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[70.31.27.79]) by smtp.gmail.com with ESMTPSA id ay31-20020a5d9d9f000000b006c75c702342sm1493014iob.14.2022.10.28.06.15.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Oct 2022 06:15:59 -0700 (PDT) Date: Fri, 28 Oct 2022 09:15:57 -0400 From: Peter Xu To: Yuanzheng Song Cc: akpm@linux-foundation.org, david@redhat.com, hughd@google.com, gregkh@linuxfoundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH STABLE 5.10 v2] mm/memory: add non-anonymous page check in the copy_present_page() Message-ID: References: <20221028030705.2840539-1-songyuanzheng@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20221028030705.2840539-1-songyuanzheng@huawei.com> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Fri, Oct 28, 2022 at 03:07:05AM +0000, Yuanzheng Song wrote: > 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 -- Peter Xu