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Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1htSq9-0000Ry-FM; Fri, 02 Aug 2019 08:23:05 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1htSq6-0000RS-AA for linux-arm-kernel@lists.infradead.org; Fri, 02 Aug 2019 08:23:03 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E8E17337; Fri, 2 Aug 2019 01:22:59 -0700 (PDT) Received: from localhost (unknown [10.37.6.20]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 688A43F575; Fri, 2 Aug 2019 01:22:59 -0700 (PDT) Date: Fri, 2 Aug 2019 09:22:57 +0100 From: Andrew Murray To: Peter Zijlstra Subject: Re: [PATCH v2 1/5] jump_label: Don't warn on __exit jump entries Message-ID: <20190802082257.GN56241@e119886-lin.cambridge.arm.com> References: <20190731161256.22210-1-andrew.murray@arm.com> <20190731161256.22210-2-andrew.murray@arm.com> <20190731164156.GX31398@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190731164156.GX31398@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1+81 (426a6c1) (2018-08-26) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190802_012302_399468_362D498E X-CRM114-Status: GOOD ( 21.30 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Catalin Marinas , Boqun Feng , Will Deacon , Ard.Biesheuvel@arm.com, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jul 31, 2019 at 06:41:56PM +0200, Peter Zijlstra wrote: > On Wed, Jul 31, 2019 at 05:12:52PM +0100, Andrew Murray wrote: > > On architectures that discard .exit.* sections at runtime, a > > warning is printed for each jump label that is used within an > > in-kernel __exit annotated function: > > > > can't patch jump_label at ehci_hcd_cleanup+0x8/0x3c > > WARNING: CPU: 0 PID: 1 at kernel/jump_label.c:410 __jump_label_update+0x12c/0x138 > > > > As these functions will never get executed (they are free'd along > > with the rest of initmem) - we do not need to patch them and should > > not display any warnings. > > > > The warning is displayed because the test required to satisfy > > jump_entry_is_init is based on init_section_contains (__init_begin to > > __init_end) whereas the test in __jump_label_update is based on > > init_kernel_text (_sinittext to _einittext) via kernel_text_address). > > > > In addition to fixing this, we also remove an out-of-date comment > > and use a WARN instead of a WARN_ONCE. > > > > Fixes: 19483677684b ("jump_label: Annotate entries that operate on __init code earlier") > > Signed-off-by: Andrew Murray > > --- > > kernel/jump_label.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/kernel/jump_label.c b/kernel/jump_label.c > > index df3008419a1d..c984078a5c28 100644 > > --- a/kernel/jump_label.c > > +++ b/kernel/jump_label.c > > @@ -407,7 +407,9 @@ static bool jump_label_can_update(struct jump_entry *entry, bool init) > > return false; > > > > if (!kernel_text_address(jump_entry_code(entry))) { > > - WARN_ONCE(1, "can't patch jump_label at %pS", (void *)jump_entry_code(entry)); > > + if (!jump_entry_is_init(entry)) > > + WARN_ONCE(1, "can't patch jump_label at %pS", > > + (void *)jump_entry_code(entry)); > > It seems to me we can writes that as: > > WARN_ONCE(!jump_entry_is_init(entry), > "can't patch jump_label at %pS", > (void *)jump_entry_code(entry)); > > > return false; > > } > > Other than that, > > Acked-by: Peter Zijlstra (Intel) Ah of course! I'll make this change on my respin and add your ack. Thanks. Thanks, Andrew Murray _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel