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 BF06A1ADC83; Mon, 4 May 2026 14:05:39 +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=1777903539; cv=none; b=hkanZ1Y3iGFi5ZVkQwaYkx1I39izuPGbiG9/tJx3IBJ1cfBiITjlP/w19MW3AuyRfDXJiA7JAAlyckqiqM7acB96s62J6Kd3PqelcjHNnM8f58xZgS0A3inlFQNNyJhkVhA8fhDKKDX4H1JcjZVNMKZwuMgmXHVznMpuDuzaF6I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777903539; c=relaxed/simple; bh=IzA9ou30KLzLCCi/ATmoSIhGVksXepwx0KAqu/OGf6Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tpVIhGIRAiaiMf0x5WoN/o0WrS8TazlIrTM4YB+8inJ+qxMUhaddASje9jOealDnPJ292f/ooyBpx+bC9HWTVrwdbuxVF9B+ETo25Qn4jNlhgUa1ivT8DczY2q2jS4VohBLto0MTny1O2KKXUVoK5b3E96UstVV5I2TXmk6CUdo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Suhn4zR7; 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="Suhn4zR7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15333C2BCC4; Mon, 4 May 2026 14:05:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1777903539; bh=IzA9ou30KLzLCCi/ATmoSIhGVksXepwx0KAqu/OGf6Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Suhn4zR7CwjrSiC3ikEDCpRGmzEx5GuO9r5eMCAdDNaw1+0tNJ4kXpLww3P3FeuqN xml3BZvXFPYHJ08a+jky9U2CkEpNFQLyi94+o2YZaUb+1UkhQLDa26d4gk5NMrUg9F uqIHF5iGfZYivCbjm+hUwTh9b0sxUhl2fOShqsS8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sam Edwards , Viacheslav Dubeyko , Ilya Dryomov Subject: [PATCH 7.0 272/307] ceph: fix num_ops off-by-one when crypto allocation fails Date: Mon, 4 May 2026 15:52:37 +0200 Message-ID: <20260504135153.039404965@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260504135142.814938198@linuxfoundation.org> References: <20260504135142.814938198@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sam Edwards commit a0d9555bf9eaeba34fe6b6bb86f442fe08ba3842 upstream. move_dirty_folio_in_page_array() may fail if the file is encrypted, the dirty folio is not the first in the batch, and it fails to allocate a bounce buffer to hold the ciphertext. When that happens, ceph_process_folio_batch() simply redirties the folio and flushes the current batch -- it can retry that folio in a future batch. However, if this failed folio is not contiguous with the last folio that did make it into the batch, then ceph_process_folio_batch() has already incremented `ceph_wbc->num_ops`; because it doesn't follow through and add the discontiguous folio to the array, ceph_submit_write() -- which expects that `ceph_wbc->num_ops` accurately reflects the number of contiguous ranges (and therefore the required number of "write extent" ops) in the writeback -- will panic the kernel: BUG_ON(ceph_wbc->op_idx + 1 != req->r_num_ops); This issue can be reproduced on affected kernels by writing to fscrypt-enabled CephFS file(s) with a 4KiB-written/4KiB-skipped/repeat pattern (total filesize should not matter) and gradually increasing the system's memory pressure until a bounce buffer allocation fails. Fix this crash by decrementing `ceph_wbc->num_ops` back to the correct value when move_dirty_folio_in_page_array() fails, but the folio already started counting a new (i.e. still-empty) extent. The defect corrected by this patch has existed since 2022 (see first `Fixes:`), but another bug blocked multi-folio encrypted writeback until recently (see second `Fixes:`). The second commit made it into 6.18.16, 6.19.6, and 7.0-rc1, unmasking the panic in those versions. This patch therefore fixes a regression (panic) introduced by cac190c7674f. Cc: stable@vger.kernel.org Fixes: d55207717ded ("ceph: add encryption support to writepage and writepages") Fixes: cac190c7674f ("ceph: fix write storm on fscrypted files") Signed-off-by: Sam Edwards Reviewed-by: Viacheslav Dubeyko Signed-off-by: Ilya Dryomov Signed-off-by: Greg Kroah-Hartman --- fs/ceph/addr.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -1365,6 +1365,10 @@ void ceph_process_folio_batch(struct add rc = move_dirty_folio_in_page_array(mapping, wbc, ceph_wbc, folio); if (rc) { + /* Did we just begin a new contiguous op? Nevermind! */ + if (ceph_wbc->len == 0) + ceph_wbc->num_ops--; + folio_redirty_for_writepage(wbc, folio); folio_unlock(folio); break;