From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
live-patching@vger.kernel.org, Michal Marek <mmarek@suse.cz>,
Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Pedro Alves <palves@redhat.com>,
Namhyung Kim <namhyung@gmail.com>,
Bernd Petrovitsch <bernd@petrovitsch.priv.at>,
Chris J Arges <chris.j.arges@canonical.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v11 03/20] x86/stackvalidate: Compile-time stack validation
Date: Fri, 28 Aug 2015 14:54:57 -0500 [thread overview]
Message-ID: <20150828195457.GB27761@treble.redhat.com> (raw)
In-Reply-To: <20150828172622.GO1747@two.firstfloor.org>
On Fri, Aug 28, 2015 at 07:26:23PM +0200, Andi Kleen wrote:
> > > BTW how do handle the increasing number of JITs in the kernel?
> >
> > Yeah, compile-time CFI wouldn't be applicable for code which is
> > generated at runtime. Maybe we will need a mechanism to allow eBPF to
> > quickly create minimal CFI-like metadata corresponding to the JIT code
> > it generates, which can be used by stack dumping code to identify the
> > JIT code and find the previous stack pointer on the stack.
>
> Perhaps I'm missing something, but for the hot patching you need
> some solution for this, as you rely on 100% accuracy. Right?
We'll probably need something like that eventually, once we have an
in-kernel CFI unwinder. Until then, for live patching we would just
need to make sure the JIT generated code honors CONFIG_FRAME_POINTER.
> I guess for now it could be some kind of big reader/writer lock
> for JIT code and reject hot patching if something is active there.
Yeah, maybe. Another easy way to handle it would be to bail if we can't
find the CFI for a given address on a task's stack.
--
Josh
next prev parent reply other threads:[~2015-08-28 19:55 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-24 14:45 [PATCH v11 00/20] Compile-time stack validation Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 01/20] x86/asm: Frame pointer macro cleanup Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 02/20] x86/asm: Add C versions of frame pointer macros Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 03/20] x86/stackvalidate: Compile-time stack validation Josh Poimboeuf
2015-08-26 14:26 ` Andi Kleen
2015-08-27 14:29 ` Josh Poimboeuf
2015-08-28 17:26 ` Andi Kleen
2015-08-28 19:54 ` Josh Poimboeuf [this message]
2015-08-24 14:45 ` [PATCH v11 04/20] x86/stackvalidate: Add file and directory ignores Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 05/20] x86/stackvalidate: Add ignore macros Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 06/20] x86/xen: Add stack frame dependency to hypercall inline asm calls Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 07/20] x86/paravirt: Add stack frame dependency to PVOP " Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 08/20] x86/paravirt: Create a stack frame in PV_CALLEE_SAVE_REGS_THUNK Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 09/20] x86/amd: Set ELF function type for vide() Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 10/20] x86/reboot: Add ljmp instructions to stackvalidate whitelist Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 11/20] x86/xen: Add xen_cpuid() and xen_setup_gdt() to stackvalidate whitelists Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 12/20] x86/asm/crypto: Create stack frames in aesni-intel_asm.S Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 13/20] x86/asm/crypto: Move .Lbswap_mask data to .rodata section Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 14/20] x86/asm/crypto: Move jump_table " Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 15/20] x86/asm/crypto: Create stack frames in clmul_ghash_mul/update() Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 16/20] x86/asm/entry: Create stack frames in thunk functions Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 17/20] x86/asm/acpi: Create a stack frame in do_suspend_lowlevel() Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 18/20] x86/asm: Create stack frames in rwsem functions Josh Poimboeuf
2015-08-24 14:45 ` [PATCH v11 19/20] x86/asm/efi: Create a stack frame in efi_call() Josh Poimboeuf
2015-08-24 14:46 ` [PATCH v11 20/20] x86/asm/power: Create stack frames in hibernate_asm_64.S Josh Poimboeuf
2015-08-25 8:05 ` [PATCH v11 00/20] Compile-time stack validation Ingo Molnar
2015-08-25 15:25 ` Josh Poimboeuf
2015-08-26 7:07 ` Ingo Molnar
2015-08-26 8:44 ` Jiri Kosina
2015-08-27 13:11 ` Josh Poimboeuf
2015-08-28 8:21 ` Ingo Molnar
2015-08-28 13:54 ` Josh Poimboeuf
2015-09-14 13:19 ` Ingo Molnar
2015-09-14 14:10 ` Josh Poimboeuf
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