From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) by kanga.kvack.org (Postfix) with ESMTP id 110096B026A for ; Fri, 12 Oct 2018 13:34:35 -0400 (EDT) Received: by mail-wr1-f71.google.com with SMTP id w17-v6so8364145wrt.0 for ; Fri, 12 Oct 2018 10:34:35 -0700 (PDT) Received: from mail.skyhub.de (mail.skyhub.de. [2a01:4f8:190:11c2::b:1457]) by mx.google.com with ESMTPS id e12-v6si1408671wrq.414.2018.10.12.10.34.33 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 12 Oct 2018 10:34:33 -0700 (PDT) Date: Fri, 12 Oct 2018 19:34:32 +0200 From: Borislav Petkov Subject: Re: [PATCH v6 15/18] ACPI / APEI: Only use queued estatus entry during _in_nmi_notify_one() Message-ID: <20181012173432.GH580@zn.tnic> References: <20180921221705.6478-1-james.morse@arm.com> <20180921221705.6478-16-james.morse@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20180921221705.6478-16-james.morse@arm.com> Sender: owner-linux-mm@kvack.org List-ID: To: James Morse Cc: linux-acpi@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, Marc Zyngier , Christoffer Dall , Will Deacon , Catalin Marinas , Naoya Horiguchi , Rafael Wysocki , Len Brown , Tony Luck , Tyler Baicar , Dongjiu Geng , Xie XiuQi , Punit Agrawal , jonathan.zhang@cavium.com On Fri, Sep 21, 2018 at 11:17:02PM +0100, James Morse wrote: > Each struct ghes has an worst-case sized buffer for storing the > estatus. If an error is being processed by ghes_proc() in process > context this buffer will be in use. If the error source then triggers > an NMI-like notification, the same buffer will be used by > _in_nmi_notify_one() to stage the estatus data, before > __process_error() copys it into a queued estatus entry. > > Merge __process_error()s work into _in_nmi_notify_one() so that > the queued estatus entry is used from the beginning. Use the > ghes_peek_estatus() so we know how much memory to allocate from > the ghes_estatus_pool before we read the records. > > Reported-by: Borislav Petkov > Signed-off-by: James Morse > --- > drivers/acpi/apei/ghes.c | 45 ++++++++++++++++++++-------------------- > 1 file changed, 22 insertions(+), 23 deletions(-) > > diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c > index 055176ed68ac..a0c10b60ad44 100644 > --- a/drivers/acpi/apei/ghes.c > +++ b/drivers/acpi/apei/ghes.c > @@ -722,40 +722,32 @@ static void ghes_print_queued_estatus(void) > } > } > > -/* Save estatus for further processing in IRQ context */ > -static void __process_error(struct ghes *ghes, > - struct acpi_hest_generic_status *ghes_estatus) > +static int _in_nmi_notify_one(struct ghes *ghes, int fixmap_idx) > { > + u64 buf_paddr; > + int sev, rc = 0; > u32 len, node_len; > struct ghes_estatus_node *estatus_node; > struct acpi_hest_generic_status *estatus; Please sort function local variables declaration in a reverse christmas tree order: longest_variable_name; shorter_var_name; even_shorter; i; > > - if (ghes_estatus_cached(ghes_estatus)) > - return; > + rc = ghes_peek_estatus(ghes, fixmap_idx, &buf_paddr, &len); Oh ok, maybe not prefix it with "__" - we're using it somewhere else. > + if (rc) > + return rc; > > - len = cper_estatus_len(ghes_estatus); > node_len = GHES_ESTATUS_NODE_LEN(len); > > estatus_node = (void *)gen_pool_alloc(ghes_estatus_pool, node_len); > if (!estatus_node) > - return; > + return -ENOMEM; > > estatus_node->ghes = ghes; > estatus_node->generic = ghes->generic; > estatus = GHES_ESTATUS_FROM_NODE(estatus_node); > - memcpy(estatus, ghes_estatus, len); > - llist_add(&estatus_node->llnode, &ghes_estatus_llist); > -} > - > -static int _in_nmi_notify_one(struct ghes *ghes, int fixmap_idx) > -{ > - int sev; > - u64 buf_paddr; > - struct acpi_hest_generic_status *estatus = ghes->estatus; > > - if (ghes_read_estatus(ghes, estatus, &buf_paddr, fixmap_idx)) { > + if (__ghes_read_estatus(estatus, buf_paddr, len, fixmap_idx)) { > ghes_clear_estatus(estatus, buf_paddr, fixmap_idx); > - return -ENOENT; > + rc = -ENOENT; > + goto no_work; > } > > sev = ghes_severity(estatus->error_severity); > @@ -764,13 +756,20 @@ static int _in_nmi_notify_one(struct ghes *ghes, int fixmap_idx) > __ghes_panic(ghes, estatus); > } > > - if (!buf_paddr) > - return 0; > - > - __process_error(ghes, estatus); > ghes_clear_estatus(estatus, buf_paddr, fixmap_idx); > > - return 0; > + if (!buf_paddr || ghes_estatus_cached(estatus)) > + goto no_work; > + > + llist_add(&estatus_node->llnode, &ghes_estatus_llist); > + > + return rc; > + > +no_work: > + gen_pool_free(ghes_estatus_pool, (unsigned long)estatus_node, > + node_len); Yeah, let it stick out. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.