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[143.89.191.9]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-47f4b2672d6sm59459595e9.14.2026.01.15.09.55.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Jan 2026 09:55:07 -0800 (PST) From: Chengfeng Ye To: "James E . J . Bottomley" , "Martin K . Petersen" , Bart Van Assche Cc: Jack Wang , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Chengfeng Ye Subject: [PATCH v2] scsi: pm8001: Fix data race in sysfs SAS address read Date: Thu, 15 Jan 2026 17:54:27 +0000 Message-Id: <20260115175427.290819-1-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" From: Chengfeng Ye Fix a data race where pm8001_ctl_host_sas_address_show() reads pm8001_ha->sas_addr without synchronization while it can be written from interrupt context in pm8001_mpi_get_nvmd_resp(). The write path is already protected by pm8001_ha->lock (held by process_oq() when calling pm8001_mpi_get_nvmd_resp()), but the sysfs read path accesses the 8-byte SAS address without any synchronization, allowing torn reads. Thread interleaving scenario: Thread A (sysfs read) | Thread B (interrupt context) -------------------------------------+------------------------------------ pm8001_ctl_host_sas_address_show() | |- read sas_addr[0..3] | | process_oq() | |- spin_lock_irqsave(&lock) | |- process_one_iomb() | | |- pm8001_mpi_get_nvmd_resp() | | |- memcpy(sas_addr, new, 8) | | /* writes all 8 bytes */ | |- spin_unlock_irqrestore(&lock) |- read sas_addr[4..7] | /* gets mix of old and new */ | Fix by protecting the sysfs read with the same pm8001_ha->lock using guard(spinlock_irqsave) for automatic lock cleanup. Signed-off-by: Chengfeng Ye --- V1 -> V2: Use guard instead of lock/unlock pair drivers/scsi/pm8001/pm8001_ctl.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/pm8001/pm8001_ctl.c b/drivers/scsi/pm8001/pm8001_= ctl.c index cbfda8c04e95..200ee6bbd413 100644 --- a/drivers/scsi/pm8001/pm8001_ctl.c +++ b/drivers/scsi/pm8001/pm8001_ctl.c @@ -311,6 +311,8 @@ static ssize_t pm8001_ctl_host_sas_address_show(struct = device *cdev, struct Scsi_Host *shost =3D class_to_shost(cdev); struct sas_ha_struct *sha =3D SHOST_TO_SAS_HA(shost); struct pm8001_hba_info *pm8001_ha =3D sha->lldd_ha; + + guard(spinlock_irqsave)(&pm8001_ha->lock); return sysfs_emit(buf, "0x%016llx\n", be64_to_cpu(*(__be64 *)pm8001_ha->sas_addr)); } --=20 2.25.1