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Date:   Wed, 15 Sep 2021 01:06:56 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Michael Schmitz <schmitzmic@gmail.com>,
        Christoph Hellwig <hch@lst.de>,
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Subject: Re: RFC: remove set_fs for m68k
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On Tue, Sep 14, 2021 at 09:38:58AM -0700, Linus Torvalds wrote:
> On Tue, Sep 14, 2021 at 9:28 AM Al Viro <viro@zeniv.linux.org.uk> wrote:
> >
> > See https://lkml.kernel.org/lkml/YP2dTQPm1wGPWFgD@zeniv-ca.linux.org.uk/T/
> > for original thread.
> 
> Ok, thanks for the pointer.
> 
> I'm actually surprised we have that "multiple nested signals" thing
> still. I had this memory of us having removed that, and just returning
> to user space with the one signal frame set up.

Too much headache and too many things to keep track of - for example,
you have to cope with fun like raising (and handling) SIGTRAP on
singlestepping into signal handler on some architectures.  That would
need to be special-cased and so would SIGSEGV on failure to set sigframe
up, etc.

Al, back to digging through io_uring and hating every minute of that...