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 C25BE280A29; Fri, 27 Feb 2026 01:12:12 +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=1772154732; cv=none; b=GvdW+RcZ8b+pLTZm6gh0VCsYt4QE6rMO1uV8gdaZin+YQDa9+6X2bAL+nLgwLZIXBSSzPcOhBYnO95jrK7CGnT+qcEJMXx0ePIZ+GjezR1aPXT3KsYU8ptIKv6Le3B47tjh8E3jqSaRj7w0EBLR25Ks180bNyco9dpLsHgAT7VM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772154732; c=relaxed/simple; bh=toaYxiPZ/lCeBM7C8uOMFWILyi4ngU7RTn1w2G8GD5A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hSmJu2unmcknpE33JRSlQ48ya021IQzwO+NNoOJHOIhp5f2uEkQb+4eWFyU+4QoJVPNNH08x2Gg0lu1bUIPTx0Hzbt23Mi0rrw2nAmmYRi8eplId+ZwbcAJviWQ/dFlJzYNX5AKjGQA9jk7bgCgJRL7sZot1614sYFh2RGOhr6Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KoJ8+tCq; 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="KoJ8+tCq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9074EC116C6; Fri, 27 Feb 2026 01:12:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772154732; bh=toaYxiPZ/lCeBM7C8uOMFWILyi4ngU7RTn1w2G8GD5A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KoJ8+tCqPmwPW2nqtGZARcr0hjJVC/K5l9WBoZd+sqMpYELts0SvdJ6gtiDYPzAgz OQ/CcOVyraLKD0E3KIdka1B8z5QrL8zcn8u2QaGrs8vzS/C8opOdfGi3T3yStQloTv +ZTXamB6IlPyZo/YDSl6DdvljAwHRWiyTJ+XNX7Xz4qlFUNJBfyV719DCt2RZjJJgW cKTOhCQCbPzohQxVEb3L+aD56RDxTv6YR2MQMdS9mlx3hS4YQtU3lKLGFHq5hwHpeZ uO1bb/xOgHTqADagudFMUPAK+NpI74MLlpRy39MCk4aJoo9835DfH0viTRBwtxmNQp KF2Ze1ivOMkiw== Date: Thu, 26 Feb 2026 18:12:01 -0700 From: Nathan Chancellor To: Mathieu Desnoyers Cc: Heiko Carstens , Andrew Morton , linux-kernel@vger.kernel.org, "Paul E. McKenney" , Steven Rostedt , Masami Hiramatsu , Dennis Zhou , Tejun Heo , Christoph Lameter , Martin Liu , David Rientjes , christian.koenig@amd.com, Shakeel Butt , SeongJae Park , Michal Hocko , Johannes Weiner , Sweet Tea Dorminy , Lorenzo Stoakes , "Liam R . Howlett" , Mike Rapoport , Suren Baghdasaryan , Vlastimil Babka , Christian Brauner , Wei Yang , David Hildenbrand , Miaohe Lin , Al Viro , linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, Yu Zhao , Roman Gushchin , Mateusz Guzik , Matthew Wilcox , Baolin Wang , Aboorva Devarajan , Vasily Gorbik , linux-s390@vger.kernel.org Subject: Re: [PATCH v17 0/3] Improve proc RSS accuracy Message-ID: <20260227011201.GA1577380@ax162> References: <20260217161006.1105611-1-mathieu.desnoyers@efficios.com> <20260226120422.8101Cc2-hca@linux.ibm.com> <59b28cb4-4fff-4888-b562-7b7236e29d27@efficios.com> <73e6fea9-caf2-4404-b511-11646013f8db@efficios.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@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: <73e6fea9-caf2-4404-b511-11646013f8db@efficios.com> Hi Mathieu, On Thu, Feb 26, 2026 at 02:38:04PM -0500, Mathieu Desnoyers wrote: > I've successfully booted a defconfig s390x next-20260226 kernel in qemu > with 1 and 4 CPUs, and within a nested s390x VM on 2 cpus. > > I guess I'll really need more info about your specific .config and > command line args to help further. FWIW, the ClangBuiltLinux CI sees a boot failure with sparc64_defconfig, which does not appear to be clang specific. I can reproduce it here with: $ make -skj"$(nproc)" ARCH=sparc CROSS_COMPILE=sparc64-linux- mrproper sparc64_defconfig image $ curl -LSs https://github.com/ClangBuiltLinux/boot-utils/releases/download/20241120-044434/sparc64-rootfs.cpio.zst | zstd -d >rootfs.cpio $ qemu-system-sparc64 \ -display none \ -nodefaults \ -M sun4u \ -cpu 'TI UltraSparc IIi' \ -append console=ttyS0 \ -kernel arch/sparc/boot/image \ -initrd rootfs.cpio \ -m 1G \ -serial mon:stdio ... [ 0.001502] Linux version 7.0.0-rc1+ (nathan@framework-amd-ryzen-maxplus-395) (sparc64-linux-gcc (GCC) 15.2.0, GNU ld (GNU Binutils) 2.45) #1 SMP Thu Feb 26 18:00:08 MST 2026 ... [ 1.339282] Run /init as init process [ 1.340037] Unable to handle kernel NULL pointer dereference [ 1.340515] tsk->{mm,active_mm}->context = 0000000000000000 [ 1.340684] tsk->{mm,active_mm}->pgd = fffff80000402000 [ 1.340838] \|/ ____ \|/ [ 1.340838] "@'/ .. \`@" [ 1.340838] /_| \__/ |_\ [ 1.340838] \__U_/ [ 1.341260] swapper/0(1): Oops [#1] [ 1.341575] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 7.0.0-rc1+ #1 VOLUNTARY [ 1.341937] TSTATE: 0000004411001606 TPC: 0000000000465674 TNPC: 0000000000465678 Y: 00000021 Not tainted [ 1.342199] TPC: [ 1.342584] g0: 0000000000000000 g1: 0000000000000000 g2: 0000000000000000 g3: 0000000000000000 [ 1.342815] g4: fffff80004170000 g5: fffff8003e1d2000 g6: fffff80004134000 g7: fffff8003f814598 [ 1.343047] o0: fffff8000479c0a0 o1: 0000000000000000 o2: 0000000000002000 o3: 0000000000000000 [ 1.343276] o4: fffff80004621200 o5: fffff80004006e00 sp: fffff80004137331 ret_pc: 000000000062a520 [ 1.343513] RPC: [ 1.343681] l0: ffffffffffffffff l1: 0000000000000000 l2: 0000000000000001 l3: 0000000000000000 [ 1.343917] l4: 000000004fd6805e l5: 0000000001503c00 l6: 0000000001423800 l7: 0000000000000012 [ 1.344144] i0: fffff80004170000 i1: fffff8000479c0a0 i2: 0000000000472030 i3: 000000000180ac00 [ 1.344371] i4: 0000000000000000 i5: fffff8000400b500 i6: fffff800041373e1 i7: 0000000000472044 [ 1.344601] I7: [ 1.344751] Call Trace: [ 1.344871] [<0000000000472044>] mm_init.isra.0+0x144/0x1e0 [ 1.345054] [<00000000006602ec>] alloc_bprm+0xcc/0x1e0 [ 1.345195] [<0000000000660e6c>] kernel_execve+0x2c/0x1c0 [ 1.345345] [<0000000000be4060>] kernel_init+0x70/0x128 [ 1.345496] [<00000000004060f0>] ret_from_fork+0x24/0x34 [ 1.345652] [<0000000000000000>] 0x0 [ 1.345823] Disabling lock debugging due to kernel taint [ 1.346046] Caller[0000000000472044]: mm_init.isra.0+0x144/0x1e0 [ 1.346229] Caller[00000000006602ec]: alloc_bprm+0xcc/0x1e0 [ 1.346388] Caller[0000000000660e6c]: kernel_execve+0x2c/0x1c0 [ 1.346553] Caller[0000000000be4060]: kernel_init+0x70/0x128 [ 1.346707] Caller[00000000004060f0]: ret_from_fork+0x24/0x34 [ 1.346864] Caller[0000000000000000]: 0x0 [ 1.346985] Instruction DUMP: [ 1.347007] 92102000 [ 1.347135] 90100019 [ 1.347204] f85e6490 [ 1.347281] [ 1.347349] c25e6388 [ 1.347416] fa5e6488 [ 1.347485] 82004003 [ 1.347552] c65e63c0 [ 1.347619] 83784c00 [ 1.347689] [ 1.348041] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 [ 1.348649] Press Stop-A (L1-A) from sun keyboard or send break [ 1.348649] twice on console to return to the boot prom [ 1.348940] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009 ]--- This series is not bisectable to see which specific patch causes this, as I get In file included from mm/init-mm.c:2: include/linux/mm_types.h:1419:57: error: 'PERCPU_COUNTER_TREE_ITEMS_STATIC_SIZE' undeclared here (not in a function) 1419 | [0 ... sizeof(cpumask_t) + MM_CID_STATIC_SIZE + PERCPU_COUNTER_TREE_ITEMS_STATIC_SIZE. - 1] = 0 \ | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/init-mm.c:50:27: note: in expansion of macro 'MM_STRUCT_FLEXIBLE_ARRAY_INIT' 50 | .flexible_array = MM_STRUCT_FLEXIBLE_ARRAY_INIT, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/mm_types.h:1419:10: error: array index in initializer not of integer type 1419 | [0 ... sizeof(cpumask_t) + MM_CID_STATIC_SIZE + PERCPU_COUNTER_TREE_ITEMS_STATIC_SIZE - 1] = 0 \ | ^ mm/init-mm.c:50:27: note: in expansion of macro 'MM_STRUCT_FLEXIBLE_ARRAY_INIT' 50 | .flexible_array = MM_STRUCT_FLEXIBLE_ARRAY_INIT, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/mm_types.h:1419:10: note: (near initialization for 'init_mm.flexible_array') 1419 | [0 ... sizeof(cpumask_t) + MM_CID_STATIC_SIZE + PERCPU_COUNTER_TREE_ITEMS_STATIC_SIZE - 1] = 0 \ | ^ mm/init-mm.c:50:27: note: in expansion of macro 'MM_STRUCT_FLEXIBLE_ARRAY_INIT' 50 | .flexible_array = MM_STRUCT_FLEXIBLE_ARRAY_INIT, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ prior to this change that removes PERCPU_COUNTER_TREE_ITEMS_STATIC_SIZE. Cheers, Nathan