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=1793817233; b=uByPyZhvtlpEDg7WANglaEyXgohJab8i0wD95UAiduwmM2Wp6LqWYVkrb5viCqXWF1LB sjIrNhAL5FolyaYKEk3i02RTY/nmXz0bhLer2U9avRtuPWNxU6B58dUuiiTmKCKRsRpDi Br+2bsWqWZGWJmTxhhPsXRDZIeQbIETDaDFFIfhy4q4B0gSMBuQFan7qBPcl3qtwOLaQa xCNimt2EGZnTL4DYqzSUWfncDDwDr789j74aFDKrwsS3Bbm1fpIu/JnuxN/yX1iZ0SAs8 c9I6sD79aQiXVVNU+ERHtvz0exiSydCEmOnh/5o7yF2ewgH0ZwXMkL6kovewlJJuVxg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793817233; h=Received:DKIM-Signature:Subject:To:Cc:From:Date:Message-ID: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=1XDFCuGe4mWXTesmGkPv+jkaNe5h0463nEIp/3qjxwg=; b=0rnS2Iu6jzwBvOCuxE7YLUaeVlOyRjNZziRojnXlbOfoZfKAzfJiifj9VSmEPsJPDwWK Xc6DrO5Ugjphc1T284iDMjovEZAht3MVn8JHhe5qC5h5EcwOsobgQZjI+besO5Cy52q1Y 7KLw7gl4IvNm2KGTstunCyG8hEj7xAQOlPTYMgMSUjQAM6vhAZ9z+sDbr9t+ZhhsMZP3/ Ok3YwiXV3Rqa91WulfQVHjI0TvO0aqmO86j6jLABghYaF0Cr4TLKLWdf7zHGcmBnxdlGO pfRJPjMmfnrXVK8nEAJyrOWikZTZ//u9E1Dfoy7FnjUvJNfZ0UzkAIbvMJMJureu86w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=i3CuT36x; 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 14CD4606A32C for ; Wed, 4 Nov 2026 18:33:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=i3CuT36x Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9D12C1F000C1; Wed, 4 Nov 2026 18:33:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793817232; bh=1XDFCuGe4mWXTesmGkPv+jkaNe5h0463nEIp/3qjxwg=; h=Subject:To:Cc:From:Date; b=i3CuT36xR+gmhy1zbOFMZ3FyivZZmXm6N7auco9pe1YpQQ0Vlm7khHxGu4pIAEmim 2p1EE1x4jwcw/BkIIMxeBfpAleF6PJG3VeZgW3fm9AJtNKk7tcAAggf9ziZfR1Lj84 IvKmUFrhgWGzsix80dR7pMcpXP6GNGzRTrTgH82s= Subject: FAILED: patch "[PATCH] smb: client: reclaim credits for decrypted reads with no" failed to apply to 5.15-stable tree To: pc@manguebit.org,bharathsm@microsoft.com,dhowells@redhat.com,linkinjeon@kernel.org,ronniesahlberg@gmail.com,sprasad@microsoft.com,tom@talpey.com Cc: From: Date: Wed, 04 Nov 2026 13:33:44 -0500 Message-ID: <2026110444-glance-splashing-5f08@gregkh> X-Mailing-List: stable@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=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 78f73985846465a25a7bd1d89904053661f3ca92 # git commit -s git send-email --to '' --in-reply-to '2026110444-glance-splashing-5f08@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 78f73985846465a25a7bd1d89904053661f3ca92 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara Date: Thu, 15 Oct 2026 15:53:32 -0300 Subject: [PATCH] smb: client: reclaim credits for decrypted reads with no matching mid When a decrypted SMB2 READ response carries a MessageId that matches no outstanding request, both the inline receive_encrypted_read() and the offloaded smb2_decrypt_offload() paths drop the frame without accounting the credits the server granted in it. The plaintext unknown-frame path in cifs_demultiplex_thread() already reclaims them with smb2_add_credits_from_hdr(), so encrypted reads leak credits that the plaintext path would not. This also happens for legitimate frames - e.g. a reply that arrives after the client has timed out and dropped the mid - so over a long-lived connection the client's credit count drifts down and can eventually starve it of the ability to issue requests. The frame is AEAD-authenticated, so the granted credits in the decrypted header come from the real server and are safe to apply. Reclaim the credits from the decrypted header before dropping the frame, and export smb2_add_credits_from_hdr() so the SMB2 receive paths can use it. Fixes: c42a6abe3012 ("CIFS: Add capability to decrypt big read responses") Fixes: 35cf94a39728 ("smb3: allow parallelizing decryption of reads") Signed-off-by: Paulo Alcantara Reviewed-by: David Howells Cc: Namjae Jeon Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Bharath SM Cc: stable@vger.kernel.org diff --git a/fs/smb/client/cifsproto.h b/fs/smb/client/cifsproto.h index 7b9eca22281f..9c44d1d2ae20 100644 --- a/fs/smb/client/cifsproto.h +++ b/fs/smb/client/cifsproto.h @@ -131,6 +131,7 @@ void cifs_signal_cifsd_for_reconnect(struct TCP_Server_Info *server, void cifs_mark_tcp_ses_conns_for_reconnect(struct TCP_Server_Info *server, bool mark_smb_session); int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session); +void smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server); bool backup_cred(struct cifs_sb_info *cifs_sb); bool is_size_safe_to_change(struct cifsInodeInfo *cifsInode, __u64 end_of_file, bool from_readdir); diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c index f46c37e9b3c7..c3614c077746 100644 --- a/fs/smb/client/connect.c +++ b/fs/smb/client/connect.c @@ -1249,8 +1249,7 @@ cifs_handle_standard(struct TCP_Server_Info *server, struct mid_q_entry *mid) return 0; } -static void -smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server) +void smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server) { struct smb2_hdr *shdr = (struct smb2_hdr *)buffer; int scredits, in_flight; diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index a0b9363ba89d..83d5c6a05ef6 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -5263,9 +5263,10 @@ static void smb2_decrypt_offload(struct work_struct *work) dw->server->lstrp = jiffies; mid = smb2_find_dequeue_mid(dw->server, dw->buf); - if (mid == NULL) + if (mid == NULL) { cifs_dbg(FYI, "mid not found\n"); - else { + smb2_add_credits_from_hdr(dw->buf, dw->server); + } else { mid->decrypted = true; rc = handle_read_data(dw->server, mid, dw->buf, dw->server->vals->read_rsp_size, @@ -5396,6 +5397,7 @@ receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid, *mid = smb2_find_mid(server, buf); if (*mid == NULL) { cifs_dbg(FYI, "mid not found\n"); + smb2_add_credits_from_hdr(buf, server); rc = -1; } else { cifs_dbg(FYI, "mid found\n");