From nobody Tue Apr 7 17:40:38 2026 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 711B2C433FE for ; Tue, 18 Oct 2022 13:05:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229911AbiJRNFs (ORCPT ); Tue, 18 Oct 2022 09:05:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229680AbiJRNFq (ORCPT ); Tue, 18 Oct 2022 09:05:46 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 14FD2C5895 for ; Tue, 18 Oct 2022 06:05:42 -0700 (PDT) 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 3CF1A113E; Tue, 18 Oct 2022 06:05:48 -0700 (PDT) Received: from pierre123.arm.com (pierre123.nice.arm.com [10.34.100.128]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D5CE53F792; Tue, 18 Oct 2022 06:05:39 -0700 (PDT) From: Pierre Gondois To: linux-kernel@vger.kernel.org Cc: Pierre Gondois , James Morse , Will Deacon , Huacai Chen , John Garry , Shaokun Zhang , WANG Xuerui , Qi Liu , Bharat Bhushan , Huang Ying , Bibo Mao , "Jason A. Donenfeld" , Daniel Lezcano , linux-arm-kernel@lists.infradead.org Subject: [PATCH v2] firmware: arm_sdei: Fix sleep from invalid context BUG Date: Tue, 18 Oct 2022 15:04:53 +0200 Message-Id: <20221018130456.1356081-1-pierre.gondois@arm.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" On an Ampere Altra, Running a preemp_rt kernel based on v5.19-rc3-rt5 on an Ampere Altra triggers: [ 15.683141] BUG: sleeping function called from invalid context at kernel= /locking/spinlock_rt.c:46 [ 15.683154] in_atomic(): 0, irqs_disabled(): 128, non_block: 0, pid: 24,= name: cpuhp/0 [ 15.683157] preempt_count: 0, expected: 0 [ 15.683159] RCU nest depth: 0, expected: 0 [ 15.683163] 3 locks held by cpuhp/0/24: [ 15.683167] #0: ffffda30217c70d0 (cpu_hotplug_lock){++++}-{0:0}, at: cp= uhp_thread_fun+0x5c/0x248 [ 15.683201] #1: ffffda30217c7120 (cpuhp_state-up){+.+.}-{0:0}, at: cpuh= p_thread_fun+0x5c/0x248 [ 15.683205] #2: ffffda3021c711f0 (sdei_list_lock){....}-{3:3}, at: sdei= _cpuhp_up+0x3c/0x130 [ 15.683224] irq event stamp: 36 [ 15.683226] hardirqs last enabled at (35): [] finish_= task_switch+0xb4/0x2b0 [ 15.683236] hardirqs last disabled at (36): [] cpuhp_t= hread_fun+0x21c/0x248 [ 15.683238] softirqs last enabled at (0): [] copy_pro= cess+0x63c/0x1ac0 [ 15.683245] softirqs last disabled at (0): [<0000000000000000>] 0x0 [ 15.683258] CPU: 0 PID: 24 Comm: cpuhp/0 Not tainted 5.19.0-rc3-rt5-[...] [ 15.683265] Hardware name: WIWYNN Mt.Jade Server System B81.03001.0005/M= t.Jade Motherboard, BIOS 1.08.20220218 (SCP: 1.08.20220218) 2022/02/18 [ 15.683268] Call trace: [ 15.683271] dump_backtrace+0x114/0x120 [ 15.683277] show_stack+0x20/0x70 [ 15.683279] dump_stack_lvl+0x9c/0xd8 [ 15.683288] dump_stack+0x18/0x34 [ 15.683289] __might_resched+0x188/0x228 [ 15.683292] rt_spin_lock+0x70/0x120 [ 15.683301] sdei_cpuhp_up+0x3c/0x130 [ 15.683303] cpuhp_invoke_callback+0x250/0xf08 [ 15.683305] cpuhp_thread_fun+0x120/0x248 [ 15.683308] smpboot_thread_fn+0x280/0x320 [ 15.683315] kthread+0x130/0x140 [ 15.683321] ret_from_fork+0x10/0x20 sdei_cpuhp_up() is called in the STARTING hotplug section, which runs whith interrupts disabled. Move CPUHP_AP_ARM_SDEI_ state to the _ONLINE section to execute the cpuhp cb with preemption enabled. Some SDEI calls (e.g. SDEI_1_0_FN_SDEI_PE_MASK) take actions on the calling CPU. It is checked that preemption is disabled for them. _ONLINE cpuhp cb are executed in the 'per CPU hotplug thread'. Preemption is enabled in those threads, but their cpumask is limited to 1 CPU. Move 'WARN_ON_ONCE(preemptible())' statements so that SDEI cpuhp cb don't trigger them. This means that no check will be done for some cases, e.g. sdei_mask_local_cpu() invocations. Also add a check for the SDEI_1_0_FN_SDEI_PRIVATE_RESET SDEI call which acts on the calling CPU. Suggested-by: James Morse Signed-off-by: Pierre Gondois Reviewed-by: James Morse --- drivers/firmware/arm_sdei.c | 28 ++++++++++++++-------------- include/linux/cpuhotplug.h | 2 +- 2 files changed, 15 insertions(+), 15 deletions(-) diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c index 1e1a51510e83..9b03e164a37a 100644 --- a/drivers/firmware/arm_sdei.c +++ b/drivers/firmware/arm_sdei.c @@ -301,8 +301,6 @@ int sdei_mask_local_cpu(void) { int err; =20 - WARN_ON_ONCE(preemptible()); - err =3D invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_MASK, 0, 0, 0, 0, 0, NULL); if (err && err !=3D -EIO) { pr_warn_once("failed to mask CPU[%u]: %d\n", @@ -315,6 +313,7 @@ int sdei_mask_local_cpu(void) =20 static void _ipi_mask_cpu(void *ignored) { + WARN_ON_ONCE(preemptible()); sdei_mask_local_cpu(); } =20 @@ -322,8 +321,6 @@ int sdei_unmask_local_cpu(void) { int err; =20 - WARN_ON_ONCE(preemptible()); - err =3D invoke_sdei_fn(SDEI_1_0_FN_SDEI_PE_UNMASK, 0, 0, 0, 0, 0, NULL); if (err && err !=3D -EIO) { pr_warn_once("failed to unmask CPU[%u]: %d\n", @@ -336,6 +333,7 @@ int sdei_unmask_local_cpu(void) =20 static void _ipi_unmask_cpu(void *ignored) { + WARN_ON_ONCE(preemptible()); sdei_unmask_local_cpu(); } =20 @@ -343,6 +341,8 @@ static void _ipi_private_reset(void *ignored) { int err; =20 + WARN_ON_ONCE(preemptible()); + err =3D invoke_sdei_fn(SDEI_1_0_FN_SDEI_PRIVATE_RESET, 0, 0, 0, 0, 0, NULL); if (err && err !=3D -EIO) @@ -389,8 +389,6 @@ static void _local_event_enable(void *data) int err; struct sdei_crosscall_args *arg =3D data; =20 - WARN_ON_ONCE(preemptible()); - err =3D sdei_api_event_enable(arg->event->event_num); =20 sdei_cross_call_return(arg, err); @@ -401,6 +399,8 @@ int sdei_event_enable(u32 event_num) int err =3D -EINVAL; struct sdei_event *event; =20 + WARN_ON_ONCE(preemptible()); + mutex_lock(&sdei_events_lock); event =3D sdei_event_find(event_num); if (!event) { @@ -479,8 +479,6 @@ static void _local_event_unregister(void *data) int err; struct sdei_crosscall_args *arg =3D data; =20 - WARN_ON_ONCE(preemptible()); - err =3D sdei_api_event_unregister(arg->event->event_num); =20 sdei_cross_call_return(arg, err); @@ -492,6 +490,7 @@ int sdei_event_unregister(u32 event_num) struct sdei_event *event; =20 WARN_ON(in_nmi()); + WARN_ON_ONCE(preemptible()); =20 mutex_lock(&sdei_events_lock); event =3D sdei_event_find(event_num); @@ -561,8 +560,6 @@ static void _local_event_register(void *data) struct sdei_registered_event *reg; struct sdei_crosscall_args *arg =3D data; =20 - WARN_ON(preemptible()); - reg =3D per_cpu_ptr(arg->event->private_registered, smp_processor_id()); err =3D sdei_api_event_register(arg->event->event_num, sdei_entry_point, reg, 0, 0); @@ -576,6 +573,7 @@ int sdei_event_register(u32 event_num, sdei_event_callb= ack *cb, void *arg) struct sdei_event *event; =20 WARN_ON(in_nmi()); + WARN_ON_ONCE(preemptible()); =20 mutex_lock(&sdei_events_lock); if (sdei_event_find(event_num)) { @@ -717,6 +715,8 @@ static int sdei_pm_notifier(struct notifier_block *nb, = unsigned long action, { int rv; =20 + WARN_ON_ONCE(preemptible()); + switch (action) { case CPU_PM_ENTER: rv =3D sdei_mask_local_cpu(); @@ -765,7 +765,7 @@ static int sdei_device_freeze(struct device *dev) int err; =20 /* unregister private events */ - cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING); + cpuhp_remove_state(CPUHP_AP_ARM_SDEI_ONLINE); =20 err =3D sdei_unregister_shared(); if (err) @@ -786,7 +786,7 @@ static int sdei_device_thaw(struct device *dev) return err; } =20 - err =3D cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI", + err =3D cpuhp_setup_state(CPUHP_AP_ARM_SDEI_ONLINE, "SDEI", &sdei_cpuhp_up, &sdei_cpuhp_down); if (err) pr_warn("Failed to re-register CPU hotplug notifier...\n"); @@ -823,7 +823,7 @@ static int sdei_reboot_notifier(struct notifier_block *= nb, unsigned long action, * We are going to reset the interface, after this there is no point * doing work when we take CPUs offline. */ - cpuhp_remove_state(CPUHP_AP_ARM_SDEI_STARTING); + cpuhp_remove_state(CPUHP_AP_ARM_SDEI_ONLINE); =20 sdei_platform_reset(); =20 @@ -1003,7 +1003,7 @@ static int sdei_probe(struct platform_device *pdev) goto remove_cpupm; } =20 - err =3D cpuhp_setup_state(CPUHP_AP_ARM_SDEI_STARTING, "SDEI", + err =3D cpuhp_setup_state(CPUHP_AP_ARM_SDEI_ONLINE, "SDEI", &sdei_cpuhp_up, &sdei_cpuhp_down); if (err) { pr_warn("Failed to register CPU hotplug notifier...\n"); diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index f61447913db9..63b89e00a4c3 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -161,7 +161,6 @@ enum cpuhp_state { CPUHP_AP_PERF_X86_CSTATE_STARTING, CPUHP_AP_PERF_XTENSA_STARTING, CPUHP_AP_MIPS_OP_LOONGSON3_STARTING, - CPUHP_AP_ARM_SDEI_STARTING, CPUHP_AP_ARM_VFP_STARTING, CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING, CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING, @@ -209,6 +208,7 @@ enum cpuhp_state { CPUHP_AP_IRQ_AFFINITY_ONLINE, CPUHP_AP_BLK_MQ_ONLINE, CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS, + CPUHP_AP_ARM_SDEI_ONLINE, CPUHP_AP_X86_INTEL_EPB_ONLINE, CPUHP_AP_PERF_ONLINE, CPUHP_AP_PERF_X86_ONLINE, --=20 2.25.1