On Tue, Apr 21, 2026 at 07:59:08AM +0200, Jerome Marchand wrote: > On 4/20/26 6:52 PM, Mykyta Yatsenko wrote: > > On 4/20/26 2:46 PM, Jerome Marchand wrote: > > > The file_reader/on_open_expect_fault fails consistently on my system. > > > It expects a page fault on first dynptr read of some range the exe > > > file of the current process because it has paged out that page range > > > earlier. However a lot can happen to that range (which depending on > > > the actual memory layout could contain text section, data section, > > > sections )related to dynamic linking...) between the moment it was > > > paged out and the moment the bpf program expected to hit a pagefault > > > actually run. > > > > > > A bit of instrumentation with mincore() shows that pages from that > > > range were accessed several times before the program is run. In > > > particular the call of file_reader__load() seems to fault all the > > > range in. > > > > > > Move the call to madvise(MADV_PAGEOUT) to just before attaching the > > > program to minimize the risk of having those page pulled back in from > > > under our feet. > > > > > > Signed-off-by: Jerome Marchand <[email protected]> > > > --- > > > > Thank you for the patch, the change looks good. Does it fail > > consistently on 4K page size? > > It did when I ran the test manually. On our automated testing system, it > failed intermittently.
On my fork of BPF CI the test was failing[1] consistently, even when this commit is applied. However I wasn't able to reproduce locally on my laptop when I ran manually. Any hints regarding where to look and how to reproduce? Thanks, Shung-Hsi 1: https://github.com/shunghsiyu/libbpf/actions/runs/26807198259/job/79027625188 ...
