Messages in this thread | | | Date | Wed, 13 Nov 2019 22:34:50 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: Help requested: futex(..., FUTEX_WAIT_PRIVATE, ...) returns EPERM |
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On Wed, 13 Nov 2019, Harris, Robert wrote: > > On 13 Nov 2019, at 09:04, Thomas Gleixner <tglx@linutronix.de> wrote: > > On Tue, 12 Nov 2019, Harris, Robert wrote: > >> Understanding the circumstances under which EPERM can be returned for > >> FUTEX_WAIT_PRIVATE would be useful but it is not a documented failure > >> mode. I have spent some time looking through futex.c but have not > >> found anything yet. I would be grateful for a hint from someone more > >> knowledgeable. > > > > sys_futex(FUTEX_WAIT_PRIVATE) does not return -EPERM. Only the PI variants > > do that. > > In that case I would appreciate a second pair of eyes. The error I see > (intermittently) is
The code looks innocent enough. As I don't know whether the kernel version you mentioned is a vanilla 4.19.184 from the stable tree or some patched up frankenkernel which pretends to have this version number, I can't be sure that this is an issue in that particular kernel.
In the vanilla 4.19.184 I really cant find how that would return EPERM for regular futexes.
Thanks,
tglx
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