From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DAA14D206AC for ; Thu, 4 Dec 2025 14:22:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: References:In-Reply-To:Subject:Cc:To:From:Message-ID:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=b+la2Ls6xihgxzAduBENntpsex19eBi3G4VVpf0iliU=; b=y8pP0SmqOuH/dKZQ5UrXow1M2Z DwlSnvOJk8uTDpNktwUZO74hVFnTXCHa3L9uloYRv97aj6/bE086Hx5ATaichhaoYnJWzPjQu3PFm sE2FW4K3yvvko08jVd69mnz0HbNS6RvtkVVGWn/RBmlSSAggPTR+3XQzMacHpsySamGZyag7y7Mw2 ba5JNn0Zwh9QFo5/0UR4orQiXkJQa2l3IG7SJxc1PhHB/ZytZ7wqJSvddZxAJuNnJKk7w9tdHMffT BSggxLPeT+xZZT99/vCLG/kxLcmyTx9/VaylCNcSRZPu/KuxB4gjcFQTkB0OWGYvM4IguYLbGJ2ru p4ZUOeGQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vRADV-00000008723-2UYv; Thu, 04 Dec 2025 14:21:57 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vRADU-0000000871u-1hOR for linux-arm-kernel@lists.infradead.org; Thu, 04 Dec 2025 14:21:56 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 299E8601E7; Thu, 4 Dec 2025 14:21:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5353C4CEFB; Thu, 4 Dec 2025 14:21:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764858114; bh=Ix4HAjzi2WlFfbJt7VTMxHQfAkw4id96Xxu6hbqhPmA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Y+bDJ+oBSuytrRGrA1/IeWKGjwOp/ZGF7vweh2xg2gWzgCyssqRjWsrI41ZAUass8 0ZyjkEcxeEDfLkb8i3ZjzGBGRr1z3eCHdOmLi9qeeF4uh3KuI6kGjS6flpdv+sWhCE x058GGYzauOameSVw86ITd5aIngE+grBP6RBIUiwkDvmf/t8T/YdwyhIgZmMugFbs0 9+dyM2PjIsQ+yA6mhL+qjZoDlOHQD1xyKRBzJWAXo/3GaeyKLE0ftRUOIbQH6kHaxM rTVM7WMh1EvKMT20Ynl+pQ/dSXo9mj5YJunSM/lfEAdsFwT5rzaCSywiOvSp6AaBBD c35yjxCXPdknA== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1vRADQ-0000000AT9t-1T1w; Thu, 04 Dec 2025 14:21:52 +0000 Date: Thu, 04 Dec 2025 14:21:51 +0000 Message-ID: <867bv2pbsw.wl-maz@kernel.org> From: Marc Zyngier To: Daniel Thompson Cc: Thomas Bogendoerfer , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, Thomas Gleixner , Mark Rutland , Will Deacon , "Rafael J. Wysocki" , Rob Herring , Saravana Kannan , Greg Kroah-Hartman , Sven Peter , Janne Grunau , Suzuki K Poulose , James Clark , Jonathan Cameron , Jinjie Ruan , Alexandru Elisei , linux-mips@vger.kernel.org Subject: Re: [PATCH v4 16/26] genirq: Allow per-cpu interrupt sharing for non-overlapping affinities In-Reply-To: References: <20251020122944.3074811-1-maz@kernel.org> <20251020122944.3074811-17-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: danielt@kernel.org, tsbogend@alpha.franken.de, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, tglx@linutronix.de, mark.rutland@arm.com, will@kernel.org, rafael@kernel.org, robh@kernel.org, saravanak@google.com, gregkh@linuxfoundation.org, sven@kernel.org, j@jannau.net, suzuki.poulose@arm.com, james.clark@linaro.org, jonathan.cameron@huawei.com, ruanjinjie@huawei.com, alexandru.elisei@arm.com, linux-mips@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, 04 Dec 2025 10:56:13 +0000, Daniel Thompson wrote: > > On Mon, Oct 20, 2025 at 01:29:33PM +0100, Marc Zyngier wrote: > > Interrupt sharing for percpu-devid interrupts is forbidden, and > > for good reasons. These are interrupts generated *from* a CPU and > > handled by itself (timer, for example). Nobody in their right mind > > would put two devices on the same pin (and if they have, they get to > > keep the pieces...). > > > > But this also prevents more benign cases, where devices are connected > > to groups of CPUs, and for which the affinities are not overlapping. > > Effectively, the only thing they share is the interrupt number, and > > nothing else. > > > > Let's tweak the definition of IRQF_SHARED applied to percpu_devid > > interrupts to allow this particular case. This results in extra > > validation at the point of the interrupt being setup and freed, > > as well as a tiny bit of extra complexity for interrupts at handling > > time (to pick the correct irqaction). > > > > Tested-by: Will Deacon > > Signed-off-by: Marc Zyngier > > I picked up this patch via linux-next and it appears be causing boot > regressions on MIPS/qemu. This patch was identified with a bisect and > a git revert of this patch from the linux-next tip resolves the problem > (specifically, next-20251204 with git revert bdf4e2ac295f). > > I'm running the code as part of the kgdb test suite but the system > doesn't survive long enough for kgdb to be involved. In fact I was able > to reduce things to the following reproduction with all the kgdb pieces > removed: > > make malta_kvm_defconfig generic/64r6.config > ../scripts/config \ > --enable WERROR --enable CPU_MIPS64_R6 --enable MIPS_CPS \ > --enable BLK_DEV_INITRD --set-val FRAME_WARN 2048 > make olddefconfig > make -j$(nproc) all > qemu-system-mips64el -cpu I6400 -M malta -m 1G -smp 2 \ > -kernel vmlinux -nographic \ > -append " console=ttyS0,115200 clk_ignore_unused" Many thanks for the minimal reproducer, that really helped a lot! [...] > CPU 0 Unable to handle kernel paging request at virtual address 0000000000000000, epc == ffffffff801c2398, ra == ffffffff801bab00 > Oops[#1]: > CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.18.0-next-20251204 #20 NONE > Hardware name: mti,malta > $ 0 : 0000000000000000 0000000000000001 0000000000000000 0000000000000000 > $ 4 : 0000000000000001 a8000000020e8008 0000000000000000 ffffffff80c23b80 > $ 8 : 0000000000000004 0000000000000000 0000000000000000 000000000000002f > $12 : a8000000020f4000 0000000000003ff0 0000000000003000 0000000000000003 > $16 : ffffffff80d095c0 ffffffff80ceb410 0000000000000019 ffffffff80c378c0 > $20 : ffffffff80c4bec8 0000000000000000 ffffffff80e00000 ffffffff80de0000 > $24 : 0000000000000000 0000000000000010 > $28 : ffffffff80c20000 a8000000020f7ec0 a800000000e12fcd ffffffff801bab00 > epc : ffffffff801c2398 handle_percpu_devid_irq+0xb8/0x250 > ra : ffffffff801bab00 handle_irq_desc+0x48/0x88 > Status: 1400a4e2 KX SX UX KERNEL EXL > Cause : 00800408 (ExcCode 02) > BadVA : 0000000000000000 > PrId : 0001a900 (MIPS I6400) > Modules linked in: > Process swapper/0 (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____), tls=0000000000000000) > Stack : ffffffff80c35a2c 0000000000000002 ffffffff80e00000 0fffffffffffffff > ffffffff80c50000 0000000000000001 0000000000000003 ffffffff801bab00 > 0000000000000000 ffffffff805d82a8 0000000000000000 0000000000000008 > 0000000000000000 0000000000000000 0000000000000000 5189d95a7a4f4800 > a800000002014300 0000000000000002 0000000000000001 000000000000001f > ffffffff80e00000 0000000000000004 0000000000000000 ffffffff801bab00 > 0000000000000000 ffffffff809ec128 0000000000000001 fffffffffffffffb > 0000000000000001 ffffffff805d7ebc 0000000000000000 0000000000000000 > ffffffff80c23c80 ffffffff80c50000 ffffffff80de0000 ffffffff80db0000 > 0000000000000000 ffffffff80112f10 ffffffff80c23c80 0000000000000000 > Call Trace: > [] handle_percpu_devid_irq+0xb8/0x250 > [] handle_irq_desc+0x48/0x88 > [] gic_irq_dispatch+0xc0/0x288 > [] handle_irq_desc+0x48/0x88 > [] do_domain_IRQ+0x28/0x40 > [] plat_irq_dispatch+0x64/0xe8 > [] handle_int+0x134/0x140 > [] calibrate_delay+0x158/0x290 > [] start_kernel+0x754/0x7a4 This hack fixes it for me, but really, mips needs to grow up and stop using these antiquated APIs. Can please you give it a go? Thanks, M. diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 0bb29316b4362..8b1b4c8a4f54c 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -2470,6 +2470,9 @@ int setup_percpu_irq(unsigned int irq, struct irqaction *act) if (retval < 0) return retval; + if (!act->affinity) + act->affinity = cpu_online_mask; + retval = __setup_irq(irq, desc, act); if (retval) -- Without deviation from the norm, progress is not possible.