From: Peter Zijlstra <peterz@infradead.org>
To: Borislav Petkov <bp@alien8.de>
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: Mon, 4 Jan 2021 14:19:19 +0100 [thread overview]
Message-ID: <20210104131919.GN3021@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20201223174233.28638-7-bp@alien8.de>
On Wed, Dec 23, 2020 at 06:42:20PM +0100, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
>
> intel_pmu_pebs_fixup_ip() needs only the insn length so use the
> appropriate helper instead of a full decode. A full decode differs only
> in running insn_complete() on the decoded insn but that is not needed
> here.
>
> Signed-off-by: Borislav Petkov <bp@suse.de>
> ---
> arch/x86/events/intel/ds.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c
> index 67dbc91bccfe..3786b4e07078 100644
> --- a/arch/x86/events/intel/ds.c
> +++ b/arch/x86/events/intel/ds.c
> @@ -1265,14 +1265,14 @@ static int intel_pmu_pebs_fixup_ip(struct pt_regs *regs)
> is_64bit = kernel_ip(to) || any_64bit_mode(regs);
> #endif
> insn_init(&insn, kaddr, size, is_64bit);
> - insn_get_length(&insn);
> +
> /*
> * Make sure there was not a problem decoding the
> * instruction and getting the length. This is
> * doubly important because we have an infinite
> * loop if insn.length=0.
> */
> - if (!insn.length)
> + if (insn_get_length(&insn) || !insn.length)
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.
next prev parent reply other threads:[~2021-01-04 13:21 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 [this message]
2021-01-19 10:40 ` Borislav Petkov
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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