FAILED: patch "[PATCH] scsi: ses: Handle enclosure with just a primary component" failed to apply to 4.14-stable tree

The patch below does not apply to the 4.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.14.y
git checkout FETCH_HEAD
git cherry-pick -x c8e22b7a1694bb8d025ea636816472739d859145
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023041705-wages-cabbage-66be@gregkh' --subject-prefix 'PATCH 4.14.y' HEAD^..

Possible dependencies:

c8e22b7a1694 ("scsi: ses: Handle enclosure with just a primary component gracefully") 3fe97ff3d949 ("scsi: ses: Don't attach if enclosure has no components") 6396bb221514 ("treewide: kzalloc() -> kcalloc()")
5f85942c2ea2 ("Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c8e22b7a1694bb8d025ea636816472739d859145 Mon Sep 17 00:00:00 2001
From: Jiri Kosina <[email protected]>
Date: Tue, 4 Apr 2023 21:23:42 +0200
Subject: [PATCH] scsi: ses: Handle enclosure with just a primary component
gracefully

This reverts commit 3fe97ff3d949 ("scsi: ses: Don't attach if enclosure has no components") and introduces proper handling of case where there are no detected secondary components, but primary component (enumerated in num_enclosures) does exist. That fix was originally proposed by Ding Hui <[email protected]>.

Completely ignoring devices that have one primary enclosure and no secondary one results in ses_intf_add() bailing completely

scsi 2:0:0:254: enclosure has no enumerated components
scsi 2:0:0:254: Failed to bind enclosure -12ven in valid configurations such

even on valid configurations with 1 primary and 0 secondary enclosures as below:

	# sg_ses /dev/sg0
	  3PARdata  SES               3321
	Supported diagnostic pages:
	  Supported Diagnostic Pages [sdp] [0x0]
	  Configuration (SES) [cf] [0x1]
	  Short Enclosure Status (SES) [ses] [0x8]
	# sg_ses -p cf /dev/sg0
	  3PARdata  SES               3321
	Configuration diagnostic page:
	  number of secondary subenclosures: 0
	  generation code: 0x0
	  enclosure descriptor list
	    Subenclosure identifier: 0 [primary]
	      relative ES process id: 0, number of ES processes: 1
	      number of type descriptor headers: 1
	      enclosure logical identifier (hex): 20000002ac02068d
	      enclosure vendor: 3PARdata  product: VV                rev: 3321
	  type descriptor header and text list
	    Element type: Unspecified, subenclosure id: 0
	      number of possible elements: 1

The changelog for the original fix follows

=====
We can get a crash when disconnecting the iSCSI session, the call trace like this:

[ffff00002a00fb70] kfree at ffff00000830e224 [ffff00002a00fba0] ses_intf_remove at ffff000001f200e4 [ffff00002a00fbd0] device_del at ffff0000086b6a98 [ffff00002a00fc50] device_unregister at ffff0000086b6d58 [ffff00002a00fc70] __scsi_remove_device at ffff00000870608c [ffff00002a00fca0] scsi_remove_device at ffff000008706134 [ffff00002a00fcc0] __scsi_remove_target at ffff0000087062e4 [ffff00002a00fd10] scsi_remove_target at ffff0000087064c0 [ffff00002a00fd70] __iscsi_unbind_session at ffff000001c872c4 [ffff00002a00fdb0] process_one_work at ffff00000810f35c [ffff00002a00fe00] worker_thread at ffff00000810f648 [ffff00002a00fe70] kthread at ffff000008116e98

In ses_intf_add, components count could be 0, and kcalloc 0 size scomp, but not saved in edev->component[i].scratch

In this situation, edev->component[0].scratch is an invalid pointer, when kfree it in ses_intf_remove_enclosure, a crash like above would happen The call trace also could be other random cases when kfree cannot catch the invalid pointer

We should not use edev->component[] array when the components count is 0 We also need check index when use edev->component[] array in ses_enclosure_data_process
=====

index b11a9162e73a..b54f2c6c08c3 100644
@@ -509,9 +509,6 @@ static int ses_enclosure_find_by_addr(struct enclosure_device *edev,
 	int i;
 	struct ses_component *scomp;
 
-	if (!edev->component[0].scratch)
-		return 0;
-
 	for (i = 0; i < edev->components; i++) {
 		scomp = edev->component[i].scratch;
 		if (scomp->addr != efd->addr)

@@ -602,8 +599,10 @@ static void ses_enclosure_data_process(struct enclosure_device *edev,
 						components++,
 						type_ptr[0],
 						name);
-				else
+				else if (components < edev->components)
 					ecomp = &edev->component[components++];
+				else
+					ecomp = ERR_PTR(-EINVAL);
 
 				if (!IS_ERR(ecomp)) {
 					if (addl_desc_ptr) {

@@ -734,11 +733,6 @@ static int ses_intf_add(struct device *cdev,
 			components += type_ptr[1];
 	}
 
-	if (components == 0) {
-		sdev_printk(KERN_WARNING, sdev, "enclosure has no enumerated components\n");
-		goto err_free;
-	}
-
 	ses_dev->page1 = buf;
 	ses_dev->page1_len = len;
 	buf = NULL;

@@ -780,9 +774,11 @@ static int ses_intf_add(struct device *cdev,
 		buf = NULL;
 	}
 page2_not_supported:
-	scomp = kcalloc(components, sizeof(struct ses_component), GFP_KERNEL);
-	if (!scomp)
-		goto err_free;
+	if (components > 0) {
+		scomp = kcalloc(components, sizeof(struct ses_component), GFP_KERNEL);
+		if (!scomp)
+			goto err_free;
+	}
 
 	edev = enclosure_register(cdev->parent, dev_name(&sdev->sdev_gendev),
 				  components, &ses_enclosure_callbacks);