kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-10-22 19:14:51 +00:00
Code Issues Releases Packages Activity
No description
1,153,491 commits 117 branches 5,803 tags 5.7 GiB
  • C 96.8%
  • Assembly 0.9%
  • Rust 0.7%
  • Shell 0.6%
  • Python 0.5%
  • Other 0.3%
Find a file
Guenter Roeck 3b64d68d90 parisc: Fix ip_fast_csum 
[ Upstream commit a2abae8f0b ]

IP checksum unit tests report the following error when run on hppa/hppa64.

    # test_ip_fast_csum: ASSERTION FAILED at lib/checksum_kunit.c:463
    Expected ( u64)csum_result == ( u64)expected, but
        ( u64)csum_result == 33754 (0x83da)
        ( u64)expected == 10946 (0x2ac2)
    not ok 4 test_ip_fast_csum

0x83da is the expected result if the IP header length is 20 bytes. 0x2ac2
is the expected result if the IP header length is 24 bytes. The test fails
with an IP header length of 24 bytes. It appears that ip_fast_csum()
always returns the checksum for a 20-byte header, no matter how long
the header actually is.

Code analysis shows a suspicious assembler sequence in ip_fast_csum().

 "      addc            %0, %3, %0\n"
 "1:    ldws,ma         4(%1), %3\n"
 "      addib,<         0, %2, 1b\n"	<---

While my understanding of HPPA assembler is limited, it does not seem
to make much sense to subtract 0 from a register and to expect the result
to ever be negative. Subtracting 1 from the length parameter makes more
sense. On top of that, the operation should be repeated if and only if
the result is still > 0, so change the suspicious instruction to
 "      addib,>         -1, %2, 1b\n"

The IP checksum unit test passes after this change.

Cc: Palmer Dabbelt <palmer@rivosinc.com>
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2024-04-03 15:19:28 +02:00
arch
block
certs
crypto
Documentation
drivers
fs
include
init
io_uring
ipc
kernel
lib
LICENSES
mm
net
rust
samples
scripts
security
sound
tools
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
.rustfmt.toml
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile
README

README 

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.