From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794653301; b=BWmA5i4GQSy5AERzJ1qCgN6EOR+9Z4ImOJJyWoDNgTALh02HfKkiQtlDqW1C97ZLIfzx CNMvg3ouM0M7Bf/YxGFcUlnVmDMx/4Nl0MpQWmtO/tYFDROM2R/Ek629gs/NMGeTliijc +O3AzvBcWIfqpJEfE8fd+6oIWJ/HJLI75XfGU52tn4Ewzy7aaaU3hmNbkDoexva674TU0 Ua3MCkHuF6Iv740oU1pPyuDzQUMpYVc2FGurWqhDkwWC6j4oYS44R0OmFJPIi1I6UmUW6 COcxoAOWqIVSkxrjS96yr+1WUS0M0p++Qe1PPXHP+Nc0R5/SLAA59tHEXp10JXyEfBw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794653301; h=Received:DKIM-Signature:From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:References:In-Reply-To:To:Cc: X-Mailer:X-Developer-Signature:X-Developer-Key; bh=pjbhVx2fs5v7PEkUYOgJa+aS4bC1ZGO8oQVzHBWC01U=; b=QAjSL+4UMiEOLyG8B/fhsSnhVdU5qXgJTr8S8Sx3mahrsoe1E0PqtL9K32y3AoHyKceh PvAhIPLNKhA/Cf4SZ2uvCiqqwGprsqajyU6YSISNbIVvmP8GCq4sNR//zNRvTBs+GXx4K d2gwgjW40EqwT+5Uah4uDQX7eoyuKe3DDmponBaLoG7PG2whrjozJbSgcRqx+qlNX38+T GPZKt6NnRk1GH5p5I+EzG3ngEZGd+jFw4qx4Spl+e4wvd48DCfRN1ganWQVvBlGSfAOyL /Oq/8/RKupHU89KBnsl3DzdKGVbYN6ZzzIc8mo3MWIrVRynHrMDRhCgXRSwjGkXQ+tw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Af+KKCs4; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0BF060A6F71; Sat, 14 Nov 2026 10:48:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Af+KKCs4 Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB7AC1F000C5; Sat, 14 Nov 2026 10:48:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794653301; bh=pjbhVx2fs5v7PEkUYOgJa+aS4bC1ZGO8oQVzHBWC01U=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=Af+KKCs45CAl7fomaGE+uUOySiwEadp9iG1LotBHwhmhbghDQTIHCPSuh6eDy1e0P Fnd1yVYV2Y5wDitIEf/NJcz++yTe0hJZbxOjRSoaQMibUYt4hRs15JM/1YKCmWuwHs 3hjcXUrJjY4kESZeln2Z+kqoXaLfu/Rin3xwffDJbUAG9liYRqNnu/4HZRUBCHGmil ef8H4xARIwaAZM0JMbVOL2nhyeZWBNJj5g6BcBLFmyUsVhRxG5HpU9MplP3aYwCqXo m2gm6RCzHr5UE46ZXE3xH8jPlFrd7uZBmAgT5xivoAioLXGpHADKB3F4ybToeszXwK unVsVQJuFNETA== From: Christian Brauner Date: Sat, 14 Nov 2026 11:47:16 +0100 Subject: [PATCH 09/12] coredump: take freeze protection for the truncate X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261114-work-fs-frozen_writes-v1-9-f5ae61c898b1@kernel.org> References: <20261114-work-fs-frozen_writes-v1-0-f5ae61c898b1@kernel.org> In-Reply-To: <20261114-work-fs-frozen_writes-v1-0-f5ae61c898b1@kernel.org> To: Jan Kara Cc: Shakeel Butt , Alexander Viro , Jens Axboe , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, io-uring@vger.kernel.org, Christoph Hellwig , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-unionfs@vger.kernel.org, bpf@vger.kernel.org, linux-nfs@vger.kernel.org, "Christian Brauner (Amutable)" , stable@vger.kernel.org X-Mailer: b4 0.17-dev-ce4c1 X-Developer-Signature: v=1; a=openpgp-sha256; l=1200; i=brauner@kernel.org; h=from:subject:message-id; bh=34ncq8Kdq+MSTLVnNDtgt7r/DShig8xHabTi/tdVmLw=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWT9sHE//KxCTm/yQQbrTLaAG2s4RYXWfBTX5mt5mD7ZT 2gfb7NYRykLgxgXg6yYIotDu0m43HKeis1GmRowc1iZQIYwcHEKwET+PWH4X+bDXclb0HDtNpeZ 5PPGQxfuqW20XvRg28kO7XU7H+XMaGJk+NGZaeWr687tmjInzW3nouY5zUEmt8+0ccY1NunfOPW QCQA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 coredump_file() truncates the core file after filp_open() returned. The open took freeze protection for the create but dropped it again before returning and coredump_write() only takes it for the dump itself. So a freeze that lands in between lets the truncate modify a frozen filesystem. Take freeze protection around the truncate like do_ftruncate() does. Fixes: 14da9200140f ("fs: Protect write paths by sb_start_write - sb_end_write") Cc: stable@vger.kernel.org Signed-off-by: Christian Brauner (Amutable) --- fs/coredump.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/coredump.c b/fs/coredump.c index 82ef9d115999a..cc6a0c7e48ce2 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -1060,8 +1060,10 @@ static bool coredump_file(struct core_name *cn, struct coredump_params *cprm, } if (!(file->f_mode & FMODE_CAN_WRITE)) return false; - if (do_truncate(idmap, file->f_path.dentry, 0, 0, file)) - return false; + scoped_guard(super_write, inode->i_sb) { + if (do_truncate(idmap, file->f_path.dentry, 0, 0, file)) + return false; + } cprm->file = no_free_ptr(file); return true; -- 2.53.0