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, 57 insertions, 0 deletions

diff --git a/tools/perf/util/capstone.h b/tools/perf/util/capstone.h
new file mode 100644
index 000000000..7c0baaa01
--- /dev/null
+++ b/tools/perf/util/capstone.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_CAPSTONE_H
+#define __PERF_CAPSTONE_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <linux/compiler.h>
+#include <linux/types.h>
+
+struct annotate_args;
+struct machine;
+struct symbol;
+struct thread;
+
+#ifdef HAVE_LIBCAPSTONE_SUPPORT
+ssize_t capstone__fprintf_insn_asm(struct machine *machine, struct thread *thread, u8 cpumode,
+				   bool is64bit, const uint8_t *code, size_t code_size,
+				   uint64_t ip, int *lenp, int print_opts, FILE *fp);
+int symbol__disassemble_capstone(const char *filename, struct symbol *sym,
+				 struct annotate_args *args);
+int symbol__disassemble_capstone_powerpc(const char *filename, struct symbol *sym,
+					 struct annotate_args *args);
+
+#else /* !HAVE_LIBCAPSTONE_SUPPORT */
+static inline ssize_t capstone__fprintf_insn_asm(struct machine *machine __maybe_unused,
+						 struct thread *thread __maybe_unused,
+						 u8 cpumode __maybe_unused,
+						 bool is64bit __maybe_unused,
+						 const uint8_t *code __maybe_unused,
+						 size_t code_size __maybe_unused,
+						 uint64_t ip __maybe_unused,
+						 int *lenp __maybe_unused,
+						 int print_opts __maybe_unused,
+						 FILE *fp __maybe_unused)
+{
+	return -1;
+}
+
+static inline int symbol__disassemble_capstone(const char *filename __maybe_unused,
+					       struct symbol *sym __maybe_unused,
+					       struct annotate_args *args __maybe_unused)
+{
+	return -1;
+}
+
+static inline int symbol__disassemble_capstone_powerpc(const char *filename __maybe_unused,
+						       struct symbol *sym __maybe_unused,
+						       struct annotate_args *args __maybe_unused)
+{
+	return -1;
+}
+
+#endif /* HAVE_LIBCAPSTONE_SUPPORT */
+
+#endif /* __PERF_CAPSTONE_H */