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, 205 insertions, 0 deletions

diff --git a/tools/include/nolibc/time.h b/tools/include/nolibc/time.h
new file mode 100644
index 000000000..9ba930710
--- /dev/null
+++ b/tools/include/nolibc/time.h
@@ -0,0 +1,205 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * time function definitions for NOLIBC
+ * Copyright (C) 2017-2022 Willy Tarreau <w@1wt.eu>
+ */
+
+/* make sure to include all global symbols */
+#include "nolibc.h"
+
+#ifndef _NOLIBC_TIME_H
+#define _NOLIBC_TIME_H
+
+#include "std.h"
+#include "arch.h"
+#include "types.h"
+#include "sys.h"
+
+#include <linux/signal.h>
+#include <linux/time.h>
+
+#define __nolibc_assert_time64_type(t) \
+	__nolibc_static_assert(sizeof(t) == 8)
+
+#define __nolibc_assert_native_time64() \
+	__nolibc_assert_time64_type(__kernel_old_time_t)
+
+/*
+ * int clock_getres(clockid_t clockid, struct timespec *res);
+ * int clock_gettime(clockid_t clockid, struct timespec *tp);
+ * int clock_settime(clockid_t clockid, const struct timespec *tp);
+ * int clock_nanosleep(clockid_t clockid, int flags, const struct timespec *rqtp,
+ *                     struct timespec *rmtp)
+ */
+
+static __attribute__((unused))
+int _sys_clock_getres(clockid_t clockid, struct timespec *res)
+{
+#if defined(__NR_clock_getres_time64)
+	__nolibc_assert_time64_type(res->tv_sec);
+	return __nolibc_syscall2(__NR_clock_getres_time64, clockid, res);
+#else
+	__nolibc_assert_native_time64();
+	return __nolibc_syscall2(__NR_clock_getres, clockid, res);
+#endif
+}
+
+static __attribute__((unused))
+int clock_getres(clockid_t clockid, struct timespec *res)
+{
+	return __sysret(_sys_clock_getres(clockid, res));
+}
+
+static __attribute__((unused))
+int _sys_clock_gettime(clockid_t clockid, struct timespec *tp)
+{
+#if defined(__NR_clock_gettime64)
+	__nolibc_assert_time64_type(tp->tv_sec);
+	return __nolibc_syscall2(__NR_clock_gettime64, clockid, tp);
+#else
+	__nolibc_assert_native_time64();
+	return __nolibc_syscall2(__NR_clock_gettime, clockid, tp);
+#endif
+}
+
+static __attribute__((unused))
+int clock_gettime(clockid_t clockid, struct timespec *tp)
+{
+	return __sysret(_sys_clock_gettime(clockid, tp));
+}
+
+static __attribute__((unused))
+int _sys_clock_settime(clockid_t clockid, struct timespec *tp)
+{
+#if defined(__NR_clock_settime64)
+	__nolibc_assert_time64_type(tp->tv_sec);
+	return __nolibc_syscall2(__NR_clock_settime64, clockid, tp);
+#else
+	__nolibc_assert_native_time64();
+	return __nolibc_syscall2(__NR_clock_settime, clockid, tp);
+#endif
+}
+
+static __attribute__((unused))
+int clock_settime(clockid_t clockid, struct timespec *tp)
+{
+	return __sysret(_sys_clock_settime(clockid, tp));
+}
+
+static __attribute__((unused))
+int _sys_clock_nanosleep(clockid_t clockid, int flags, const struct timespec *rqtp,
+			 struct timespec *rmtp)
+{
+#if defined(__NR_clock_nanosleep_time64)
+	__nolibc_assert_time64_type(rqtp->tv_sec);
+	return __nolibc_syscall4(__NR_clock_nanosleep_time64, clockid, flags, rqtp, rmtp);
+#else
+	__nolibc_assert_native_time64();
+	return __nolibc_syscall4(__NR_clock_nanosleep, clockid, flags, rqtp, rmtp);
+#endif
+}
+
+static __attribute__((unused))
+int clock_nanosleep(clockid_t clockid, int flags, const struct timespec *rqtp,
+		    struct timespec *rmtp)
+{
+	/* Directly return a positive error number */
+	return -_sys_clock_nanosleep(clockid, flags, rqtp, rmtp);
+}
+
+static __inline__
+double difftime(time_t time1, time_t time2)
+{
+	return time1 - time2;
+}
+
+static __inline__
+int nanosleep(const struct timespec *rqtp, struct timespec *rmtp)
+{
+	return __sysret(_sys_clock_nanosleep(CLOCK_REALTIME, 0, rqtp, rmtp));
+}
+
+
+static __attribute__((unused))
+time_t time(time_t *tptr)
+{
+	struct timeval tv;
+
+	/* note, cannot fail here */
+	_sys_gettimeofday(&tv, NULL);
+
+	if (tptr)
+		*tptr = tv.tv_sec;
+	return tv.tv_sec;
+}
+
+
+/*
+ * int timer_create(clockid_t clockid, struct sigevent *evp, timer_t *timerid);
+ * int timer_gettime(timer_t timerid, struct itimerspec *curr_value);
+ * int timer_settime(timer_t timerid, int flags, const struct itimerspec *new_value, struct itimerspec *old_value);
+ */
+
+static __attribute__((unused))
+int _sys_timer_create(clockid_t clockid, struct sigevent *evp, timer_t *timerid)
+{
+	return __nolibc_syscall3(__NR_timer_create, clockid, evp, timerid);
+}
+
+static __attribute__((unused))
+int timer_create(clockid_t clockid, struct sigevent *evp, timer_t *timerid)
+{
+	return __sysret(_sys_timer_create(clockid, evp, timerid));
+}
+
+static __attribute__((unused))
+int _sys_timer_delete(timer_t timerid)
+{
+	return __nolibc_syscall1(__NR_timer_delete, timerid);
+}
+
+static __attribute__((unused))
+int timer_delete(timer_t timerid)
+{
+	return __sysret(_sys_timer_delete(timerid));
+}
+
+static __attribute__((unused))
+int _sys_timer_gettime(timer_t timerid, struct itimerspec *curr_value)
+{
+#if defined(__NR_timer_gettime64)
+	__nolibc_assert_time64_type(curr_value->it_value.tv_sec);
+	return __nolibc_syscall2(__NR_timer_gettime64, timerid, curr_value);
+#else
+	__nolibc_assert_native_time64();
+	return __nolibc_syscall2(__NR_timer_gettime, timerid, curr_value);
+#endif
+}
+
+static __attribute__((unused))
+int timer_gettime(timer_t timerid, struct itimerspec *curr_value)
+{
+	return __sysret(_sys_timer_gettime(timerid, curr_value));
+}
+
+static __attribute__((unused))
+int _sys_timer_settime(timer_t timerid, int flags,
+		       const struct itimerspec *new_value, struct itimerspec *old_value)
+{
+#if defined(__NR_timer_settime64)
+	__nolibc_assert_time64_type(new_value->it_value.tv_sec);
+	return __nolibc_syscall4(__NR_timer_settime64, timerid, flags, new_value, old_value);
+#else
+	__nolibc_assert_native_time64();
+	return __nolibc_syscall4(__NR_timer_settime, timerid, flags, new_value, old_value);
+#endif
+}
+
+static __attribute__((unused))
+int timer_settime(timer_t timerid, int flags,
+		  const struct itimerspec *new_value, struct itimerspec *old_value)
+{
+	return __sysret(_sys_timer_settime(timerid, flags, new_value, old_value));
+}
+
+#endif /* _NOLIBC_TIME_H */