From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 438902F1FDF; Fri, 21 Nov 2025 21:58:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763762304; cv=none; b=lTPQ2BPMXkzJ/kYPgVJ2U6j1cvbiMDky/x98whuEedrV6+3SrYAq0xX/lOqz6OulnAlYSktzamIez4y+E0TkqzSXznxBNBMQQ7NygXF9AAFogcxvRV4Ehj0gHBv/S26ce/oWItCQ3m2ZLUuqScS2N2x2gALwLM2g7ePgjeSTc/w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763762304; c=relaxed/simple; bh=n+kovUuGccZ0u970pTw2K5c8zERrymNbuteXqtMGhTc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sXR5HX0qBPviw2aGdX+8Bcywuun/3BTKZ0TqMfIn1XSSMbTEDsbmhvnmSN4euvlEOth2XRYJrqRgWwGZQD5a0mUZrhY8g6oN7eqAdIHZf3FRNyL6sdcBg4AGwgT5J8bcGI1HQl6+GsiUU6dKvH7e1IxzLmWT7tCZAxV0JB4OsC4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aoOs6clk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aoOs6clk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 42FF2C4CEF1; Fri, 21 Nov 2025 21:58:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763762303; bh=n+kovUuGccZ0u970pTw2K5c8zERrymNbuteXqtMGhTc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aoOs6clkqz0FgeJj7lCZcoTKH8LLaQySgVIy5EJU0NS7G2ehbDDkYvDYePUYjiN61 Y3Zz9rvGz9cS/wEKowkQC2MXxSr3RdXcIuHhb+emede96EBJg/z9NT3yguUxTXJ8u7 u2USUklIACxR4SYp1X8dAodMY4xGrKIiU17f/qAIuDx6gfAjgC3Ou0NrPNQzhv4amp FyzHldRF3Mndm8ywEth1A2oejpmjUzJimpxJ3PwNF4aU9Aa+li87c0NV0xYS/7F64F 2yULUbkco2w6DKA2BIT0R+sl/5jcU5xqbCIYZ/Y/t/fwIsRokWXCZKzhuYwMu4uUhu msnkoVXdUELHw== Date: Fri, 21 Nov 2025 14:58:19 -0700 From: Nathan Chancellor To: Stephen Rothwell , Sebastian Andrzej Siewior Cc: Andrew Morton , Linux Kernel Mailing List , Linux Next Mailing List , Boqun Feng , Waiman Long Subject: Re: linux-next: boot warning from the final tree Message-ID: <20251121215819.GA1374726@ax162> References: <20251117202214.4f710f02@canb.auug.org.au> Precedence: bulk X-Mailing-List: linux-next@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251117202214.4f710f02@canb.auug.org.au> On Mon, Nov 17, 2025 at 08:22:14PM +1100, Stephen Rothwell wrote: > Hi all, > > Today's linux-next qemu boot (powerpc pseries_le_defconfig) produced > this warning: > > ftrace: allocating 48915 entries in 288 pages > ftrace: allocated 287 pages with 6 groups > ------------[ cut here ]------------ > DEBUG_LOCKS_WARN_ON(lock->magic != lock) > WARNING: kernel/locking/mutex.c:156 at mutex_lock+0xcc/0x100, CPU#0: swapper/0/0 > Modules linked in: > CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.18.0-rc6-09359-g921087e37218 #1 VOLUNTARY > Hardware name: IBM pSeries (emulated by qemu) POWER9 (architected) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries > NIP: c00000000148041c LR: c000000001480418 CTR: 0000000000000000 > REGS: c000000002957a10 TRAP: 0700 Not tainted (6.18.0-rc6-09359-g921087e37218) > MSR: 8000000002021033 CR: 24022240 XER: 00000000 > CFAR: c00000000021123c IRQMASK: 3 > GPR00: c000000001480418 c000000002957cb0 c000000001a3a100 0000000000000028 > GPR04: 00000000ffffe04a c0000000026abe88 0000000000000001 000000000000004b > GPR08: c0000000026abd28 0000000000000000 0000000000000000 0000000044022240 > GPR12: 0000000000000000 c000000002ae9000 0000000000000000 0000000001bff430 > GPR16: 000000007e68f070 c00000007f79c480 c000000002969160 c000000002a0f5d8 > GPR20: c0000000026a1138 c0000000026a1120 0000000000000000 c0000000019541b8 > GPR24: c00000000218a480 c00000000296e1d0 000000007d612000 c00000000380be10 > GPR28: c00000000380be20 c00000000380be00 c000000002640100 c00000000380be20 > NIP [c00000000148041c] mutex_lock+0xcc/0x100 > LR [c000000001480418] mutex_lock+0xc8/0x100 > Call Trace: > [c000000002957cb0] [c000000001480418] mutex_lock+0xc8/0x100 (unreliable) > [c000000002957d20] [c00000000024a60c] alloc_workqueue_noprof+0x38c/0x8ec > [c000000002957e00] [c00000000203018c] workqueue_init_early+0x4d8/0x6ec > [c000000002957f30] [c000000002004448] start_kernel+0x74c/0xa4c > [c000000002957fe0] [c00000000000e99c] start_here_common+0x1c/0x20 > Code: 4182ffb4 3d2200f3 392971e4 81290000 2c090000 4082ffa0 3c82ffe0 3c62ffe0 3884bfe0 3863bf68 4ad90d45 60000000 <0fe00000> 4bffff80 60000000 60000000 > ---[ end trace 0000000000000000 ]--- > rcu: Hierarchical RCU implementation. > > I have no idea what caused this. I noticed this warning in my QEMU boot tests as well and bisected it down to commit 3572e2edc7b6 ("locking/mutex: Redo __mutex_init()"). $ make -skj"$(nproc)" ARCH=powerpc CROSS_COMPILE=powerpc64-linux- clean ppc64le_guest_defconfig zImage.epapr $ curl -LSs https://github.com/ClangBuiltLinux/boot-utils/releases/download/20241120-044434/ppc64le-rootfs.cpio.zst | zstd -d >rootfs.cpio $ qemu-system-ppc64 \ -display none \ -nodefaults \ -device ipmi-bmc-sim,id=bmc0 \ -device isa-ipmi-bt,bmc=bmc0,irq=10 \ -machine powernv \ -kernel arch/powerpc/boot/zImage.epapr \ -initrd rootfs.cpio \ -m 2G \ -serial mon:stdio ... [ 0.000000][ T0] Linux version 6.18.0-rc2-00016-g3572e2edc7b6 (nathan@ax162) (powerpc64-linux-gcc (GCC) 15.2.0, GNU ld (GNU Binutils) 2.45) #1 SMP Fri Nov 21 13:55:26 MST 2025 ... [ 0.000000][ T0] ------------[ cut here ]------------ [ 0.000000][ T0] DEBUG_LOCKS_WARN_ON(lock->magic != lock) [ 0.000000][ T0] WARNING: CPU: 0 PID: 0 at kernel/locking/mutex.c:156 mutex_lock+0xd4/0x100 [ 0.000000][ T0] Modules linked in: [ 0.000000][ T0] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.18.0-rc2-00016-g3572e2edc7b6 #1 VOLUNTARY [ 0.000000][ T0] Hardware name: IBM PowerNV (emulated by qemu) POWER10 0x801200 opal:v7.1-106-g785a5e307 PowerNV [ 0.000000][ T0] NIP: c0000000014b2974 LR: c0000000014b2970 CTR: 0000000000000000 [ 0.000000][ T0] REGS: c0000000029979f0 TRAP: 0700 Not tainted (6.18.0-rc2-00016-g3572e2edc7b6) [ 0.000000][ T0] MSR: 9000000002021033 CR: 24000220 XER: 00000000 [ 0.000000][ T0] CFAR: c00000000021ed7c IRQMASK: 3 [ 0.000000][ T0] GPR00: c0000000014b2970 c000000002997c90 c000000001a78100 0000000000000028 [ 0.000000][ T0] GPR04: 00000000ffffe04a c0000000026ed958 0000000000000001 000000000000004b [ 0.000000][ T0] GPR08: c0000000026ed7f0 0000000000000000 0000000000000000 0000000044000220 [ 0.000000][ T0] GPR12: c0000000026ed880 c000000002ba0000 0000000000000018 0000000000000000 [ 0.000000][ T0] GPR16: 0000000000000000 c0000000026e2b88 c0000000026e2ba0 c00000007be5a400 [ 0.000000][ T0] GPR20: c0000000029ed0e0 c000000002aaf7e0 0000000000000000 c0000000019911b8 [ 0.000000][ T0] GPR24: c0000000021ca400 c0000000029f2150 0000000079c90000 c000000003081410 [ 0.000000][ T0] GPR28: c000000003081420 c000000003081400 c0000000021cce98 c000000003081420 [ 0.000000][ T0] NIP [c0000000014b2974] mutex_lock+0xd4/0x100 [ 0.000000][ T0] LR [c0000000014b2970] mutex_lock+0xd0/0x100 [ 0.000000][ T0] Call Trace: [ 0.000000][ T0] [c000000002997c90] [c0000000014b2970] mutex_lock+0xd0/0x100 (unreliable) [ 0.000000][ T0] [c000000002997d10] [c000000000258ddc] alloc_workqueue_noprof+0x44c/0x8c8 [ 0.000000][ T0] [c000000002997df0] [c00000000203080c] workqueue_init_early+0x4e4/0x700 [ 0.000000][ T0] [c000000002997f30] [c000000002004388] start_kernel+0x638/0x938 [ 0.000000][ T0] [c000000002997fe0] [c00000000000e99c] start_here_common+0x1c/0x20 [ 0.000000][ T0] Code: 4182ffa8 3d2200f8 3929d134 81290000 2c090000 4082ff94 3c82ffde 3c62ffde 38846d98 38636d20 4ad6c32d 60000000 <0fe00000> e9410068 4bffff70 38210080 [ 0.000000][ T0] ---[ end trace 0000000000000000 ]--- ... At the parent change, there is no warning. Cheers, Nathan