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, 135 insertions, 0 deletions

diff --git a/tools/perf/util/c2c.h b/tools/perf/util/c2c.h
new file mode 100644
index 000000000..53f024e25
--- /dev/null
+++ b/tools/perf/util/c2c.h
@@ -0,0 +1,135 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_UTIL_C2C_H
+#define __PERF_UTIL_C2C_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <linux/types.h>
+#include "hist.h"
+#include "mem-events.h"
+#include "stat.h"
+
+struct sort_entry;
+
+struct c2c_hists {
+	struct hists		hists;
+	struct perf_hpp_list	list;
+	struct c2c_stats	stats;
+};
+
+struct compute_stats {
+	struct stats		 lcl_hitm;
+	struct stats		 rmt_hitm;
+	struct stats		 lcl_peer;
+	struct stats		 rmt_peer;
+	struct stats		 load;
+};
+
+struct c2c_hist_entry {
+	struct c2c_hists	*hists;
+	struct evsel		*evsel;
+	struct c2c_stats	 stats;
+	unsigned long		*cpuset;
+	unsigned long		*nodeset;
+	struct c2c_stats	*node_stats;
+	unsigned int		 cacheline_idx;
+
+	struct compute_stats	 cstats;
+
+	unsigned long		 paddr;
+	unsigned long		 paddr_cnt;
+	bool			 paddr_zero;
+	char			*nodestr;
+
+	/*
+	 * must be at the end,
+	 * because of its callchain dynamic entry
+	 */
+	struct hist_entry	he;
+};
+
+#define C2C_HEADER_MAX 2
+
+struct c2c_header {
+	struct {
+		const char *text;
+		int	    span;
+	} line[C2C_HEADER_MAX];
+};
+
+struct c2c_dimension {
+	struct c2c_header	 header;
+	const char		*name;
+	int			 width;
+	struct sort_entry	*se;
+
+	int64_t (*cmp)(struct perf_hpp_fmt *fmt,
+		       struct hist_entry *left, struct hist_entry *right);
+	int   (*entry)(struct perf_hpp_fmt *fmt, struct perf_hpp *hpp,
+		       struct hist_entry *he);
+	int   (*color)(struct perf_hpp_fmt *fmt, struct perf_hpp *hpp,
+		       struct hist_entry *he);
+};
+
+struct c2c_fmt {
+	struct perf_hpp_fmt	 fmt;
+	struct c2c_dimension	*dim;
+};
+
+#define SYMBOL_WIDTH 30
+
+#define HEADER_LOW(__h)			\
+	{				\
+		.line[1] = {		\
+			.text = __h,	\
+		},			\
+	}
+
+#define HEADER_BOTH(__h0, __h1)		\
+	{				\
+		.line[0] = {		\
+			.text = __h0,	\
+		},			\
+		.line[1] = {		\
+			.text = __h1,	\
+		},			\
+	}
+
+void c2c_fmt_free(struct perf_hpp_fmt *fmt);
+bool c2c_fmt_equal(struct perf_hpp_fmt *a, struct perf_hpp_fmt *b);
+
+/*
+ * Build the function-view hierarchy. Returns -EOPNOTSUPP when @cl_sort lacks
+ * iaddr. On success, *@hists remains valid until the next
+ * c2c_function__build() or c2c_function__reset(). On failure, *@hists is
+ * NULL.
+ */
+int c2c_function__build(struct c2c_hists *cl_hists, const char *cl_sort,
+			bool symbol_full, struct hists **hists);
+void c2c_function__reset(void);
+/* Valid only between a successful build and c2c_function__reset(). */
+struct hist_entry *c2c_function__find_cacheline(struct hist_entry *he);
+
+/* Inputs and TUI callback supplied by the c2c command. */
+struct c2c_function_view_args {
+	/* Source cacheline histograms used by the common model. */
+	struct c2c_hists	*cl_hists;
+	/* --coalesce field list, used to require iaddr. */
+	const char		*cl_sort;
+	/* Do not cap long symbol names. */
+	bool			 symbol_full;
+	/* Open the cacheline detail view for @he. */
+	int			(*browse_cacheline)(struct hist_entry *he);
+};
+
+#ifdef HAVE_SLANG_SUPPORT
+int perf_c2c__browse_function_view(struct c2c_function_view_args *args);
+#else
+static inline int
+perf_c2c__browse_function_view(struct c2c_function_view_args *args __maybe_unused)
+{
+	return 0;
+}
+#endif
+
+#endif /* __PERF_UTIL_C2C_H */