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Date:   Tue, 25 Oct 2022 12:33:54 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     kernel test robot <yujie.liu@intel.com>
Cc:     oe-lkp@lists.linux.dev, lkp@intel.com,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Seth Jenkins <sethjenkins@google.com>,
        Kees Cook <keescook@chromium.org>,
        linux-kernel@vger.kernel.org, x86@kernel.org,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        kasan-dev@googlegroups.com, "Yin, Fengwei" <fengwei.yin@intel.com>
Subject: Re: [tip:x86/mm] [x86/mm] 1248fb6a82:
 Kernel_panic-not_syncing:kasan_populate_pmd:Failed_to_allocate_page
Message-ID: <Y1e7kgKweck6S954@hirez.programming.kicks-ass.net>
References: <202210241508.2e203c3d-yujie.liu@intel.com>
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On Tue, Oct 25, 2022 at 12:54:40PM +0800, kernel test robot wrote:
> Hi Peter,
> 
> We noticed that below commit changed the value of
> CPU_ENTRY_AREA_MAP_SIZE. Seems KASAN uses this value to allocate memory,
> and failed during initialization after this change, so we send this
> mail and Cc KASAN folks. Please kindly check below report for more
> details. Thanks.
> 
> 
> Greeting,
> 
> FYI, we noticed Kernel_panic-not_syncing:kasan_populate_pmd:Failed_to_allocate_page due to commit (built with gcc-11):
> 
> commit: 1248fb6a8201ddac1c86a202f05a0a1765efbfce ("x86/mm: Randomize per-cpu entry area")
> https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git x86/mm
> 
> in testcase: boot
> 
> on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
> 
> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
> 
> 
> [    7.114808][    T0] Kernel panic - not syncing: kasan_populate_pmd+0x142/0x1d2: Failed to allocate page, nid=0 from=1000000
> [    7.119742][    T0] CPU: 0 PID: 0 Comm: swapper Not tainted 6.1.0-rc1-00001-g1248fb6a8201 #1
> [    7.122122][    T0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014
> [    7.124976][    T0] Call Trace:
> [    7.125849][    T0]  <TASK>
> [    7.126642][    T0]  ? dump_stack_lvl+0x45/0x5d
> [    7.127908][    T0]  ? panic+0x21e/0x46a
> [    7.129009][    T0]  ? panic_print_sys_info+0x77/0x77
> [    7.130618][    T0]  ? memblock_alloc_try_nid_raw+0x106/0x106
> [    7.132224][    T0]  ? memblock_alloc_try_nid+0xd9/0x118
> [    7.133717][    T0]  ? memblock_alloc_try_nid_raw+0x106/0x106
> [    7.135252][    T0]  ? kasan_populate_pmd+0x142/0x1d2
> [    7.136655][    T0]  ? early_alloc+0x95/0x9d
> [    7.137738][    T0]  ? kasan_populate_pmd+0x142/0x1d2
> [    7.138936][    T0]  ? kasan_populate_pud+0x182/0x19f
> [    7.140335][    T0]  ? kasan_populate_shadow+0x1e0/0x233
> [    7.141759][    T0]  ? kasan_init+0x3be/0x57f
> [    7.142942][    T0]  ? setup_arch+0x101d/0x11f0
> [    7.144229][    T0]  ? start_kernel+0x6f/0x3d0
> [    7.145449][    T0]  ? secondary_startup_64_no_verify+0xe0/0xeb
> [    7.147051][    T0]  </TASK>
> [    7.147868][    T0] ---[ end Kernel panic - not syncing: kasan_populate_pmd+0x142/0x1d2: Failed to allocate page, nid=0 from=1000000 ]---

Ufff, no idea about what KASAN wants here; Andrey, you have clue?

Are you trying to allocate backing space for .5T of vspace and failing
that because the kvm thing doesn't have enough memory?