mainloop: fix stuck when io_uring is enabled#4304
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stgraber merged 4 commits intolxc:masterfrom Apr 21, 2023
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Currently, fd_make_nonblocking does exactly the opposite thing, it clears O_NONBLOCK flag and makes fd blocking. Signed-off-by: Alexander Mikhalitsyn <[email protected]>
Signed-off-by: Alexander Mikhalitsyn <[email protected]>
Let's prevent freezes on read(2) by making a terminal FDs non-blocking. It was discovered that there is an issue with io_uring mainloop when multishot poll (IORING_POLL_ADD_MULTI) mode is enabled. Sometimes false-positive poll events are put into a CQ. It makes further read(2) stuck forever and blocks all mainloop processing for an infinite time. Signed-off-by: Alexander Mikhalitsyn <[email protected]>
Let's disable IORING_POLL_ADD_MULTI to workaround an issue with false-positive POLLIN events in CQ. In my local setup I managed to fix an issue without this by making terminal FDs non-blocking, but during full testsuite execution in Jenkins it was found that issue still persists. So, let's add this ugly workaround too. Signed-off-by: Alexander Mikhalitsyn <[email protected]>
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Testsuite passed |
This was referenced Feb 21, 2024
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Something is wrong with multishot polling mode in io_uring. Let's workaround that and safe from possible stucks on read.