Date: Mon, 31 Jul 2017 13:20:34 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 219399] System panics after several hours of 14-threads-compilation orgies using poudriere on AMD Ryzen... Message-ID: <bug-219399-8-tgmDxZiYgw@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-219399-8@https.bugs.freebsd.org/bugzilla/> References: <bug-219399-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=219399 --- Comment #190 from rozhuk.im@gmail.com --- "On AMD, the tool discovered that some processors generate a #UD (undefined opcode) exception prior to completing the instruction fetch. Per AMD specifications, a #PF (page fault) exception occurring during an instruction fetch should supersede a #UD exception, but in the instruction search, which places the last bytes of the instruction on a non - executable page, some processors generate the #UD before the final bytes are moved off of the read/write page. It appears that AMD discovered this at around the same time as this research; the newest AMD Architecture Programmer’s Manual (March 2017) was updated to allow this situation." From: https://github.com/xoreaxeaxeax/sandsifter/blob/master/references/domas_breaking_the_x86_isa_wp.pdf Tool: https://github.com/xoreaxeaxeax/sandsifter -- You are receiving this mail because: You are the assignee for the bug.
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