From: Nadav Amit <namit@vmware.com> To: Borislav Petkov <bp@alien8.de> Cc: Peter Zijlstra <peterz@infradead.org>, Rick Edgecombe <rick.p.edgecombe@intel.com>, Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>, LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>, Dave Hansen <dave.hansen@linux.intel.com>, Damian Tometzki <linux_dti@icloud.com>, linux-integrity <linux-integrity@vger.kernel.org>, LSM List <linux-security-module@vger.kernel.org>, Andrew Morton <akpm@linux-foundation.org>, Kernel Hardening <kernel-hardening@lists.openwall.com>, Linux-MM <linux-mm@kvack.org>, Will Deacon <will.deacon@arm.com>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, Kristen Carlson Accardi <kristen@linux.intel.com>, "Dock, Deneen T" <deneen.t.dock@intel.com>, Kees Cook <keescook@chromium.org>, Dave Hansen <dave.hansen@intel.com>, Masami Hiramatsu <mhiramat@kernel.org> Subject: Re: [PATCH v2 06/20] x86/alternative: use temporary mm for text poking Date: Tue, 5 Feb 2019 17:54:56 +0000 Message-ID: <6D321F51-6B19-46F6-91AC-74248A542BA0@vmware.com> (raw) In-Reply-To: <20190205123533.GN21801@zn.tnic> > On Feb 5, 2019, at 4:35 AM, Borislav Petkov <bp@alien8.de> wrote: > > On Tue, Feb 05, 2019 at 12:31:46PM +0100, Peter Zijlstra wrote: >> ... >> >> So while in general I agree with BUG_ON() being undesirable, I think >> liberal sprinking in text_poke() is fine; you really _REALLY_ want this >> to work or fail loudly. Text corruption is just painful. > > Ok. It would be good to have the gist of this sentiment in a comment > above it so that it is absolutely clear why we're doing it. I added a short comment for v3 above each BUG_ON(). > And since text_poke() can't fail, then it doesn't need a retval too. > AFAICT, nothing is actually using it. As Peter said, this is addressed in a separate patch (one patch per logical change).
next prev parent reply index Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-29 0:34 [PATCH v2 00/20] Merge text_poke fixes and executable lockdowns Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 01/20] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()" Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 02/20] x86/jump_label: Use text_poke_early() during early init Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 03/20] x86/mm: temporary mm struct Rick Edgecombe 2019-01-31 11:29 ` Borislav Petkov 2019-01-31 22:19 ` Nadav Amit 2019-02-01 0:08 ` Borislav Petkov 2019-02-01 0:25 ` Nadav Amit 2019-02-04 14:28 ` Borislav Petkov 2019-01-29 0:34 ` [PATCH v2 04/20] fork: provide a function for copying init_mm Rick Edgecombe 2019-02-05 8:53 ` Borislav Petkov 2019-02-05 9:03 ` Nadav Amit 2019-01-29 0:34 ` [PATCH v2 05/20] x86/alternative: initializing temporary mm for patching Rick Edgecombe 2019-02-05 9:18 ` Borislav Petkov 2019-02-11 0:39 ` Nadav Amit 2019-02-11 5:18 ` Andy Lutomirski 2019-02-11 18:04 ` Nadav Amit 2019-02-11 19:07 ` Andy Lutomirski 2019-02-11 19:18 ` Nadav Amit 2019-02-11 22:47 ` Andy Lutomirski 2019-02-12 18:23 ` Nadav Amit 2019-01-29 0:34 ` [PATCH v2 06/20] x86/alternative: use temporary mm for text poking Rick Edgecombe 2019-02-05 9:58 ` Borislav Petkov 2019-02-05 11:31 ` Peter Zijlstra 2019-02-05 12:35 ` Borislav Petkov 2019-02-05 13:25 ` Peter Zijlstra 2019-02-05 17:54 ` Nadav Amit [this message] 2019-02-05 13:29 ` Peter Zijlstra 2019-01-29 0:34 ` [PATCH v2 07/20] x86/kgdb: avoid redundant comparison of patched code Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 08/20] x86/ftrace: set trampoline pages as executable Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 09/20] x86/kprobes: instruction pages initialization enhancements Rick Edgecombe 2019-02-11 18:22 ` Borislav Petkov 2019-02-11 19:36 ` Nadav Amit 2019-01-29 0:34 ` [PATCH v2 10/20] x86: avoid W^X being broken during modules loading Rick Edgecombe 2019-02-11 18:29 ` Borislav Petkov 2019-02-11 18:45 ` Nadav Amit 2019-02-11 19:01 ` Borislav Petkov 2019-02-11 19:09 ` Nadav Amit 2019-02-11 19:10 ` Borislav Petkov 2019-02-11 19:27 ` Nadav Amit 2019-02-11 19:42 ` Borislav Petkov 2019-02-11 20:32 ` Nadav Amit 2019-03-07 15:10 ` [PATCH] x86/cpufeature: Remove __pure attribute to _static_cpu_has() Borislav Petkov 2019-03-07 16:43 ` hpa 2019-03-07 17:02 ` Borislav Petkov 2019-03-07 7:29 ` [PATCH v2 10/20] x86: avoid W^X being broken during modules loading Borislav Petkov 2019-03-07 16:53 ` hpa 2019-03-07 17:06 ` Borislav Petkov 2019-03-07 20:02 ` Andy Lutomirski 2019-03-07 20:25 ` Borislav Petkov 2019-01-29 0:34 ` [PATCH v2 11/20] x86/jump-label: remove support for custom poker Rick Edgecombe 2019-02-11 18:37 ` Borislav Petkov 2019-01-29 0:34 ` [PATCH v2 12/20] x86/alternative: Remove the return value of text_poke_*() Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 13/20] Add set_alias_ function and x86 implementation Rick Edgecombe 2019-02-11 19:09 ` Borislav Petkov 2019-02-11 19:27 ` Edgecombe, Rick P 2019-02-11 22:59 ` Andy Lutomirski 2019-02-12 0:01 ` Edgecombe, Rick P 2019-01-29 0:34 ` [PATCH v2 14/20] mm: Make hibernate handle unmapped pages Rick Edgecombe 2019-02-19 11:04 ` Borislav Petkov 2019-02-19 21:28 ` Edgecombe, Rick P 2019-02-20 16:07 ` Borislav Petkov 2019-01-29 0:34 ` [PATCH v2 15/20] vmalloc: New flags for safe vfree on special perms Rick Edgecombe 2019-02-19 12:48 ` Borislav Petkov 2019-02-19 19:42 ` Edgecombe, Rick P 2019-02-20 16:14 ` Borislav Petkov 2019-01-29 0:34 ` [PATCH v2 16/20] modules: Use vmalloc special flag Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 17/20] bpf: " Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 18/20] x86/ftrace: " Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 19/20] x86/kprobes: " Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 20/20] x86/alternative: comment about module removal races Rick Edgecombe
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