Amiga RDB partition support fixes

Hi Jens,

another last version of this patch series, only change in this version is in the patch 2 subject (to better reflect what it's about), and adding Geert's review tag to said patch.

I hope I've crossed all i's and dotted all t's now...

Cheers,

Michael

Michael Schmitz (3):
block: fix signed int overflow in Amiga partition support
block: change all __u32 annotations to __be32 in affs_hardblocks.h
block: add overflow checks for Amiga partition support

 block/partitions/amiga.c             | 102 ++++++++++++++++++++++-----
 include/uapi/linux/affs_hardblocks.h |  68 +++++++++---------
 2 files changed, 119 insertions(+), 51 deletions(-)

2.17.1

The Amiga partition parser module uses signed int for partition sector address and count, which will overflow for disks larger than 1 TB.

Use sector_t as type for sector address and size to allow using disks up to 2 TB without LBD support, and disks larger than 2 TB with LBD.

This bug was reported originally in 2012, and the fix was created by the RDB author, Joanne Dow <[email protected]>. A patch had been discussed and reviewed on linux-m68k at that time but never officially submitted. This patch differs from Joanne's patch only in its use of sector_t instead of unsigned int. No checking for overflows is done (see patch 3 of this series for that).

Message-ID: <[email protected]>

---

Changes from v3:

- split off change of sector address type as quick fix.
- cast to sector_t in sector address calculations.
- move overflow checking to separate patch for more thorough review.

Changes from v4:

Andreas Schwab:
- correct cast to sector_t in sector address calculations

Changes from v7:

Christoph Hellwig
- correct style issues

Changes from v9:

- add Fixes: tags and stable backport prereq

---
 block/partitions/amiga.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

index 5c8624e26a54..85c5c79aae48 100644
@@ -31,7 +31,8 @@ int amiga_partition(struct parsed_partitions *state)
 	unsigned char *data;
 	struct RigidDiskBlock *rdb;
 	struct PartitionBlock *pb;
-	int start_sect, nr_sects, blk, part, res = 0;
+	sector_t start_sect, nr_sects;
+	int blk, part, res = 0;
 	int blksize = 1;	/* Multiplier for disk block size */
 	int slot = 1;
 

@@ -96,14 +97,14 @@ int amiga_partition(struct parsed_partitions *state)
 
 		/* Tell Kernel about it */
 
-		nr_sects = (be32_to_cpu(pb->pb_Environment[10]) + 1 -
-			    be32_to_cpu(pb->pb_Environment[9])) *
+		nr_sects = ((sector_t)be32_to_cpu(pb->pb_Environment[10]) + 1 -
+			   be32_to_cpu(pb->pb_Environment[9])) *
 			   be32_to_cpu(pb->pb_Environment[3]) *
 			   be32_to_cpu(pb->pb_Environment[5]) *
 			   blksize;
 		if (!nr_sects)
 			continue;
-		start_sect = be32_to_cpu(pb->pb_Environment[9]) *
+		start_sect = (sector_t)be32_to_cpu(pb->pb_Environment[9]) *
 			     be32_to_cpu(pb->pb_Environment[3]) *
 			     be32_to_cpu(pb->pb_Environment[5]) *
 			     blksize;

2.17.1

The Amiga partition parser module uses signed int for partition sector address and count, which will overflow for disks larger than 1 TB.

Use u64 as type for sector address and size to allow using disks up to 2 TB without LBD support, and disks larger than 2 TB with LBD. The RBD format allows to specify disk sizes up to 2^128 bytes (though native OS limitations reduce this somewhat, to max 2^68 bytes), so check for u64 overflow carefully to protect against overflowing sector_t.

This bug was reported originally in 2012, and the fix was created by the RDB author, Joanne Dow <[email protected]>. A patch had been discussed and reviewed on linux-m68k at that time but never officially submitted (now resubmitted as patch 1 of this series).

Patch 3 (this series) adds additional error checking and warning messages. One of the error checks now makes use of the previously unused rdb_CylBlocks field, which causes a 'sparse' warning (cast to restricted __be32).

Annotate all 32 bit fields in affs_hardblocks.h as __be32, as the on-disk format of RDB and partition blocks is always big endian.

Message-ID: <[email protected]>

---

Changes from v10:

Christoph Hellwig:
- change annotation of all __u32 fields to __be32

Changes from v11:

Geert Uytterhoeven:
- also change annotation of the two __s32 checksum fields

Changes from v12:

- change patch subject to reflect changes in v11 and v12

---
 include/uapi/linux/affs_hardblocks.h | 68 ++++++++++++++--------------
 1 file changed, 34 insertions(+), 34 deletions(-)

index 5e2fb8481252..a5aff2eb5f70 100644
@@ -7,42 +7,42 @@
 /* Just the needed definitions for the RDB of an Amiga HD. */
 
 struct RigidDiskBlock {
-	__u32	rdb_ID;
+	__be32	rdb_ID;
 	__be32	rdb_SummedLongs;
-	__s32	rdb_ChkSum;
-	__u32	rdb_HostID;
+	__be32	rdb_ChkSum;
+	__be32	rdb_HostID;
 	__be32	rdb_BlockBytes;
-	__u32	rdb_Flags;
-	__u32	rdb_BadBlockList;
+	__be32	rdb_Flags;
+	__be32	rdb_BadBlockList;
 	__be32	rdb_PartitionList;
-	__u32	rdb_FileSysHeaderList;
-	__u32	rdb_DriveInit;
-	__u32	rdb_Reserved1[6];
-	__u32	rdb_Cylinders;
-	__u32	rdb_Sectors;
-	__u32	rdb_Heads;
-	__u32	rdb_Interleave;
-	__u32	rdb_Park;
-	__u32	rdb_Reserved2[3];
-	__u32	rdb_WritePreComp;
-	__u32	rdb_ReducedWrite;
-	__u32	rdb_StepRate;
-	__u32	rdb_Reserved3[5];
-	__u32	rdb_RDBBlocksLo;
-	__u32	rdb_RDBBlocksHi;
-	__u32	rdb_LoCylinder;
-	__u32	rdb_HiCylinder;
-	__u32	rdb_CylBlocks;
-	__u32	rdb_AutoParkSeconds;
-	__u32	rdb_HighRDSKBlock;
-	__u32	rdb_Reserved4;
+	__be32	rdb_FileSysHeaderList;
+	__be32	rdb_DriveInit;
+	__be32	rdb_Reserved1[6];
+	__be32	rdb_Cylinders;
+	__be32	rdb_Sectors;
+	__be32	rdb_Heads;
+	__be32	rdb_Interleave;
+	__be32	rdb_Park;
+	__be32	rdb_Reserved2[3];
+	__be32	rdb_WritePreComp;
+	__be32	rdb_ReducedWrite;
+	__be32	rdb_StepRate;
+	__be32	rdb_Reserved3[5];
+	__be32	rdb_RDBBlocksLo;
+	__be32	rdb_RDBBlocksHi;
+	__be32	rdb_LoCylinder;
+	__be32	rdb_HiCylinder;
+	__be32	rdb_CylBlocks;
+	__be32	rdb_AutoParkSeconds;
+	__be32	rdb_HighRDSKBlock;
+	__be32	rdb_Reserved4;
 	char	rdb_DiskVendor[8];
 	char	rdb_DiskProduct[16];
 	char	rdb_DiskRevision[4];
 	char	rdb_ControllerVendor[8];
 	char	rdb_ControllerProduct[16];
 	char	rdb_ControllerRevision[4];
-	__u32	rdb_Reserved5[10];
+	__be32	rdb_Reserved5[10];
 };
 
 #define	IDNAME_RIGIDDISK	0x5244534B	/* "RDSK" */

@@ -50,16 +50,16 @@ struct RigidDiskBlock {
 struct PartitionBlock {
 	__be32	pb_ID;
 	__be32	pb_SummedLongs;
-	__s32	pb_ChkSum;
-	__u32	pb_HostID;
+	__be32	pb_ChkSum;
+	__be32	pb_HostID;
 	__be32	pb_Next;
-	__u32	pb_Flags;
-	__u32	pb_Reserved1[2];
-	__u32	pb_DevFlags;
+	__be32	pb_Flags;
+	__be32	pb_Reserved1[2];
+	__be32	pb_DevFlags;
 	__u8	pb_DriveName[32];
-	__u32	pb_Reserved2[15];
+	__be32	pb_Reserved2[15];
 	__be32	pb_Environment[17];
-	__u32	pb_EReserved[15];
+	__be32	pb_EReserved[15];
 };
 
 #define	IDNAME_PARTITION	0x50415254	/* "PART" */

2.17.1

The Amiga partition parser module uses signed int for partition sector address and count, which will overflow for disks larger than 1 TB.

Use u64 as type for sector address and size to allow using disks up to 2 TB without LBD support, and disks larger than 2 TB with LBD. The RBD format allows to specify disk sizes up to 2^128 bytes (though native OS limitations reduce this somewhat, to max 2^68 bytes), so check for u64 overflow carefully to protect against overflowing sector_t.

Bail out if sector addresses overflow 32 bits on kernels without LBD support.

This bug was reported originally in 2012, and the fix was created by the RDB author, Joanne Dow <[email protected]>. A patch had been discussed and reviewed on linux-m68k at that time but never officially submitted (now resubmitted as patch 1 in this series).
This patch adds additional error checking and warning messages.

Message-ID: <[email protected]>

---

Changes from RFC:

- use u64 instead of sector_t, since that may be u32 without LBD support
- check multiplication overflows each step - 3 u32 values may exceed u64!
- warn against use on AmigaDOS if partition data overflow u32 sector count.
- warn if partition CylBlocks larger than what's stored in the RDSK header.
- bail out if we were to overflow sector_t (32 or 64 bit).

Changes from v1:

Kars de Jong:
- use defines for magic offsets in DosEnvec struct

Geert Uytterhoeven:
- use u64 cast for multiplications of u32 numbers
- use array3_size for overflow checks
- change pr_err to pr_warn
- discontinue use of pr_cont
- reword log messages
- drop redundant nr_sects overflow test
- warn against 32 bit overflow for each affected partition
- skip partitions that overflow sector_t size instead of aborting scan

Changes from v2:

- further trim 32 bit overflow test
- correct duplicate types.h inclusion introduced in v2

Changes from v3:

- split off sector address type fix for independent review
- change blksize to unsigned
- use check_mul_overflow() instead of array3_size()
- rewrite checks to avoid 64 bit divisions in check_mul_overflow()

Changes from v5:

Geert Uytterhoeven:
- correct ineffective u64 cast to avoid 32 bit mult. overflow
- fix mult. overflow in partition block address calculation

Changes from v6:

Geert Uytterhoeven:
- don't fail hard on partition block address overflow

Changes from v7:

- replace bdevname(state->bdev, b) by state->disk->disk_name
- drop warn_no_part conditionals
- remove remaining warn_no_part

Changes from v8:

Christoph Hellwig:
- whitespace fix, drop unnecessary u64 casts

kbuild warning:
- sparse warning fix

Changes from v9:

- revert ineffective sparse warning fix, and rely on change to annotation of rdb_CylBlocks (patch 2 this series) instead.
- add Fixes: tags and stable backport prereq

---
 block/partitions/amiga.c | 103 ++++++++++++++++++++++++++++++++-------
 1 file changed, 85 insertions(+), 18 deletions(-)

index 85c5c79aae48..ed222b9c901b 100644
@@ -11,10 +11,18 @@
 #define pr_fmt(fmt) fmt
 
 #include <linux/types.h>
+#include <linux/mm_types.h>
+#include <linux/overflow.h>
 #include <linux/affs_hardblocks.h>
 
 #include "check.h"
 
+/* magic offsets in partition DosEnvVec */
+#define NR_HD	3
+#define NR_SECT	5
+#define LO_CYL	9
+#define HI_CYL	10
+
 static __inline__ u32
 checksum_block(__be32 *m, int size)
 {

@@ -31,9 +39,12 @@ int amiga_partition(struct parsed_partitions *state)
 	unsigned char *data;
 	struct RigidDiskBlock *rdb;
 	struct PartitionBlock *pb;
-	sector_t start_sect, nr_sects;
-	int blk, part, res = 0;
-	int blksize = 1;	/* Multiplier for disk block size */
+	u64 start_sect, nr_sects;
+	sector_t blk, end_sect;
+	u32 cylblk;		/* rdb_CylBlocks = nr_heads*sect_per_track */
+	u32 nr_hd, nr_sect, lo_cyl, hi_cyl;
+	int part, res = 0;
+	unsigned int blksize = 1;	/* Multiplier for disk block size */
 	int slot = 1;
 
 	for (blk = 0; ; blk++, put_dev_sector(sect)) {

@@ -41,7 +52,7 @@ int amiga_partition(struct parsed_partitions *state)
 			goto rdb_done;
 		data = read_part_sector(state, blk, &sect);
 		if (!data) {
-			pr_err("Dev %s: unable to read RDB block %d\n",
+			pr_err("Dev %s: unable to read RDB block %llu\n",
 			       state->disk->disk_name, blk);
 			res = -1;
 			goto rdb_done;

@@ -58,12 +69,12 @@ int amiga_partition(struct parsed_partitions *state)
 		*(__be32 *)(data+0xdc) = 0;
 		if (checksum_block((__be32 *)data,
 				be32_to_cpu(rdb->rdb_SummedLongs) & 0x7F)==0) {
-			pr_err("Trashed word at 0xd0 in block %d ignored in checksum calculation\n",
+			pr_err("Trashed word at 0xd0 in block %llu ignored in checksum calculation\n",
 			       blk);
 			break;
 		}
 
-		pr_err("Dev %s: RDB in block %d has bad checksum\n",
+		pr_err("Dev %s: RDB in block %llu has bad checksum\n",
 		       state->disk->disk_name, blk);
 	}
 

@@ -80,10 +91,15 @@ int amiga_partition(struct parsed_partitions *state)
 	blk = be32_to_cpu(rdb->rdb_PartitionList);
 	put_dev_sector(sect);
 	for (part = 1; blk>0 && part<=16; part++, put_dev_sector(sect)) {
-		blk *= blksize;	/* Read in terms partition table understands */
+		/* Read in terms partition table understands */
+		if (check_mul_overflow(blk, (sector_t) blksize, &blk)) {
+			pr_err("Dev %s: overflow calculating partition block %llu! Skipping partitions %u and beyond\n",
+				state->disk->disk_name, blk, part);
+			break;
+		}
 		data = read_part_sector(state, blk, &sect);
 		if (!data) {
-			pr_err("Dev %s: unable to read partition block %d\n",
+			pr_err("Dev %s: unable to read partition block %llu\n",
 			       state->disk->disk_name, blk);
 			res = -1;
 			goto rdb_done;

@@ -95,19 +111,70 @@ int amiga_partition(struct parsed_partitions *state)
 		if (checksum_block((__be32 *)pb, be32_to_cpu(pb->pb_SummedLongs) & 0x7F) != 0 )
 			continue;
 
-		/* Tell Kernel about it */
+		/* RDB gives us more than enough rope to hang ourselves with,
+		 * many times over (2^128 bytes if all fields max out).
+		 * Some careful checks are in order, so check for potential
+		 * overflows.
+		 * We are multiplying four 32 bit numbers to one sector_t!
+		 */
+
+		nr_hd   = be32_to_cpu(pb->pb_Environment[NR_HD]);
+		nr_sect = be32_to_cpu(pb->pb_Environment[NR_SECT]);
+
+		/* CylBlocks is total number of blocks per cylinder */
+		if (check_mul_overflow(nr_hd, nr_sect, &cylblk)) {
+			pr_err("Dev %s: heads*sects %u overflows u32, skipping partition!\n",
+				state->disk->disk_name, cylblk);
+			continue;
+		}
+
+		/* check for consistency with RDB defined CylBlocks */
+		if (cylblk > be32_to_cpu(rdb->rdb_CylBlocks)) {
+			pr_warn("Dev %s: cylblk %u > rdb_CylBlocks %u!\n",
+				state->disk->disk_name, cylblk,
+				be32_to_cpu(rdb->rdb_CylBlocks));
+		}
+
+		/* RDB allows for variable logical block size -
+		 * normalize to 512 byte blocks and check result.
+		 */
+
+		if (check_mul_overflow(cylblk, blksize, &cylblk)) {
+			pr_err("Dev %s: partition %u bytes per cyl. overflows u32, skipping partition!\n",
+				state->disk->disk_name, part);
+			continue;
+		}
+
+		/* Calculate partition start and end. Limit of 32 bit on cylblk
+		 * guarantees no overflow occurs if LBD support is enabled.
+		 */
+
+		lo_cyl = be32_to_cpu(pb->pb_Environment[LO_CYL]);
+		start_sect = ((u64) lo_cyl * cylblk);
+
+		hi_cyl = be32_to_cpu(pb->pb_Environment[HI_CYL]);
+		nr_sects = (((u64) hi_cyl - lo_cyl + 1) * cylblk);
 
-		nr_sects = ((sector_t)be32_to_cpu(pb->pb_Environment[10]) + 1 -
-			   be32_to_cpu(pb->pb_Environment[9])) *
-			   be32_to_cpu(pb->pb_Environment[3]) *
-			   be32_to_cpu(pb->pb_Environment[5]) *
-			   blksize;
 		if (!nr_sects)
 			continue;
-		start_sect = (sector_t)be32_to_cpu(pb->pb_Environment[9]) *
-			     be32_to_cpu(pb->pb_Environment[3]) *
-			     be32_to_cpu(pb->pb_Environment[5]) *
-			     blksize;
+
+		/* Warn user if partition end overflows u32 (AmigaDOS limit) */
+
+		if ((start_sect + nr_sects) > UINT_MAX) {
+			pr_warn("Dev %s: partition %u (%llu-%llu) needs 64 bit device support!\n",
+				state->disk->disk_name, part,
+				start_sect, start_sect + nr_sects);
+		}
+
+		if (check_add_overflow(start_sect, nr_sects, &end_sect)) {
+			pr_err("Dev %s: partition %u (%llu-%llu) needs LBD device support, skipping partition!\n",
+				state->disk->disk_name, part,
+				start_sect, end_sect);
+			continue;
+		}
+
+		/* Tell Kernel about it */
+
 		put_partition(state,slot++,start_sect,nr_sects);
 		{
 			/* Be even more informative to aid mounting */

2.17.1

Applied, thanks!

[1/3] block: fix signed int overflow in Amiga partition support

      commit: fc3d092c6bb48d5865fec15ed5b333c12f36288c
[2/3] block: change all __u32 annotations to __be32 in affs_hardblocks.h
      commit: 95a55437dc49fb3342c82e61f5472a71c63d9ed0
[3/3] block: add overflow checks for Amiga partition support
      commit: b6f3f28f604ba3de4724ad82bea6adb1300c0b5f

Best regards,

Jens Axboe

Jens Axboe - 20.06.23, 22:28:34 CEST:

Wonderful! Thanks to everyone involved! Thanks to Jens for applying it! And special thanks to Michael for going through 13 iterations!

Best,

Martin

Amazing. Thanks to everyone who worked hard to get these fixes in!

Serious motivation booster for me to do more work on retro Linux ;-).

Adrian

 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

Thanks Jens!

And a big 'Thank You' to all who helped with suggestions and comments.

Cheers,

    Michael

Hi Jens,

my (again, hopefully) final version of the bugfix for the bug reported by Christian Zigotzky against the Amiga RDB partition code currently in linux-block as well as upstream.

This bug affects any users of RDB disks where the value of (signed 32 bit) -1 signals the end of the linked list of partitions. One of the popular AmigaOS tools used to partition disks (Media Toolbox) uses this value. As a result, the last partition is considered invalid and cannot be used.

The bug and this fix have been discussed on linux-block and linux-m68k at length.

Testing by Christian also exposed another aspect of the old bug fixed in commits fc3d092c6b ("block: fix signed int overflow in Amiga partition support") and b6f3f28f60 ("block: add overflow checks for Amiga partition support") that I document here for future reference:

Partitions that did overflow the disk size (due to 32 bit int overflow) were not skipped but truncated to the end of the disk. Users who missed the warning message during boot would go on to create a filesystem with a size exceeding the actual partition size. Now that the 32 bit overflow has been corrected, such filesystems may refuse to mount with a 'filesystem exceeds partition size' error. Users should either correct the partition size, or resize the filesystem before attempting to boot a kernel with the ealier RDB fixes in place.

Note that this is not a new bug in the current code - just one particular result of the old overflow bug that has only now been noticed.

Cheers,

Michael

Michael Schmitz (1):
block: bugfix for Amiga partition overflow check patch

 block/partitions/amiga.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

2.17.1

Making 'blk' sector_t (i.e. 64 bit if LBD support is active) fails the 'blk>0' test in the partition block loop if a value of (signed int) -1 is used to mark the end of the partition block list.

This bug was introduced in patch 3 of my prior Amiga partition support fixes series, and spotted by Christian Zigotzky when testing the latest block updates.

Explicitly cast 'blk' to signed int to allow use of -1 to terminate the partition block linked list.

Message-ID: [email protected]

--

Changes since v1:

- corrected Fixes: tag
- added Tested-by:
- reworded commit message to describe filesystem partition size mismatch problem

Changes since v2:

Adrian Glaubitz:
- fix typo in commit message

Changes since v3:

Greg KH:
- fix stable tag

Geert Uytterhoeven:
- revert changes to commit message since v1

---
 block/partitions/amiga.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index ed222b9c901b..506921095412 100644
@@ -90,7 +90,7 @@ int amiga_partition(struct parsed_partitions *state)
 	}
 	blk = be32_to_cpu(rdb->rdb_PartitionList);
 	put_dev_sector(sect);
-	for (part = 1; blk>0 && part<=16; part++, put_dev_sector(sect)) {
+	for (part = 1; (s32) blk>0 && part<=16; part++, put_dev_sector(sect)) {
 		/* Read in terms partition table understands */
 		if (check_mul_overflow(blk, (sector_t) blksize, &blk)) {
 			pr_err("Dev %s: overflow calculating partition block %llu! Skipping partitions %u and beyond\n",

2.17.1

Please drop this line.

Gr{oetje,eeting}s,

Geert

Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Hi Geert,

thanks for the review!

Am 05.07.2023 um 19:28 schrieb Geert Uytterhoeven:

Because it's redundant, as I've also used Link:?

Cheers,

Michael

Hi Michael,

(That, too ;-)

Because the use of the Message-ID: tag in patches is not documented. IIRC, it might also cause issues when applying, as the downloaded patch will appear to have two Message-IDs.
I'm not sure the sample git hook in Documentation/maintainer/configure-git.rst (and all variants the various maintainers are using) handles this correctly.

Gr{oetje,eeting}s,

Geert

Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Hi Geert,

Now I wonder where I picked up that habit ...

That's correct (if you refer to a patch in mbox format), but from the context of the two Message-ID lines, it ought to be clear which one matters.

You're right, it won't check for context there.

In this particular instance, it won't use my Message-ID tag anyway though (forgot the angle brackets).

I'll fix that in v5 later.

Cheers,

    Michael

This is confusing - it's being marked for stable, but also labeled as fixing a commit that isn't even a release yet?

Jens Axboe

Hi Jens,

True - but as you had pointed out, the commit this fixes is set in stone. How do we ensure this bugfix is picked up as well when the other patches are backported? Does that  happen automatically, or do I need to add a Link: tag to the patch being fixed?

(Greg didn't seem to object to the Fixes: as such, just to the incorrect version prereq)

Cheers,

    Michael

This:

should be enough for it to go into stable from 5.2 and onwards.

I think it's really confusing... A patch should only have a Fixes tag if it's fixing a specific bug in that patch. Either it is, in which case you would not need Cc stable at all since it's only in 6.5-rc, or it isn't and you should just have the stable tag with 5.2+ as you already have.

I'll apply this and remove the Fixes line, and the message id thing too.

Jens Axboe

Hi Jens,

OK - I wasn't certain whether you wanted the Fixes or stable tag dropped.

It is fixing a bug in b6f3f28f60. I should have checked whether the patch series had already gone to release, not just -rc, instead of just adding the stable tag out of caution.

Thanks - whatever is least confusing is fine, as long as it's backported to stable in the end.

Won't be sending v5 then...

Cheers,

    Michael

But this is the confusion - if it's fixing a bug in b6f3f28f60, then why is it marked as needing to get backported much further back, predating that commit?

Jens Axboe

Hi Jens,

I see - it doesn't need to be backported that far back _alone_. It only needs to be applied after  b6f3f28f60 once that one has been backported.

Cheers,

    Michael

OK I see - I think there's some serious misunderstandings here then :-)

It sounds like it fixes a bug in b6f3f28f60 alone, and it has no business going into stable. The commit should _just_ be marked with it fixing that. If someone were to backport that previous series, then their tooling or diligence should notice this dependency and this current commit should be picked as well.

There should be no Cc: stable on this patch at all, I'll fix it up.

Jens Axboe

Here's what I have:

https://git.kernel.dk/cgit/linux/commit/?h=block-6.5&id=7eb1e47696aa231b1a567846bbe3a1e1befe1854

which has the following manual edits:

1) Change the title/subject line of the patch. "bugfix for Amiga partition overflow check patch" means very little. The fact that this patch is a bug fix for a previous commit is explicit with the Fixes line.

2) Break lines at 72-74 chars, yours were very short.

3) Drop message-id

4) Drop cc stable tag

5) Drop the revision history. This should be behind three '---' lines and then it's dropped automatically.

Let's hope this is it for Amiga partition handling!

Jens Axboe

Hi Jens,

thanks for patching this all up!

That's probably understating it. I need to reread the patch submission notes.

Somehow a limit of 60 had stuck in my mind.

Argh - looks like I've made that mistake more often than not in the past few years. I'll remember that now.

I should certainly hope so!

Cheers,

    Michael

Michael Schmitz - 06.07.23, 01:54:49 CEST:

Yeah, really. For good.

Thank you, Michael and Jens!

Martin