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=1793007766; b=L8am0gI4z9r3MbRIfTFPWtEno9rThmoUpWEcbV/3uhq+FqfP58pnQsmIgB25TvCxTDh7 Cjoz4ZJWu2acDH7w32nN3fdyLmjfD2wKkI9Vu18wdxXqIHi9IjOVWXHLkCCYy8WzdF1iT 1i4n/TQVs29TM8QvucMkPvE7VDrmCpPKA2Qu7TGXFB0kX4zOoMmR1GOu47LOJDPII3ymD pcyMcq3uIJn9IPjret4PijTEVcm3B2Oz+1EKXGbIm0202pRn3iKG22sSdRpFu2Q8Onk00 jHayfKVdTTZ7LGcer4IGNbcEV+xgPYYLL15K5c2Q/IVRcZU8zewOcCXPTO0bf+C3mLQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793007766; 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=84TwrUWL26n6L+6NQSuJMlNmIQWaVGoOxoCZs9H9buM=; b=ITkdZHtbMO7q11ltduCfdyRXWprRFhieZhUL7bUN/Q2q+Z69xM3jHk7ZMrKPOHmmx4w/ XzMx20YDDz1neyxxO+yEmJvZW04tuRBP0Ryne++VQdrSiWUmGPvZwkHG22MYaaLyNjKEC iBKuLQN7RLZTiLqeZoiPhZ7LZI9jkQY0KWSC/ilqpLTfbsFSJKnGJQxVxEwkMdWpCqe0H HzNaOzUFr742jrDsLA8dw2W93OQMPc8bfC5dxmH8uTct1ZtLt7S2+/3RDv1Zu7emhkqud ce36X3nfG4WVFlbm+TW3GbGTjxLdltfaAVU0Z1EGybsgSCYkVWcnkWCutMHiDGfQ5XA== 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=i7mb91Qq; 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 8504A606A328; Mon, 26 Oct 2026 09:42:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=i7mb91Qq Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDD0A1F01485; Mon, 26 Oct 2026 09:42:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793007766; bh=84TwrUWL26n6L+6NQSuJMlNmIQWaVGoOxoCZs9H9buM=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=i7mb91QqykwQoDgzWY9M6nfCGF9CtYL0miYdF1FjCRh0LaqHPRJb//tCmgbKC/umF WgVtyNPI5exENTXXI6xwP2+99qN9n+9hrWnjuf1xfV+BNi2cKGams7B+AsxNWyQxiR bJlInhJx9qAq2tEv93oHYdzY4dxGjx+gnA1bBqwYt1dlsykhpcsPO3BNK+7Mvmq4lk 37s7HkIWBH3DHE+TPd4uELH3PWaS4exrVNnGexWjkfvysOXcvx4L3B1Apbqq+jSy/c 3A0lxJUmTALBaoajpr2hTpbrtd1EBQjh9efnquvyc7chjrx5YlNdy/j8/JRjAnLKB0 LuVgsqs5p31bw== From: "David Hildenbrand (Arm)" Date: Mon, 26 Oct 2026 10:40:49 +0100 Subject: [PATCH 16/16] mm/shmem: fix truncation of files containing only swapin-error markers 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: <20261026-fixes_shmem-v1-16-703206d5fa0c@kernel.org> References: <20261026-fixes_shmem-v1-0-703206d5fa0c@kernel.org> In-Reply-To: <20261026-fixes_shmem-v1-0-703206d5fa0c@kernel.org> To: Andrew Morton , Gregory Price , Zi Yan , Joshua Hahn , Rakie Kim , Ying Huang , Johannes Weiner , Vladimir Davydov , Michal Hocko , Hugh Dickins , Baolin Wang , Lukas Czerner , Carlos Maiolino , Christian Brauner , Jan Kara , Daniel Verkamp , Jeff Xu , Muchun Song , Oscar Salvador , David Stevens , "Matthew Wilcox (Oracle)" , William Kucharski , Chris Li , Kairui Song , Nhat Pham , Miaohe Lin , Naoya Horiguchi Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "David Hildenbrand (Arm)" , stable@vger.kernel.org X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1500; i=david@kernel.org; h=from:subject:message-id; bh=IWKD21922t1O1049MId3yRDZkDpskSIBwZEf2NiLDd8=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLLuK0h0lVU6Mlkwfkq8/3HWSbnEHS8VvvN47eBda8snY nvuQMinjlIWBjEOBlkxRZag4PsGL1+uq61242OGmcPKBDKEgYtTACayKYKRYd722qp1zevZ/C8e 8VttVznfrGVK/cnM5SvPs0VZ1men+zEy/OSZbHT2zvkO5zar7b931FU7pyTu/2a9sV3p9sQd2SK /mAE= X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A It might not be very common, but we can end up with shmem files that are composed only of swapin-error/poison markers. Such markers are not counted in info->alloced. Consequently, shmem_setattr() can skip shmem_truncate_range(), leaving the markers behind. Truncating the file to zero and growing it again will result in reads failing with -EIO instead of returning zeroes. Check whether the mapping contains entries, in addition to info->alloced, before skipping the truncation. Keep the info->alloced check so that shmem_recalc_inode(), called at the end of shmem_undo_range(), can fix up accounting after reclaim has emptied the mapping. Fixes: 6cec2b95dadf ("mm/shmem: fix infinite loop when swap in shmem error at swapoff time") Cc: stable@vger.kernel.org Signed-off-by: David Hildenbrand (Arm) --- mm/shmem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/shmem.c b/mm/shmem.c index f5b5c9a312c53..45f6c34f161e4 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1602,7 +1602,8 @@ static int shmem_setattr(const struct mnt_idmap *idmap, if (oldsize > holebegin) unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); - if (info->alloced) + /* Swapin-error markers are not counted in alloced. */ + if (info->alloced || !mapping_empty(inode->i_mapping)) shmem_truncate_range(inode, newsize, (loff_t)-1); /* unmap again to remove racily COWed private pages */ -- 2.43.0