FAILED: patch "[PATCH] dm: fix improper splitting for abnormal bios" failed to apply to 6.1-stable tree

The patch below does not apply to the 6.1-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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x f7b58a69fad9d2c4c90cab0247811155dd0d48e7
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2023040334-attire-drone-2c8b@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

f7b58a69fad9 ("dm: fix improper splitting for abnormal bios")
86a3238c7b9b ("dm: change "unsigned" to "unsigned int"")
7533afa1d27b ("dm: send just one event on resize, not two")
5cd6d1d53a1f ("dm integrity: Remove bi_sector that's only used by commented debug code") 22c40e134c4c ("dm cache: Add some documentation to dm-cache-background-tracker.h")

thanks,

greg k-h

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

From f7b58a69fad9d2c4c90cab0247811155dd0d48e7 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <[email protected]>
Date: Thu, 30 Mar 2023 14:56:38 -0400
Subject: [PATCH] dm: fix improper splitting for abnormal bios

"Abnormal" bios include discards, write zeroes and secure erase. By no longer passing the calculated 'len' pointer, commit 7dd06a2548b2 ("dm:
allow dm_accept_partial_bio() for dm_io without duplicate bios") took a senseless approach to disallowing dm_accept_partial_bio() from working for duplicate bios processed using __send_duplicate_bios().

It inadvertently and incorrectly stopped the use of 'len' when initializing a target's io (in alloc_tio). As such the resulting tio could address more area of a device than it should.

For example, when discarding an entire DM striped device with the following DM table:
vg-lvol0: 0 159744 striped 2 128 7:0 2048 7:1 2048
vg-lvol0: 159744 45056 striped 2 128 7:2 2048 7:3 2048

Before this fix:

device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=102400
blkdiscard: attempt to access beyond end of device
loop0: rw=2051, sector=2048, nr_sectors = 102400 limit=81920

device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=102400
blkdiscard: attempt to access beyond end of device
loop1: rw=2051, sector=2048, nr_sectors = 102400 limit=81920

After this fix;

device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=79872
device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=79872

index 2d0f934ba6e6..e67a2757c53e 100644
@@ -1467,7 +1467,8 @@ static void setup_split_accounting(struct clone_info *ci, unsigned int len)
 }
 
 static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci,
-				struct dm_target *ti, unsigned int num_bios)
+				struct dm_target *ti, unsigned int num_bios,
+				unsigned *len)
 {
 	struct bio *bio;
 	int try;

@@ -1478,7 +1479,7 @@ static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci,
 		if (try)
 			mutex_lock(&ci->io->md->table_devices_lock);
 		for (bio_nr = 0; bio_nr < num_bios; bio_nr++) {
-			bio = alloc_tio(ci, ti, bio_nr, NULL,
+			bio = alloc_tio(ci, ti, bio_nr, len,
 					try ? GFP_NOIO : GFP_NOWAIT);
 			if (!bio)
 				break;

@@ -1514,7 +1515,7 @@ static int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
 		break;
 	default:
 		/* dm_accept_partial_bio() is not supported with shared tio->len_ptr */
-		alloc_multiple_bios(&blist, ci, ti, num_bios);
+		alloc_multiple_bios(&blist, ci, ti, num_bios, len);
 		while ((clone = bio_list_pop(&blist))) {
 			dm_tio_set_flag(clone_to_tio(clone), DM_TIO_IS_DUPLICATE_BIO);
 			__map_bio(clone);

From: Benjamin Marzinski <[email protected]>

Conflicts: Code changes due to missing upstream commit 86a3238c7b9b
('dm: change "unsigned" to "unsigned int"')

commit f7b58a69fad9d2c4c90cab0247811155dd0d48e7

Author: Mike Snitzer <[email protected]>
Date:   Thu Mar 30 14:56:38 2023 -0400

dm: fix improper splitting for abnormal bios

"Abnormal" bios include discards, write zeroes and secure erase. By no longer passing the calculated 'len' pointer, commit 7dd06a2548b2 ("dm:
allow dm_accept_partial_bio() for dm_io without duplicate bios") took a senseless approach to disallowing dm_accept_partial_bio() from working for duplicate bios processed using __send_duplicate_bios().

It inadvertently and incorrectly stopped the use of 'len' when initializing a target's io (in alloc_tio). As such the resulting tio could address more area of a device than it should.

For example, when discarding an entire DM striped device with the following DM table:
vg-lvol0: 0 159744 striped 2 128 7:0 2048 7:1 2048
vg-lvol0: 159744 45056 striped 2 128 7:2 2048 7:3 2048

Before this fix:

device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=102400
blkdiscard: attempt to access beyond end of device
loop0: rw=2051, sector=2048, nr_sectors = 102400 limit=81920

device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=102400
blkdiscard: attempt to access beyond end of device
loop1: rw=2051, sector=2048, nr_sectors = 102400 limit=81920

After this fix;

device-mapper: striped: target_stripe=0, bdev=7:0, start=2048 len=79872
device-mapper: striped: target_stripe=1, bdev=7:1, start=2048 len=79872

---
 drivers/md/dm.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

index f9a402c04666..e624a919fe55 100644
@@ -1460,7 +1460,8 @@ static void setup_split_accounting(struct clone_info *ci, unsigned len)
 }
 
 static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci,
-				struct dm_target *ti, unsigned num_bios)
+				struct dm_target *ti, unsigned num_bios,
+				unsigned *len)
 {
 	struct bio *bio;
 	int try;

@@ -1471,7 +1472,7 @@ static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci,
 		if (try)
 			mutex_lock(&ci->io->md->table_devices_lock);
 		for (bio_nr = 0; bio_nr < num_bios; bio_nr++) {
-			bio = alloc_tio(ci, ti, bio_nr, NULL,
+			bio = alloc_tio(ci, ti, bio_nr, len,
 					try ? GFP_NOIO : GFP_NOWAIT);
 			if (!bio)
 				break;

@@ -1507,7 +1508,7 @@ static int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
 		break;
 	default:
 		/* dm_accept_partial_bio() is not supported with shared tio->len_ptr */
-		alloc_multiple_bios(&blist, ci, ti, num_bios);
+		alloc_multiple_bios(&blist, ci, ti, num_bios, len);
 		while ((clone = bio_list_pop(&blist))) {
 			dm_tio_set_flag(clone_to_tio(clone), DM_TIO_IS_DUPLICATE_BIO);
 			__map_bio(clone);

2.30.0