Re: [PATCH 1/2] alpha/ptrace: Record and handle the absence of switch_stack
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: 2021-06-16 20:01:16
Also in:
linux-arch, linux-m68k, lkml
Possibly related (same subject, not in this thread)
- 2021-06-16 · Re: [PATCH 1/2] alpha/ptrace: Record and handle the absence of switch_stack · Linus Torvalds <torvalds@linux-foundation.org>
- 2021-06-16 · Re: [PATCH 1/2] alpha/ptrace: Record and handle the absence of switch_stack · Al Viro <viro@zeniv.linux.org.uk>
- 2021-06-16 · Re: [PATCH 1/2] alpha/ptrace: Record and handle the absence of switch_stack · Eric W. Biederman <hidden>
- 2021-06-16 · Re: [PATCH 1/2] alpha/ptrace: Record and handle the absence of switch_stack · Eric W. Biederman <hidden>
On Wed, Jun 16, 2021 at 11:32 AM Eric W. Biederman [off-list ref] wrote:
Prevent security holes by recording when all of the registers are available so generic code changes do not result in security holes on alpha.
Please no, not this way. ldl/stc is extremely expensive on some alpha cpus.
I really think thatTIF_ALLREGS_SAVED bit isn't worth it, except
perhaps for debugging.
And even for debugging, I think it would be both easier and cheaper to
just add a magic word to the entry stack instead.
Linus