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011b9e1c2a
commit c4e792d1ac upstream.
The LLVM ld.lld linker uses a different symbol type for __bss_start,
resulting in the calculation of KBSS_SZ to be thrown off. Up until now,
this has gone unnoticed as it only affects the appended DTB case, but
pending changes for ARM in the way the decompressed kernel is cleaned
from the caches has uncovered this problem.
On a ld.lld build:
$ nm vmlinux |grep bss_
c1c22034 D __bss_start
c1c86e98 B __bss_stop
resulting in
$ readelf -s arch/arm/boot/compressed/vmlinux | grep bss_size
433: c1c86e98 0 NOTYPE GLOBAL DEFAULT ABS _kernel_bss_size
which is obviously incorrect, and may cause the cache clean to access
unmapped memory, or cause the size calculation to wrap, resulting in no
cache clean to be performed at all.
Fix this by updating the sed regex to take D type symbols into account.
Link: https://lore.kernel.org/linux-arm-kernel/6c65bcef-d4e7-25fa-43cf-2c435bb61bb9@collabora.com/
Link: https://lore.kernel.org/linux-arm-kernel/20210205085220.31232-1-ardb@kernel.org/
Cc: <stable@vger.kernel.org> # v4.19+
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reported-by: Guillaume Tucker <guillaume.tucker@collabora.com>
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.