From patchwork Mon Sep 16 23:00:08 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lyude Paul X-Patchwork-Id: 13805825 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 3C8A8C3ABCB for ; Mon, 16 Sep 2024 23:01:23 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9AAA110E12D; Mon, 16 Sep 2024 23:01:22 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="WW5Ldddi"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 50FEC10E12D for ; Mon, 16 Sep 2024 23:01:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1726527679; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=ReiFZDGjB1DBMuTATaZPvvJ9MFBiEJPVKpn5i9s1uXw=; b=WW5Ldddip6Pj1ocbO5qfKiwUQjZ4mR/uqS9ce8Fx4hIkhWDnDr+gv28vufDmJvKIXbPu2M 8Ye4NWMb3JfgNxzEZEapOuUeUGpJsyhMDrSzwN7F7FjZOr1LADFp2uVfmxBxIIPfczCGiG oob9g2cb/5nEx80RDGzadQF6kKysZ9I= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-14-QgC0bBcIPpaEtXhzXCm05A-1; Mon, 16 Sep 2024 19:01:15 -0400 X-MC-Unique: QgC0bBcIPpaEtXhzXCm05A-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9E8A91955F43; Mon, 16 Sep 2024 23:01:13 +0000 (UTC) Received: from chopper.redhat.com (unknown [10.22.33.131]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 0865C1956086; Mon, 16 Sep 2024 23:01:10 +0000 (UTC) From: Lyude Paul To: dri-devel@lists.freedesktop.org Cc: Daniel Vetter , stable@vger.kernel.org, Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Jocelyn Falempe , linux-kernel@vger.kernel.org (open list) Subject: [PATCH v2] drm/panic: Fix uninitialized spinlock acquisition with CONFIG_DRM_PANIC=n Date: Mon, 16 Sep 2024 19:00:08 -0400 Message-ID: <20240916230103.611490-1-lyude@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" It turns out that if you happen to have a kernel config where CONFIG_DRM_PANIC is disabled and spinlock debugging is enabled, along with KMS being enabled - we'll end up trying to acquire an uninitialized spin_lock with drm_panic_lock() when we try to do a commit: rvkms rvkms.0: [drm:drm_atomic_commit] committing 0000000068d2ade1 INFO: trying to register non-static key. The code is fine but needs lockdep annotation, or maybe you didn't initialize this object before use? turning off the locking correctness validator. CPU: 4 PID: 1347 Comm: modprobe Not tainted 6.10.0-rc1Lyude-Test+ #272 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20240524-3.fc40 05/24/2024 Call Trace: dump_stack_lvl+0x77/0xa0 assign_lock_key+0x114/0x120 register_lock_class+0xa8/0x2c0 __lock_acquire+0x7d/0x2bd0 ? __vmap_pages_range_noflush+0x3a8/0x550 ? drm_atomic_helper_swap_state+0x2ad/0x3a0 lock_acquire+0xec/0x290 ? drm_atomic_helper_swap_state+0x2ad/0x3a0 ? lock_release+0xee/0x310 _raw_spin_lock_irqsave+0x4e/0x70 ? drm_atomic_helper_swap_state+0x2ad/0x3a0 drm_atomic_helper_swap_state+0x2ad/0x3a0 drm_atomic_helper_commit+0xb1/0x270 drm_atomic_commit+0xaf/0xe0 ? __pfx___drm_printfn_info+0x10/0x10 drm_client_modeset_commit_atomic+0x1a1/0x250 drm_client_modeset_commit_locked+0x4b/0x180 drm_client_modeset_commit+0x27/0x50 __drm_fb_helper_restore_fbdev_mode_unlocked+0x76/0x90 drm_fb_helper_set_par+0x38/0x40 fbcon_init+0x3c4/0x690 visual_init+0xc0/0x120 do_bind_con_driver+0x409/0x4c0 do_take_over_console+0x233/0x280 do_fb_registered+0x11f/0x210 fbcon_fb_registered+0x2c/0x60 register_framebuffer+0x248/0x2a0 __drm_fb_helper_initial_config_and_unlock+0x58a/0x720 drm_fbdev_generic_client_hotplug+0x6e/0xb0 drm_client_register+0x76/0xc0 _RNvXs_CsHeezP08sTT_5rvkmsNtB4_5RvkmsNtNtCs1cdwasc6FUb_6kernel8platform6Driver5probe+0xed2/0x1060 [rvkms] ? _RNvMs_NtCs1cdwasc6FUb_6kernel8platformINtB4_7AdapterNtCsHeezP08sTT_5rvkms5RvkmsE14probe_callbackBQ_+0x2b/0x70 [rvkms] ? acpi_dev_pm_attach+0x25/0x110 ? platform_probe+0x6a/0xa0 ? really_probe+0x10b/0x400 ? __driver_probe_device+0x7c/0x140 ? driver_probe_device+0x22/0x1b0 ? __device_attach_driver+0x13a/0x1c0 ? __pfx___device_attach_driver+0x10/0x10 ? bus_for_each_drv+0x114/0x170 ? __device_attach+0xd6/0x1b0 ? bus_probe_device+0x9e/0x120 ? device_add+0x288/0x4b0 ? platform_device_add+0x75/0x230 ? platform_device_register_full+0x141/0x180 ? rust_helper_platform_device_register_simple+0x85/0xb0 ? _RNvMs2_NtCs1cdwasc6FUb_6kernel8platformNtB5_6Device13create_simple+0x1d/0x60 ? _RNvXs0_CsHeezP08sTT_5rvkmsNtB5_5RvkmsNtCs1cdwasc6FUb_6kernel6Module4init+0x11e/0x160 [rvkms] ? 0xffffffffc083f000 ? init_module+0x20/0x1000 [rvkms] ? kernfs_xattr_get+0x3e/0x80 ? do_one_initcall+0x148/0x3f0 ? __lock_acquire+0x5ef/0x2bd0 ? __lock_acquire+0x5ef/0x2bd0 ? __lock_acquire+0x5ef/0x2bd0 ? put_cpu_partial+0x51/0x1d0 ? lock_acquire+0xec/0x290 ? put_cpu_partial+0x51/0x1d0 ? lock_release+0xee/0x310 ? put_cpu_partial+0x51/0x1d0 ? fs_reclaim_acquire+0x69/0xf0 ? lock_acquire+0xec/0x290 ? fs_reclaim_acquire+0x69/0xf0 ? kfree+0x22f/0x340 ? lock_release+0xee/0x310 ? kmalloc_trace_noprof+0x48/0x340 ? do_init_module+0x22/0x240 ? kmalloc_trace_noprof+0x155/0x340 ? do_init_module+0x60/0x240 ? __se_sys_finit_module+0x2e0/0x3f0 ? do_syscall_64+0xa4/0x180 ? syscall_exit_to_user_mode+0x108/0x140 ? do_syscall_64+0xb0/0x180 ? vma_end_read+0xd0/0xe0 ? do_user_addr_fault+0x309/0x640 ? clear_bhb_loop+0x45/0xa0 ? clear_bhb_loop+0x45/0xa0 ? clear_bhb_loop+0x45/0xa0 ? entry_SYSCALL_64_after_hwframe+0x76/0x7e Fix this by stubbing these macros out when this config option isn't enabled, along with fixing the unused variable warning that introduces. Signed-off-by: Lyude Paul Reviewed-by: Daniel Vetter Fixes: e2a1cda3e0c7 ("drm/panic: Add drm panic locking") Cc: # v6.10+ --- V2: * Use static inline instead of macros so we don't need __maybe_unused --- drivers/gpu/drm/drm_atomic_helper.c | 2 +- include/drm/drm_panic.h | 14 ++++++++++++++ 2 files changed, 15 insertions(+), 1 deletion(-) base-commit: bf05aeac230e390a5aee4bd3dc978b0c4d7e745f diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 43cdf39019a44..5186d2114a503 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -3015,7 +3015,7 @@ int drm_atomic_helper_swap_state(struct drm_atomic_state *state, bool stall) { int i, ret; - unsigned long flags; + unsigned long flags = 0; struct drm_connector *connector; struct drm_connector_state *old_conn_state, *new_conn_state; struct drm_crtc *crtc; diff --git a/include/drm/drm_panic.h b/include/drm/drm_panic.h index 54085d5d05c34..f4e1fa9ae607a 100644 --- a/include/drm/drm_panic.h +++ b/include/drm/drm_panic.h @@ -64,6 +64,8 @@ struct drm_scanout_buffer { }; +#ifdef CONFIG_DRM_PANIC + /** * drm_panic_trylock - try to enter the panic printing critical section * @dev: struct drm_device @@ -149,4 +151,16 @@ struct drm_scanout_buffer { #define drm_panic_unlock(dev, flags) \ raw_spin_unlock_irqrestore(&(dev)->mode_config.panic_lock, flags) +#else + +static inline bool drm_panic_trylock(struct drm_device *dev, unsigned long flags) +{ + return true; +} + +static inline void drm_panic_lock(struct drm_device *dev, unsigned long flags) {} +static inline void drm_panic_unlock(struct drm_device *dev, unsigned long flags) {} + +#endif + #endif /* __DRM_PANIC_H__ */