freeing it. The race occurs because ioc->remove_host flag is set without synchronization, creating a window where an ioctl can pass the removal check but still access freed memory. Race scenario: CPU0 (ioctl) CPU1 (device removal) ---------------- --------------------- _ctl_ioctl_main() mutex_lock(&pci_access_mutex) if (!ioc->remove_host) [check passes] scsih_remove() ioc->remove_host =3D 1 mpt3sas_ctl_release() kfree(ioc->event_log) _ctl_eventreport() copy_to_user(..., ioc->event_log, ...) <- use-after-free mutex_unlock(&pci_access_mutex) Fix by setting ioc->remove_host while holding pci_access_mutex. This ensures the ioctl path either completes before removal starts, or sees the flag and returns -EAGAIN. Fixes: 6a965ee1892a ("scsi: mpt3sas: Suppress a warning in debug kernel") Signed-off-by: Chengfeng Ye CC: Markus Elfring CC: Sathya Prakash CC: Sreekanth Reddy CC: Suganath Prabu Subramani CC: James E.J. Bottomley CC: Martin K. Petersen CC: Tomas Henzl --- V1 -> V2: Use scoped_guard instead of lock/unlock pair drivers/scsi/mpt3sas/mpt3sas_scsih.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mp= t3sas_scsih.c index 7092d0debef3..973893528747 100644 --- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c +++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c @@ -11264,7 +11264,10 @@ static void scsih_remove(struct pci_dev *pdev) if (_scsih_get_shost_and_ioc(pdev, &shost, &ioc)) return; =20 - ioc->remove_host =3D 1; + /* Set remove_host flag under pci_access_mutex to synchronize with ioctl = path */ + scoped_guard(mutex, &ioc->pci_access_mutex) { + ioc->remove_host =3D 1; + } =20 if (!pci_device_is_present(pdev)) { mpt3sas_base_pause_mq_polling(ioc); --=20 2.25.1