Hi, On 2023-01-12 20:35:43 +1300, Thomas Munro wrote: > Subject: [PATCH] Fix WaitEventSetWait() buffer overrun. > > The WAIT_USE_EPOLL and WAIT_USE_KQUEUE implementations of > WaitEventSetWaitBlock() confused the size of their internal buffer with > the size of the caller's output buffer, and could ask the kernel for too > many events. In fact the set of events retrieved from the kernel needs > to be able to fit in both buffers, so take the minimum of the two. > > The WAIT_USE_POLL and WAIT_USE WIN32 implementations didn't have this > confusion.
> This probably didn't come up before because we always used the same > number in both places, but commit 7389aad6 calculates a dynamic size at > construction time, while using MAXLISTEN for its output event buffer on > the stack. That seems like a reasonable thing to want to do, so > consider this to be a pre-existing bug worth fixing. > As reported by skink, valgrind and Tom Lane. > > Discussion: https://postgr.es/m/901504.1673504836%40sss.pgh.pa.us Makes sense. We should backpatch this, I think? Greetings, Andres Freund
