Public bug reported:
Cross-compiling the Ubuntu kernel using the standard debian/rules
methods produces a linux-headers-{version}-{flavour} package which
contains executables (e.g. fixdep, several others) built for the build
host architecture, not the target host architecture. Those executables
are unusable when that linux-headers package gets installed on the
target.
Example from an ARM64 cross-compiled linux-headers package (note the x86-64
executable):
usr/src/linux-headers-5.10.0-14-generic/scripts/basic/fixdep: ELF 64-bit LSB
shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter
/lib64/ld-linux-x86-64.so.2,
BuildID[sha1]=77b1c89ff5560389ea272ec0e81a4770246481a1, for GNU/Linux 3.2.0,
not stripped
The kernel itself, of course, gets properly cross-compiled and the
generated packages (including linux-headers) will install fine on the
target. But the bogus executables prevent full functionality on that
installation, i.e. it cannot be used for kernel driver development.
The fundamental reason why this occurs is that the build host needs to
run some of those compiled executables itself during the build, but
those executables should NOT get packaged. Instead, the build should be
reorganized so that it compiles a set of temporary host-arch-execs for
use during the build, but then separately (cross)-compiles them as
target-arch-execs for inclusion in the linux-headers package.
This bug is Importance:Wishlist because:
- cross-compiled Ubuntu kernel package builds aren't technically "supported".
- this glitch only happens with engineer-built cross-compiled test kernels.
- building natively instead (i.e. in a Launchpad PPA) avoids the problem.
- this is not a new misbehavior; our cross-compile build rules have always
been this way.
** Affects: linux (Ubuntu)
Importance: Wishlist
Status: Confirmed
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https://bugs.launchpad.net/bugs/1916782
Title:
fixdep, etc. gets built for wrong arch when cross-compiling Ubuntu
kernel
Status in linux package in Ubuntu:
Confirmed
Bug description:
Cross-compiling the Ubuntu kernel using the standard debian/rules
methods produces a linux-headers-{version}-{flavour} package which
contains executables (e.g. fixdep, several others) built for the build
host architecture, not the target host architecture. Those
executables are unusable when that linux-headers package gets
installed on the target.
Example from an ARM64 cross-compiled linux-headers package (note the x86-64
executable):
usr/src/linux-headers-5.10.0-14-generic/scripts/basic/fixdep: ELF 64-bit LSB
shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter
/lib64/ld-linux-x86-64.so.2,
BuildID[sha1]=77b1c89ff5560389ea272ec0e81a4770246481a1, for GNU/Linux 3.2.0,
not stripped
The kernel itself, of course, gets properly cross-compiled and the
generated packages (including linux-headers) will install fine on the
target. But the bogus executables prevent full functionality on that
installation, i.e. it cannot be used for kernel driver development.
The fundamental reason why this occurs is that the build host needs to
run some of those compiled executables itself during the build, but
those executables should NOT get packaged. Instead, the build should
be reorganized so that it compiles a set of temporary host-arch-execs
for use during the build, but then separately (cross)-compiles them as
target-arch-execs for inclusion in the linux-headers package.
This bug is Importance:Wishlist because:
- cross-compiled Ubuntu kernel package builds aren't technically "supported".
- this glitch only happens with engineer-built cross-compiled test kernels.
- building natively instead (i.e. in a Launchpad PPA) avoids the problem.
- this is not a new misbehavior; our cross-compile build rules have always
been this way.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1916782/+subscriptions
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