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 0A4C51367; Thu, 8 May 2025 00:05:55 +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=1746662756; cv=none; b=TvkZmZHtoPv+2//Ifita5YxuyrCauIb8q5IJLOU9+5FjhJvlp0HEuQxRR/z2EFwslIerrkhnQfYaO7tvVn0XI5GHe+x/D1J9//crvn5glrPT8Fe8LfpniyBhsU2V0vBMPUzAUIAYlmGmpjihYr1KtsHOm81D2BYw/au0sF21vPU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746662756; c=relaxed/simple; bh=/CfN2fzHSTtiqT3tfUd7tdwMutcgTvXdnVYD4tdfri0=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=UlkTFN2kFWVBgauW8YLv5Hm/5Dayvwh7P3mHHt0jZscNkSIULKA4Xgwd2IuLFcxfGXRwk70yVbiykY6211E6XH1RAlS6fa2FsrUGpkiiKMK8FdncHiG84jaY0Oo0f8YR55OZi3WuQ34Zsmw9DW2z/wFIVcJByHT/Pm+uBvk8qKA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=JkIjJsRf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="JkIjJsRf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 32DB8C4CEE2; Thu, 8 May 2025 00:05:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1746662755; bh=/CfN2fzHSTtiqT3tfUd7tdwMutcgTvXdnVYD4tdfri0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=JkIjJsRfOUWjpcXtTKOyQRmJVattxIc8eAA843v35EmDENHsSVACMuLgcrASxC+w2 NGX6tnUBRw3k4jg8hFDmEdeXZHa38tx3S0Ow1bPnqATzhiBVYTeO9hZmhV5wW9V2o5 L0USev11lMIuDnoDnj9H1lsc4HdGp3tVnbqtJyro= Date: Wed, 7 May 2025 17:05:54 -0700 From: Andrew Morton To: Alexander Gordeev Cc: Andrey Ryabinin , Daniel Axtens , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kasan-dev@googlegroups.com, linux-s390@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v5 1/1] kasan: Avoid sleepable page allocation from atomic context Message-Id: <20250507170554.53a29e42d3edda8a9f072334@linux-foundation.org> In-Reply-To: <0388739e3a8aacdf9b9f7b11d5522b7934aea196.1746604607.git.agordeev@linux.ibm.com> References: <0388739e3a8aacdf9b9f7b11d5522b7934aea196.1746604607.git.agordeev@linux.ibm.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 7 May 2025 14:48:03 +0200 Alexander Gordeev wrote: > apply_to_pte_range() enters the lazy MMU mode and then invokes > kasan_populate_vmalloc_pte() callback on each page table walk > iteration. However, the callback can go into sleep when trying > to allocate a single page, e.g. if an architecutre disables > preemption on lazy MMU mode enter. > > On s390 if make arch_enter_lazy_mmu_mode() -> preempt_enable() > and arch_leave_lazy_mmu_mode() -> preempt_disable(), such crash > occurs: > > [ 553.332108] preempt_count: 1, expected: 0 > [ 553.332117] no locks held by multipathd/2116. > [ 553.332128] CPU: 24 PID: 2116 Comm: multipathd Kdump: loaded Tainted: > [ 553.332139] Hardware name: IBM 3931 A01 701 (LPAR) > [ 553.332146] Call Trace: > [ 553.332152] [<00000000158de23a>] dump_stack_lvl+0xfa/0x150 > [ 553.332167] [<0000000013e10d12>] __might_resched+0x57a/0x5e8 > [ 553.332178] [<00000000144eb6c2>] __alloc_pages+0x2ba/0x7c0 > [ 553.332189] [<00000000144d5cdc>] __get_free_pages+0x2c/0x88 > [ 553.332198] [<00000000145663f6>] kasan_populate_vmalloc_pte+0x4e/0x110 > [ 553.332207] [<000000001447625c>] apply_to_pte_range+0x164/0x3c8 > [ 553.332218] [<000000001448125a>] apply_to_pmd_range+0xda/0x318 > [ 553.332226] [<000000001448181c>] __apply_to_page_range+0x384/0x768 > [ 553.332233] [<0000000014481c28>] apply_to_page_range+0x28/0x38 > [ 553.332241] [<00000000145665da>] kasan_populate_vmalloc+0x82/0x98 > [ 553.332249] [<00000000144c88d0>] alloc_vmap_area+0x590/0x1c90 > [ 553.332257] [<00000000144ca108>] __get_vm_area_node.constprop.0+0x138/0x260 > [ 553.332265] [<00000000144d17fc>] __vmalloc_node_range+0x134/0x360 > [ 553.332274] [<0000000013d5dbf2>] alloc_thread_stack_node+0x112/0x378 > [ 553.332284] [<0000000013d62726>] dup_task_struct+0x66/0x430 > [ 553.332293] [<0000000013d63962>] copy_process+0x432/0x4b80 > [ 553.332302] [<0000000013d68300>] kernel_clone+0xf0/0x7d0 > [ 553.332311] [<0000000013d68bd6>] __do_sys_clone+0xae/0xc8 > [ 553.332400] [<0000000013d68dee>] __s390x_sys_clone+0xd6/0x118 > [ 553.332410] [<0000000013c9d34c>] do_syscall+0x22c/0x328 > [ 553.332419] [<00000000158e7366>] __do_syscall+0xce/0xf0 > [ 553.332428] [<0000000015913260>] system_call+0x70/0x98 Is this a crash, or a warning? From the description I suspect it was a sleep-while-atomic warning? Can we please have the complete dmesg output?