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In this long thread, Maciej Zdeb reported that the H2 mux was still going through endless loops from time to time : https://www.mail-archive.com/haproxy@formilux.org/msg33709.html What happens is the following : - in h2s_frt_make_resp_data() we can set H2_SF_BLK_SFCTL and remove the stream from the send_list - then in h2_shutr() and h2_shutw(), we check if the list is empty before subscribing the element, which is true after the case above - then in h2c_update_all_ws() we still have H2_SF_BLK_SFCTL with the item in the send_list, thus LIST_ADDQ() adds it a second time. This patch adds a check of list emptiness before performing the LIST_ADDQ() when the flow control window opens. Maciej reported that it reliably fixed the problem for him. As later discussed with Olivier, this fixes the consequence of the issue rather than its cause. The root cause is that a stream should never be in the send_list with a blocking flag set and the various places that can lead to this situation must be revisited. Thus another fix is expected soon for this issue, which will require some observation. In the mean time this one is easy enough to validate and to backport. Many thanks to Maciej for testing several versions of the patch, each time providing detailed traces which allowed to nail the problem down. This patch must be backported to 1.9.
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 - 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)