+ make-btrfs-as-broken-due-to-an-inconsistent-api-change.patch added to -mm tree

The patch titled
     Subject: linux-next: build failure after merge of the btrfs tree
has been added to the -mm tree.  Its filename is
     make-btrfs-as-broken-due-to-an-inconsistent-api-change.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/make-btrfs-as-broken-due-to-an-inconsistent-api-change.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/make-btrfs-as-broken-due-to-an-inconsistent-api-change.patch

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------------------------------------------------------
From: Stephen Rothwell <redacted>
Subject: linux-next: build failure after merge of the btrfs tree

--Sig_/WBXj/Gqj3ng9sdQkmCFxe+v
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Hi all,

[I am not sure why this error only popped up after I merged Andrew's
patch set ...]

After merging the btrfs tree, today's linux-next build (x86_64
allmodconfig) failed like this:

In file included from include/linux/string.h:253,
                 from include/linux/bitmap.h:11,
                 from include/linux/cpumask.h:12,
                 from arch/x86/include/asm/cpumask.h:5,
                 from arch/x86/include/asm/msr.h:11,
                 from arch/x86/include/asm/processor.h:22,
                 from arch/x86/include/asm/cpufeature.h:5,
                 from arch/x86/include/asm/thread_info.h:53,
                 from include/linux/thread_info.h:60,
                 from arch/x86/include/asm/preempt.h:7,
                 from include/linux/preempt.h:78,
                 from include/linux/spinlock.h:55,
                 from include/linux/wait.h:9,
                 from include/linux/mempool.h:8,
                 from include/linux/bio.h:8,
                 from fs/btrfs/ioctl.c:7:
In function 'memcpy',
    inlined from '_btrfs_ioctl_send' at fs/btrfs/ioctl.c:4846:3:
include/linux/fortify-string.h:219:4: error: call to '__write_overflow' dec=
lared with attribute error: detected write beyond size of object (1st param=
eter)
  219 |    __write_overflow();
      |    ^~~~~~~~~~~~~~~~~~

Caused by commit

  c8d9cdfc766d ("btrfs: send: prepare for v2 protocol")

This changes the "reserved" field of struct btrfs_ioctl_send_args from 4 u6=
4's to 3, but the above memcpy is copying the "reserved" filed from a struc=
t btrfs_ioctl_send_args_32 (4 u64s) into it.

All I could really do at this point was mark BTRFS_FS as BROKEN
(TEST_KMOD selects BTRFS_FS):

Date: Wed, 27 Oct 2021 20:53:24 +1100
Subject: [PATCH] make btrfs as BROKEN due to an inconsistent API change

Link: https://lkml.kernel.org/r/20211027210924.22ef5881@canb.auug.org.au
Signed-off-by: Stephen Rothwell <redacted>
Cc: David Sterba <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/btrfs/Kconfig  |    1 +
 lib/Kconfig.debug |    1 +
 2 files changed, 2 insertions(+)

--- a/fs/btrfs/Kconfig~make-btrfs-as-broken-due-to-an-inconsistent-api-change
+++ a/fs/btrfs/Kconfig

@@ -20,6 +20,7 @@ config BTRFS_FS
 	select SRCU
 	depends on !PPC_256K_PAGES	# powerpc
 	depends on !PAGE_SIZE_256KB	# hexagon
+	depends on BROKEN
 
 	help
 	  Btrfs is a general purpose copy-on-write filesystem with extents,
--- a/lib/Kconfig.debug~make-btrfs-as-broken-due-to-an-inconsistent-api-change
+++ a/lib/Kconfig.debug

@@ -2505,6 +2505,7 @@ config TEST_KMOD
 	depends on m
 	depends on NETDEVICES && NET_CORE && INET # for TUN
 	depends on BLOCK
+	depends on BROKEN
 	select TEST_LKM
 	select XFS_FS
 	select TUN

_

Patches currently in -mm which might be from sfr@canb.auug.org.au are

memblock-use-memblock_free-for-freeing-virtual-pointers-fix.patch
kernelh-drop-unneeded-linux-kernelh-inclusion-from-other-headers-fix.patch
make-btrfs-as-broken-due-to-an-inconsistent-api-change.patch