On Sat, Aug 10, 2024 at 12:52:16AM +0000, Brian Mak wrote: > On Aug 6, 2024, at 10:21 PM, Kees Cook <kees@xxxxxxxxxx> wrote: > > > > On Tue, 06 Aug 2024 18:16:02 +0000, Brian Mak wrote: > >> Large cores may be truncated in some scenarios, such as with daemons > >> with stop timeouts that are not large enough or lack of disk space. This > >> impacts debuggability with large core dumps since critical information > >> necessary to form a usable backtrace, such as stacks and shared library > >> information, are omitted. > >> > >> We attempted to figure out which VMAs are needed to create a useful > >> backtrace, and it turned out to be a non-trivial problem. Instead, we > >> try simply sorting the VMAs by size, which has the intended effect. > >> > >> [...] > > > > While waiting on rr test validation, and since we're at the start of the > > dev cycle, I figure let's get this into -next ASAP to see if anything > > else pops out. We can drop/revise if there are problems. (And as always, > > I will add any Acks/Reviews/etc that show up on the thread.) > > > > Applied to for-next/execve, thanks! > > > > [1/1] binfmt_elf: Dump smaller VMAs first in ELF cores > > https://urldefense.com/v3/__https://git.kernel.org/kees/c/9c531dfdc1bc__;!!NEt6yMaO-gk!FK3UfXVndoYpve8Y7q7vacIoHOrTj2nJgSJbugqUB5LfciKy0_Xvit9aXz_XCWlXHpdRQO2ArP0$ > > Thanks, Kees! And, thanks Linus + Eric for taking the time to comment on > this. > > Regarding the rr tests, it was not an easy task to get the environment > set up to do this, but I did it and was able to run the tests. The rr > tests require a lot of kernel config options and there's no list > documenting what's needed anywhere... Thanks for suffering through that! > All the tests pass except for the sioc and sioc-no-syscallbuf tests. > However, these test failures are due to an incompatibility with the > network adapter I'm using. It seems that it only likes older network > adapters. I've switched my virtualized network adapter twice now, and > each time, the test gets a bit further than the previous time. Will > continue trying different network adapters until something hopefully > works. In any case, since this error isn't directly related to my > changes and the rest of the tests pass, then I think we can be pretty > confident that this change is not breaking rr. Perfect! Okay, we'll keep our eyes open for any reports of breakage. :) -Kees -- Kees Cook
