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 171DD2165F0; Thu, 12 Dec 2024 15:14:00 +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=1734016440; cv=none; b=bf336ta35MnjawMcLQEVD11kaPFpkh45iCzb7rNWefsv12pMyNCvq6ViPM5LKn5DzOeTpe6iSwqCRm/njf+Ilsa8NfNoXZk3tFkMYBY7k+Uv5TGP8lm5pxUiY5PwvAD8TTA2pw31rOvkkr7PiDTneSsTQgWKxjERkIrNRuNtvL4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734016440; c=relaxed/simple; bh=4ewJqeMlQu+QDm74iejbvQaoDN8G2oKejt8VTKhjSB0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=plRMqJTL3iZ3g5NIFU89ioEkYRgtDSFsIN1EWZPRz6Vc/ZLzJ2rZ1h805Alj1E7JdlBvSJ1GX624IUs00AjvX0hKrAKYHJ+n/Xnv8zsJULlxsQbyVaqOzIaGknwmZAVcPE8NJlox6YOhaZ7jHr5xQbFEsFxOubxMEIldlEUCR2Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LA8mOzJe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="LA8mOzJe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 424F4C4CEE1; Thu, 12 Dec 2024 15:13:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734016439; bh=4ewJqeMlQu+QDm74iejbvQaoDN8G2oKejt8VTKhjSB0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LA8mOzJeiO/aROzLhr7UMMwL/vQzjYXWllv8hTE1zCUA+DuQxxGXwt7S4FHM9Ojtc nROUYPFskHAG43tiduWLWHvGIWyb6LvKRnVoD+Z+hfYCi6xgPV7D49kRE0rLc2ECHH KhAUPyf5SJ9w/iHEoQpjGPfuY7an3C1ucm01F9gQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Hildenbrand , syzbot+3511625422f7aa637f0d@syzkaller.appspotmail.com, "Liam R. Howlett" , Christoph Lameter , Andrew Morton Subject: [PATCH 6.12 200/466] mm/mempolicy: fix migrate_to_node() assuming there is at least one VMA in a MM Date: Thu, 12 Dec 2024 15:56:09 +0100 Message-ID: <20241212144314.692458423@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241212144306.641051666@linuxfoundation.org> References: <20241212144306.641051666@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Hildenbrand commit 091c1dd2d4df6edd1beebe0e5863d4034ade9572 upstream. We currently assume that there is at least one VMA in a MM, which isn't true. So we might end up having find_vma() return NULL, to then de-reference NULL. So properly handle find_vma() returning NULL. This fixes the report: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 UID: 0 PID: 6021 Comm: syz-executor284 Not tainted 6.12.0-rc7-syzkaller-00187-gf868cd251776 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024 RIP: 0010:migrate_to_node mm/mempolicy.c:1090 [inline] RIP: 0010:do_migrate_pages+0x403/0x6f0 mm/mempolicy.c:1194 Code: ... RSP: 0018:ffffc9000375fd08 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffc9000375fd78 RCX: 0000000000000000 RDX: ffff88807e171300 RSI: dffffc0000000000 RDI: ffff88803390c044 RBP: ffff88807e171428 R08: 0000000000000014 R09: fffffbfff2039ef1 R10: ffffffff901cf78f R11: 0000000000000000 R12: 0000000000000003 R13: ffffc9000375fe90 R14: ffffc9000375fe98 R15: ffffc9000375fdf8 FS: 00005555919e1380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555919e1ca8 CR3: 000000007f12a000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: kernel_migrate_pages+0x5b2/0x750 mm/mempolicy.c:1709 __do_sys_migrate_pages mm/mempolicy.c:1727 [inline] __se_sys_migrate_pages mm/mempolicy.c:1723 [inline] __x64_sys_migrate_pages+0x96/0x100 mm/mempolicy.c:1723 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f [akpm@linux-foundation.org: add unlikely()] Link: https://lkml.kernel.org/r/20241120201151.9518-1-david@redhat.com Fixes: 39743889aaf7 ("[PATCH] Swap Migration V5: sys_migrate_pages interface") Signed-off-by: David Hildenbrand Reported-by: syzbot+3511625422f7aa637f0d@syzkaller.appspotmail.com Closes: https://lore.kernel.org/lkml/673d2696.050a0220.3c9d61.012f.GAE@google.com/T/ Reviewed-by: Liam R. Howlett Reviewed-by: Christoph Lameter Cc: Liam R. Howlett Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/mempolicy.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1080,6 +1080,10 @@ static long migrate_to_node(struct mm_st mmap_read_lock(mm); vma = find_vma(mm, 0); + if (unlikely(!vma)) { + mmap_read_unlock(mm); + return 0; + } /* * This does not migrate the range, but isolates all pages that