scsi: ufs: ufs-qcom: Fix ESI null pointer dereference

JIRA: https://issues.redhat.com/browse/RHEL-120705
Upstream Status: 6300d5c

commit 6300d5c
Author: Nitin Rawat <quic_nitirawa@quicinc.com>
Date:   Mon Aug 11 13:03:30 2025 +0530

    scsi: ufs: ufs-qcom: Fix ESI null pointer dereference

    ESI/MSI is a performance optimization feature that provides dedicated
    interrupts per MCQ hardware queue. This is optional feature and UFS MCQ
    should work with and without ESI feature.

    Commit e46a28c ("scsi: ufs: qcom: Remove the MSI descriptor abuse")
    brings a regression in ESI (Enhanced System Interrupt) configuration that
    causes a null pointer dereference when Platform MSI allocation fails.

    The issue occurs in when platform_device_msi_init_and_alloc_irqs() in
    ufs_qcom_config_esi() fails (returns -EINVAL) but the current code uses
    __free() macro for automatic cleanup free MSI resources that were never
    successfully allocated.

    Unable to handle kernel NULL pointer dereference at virtual
    address 0000000000000008

      Call trace:
      mutex_lock+0xc/0x54 (P)
      platform_device_msi_free_irqs_all+0x1c/0x40
      ufs_qcom_config_esi+0x1d0/0x220 [ufs_qcom]
      ufshcd_config_mcq+0x28/0x104
      ufshcd_init+0xa3c/0xf40
      ufshcd_pltfrm_init+0x504/0x7d4
      ufs_qcom_probe+0x20/0x58 [ufs_qcom]

    Fix by restructuring the ESI configuration to try MSI allocation first,
    before any other resource allocation and instead use explicit cleanup
    instead of __free() macro to avoid cleanup of unallocated resources.

    Tested on SM8750 platform with MCQ enabled, both with and without
    Platform ESI support.

    Fixes: e46a28c ("scsi: ufs: qcom: Remove the MSI descriptor abuse")
    Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
    Signed-off-by: Nitin Rawat <quic_nitirawa@quicinc.com>
    Link: https://lore.kernel.org/r/20250811073330.20230-1-quic_nitirawa@quicinc.com
    Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Signed-off-by: Myron Stowe <mstowe@redhat.com>

Author: Myron Stowe

drivers/ufs/host/ufs-qcom.c

@@ -1782,17 +1782,6 @@ static irqreturn_t ufs_qcom_mcq_esi_handler(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
-static void ufs_qcom_irq_free(struct ufs_qcom_irq *uqi)
-{
-	for (struct ufs_qcom_irq *q = uqi; q->irq; q++)
-		devm_free_irq(q->hba->dev, q->irq, q->hba);
-
-	platform_device_msi_free_irqs_all(uqi->hba->dev);
-	devm_kfree(uqi->hba->dev, uqi);
-}
-
-DEFINE_FREE(ufs_qcom_irq, struct ufs_qcom_irq *, if (_T) ufs_qcom_irq_free(_T))
-
 static int ufs_qcom_config_esi(struct ufs_hba *hba)
 {
 	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
@@ -1807,18 +1796,18 @@ static int ufs_qcom_config_esi(struct ufs_hba *hba)
 	 */
 	nr_irqs = hba->nr_hw_queues - hba->nr_queues[HCTX_TYPE_POLL];
 
-	struct ufs_qcom_irq *qi __free(ufs_qcom_irq) =
-		devm_kcalloc(hba->dev, nr_irqs, sizeof(*qi), GFP_KERNEL);
-	if (!qi)
-		return -ENOMEM;
-	/* Preset so __free() has a pointer to hba in all error paths */
-	qi[0].hba = hba;
-
 	ret = platform_device_msi_init_and_alloc_irqs(hba->dev, nr_irqs,
 						      ufs_qcom_write_msi_msg);
 	if (ret) {
-		dev_err(hba->dev, "Failed to request Platform MSI %d\n", ret);
-		return ret;
+		dev_warn(hba->dev, "Platform MSI not supported or failed, continuing without ESI\n");
+		return ret; /* Continue without ESI */
+	}
+
+	struct ufs_qcom_irq *qi = devm_kcalloc(hba->dev, nr_irqs, sizeof(*qi), GFP_KERNEL);
+
+	if (!qi) {
+		platform_device_msi_free_irqs_all(hba->dev);
+		return -ENOMEM;
 	}
 
 	for (int idx = 0; idx < nr_irqs; idx++) {
@@ -1829,15 +1818,17 @@ static int ufs_qcom_config_esi(struct ufs_hba *hba)
 		ret = devm_request_irq(hba->dev, qi[idx].irq, ufs_qcom_mcq_esi_handler,
 				       IRQF_SHARED, "qcom-mcq-esi", qi + idx);
 		if (ret) {
-			dev_err(hba->dev, "%s: Fail to request IRQ for %d, err = %d\n",
+			dev_err(hba->dev, "%s: Failed to request IRQ for %d, err = %d\n",
 				__func__, qi[idx].irq, ret);
-			qi[idx].irq = 0;
+			/* Free previously allocated IRQs */
+			for (int j = 0; j < idx; j++)
+				devm_free_irq(hba->dev, qi[j].irq, qi + j);
+			platform_device_msi_free_irqs_all(hba->dev);
+			devm_kfree(hba->dev, qi);
 			return ret;
 		}
 	}
 
-	retain_and_null_ptr(qi);
-
 	if (host->hw_ver.major >= 6) {
 		ufshcd_rmwl(hba, ESI_VEC_MASK, FIELD_PREP(ESI_VEC_MASK, MAX_ESI_VEC - 1),
 			    REG_UFS_CFG3);