OpenAFS Master Repository branch, master, updated. openafs-devel-1_9_1-331-g2f26082

[Gerrit Code Review]

The following commit has been merged in the master branch:
commit 2f260825b96b76556aba82fc364c841357a23a7d
Author: Cheyenne Wills <cwills@sinenomine.net>
Date:   Thu Feb 29 17:58:17 2024 -0700

    Linux: Remove weak attribute for key_type_keyring
    
    The reference to the Linux symbol key_type_keyring uses a weak
    attribute to assist in determining if the symbol is exported.  This
    method was introduced in commit: 'keyring-updated-20080310' (b7fb842b1c)
    as a way to detect if the symbol was exported by the Linux kernel.  A
    later commit: 'linux-keyring-export-check-20090701' (4ca66112c2)
    introduced an autoconf test that eliminated the need for using the weak
    attribute, but the commit did not remove the attribute.
    
    On a Debian-12 system on ARM64 the use of the weak attribute in this
    case causes an error when loading the kernel module:
      "ERROR: could not insert 'openafs': Exec format error".
    The error is due to the Linux module loader not supporting the
    relocation entry type in the openafs kernel module for the
    key_type_keyring.  Further investigation showed that this problem could
    occur with gcc-12 on a ARM64 system (see below for additional
    information).
    
    The code in osi_groups.c uses a pointer, __key_type_keyring, to the
    key_type_keyring.  When this symbol is exported by the Linux kernel, the
    loader would resolve the address and __key_type_keyring would contain
    the address.  If the key_type_keyring symbol was not exported,
    __key_type_keyring would be set to NULL (due to the weak attribute
    associated with key_type_keyring).
    
    Remove the weak attribute for key_type_keyring when the configure
    test, introduced in the 4ca66112c2 commit, determines that the symbol
    is exported (EXPORTED_KEY_TYPE_KEYRING is defined).  When the symbol
    isn't exported (pre Linux 2.6.22), just set the pointer,
    __key_type_keyring to NULL.
    
    NOTE:
    
    The load error was reported on the openafs IRC channel by "clarkb"
    
    The problem of loading the openafs kernel module was also observed
    on a NixOS system as well, and is described in the NixOS ticket
    
      https://github.com/NixOS/nixpkgs/issues/284501
    
    A Debian-11 system did not have a problem loading the openafs kernel
    module. Investigation of the differences between Debian-11 and Debian-12
    showed that the problem is due to a series of fixes in the toolchain
    (in particular gcc-12) to address 'Cortex-A53 erratum #843419', which
    deals with how the ARM64 ADRP instruction is used. With gcc-12, the
    code generated uses a R_AARCH64_ADR_GOT for this particular case (which
    isn't supported by the Linux kernel module loader).  Gcc-11 created a
    R_AARCH64_ABS64 relocation entry type for the symbol.
    
    Change-Id: I3160175c82b47e244c8cedf5ef79fdb0d0dd0002
    Reviewed-on: https://gerrit.openafs.org/15668
    Tested-by: BuildBot <buildbot@rampaginggeek.com>
    Reviewed-by: Andrew Deason <adeason@sinenomine.net>
    Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
    Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
    Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>

 src/afs/LINUX/osi_groups.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

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