linux-kernel - Re: [PATCH v18 0/9] Compile-time stack metadata validation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 28 Feb 2016 07:57:29 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	Josh Poimboeuf <jpoimboe@...hat.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	linux-kernel@...r.kernel.org, live-patching@...r.kernel.org,
	Michal Marek <mmarek@...e.cz>,
	Peter Zijlstra <peterz@...radead.org>,
	Andy Lutomirski <luto@...nel.org>,
	Borislav Petkov <bp@...en8.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andi Kleen <andi@...stfloor.org>,
	Pedro Alves <palves@...hat.com>,
	Namhyung Kim <namhyung@...il.com>,
	Bernd Petrovitsch <bernd@...rovitsch.priv.at>,
	Chris J Arges <chris.j.arges@...onical.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jiri Slaby <jslaby@...e.cz>,
	Arnaldo Carvalho de Melo <acme@...nel.org>
Subject: Re: [PATCH v18 0/9] Compile-time stack metadata validation


Another thing I've noticed are _thousands_ of these warnings:

objtool: kernel/sched/core.o: preempt_schedule_irq()+0x20: function has unreachable instruction
objtool: kernel/sched/core.o: preempt_schedule_irq()+0x27: function has unreachable instruction
objtool: kernel/sched/core.o: preempt_schedule_irq()+0x2c: function has unreachable instruction
objtool: kernel/sched/core.o: preempt_schedule_irq()+0x33: function has unreachable instruction
objtool: net/ceph/pagevec.o: ceph_put_page_vector()+0x171: function has unreachable instruction
objtool: net/ceph/pagevec.o: ceph_put_page_vector()+0x178: function has unreachable instruction
objtool: net/ceph/pagevec.o: ceph_put_page_vector()+0x17d: function has unreachable instruction
objtool: net/ceph/pagevec.o: ceph_put_page_vector()+0x184: function has unreachable instruction
objtool: net/ceph/pagevec.o: ceph_get_direct_page_vector()+0xe2: function has unreachable instruction
objtool: net/ceph/pagevec.o: ceph_get_direct_page_vector()+0xe9: function has unreachable instruction
objtool: net/ceph/pagevec.o: ceph_get_direct_page_vector()+0xee: function has unreachable instruction
objtool: net/ceph/pagevec.o: ceph_get_direct_page_vector()+0xf5: function has unreachable instruction
objtool: net/ceph/pagevec.o: zero_user_segment()+0x120: function has unreachable instruction
objtool: net/ceph/pagevec.o: zero_user_segment()+0x127: function has unreachable instruction
objtool: net/ceph/pagevec.o: zero_user_segment()+0x12c: function has unreachable instruction
objtool: net/ceph/pagevec.o: zero_user_segment()+0x133: function has unreachable instruction

that's on an x86-64 allyesconfig kernel, with objtool merged to tip:master, using 
GCC 4.9.2:

  gcc version 4.9.2 20150212 (Red Hat 4.9.2-6) (GCC) 

Also, please prefix such warnings with the standard compiler prefix, something 
like this:

	kernel/sched/core.c: warning: objtool: preempt_schedule_irq()+0x20: function has unreachable instruction

so that scripts/tools monitoring new build warnings can pick them up 
automatically?

Thanks,

	Ingo