[PATCH v1 03/10] tests/docker: Kludge <linux/swab.h> breakage by pinning linux-libc-dev

["Alex Bennée" <alex.bennee@linaro.org>]

From: Philippe Mathieu-Daudé <f4bug@amsat.org>

Linux kernel commit d5767057c9a [1] aimed to fix an issue with the
swab() declaration, but doing so it introduced the BITS_PER_LONG
definition, without using the kernel __ prefix, leading to odd
failures in userland code using kernel uapi headers, such:

      CC      block/file-posix.o
    In file included from include/qemu/timer.h:4,
                     from include/qemu/timed-average.h:29,
                     from include/block/accounting.h:28,
                     from include/block/block_int.h:27,
                     from block/file-posix.c:30:
    /usr/include/linux/swab.h: In function `__swab':
    include/qemu/bitops.h:20:34: error: "sizeof" is not defined, evaluates to 0 [-Werror=undef]
       20 | #define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)
          |                                  ^~~~~~
    include/qemu/bitops.h:20:41: error: missing binary operator before token "("
       20 | #define BITS_PER_LONG           (sizeof (unsigned long) * BITS_PER_BYTE)
          |                                         ^
    cc1: all warnings being treated as errors
    make: *** [rules.mak:69: block/file-posix.o] Error 1

The issue has been fixed in Linux kernel commit 467d12f5c78 [2].
Some distributions already backported the first commit, but still
lack the second one.

This is the case for Debian Buster.
The linux-libc-dev package contains the Linux kernel headers.
Kernel commit d5767057c9a has been backported in package
commit 1fb0eb7956 "Update to 4.19.116" [3], see debian/changelog:

  +linux (4.19.116-1) UNRELEASED; urgency=medium
  ...
  +    - uapi: rename ext2_swab() to swab() and share globally in swab.h

The previous released update before it is debian/4.19.98-1,
released as debian/4.19.98-1+deb10u1.

We can find this package in the Debian snapshot archives,
luckily archived on 2020-04-28 21:20:54 (see [4]).

QEMU use Debian based Docker images for most of its cross-builds,
which are tested by our Shippable CI jobs. The current broken
package makes most of our CI red. We can kludge this by using the
latest package released before the breakage. Do so by pinning
the package version (apt hold), and using the snapshot archives,
similar to commit b4048a7cd1.
We'll revert once the fix is backported on Debian.

Reference to commits:
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d5767057c9a
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=467d12f5c78
[3] https://salsa.debian.org/kernel-team/linux/-/commit/1fb0eb7956
[4] http://snapshot.debian.org/package/linux/4.19.98-1%2Bdeb10u1/#linux-libc-dev_4.19.98-1:2b:deb10u1

Cc: Salvatore Bonaccorso <carnil@debian.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
[AJB: dropped pinning]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200513120147.21443-1-f4bug@amsat.org>
---
 tests/docker/dockerfiles/debian10.docker | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/tests/docker/dockerfiles/debian10.docker b/tests/docker/dockerfiles/debian10.docker
index 0769700a416..58b23117240 100644
--- a/tests/docker/dockerfiles/debian10.docker
+++ b/tests/docker/dockerfiles/debian10.docker
@@ -9,6 +9,15 @@
 #
 FROM debian:buster-slim
 
+ # Use a snapshot known to work (see http://snapshot.debian.org/#Usage)
+ENV DEBIAN_SNAPSHOT_DATE "20200428T212054Z"
+RUN sed -i \
+    "s%^deb \(https\?://\)deb.debian.org/debian/\? \(.*\)%deb [check-valid-until=no] \1snapshot.debian.org/archive/debian/${DEBIAN_SNAPSHOT_DATE} \2%" \
+    /etc/apt/sources.list
+RUN sed -i \
+    "s%^deb \(https\?://\)security.debian.org/debian-security/\? \(.*\)%deb [check-valid-until=no] \1snapshot.debian.org/archive/debian-security/${DEBIAN_SNAPSHOT_DATE} \2%" \
+    /etc/apt/sources.list
+
 # Duplicate deb line as deb-src
 RUN cat /etc/apt/sources.list | sed "s/^deb\ /deb-src /" >> /etc/apt/sources.list
 
-- 
2.20.1