dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel()grafted

When dma_device_put() drops the last reference on chan->device->ref,
dma_device_release() runs and may free the dma_device along with its
channels.

dma_chan_put() then still reads chan->device->owner via
dma_chan_to_owner() for the trailing module_put(). KASAN catches it:

	slab-use-after-free in dma_chan_put+0x3e6/0x4c0
	Read of size 8 by task insmod/6319
	Freed by task 6319:
	  kfree+0x225/0x470
	  dma_chan_put+0x395/0x4c0
	  dmaengine_put+0xf8/0x160

Cache the module owner in dma_chan_put() before the put so the trailing
module_put() does not need chan->device.

Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct")
Suggested-by: Sashiko <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 77 insertions, 0 deletions

diff --git a/fs/smb/server/server.h b/fs/smb/server/server.h
new file mode 100644
index 000000000..4d4d268b5
--- /dev/null
+++ b/fs/smb/server/server.h
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
+ */
+
+#ifndef __SERVER_H__
+#define __SERVER_H__
+
+#include "smbacl.h"
+
+/*
+ * Server state type
+ */
+enum {
+	SERVER_STATE_STARTING_UP,
+	SERVER_STATE_RUNNING,
+	SERVER_STATE_RESETTING,
+	SERVER_STATE_SHUTTING_DOWN,
+};
+
+/*
+ * Server global config string index
+ */
+enum {
+	SERVER_CONF_NETBIOS_NAME,
+	SERVER_CONF_SERVER_STRING,
+	SERVER_CONF_WORK_GROUP,
+};
+
+struct ksmbd_server_config {
+	unsigned int		flags;
+	unsigned int		state;
+	short			signing;
+	short			enforced_signing;
+	short			min_protocol;
+	short			max_protocol;
+	unsigned short		tcp_port;
+	unsigned short		ipc_timeout;
+	unsigned long		ipc_last_active;
+	unsigned long		deadtime;
+	unsigned int		share_fake_fscaps;
+	struct smb_sid		domain_sid;
+	unsigned int		auth_mechs;
+	unsigned int		max_connections;
+	unsigned int		max_inflight_req;
+	unsigned int		max_ip_connections;
+
+	char			*conf[SERVER_CONF_WORK_GROUP + 1];
+	struct task_struct	*dh_task;
+	bool			bind_interfaces_only;
+	/* AAPL model string for Finder icon, e.g. "Xserve" */
+	char			aapl_model[32];
+};
+
+extern struct ksmbd_server_config server_conf;
+
+int ksmbd_set_netbios_name(char *v);
+int ksmbd_set_server_string(char *v);
+int ksmbd_set_work_group(char *v);
+
+char *ksmbd_netbios_name(void);
+char *ksmbd_server_string(void);
+char *ksmbd_work_group(void);
+
+static inline int ksmbd_server_running(void)
+{
+	return READ_ONCE(server_conf.state) == SERVER_STATE_RUNNING;
+}
+
+static inline int ksmbd_server_configurable(void)
+{
+	return READ_ONCE(server_conf.state) < SERVER_STATE_RESETTING;
+}
+
+int server_queue_ctrl_init_work(void);
+int server_queue_ctrl_reset_work(void);
+#endif /* __SERVER_H__ */