hardcoded SIGSEGV in __die() ?

[Joakim Tjernlund]

On Mon, 2020-03-23 at 15:45 +0100, Christophe Leroy wrote:
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> Le 23/03/2020 à 15:43, Christophe Leroy a écrit :
> > 
> > Le 23/03/2020 à 15:17, Joakim Tjernlund a écrit :
> > > In __die(), see below, there is this call to notify_send() with
> > > SIGSEGV hardcoded, this seems odd
> > > to me as the variable "err" holds the true signal(in my case SIGBUS)
> > > Should not SIGSEGV be replaced with the true signal no.?
> > 
> > As far as I can see, comes from
> > https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git%2Fcommit%2F%3Fid%3D66fcb1059&data=02%7C01%7CJoakim.Tjernlund%40infinera.com%7C4291ac1b501e4296869a08d7cf38cdb4%7C285643de5f5b4b03a1530ae2dc8aaf77%7C1%7C0%7C637205715189366995&sdata=Z2bFsmDlD2MKhLACQvayk9ejz0dqgMEOlBTlocAmtTg%3D&reserved=0
> > 
> 
> And
> https://nam03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git%2Fcommit%2F%3Fid%3Dae87221d3ce49d9de1e43756da834fd0bf05a2ad&data=02%7C01%7CJoakim.Tjernlund%40infinera.com%7C4291ac1b501e4296869a08d7cf38cdb4%7C285643de5f5b4b03a1530ae2dc8aaf77%7C1%7C0%7C637205715189366995&sdata=97kyz3Ur88BhDUUYzya5t%2FFQVhXYu6qiHoW8hsEg81s%3D&reserved=0
> shows it is (was?) similar on x86.
> 

I tried to follow that chain thinking it would end up sending a signal to user space but I cannot see
that happens. Seems to be related to debugging.

In short, I cannot see any signal being delivered to user space. If so that would explain why
our user space process never dies.
Is there a signal hidden in machine_check handler for SIGBUS I cannot see?

     Jocke