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 88B0D2EBBA9; Sun, 1 Mar 2026 01:53:57 +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=1772330037; cv=none; b=KCMmuJC8sUECj+DGazLA+qCCY4A2ceWXW8gdYVWjooZw1xF2bMznC0XDjaeUD27N579wx/REDxXRqPJ3qWKbjsaqop/7SPjoGo4wTWRHTIoGjSX6etiH+myQQrHa1PRlirRxjfcI6Mn66fi6bOdFFRVIGTzz8vPsR8DlpYoebJo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772330037; c=relaxed/simple; bh=nWgyK4bmMA4Ntbgxd4K/ARtx6r4Ti1SthxAk+Z7Cudw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=iCw59qpSDxC8EyDtfjugMKKAwi07p4X0Kb6Rvi9KG6lVB2JaqKLZEXPBX5vqBiSbAGnW5VXfu1ubLrpSvkA94uxh9u9EG+aCPTzrqYHHoCE4vUQsyYzkdlRQeFhG8rSlusflCVMdxoILAr/JtqSaw6LhTQv+/yN9o46gPA7Bb2Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Mr4RcRxy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Mr4RcRxy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2CB5C19421; Sun, 1 Mar 2026 01:53:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772330037; bh=nWgyK4bmMA4Ntbgxd4K/ARtx6r4Ti1SthxAk+Z7Cudw=; h=From:To:Cc:Subject:Date:From; b=Mr4RcRxyMZYhSo04FNKVpetpG+SKbuPzEsh0okGNldXchpDYdPNooWQGNjfRjFRza 5pfmhfihbKpPZlXfOIvz3AxlID0gJEMlTajpoxZcZON7ZIOh8iE5IOVIihvLdNON8K eOsAs5TEfqXz2/P+1O+YwOap0pswE7mSBT53c3r/hTJQnlq+bDUH4gxkQV8fhmDuzk PFxWX6eb5kVYdjL1Vi0YXBu+1oFlv2QsySgCuGUAMAv7fH9Edx6Nq9WN2NBL47+qbB uDmkGfE7ryt4yhlSDdj3qe4EHnzvHh9cB7GzfDVab0wPud1zMV9Dj6vtV5z+rKW/U1 yZFnhKpYc9LuQ== From: Sasha Levin To: stable@vger.kernel.org, sprasad@microsoft.com Cc: Steve French , linux-cifs@vger.kernel.org, samba-technical@lists.samba.org Subject: FAILED: Patch "cifs: Fix locking usage for tcon fields" failed to apply to 5.15-stable tree Date: Sat, 28 Feb 2026 20:53:55 -0500 Message-ID: <20260301015355.1720805-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Hint: ignore X-stable: review 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 . Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 96c4af418586ee9a6aab61738644366426e05316 Mon Sep 17 00:00:00 2001 From: Shyam Prasad N Date: Sun, 1 Feb 2026 00:21:13 +0530 Subject: [PATCH] cifs: Fix locking usage for tcon fields We used to use the cifs_tcp_ses_lock to protect a lot of objects that are not just the server, ses or tcon lists. We later introduced srv_lock, ses_lock and tc_lock to protect fields within the corresponding structs. This was done to provide a more granular protection and avoid unnecessary serialization. There were still a couple of uses of cifs_tcp_ses_lock to provide tcon fields. In this patch, I've replaced them with tc_lock. Cc: stable@vger.kernel.org Signed-off-by: Shyam Prasad N Signed-off-by: Steve French --- fs/smb/client/cached_dir.c | 4 ++-- fs/smb/client/smb2misc.c | 6 +++--- fs/smb/client/smb2ops.c | 8 +++----- fs/smb/client/smb2pdu.c | 2 ++ fs/smb/client/trace.h | 1 + 5 files changed, 11 insertions(+), 10 deletions(-) diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c index df9977030d199..2a6b8ce80be23 100644 --- a/fs/smb/client/cached_dir.c +++ b/fs/smb/client/cached_dir.c @@ -792,11 +792,11 @@ static void cfids_laundromat_worker(struct work_struct *work) cfid->dentry = NULL; if (cfid->is_open) { - spin_lock(&cifs_tcp_ses_lock); + spin_lock(&cfid->tcon->tc_lock); ++cfid->tcon->tc_count; trace_smb3_tcon_ref(cfid->tcon->debug_id, cfid->tcon->tc_count, netfs_trace_tcon_ref_get_cached_laundromat); - spin_unlock(&cifs_tcp_ses_lock); + spin_unlock(&cfid->tcon->tc_lock); queue_work(serverclose_wq, &cfid->close_work); } else /* diff --git a/fs/smb/client/smb2misc.c b/fs/smb/client/smb2misc.c index f3cb62d914502..0871b9f1f86a6 100644 --- a/fs/smb/client/smb2misc.c +++ b/fs/smb/client/smb2misc.c @@ -820,14 +820,14 @@ smb2_handle_cancelled_close(struct cifs_tcon *tcon, __u64 persistent_fid, int rc; cifs_dbg(FYI, "%s: tc_count=%d\n", __func__, tcon->tc_count); - spin_lock(&cifs_tcp_ses_lock); + spin_lock(&tcon->tc_lock); if (tcon->tc_count <= 0) { struct TCP_Server_Info *server = NULL; trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, netfs_trace_tcon_ref_see_cancelled_close); WARN_ONCE(tcon->tc_count < 0, "tcon refcount is negative"); - spin_unlock(&cifs_tcp_ses_lock); + spin_unlock(&tcon->tc_lock); if (tcon->ses) { server = tcon->ses->server; @@ -841,7 +841,7 @@ smb2_handle_cancelled_close(struct cifs_tcon *tcon, __u64 persistent_fid, tcon->tc_count++; trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, netfs_trace_tcon_ref_get_cancelled_close); - spin_unlock(&cifs_tcp_ses_lock); + spin_unlock(&tcon->tc_lock); rc = __smb2_handle_cancelled_cmd(tcon, SMB2_CLOSE_HE, 0, persistent_fid, volatile_fid); diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index f6806946d0eee..653e2f29384d4 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -3107,7 +3107,9 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses, struct cifs_tcon, tcon_list); if (tcon) { + spin_lock(&tcon->tc_lock); tcon->tc_count++; + spin_unlock(&tcon->tc_lock); trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, netfs_trace_tcon_ref_get_dfs_refer); } @@ -3176,13 +3178,9 @@ smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses, out: if (tcon && !tcon->ipc) { /* ipc tcons are not refcounted */ - spin_lock(&cifs_tcp_ses_lock); - tcon->tc_count--; + cifs_put_tcon(tcon, netfs_trace_tcon_ref_put_dfs_refer); trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, netfs_trace_tcon_ref_dec_dfs_refer); - /* tc_count can never go negative */ - WARN_ON(tcon->tc_count < 0); - spin_unlock(&cifs_tcp_ses_lock); } kfree(utf16_path); kfree(dfs_req); diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c index fa22702a61a6e..a88b21e5b30e2 100644 --- a/fs/smb/client/smb2pdu.c +++ b/fs/smb/client/smb2pdu.c @@ -4263,7 +4263,9 @@ void smb2_reconnect_server(struct work_struct *work) list_for_each_entry(tcon, &ses->tcon_list, tcon_list) { if (tcon->need_reconnect || tcon->need_reopen_files) { + spin_lock(&tcon->tc_lock); tcon->tc_count++; + spin_unlock(&tcon->tc_lock); trace_smb3_tcon_ref(tcon->debug_id, tcon->tc_count, netfs_trace_tcon_ref_get_reconnect_server); list_add_tail(&tcon->rlist, &tmp_list); diff --git a/fs/smb/client/trace.h b/fs/smb/client/trace.h index a584a77431132..191f02344dcdd 100644 --- a/fs/smb/client/trace.h +++ b/fs/smb/client/trace.h @@ -189,6 +189,7 @@ EM(netfs_trace_tcon_ref_put_cancelled_close_fid, "PUT Cn-Fid") \ EM(netfs_trace_tcon_ref_put_cancelled_mid, "PUT Cn-Mid") \ EM(netfs_trace_tcon_ref_put_mnt_ctx, "PUT MntCtx") \ + EM(netfs_trace_tcon_ref_put_dfs_refer, "PUT DfsRfr") \ EM(netfs_trace_tcon_ref_put_reconnect_server, "PUT Reconn") \ EM(netfs_trace_tcon_ref_put_tlink, "PUT Tlink ") \ EM(netfs_trace_tcon_ref_see_cancelled_close, "SEE Cn-Cls") \ -- 2.51.0