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 36C997E for ; Wed, 2 Nov 2022 03:14:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33CF7C433D6; Wed, 2 Nov 2022 03:14:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1667358848; bh=4+BkRPqbg062PpCI/DARFjhlA2+K0NZKq9ooovnvxnA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=w1wX7PlAK4qpL4aOccYEsBzvl2SkjB83WM/mAwhoBRRPBqVdl39W0ufGKP3nNrf+Q Lowr/dFkyAXa4Mo37JRWaJsOauz+7dD6P8biG/vN2Y1v+XpwhYcG3RCpjmimIiQZP8 GjUl3Ww6ySRXMpq1FGceqHBztCfks1vUKs8YvShM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yuanzheng Song , Peter Xu Subject: [PATCH 5.10 34/91] mm/memory: add non-anonymous page check in the copy_present_page() Date: Wed, 2 Nov 2022 03:33:17 +0100 Message-Id: <20221102022056.007631805@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221102022055.039689234@linuxfoundation.org> References: <20221102022055.039689234@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Yuanzheng Song The vma->anon_vma of the child process may be NULL because the entire vma does not contain anonymous pages. In this case, a BUG will occur when the copy_present_page() passes a copy of a non-anonymous page of that vma to the page_add_new_anon_rmap() to set up new anonymous rmap. ------------[ cut here ]------------ kernel BUG at mm/rmap.c:1044! Internal error: Oops - BUG: 0 [#1] SMP Modules linked in: CPU: 2 PID: 3617 Comm: test Not tainted 5.10.149 #1 Hardware name: linux,dummy-virt (DT) pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--) pc : __page_set_anon_rmap+0xbc/0xf8 lr : __page_set_anon_rmap+0xbc/0xf8 sp : ffff800014c1b870 x29: ffff800014c1b870 x28: 0000000000000001 x27: 0000000010100073 x26: ffff1d65c517baa8 x25: ffff1d65cab0f000 x24: ffff1d65c416d800 x23: ffff1d65cab5f248 x22: 0000000020000000 x21: 0000000000000001 x20: 0000000000000000 x19: fffffe75970023c0 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : ffffc3096d5fb858 x8 : 0000000000000000 x7 : 0000000000000011 x6 : ffff5a5c9089c000 x5 : 0000000000020000 x4 : ffff5a5c9089c000 x3 : ffffc3096d200000 x2 : ffffc3096e8d0000 x1 : ffff1d65ca3da740 x0 : 0000000000000000 Call trace: __page_set_anon_rmap+0xbc/0xf8 page_add_new_anon_rmap+0x1e0/0x390 copy_pte_range+0xd00/0x1248 copy_page_range+0x39c/0x620 dup_mmap+0x2e0/0x5a8 dup_mm+0x78/0x140 copy_process+0x918/0x1a20 kernel_clone+0xac/0x638 __do_sys_clone+0x78/0xb0 __arm64_sys_clone+0x30/0x40 el0_svc_common.constprop.0+0xb0/0x308 do_el0_svc+0x48/0xb8 el0_svc+0x24/0x38 el0_sync_handler+0x160/0x168 el0_sync+0x180/0x1c0 Code: 97f8ff85 f9400294 17ffffeb 97f8ff82 (d4210000) ---[ end trace a972347688dc9bd4 ]--- Kernel panic - not syncing: Oops - BUG: Fatal exception SMP: stopping secondary CPUs Kernel Offset: 0x43095d200000 from 0xffff800010000000 PHYS_OFFSET: 0xffffe29a80000000 CPU features: 0x08200022,61806082 Memory Limit: none ---[ end Kernel panic - not syncing: Oops - BUG: Fatal exception ]--- This problem has been fixed by the commit ("mm/rmap: split page_dup_rmap() into page_dup_file_rmap() and page_try_dup_anon_rmap()"), but still exists in the linux-5.10.y branch. This patch is not applicable to this version because of the large version differences. Therefore, fix it by adding non-anonymous page check in the copy_present_page(). Cc: stable@vger.kernel.org Fixes: 70e806e4e645 ("mm: Do early cow for pinned pages during fork() for ptes") Signed-off-by: Yuanzheng Song Acked-by: Peter Xu Signed-off-by: Greg Kroah-Hartman --- mm/memory.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/mm/memory.c +++ b/mm/memory.c @@ -823,6 +823,17 @@ copy_present_page(struct vm_area_struct if (likely(!page_maybe_dma_pinned(page))) return 1; + /* + * The vma->anon_vma of the child process may be NULL + * because the entire vma does not contain anonymous pages. + * A BUG will occur when the copy_present_page() passes + * a copy of a non-anonymous page of that vma to the + * page_add_new_anon_rmap() to set up new anonymous rmap. + * Return 1 if the page is not an anonymous page. + */ + if (!PageAnon(page)) + return 1; + new_page = *prealloc; if (!new_page) return -EAGAIN;