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There was a special case made to allow ARMv6 to use unaligned accesses via a cast in xxHash when __ARM_FEATURE_UNALIGNED is defined. But while ARMv6 (and v7) does support unaligned accesses, it's only for 32-bit pointers, not 64-bit ones, leading to bus errors when the compiler emits an ldrd instruction and the input (e.g. a pattern) is not aligned, as in issue #1035. Note that v7 was properly using the packed approach here and was safe, however haproxy versions 2.3 and older use the old r39 xxhash code which has the same issue for armv7. A slightly different fix is required there, by using a different definition of packed for 32 and 64 bits. The problem is really visible when running v7 code on a v8 kernel because such kernels do not implement alignment trap emulation, and the process dies when this happens. This is why in the issue above it was only detected under lxc. The emulation could have been disabled on v7 as well by writing zero to /proc/cpu/alignment though. This commit is a backport of xxhash commit a470f2ef ("update default memory access for armv6"). Thanks to @srkunze for the report and tests, @stgraber for his help on setting up an easy reproducer outside of lxc, and @Cyan4973 for the discussion around the best way to fix this. Details and alternate patches available on https://github.com/Cyan4973/xxHash/issues/490.
The HAProxy documentation has been split into a number of different files for ease of use. Please refer to the following files depending on what you're looking for : - INSTALL for instructions on how to build and install HAProxy - BRANCHES to understand the project's life cycle and what version to use - LICENSE for the project's license - CONTRIBUTING for the process to follow to submit contributions The more detailed documentation is located into the doc/ directory : - doc/intro.txt for a quick introduction on HAProxy - doc/configuration.txt for the configuration's reference manual - doc/lua.txt for the Lua's reference manual - doc/SPOE.txt for how to use the SPOE engine - doc/network-namespaces.txt for how to use network namespaces under Linux - doc/management.txt for the management guide - doc/regression-testing.txt for how to use the regression testing suite - doc/peers.txt for the peers protocol reference - doc/coding-style.txt for how to adopt HAProxy's coding style - doc/internals for developer-specific documentation (not all up to date)