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From: Borislav Petkov <bp@alien8.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Masami Hiramatsu <mhiramat@kernel.org>, X86 ML <x86@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1 06/19] perf/x86/intel/ds: Check insn_get_length() retval
Date: Tue, 19 Jan 2021 11:40:07 +0100	[thread overview]
Message-ID: <20210119104007.GE27433@zn.tnic> (raw)
In-Reply-To: <20210104131919.GN3021@hirez.programming.kicks-ass.net>

On Mon, Jan 04, 2021 at 02:19:19PM +0100, Peter Zijlstra wrote:
> Do we really still need the !insn.length? That is, it *should* be
> impossible to not fail insn_get_length() and still have a 0 length,
> seeing how x86 doesn't have 0 length instructions.

I was responding to the "doubly important" thing in the comment scarying
me about an infinite loop and thus left the length check in, in case
the insn decoder would have a bug and return success but still have
insn.length 0.

With the length check the endless loop won't happen but let's be
brave here ... :-)

So removed.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2021-01-19 10:57 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-23 17:42 [PATCH v1 00/19] x86/insn: Add an insn_decode() API Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 01/19] x86/insn: Rename insn_decode() to insn_decode_regs() Borislav Petkov
2020-12-28 17:16   ` Sean Christopherson
2020-12-29 19:36     ` Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 02/19] x86/insn: Add @buf_len param to insn_init() kernel-doc comment Borislav Petkov
2020-12-28  1:44   ` Masami Hiramatsu
2020-12-23 17:42 ` [PATCH v1 03/19] x86/insn: Add an insn_decode() API Borislav Petkov
2020-12-28  1:15   ` Masami Hiramatsu
2020-12-29 20:06     ` Borislav Petkov
2020-12-30  9:00       ` Masami Hiramatsu
2020-12-30  9:28         ` Borislav Petkov
2021-01-06  5:21           ` Masami Hiramatsu
2021-01-08 18:59             ` Borislav Petkov
2021-01-12 11:34               ` Masami Hiramatsu
2021-01-13 18:06                 ` Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 04/19] x86/insn-eval: Handle return values from the decoder Borislav Petkov
2020-12-28 18:51   ` Sean Christopherson
2020-12-28 19:06     ` Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 05/19] x86/boot/compressed/sev-es: Convert to insn_decode() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 06/19] perf/x86/intel/ds: Check insn_get_length() retval Borislav Petkov
2021-01-04 13:19   ` Peter Zijlstra
2021-01-19 10:40     ` Borislav Petkov [this message]
2020-12-23 17:42 ` [PATCH v1 07/19] perf/x86/intel/ds: Check return values of insn decoder functions Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 08/19] x86/alternative: Use insn_decode() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 09/19] x86/mce: Convert to insn_decode() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 10/19] x86/kprobes: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 11/19] x86/sev-es: " Borislav Petkov
2020-12-25 10:50   ` kernel test robot
2020-12-25 12:33     ` Borislav Petkov
2020-12-28 19:15       ` Sean Christopherson
2021-01-21 16:58         ` Borislav Petkov
2021-01-21 22:35           ` Sean Christopherson
2020-12-23 17:42 ` [PATCH v1 12/19] x86/traps: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 13/19] x86/uprobes: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 14/19] x86/tools/insn_decoder_test: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 15/19] tools/objtool: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 16/19] x86/tools/insn_sanity: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 17/19] tools/perf: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 18/19] x86/insn: Remove kernel_insn_init() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 19/19] x86/insn: Make insn_complete() static Borislav Petkov
2020-12-27 15:26 ` [PATCH v1 00/19] x86/insn: Add an insn_decode() API Tom Lendacky
2021-02-03 12:00   ` Borislav Petkov

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