Messages in this thread | | | Date | Fri, 24 Dec 2021 10:37:31 +0000 | Subject | Re: [RFC] coredump: Do not interrupt dump for TIF_NOTIFY_SIGNAL | From | Pavel Begunkov <> |
| |
On 12/24/21 01:34, Olivier Langlois wrote: > On Fri, 2021-10-22 at 15:13 +0100, Pavel Begunkov wrote: >> On 6/9/21 21:17, Eric W. Biederman wrote: >> In short, a task creates an io_uring worker thread, then the worker >> submits a task_work item to the creator task and won't die until >> the item is executed/cancelled. And I found that the creator task is >> sleeping in do_coredump() -> wait_for_completion() >> [...] >> A hack executing tws there helps (see diff below). >> Any chance anyone knows what this is and how to fix it? >> [...] > Pavel, > > I cannot comment on the merit of the proposed hack but my proposed > patch to fix the coredump truncation issue when a process using > io_uring core dumps that I submitted back in August is still > unreviewed!
That's unfortunate. Not like I can help in any case, but I assumed it was dealt with by
commit 06af8679449d4ed282df13191fc52d5ba28ec536 Author: Eric W. Biederman <ebiederm@xmission.com> Date: Thu Jun 10 15:11:11 2021 -0500
coredump: Limit what can interrupt coredumps
Olivier Langlois has been struggling with coredumps being incompletely written in processes using io_uring. ...
> https://lore.kernel.org/lkml/1625bc89782bf83d9d8c7c63e8ffcb651ccb15fa.1629655338.git.olivier@trillion01.com/ > > I have been using it since then I must have generated many dozens of > perfect core dump files with it and I have not seen a single truncated > core dump files like I used to have prior to the patch. > > I am bringing back my patch to your attention because one nice side > effect of it is that it would have avoided totally the problem that you > have encountered in coredump_wait() since it does cancel io_uring > resources before calling coredump_wait()!
FWIW, I worked it around in io_uring back then by breaking the dependency.
-- Pavel Begunkov
| |