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Message-ID: <alpine.LNX.2.11.1504172128260.11963@monopod.intra.ispras.ru> Date: Fri, 17 Apr 2015 21:48:38 +0300 (MSK) From: Alexander Monakov <amonakov@...ras.ru> To: musl@...ts.openwall.com Subject: Re: [PATCH] replace 'hlt' by 'ud2' in i386/x32/x86_64 a_crash implementations > > An argument in favor of plain hlt/ud2 is that registers and memory are > > preserved, in case someone will be analyzing the coredump. > > That's a good point. The above could be fixed to preserve registers > with some minor added push/pop (simple pusha/popa on 32-bit) > before/after the syscall, but then it gets bigger. Hm, no, I wouldn't like to see that. By the time a_crash executes, "the impossible happened", so stack pointer might be pointing somewhere you wouldn't want modified. A good reason for compilers to generate ud2 is that it also works for kernel code, unlike hlt -- but then OSv carries a copy of musl to run it in the context of, as I understand, virtualized kernel -- what happens when they execute a_crash? Alexander.
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