diff --git a/kexec-tools-2.0.23-01-_PATCH_v2_1_3_add_generic_cycle_detection.patch b/kexec-tools-2.0.23-01-_PATCH_v2_1_3_add_generic_cycle_detection.patch
new file mode 100644
index 0000000..4ecbc58
--- /dev/null
+++ b/kexec-tools-2.0.23-01-_PATCH_v2_1_3_add_generic_cycle_detection.patch
@@ -0,0 +1,191 @@
+ commit feae3d1754d2b0788ce1f18b0cd4b40098ff52ff
+ Author: Philipp Rudo <prudo@redhat.com>
+ Date: Mon Mar 14 17:04:29 2022 +0100
+
+ [PATCH v2 1/3] add generic cycle detection
+
+ In order to work makedumpfile needs to interpret data read from the
+ dump. This can cause problems as the data from the dump cannot be
+ trusted (otherwise the kernel wouldn't have panicked in the first
+ place). This also means that every loop which stop condition depend on
+ data read from the dump has a chance to loop forever. Thus add a generic
+ cycle detection mechanism that allows to detect and handle such
+ situations appropriately.
+
+ For cycle detection use Brent's algorithm [1] as it has constant memory
+ usage. With this it can also be used in the kdump kernel without the
+ danger that it runs oom when iterating large data structures.
+ Furthermore it only depends on some pointer arithmetic. Thus the
+ performance impact (as long as no cycle was detected) should be
+ comparatively small.
+
+ [1] https://en.wikipedia.org/wiki/Cycle_detection#Brent's_algorithm
+
+ Suggested-by: Dave Wysochanski <dwysocha@redhat.com>
+ Signed-off-by: Philipp Rudo <prudo@redhat.com>
+ Reviewed-and-tested-by: Dave Wysochanski <dwysocha@redhat.com>
+
+ diff --git a/makedumpfile-1.7.0/Makefile b/makedumpfile-1.7.0/Makefile
+ index f118b31e45989d9590ae075fb9b8ed2f27353a92..3441364cb6c7103a20072bd50ec58f1eed01ab69 100644
+ --- a/makedumpfile-1.7.0/Makefile
+ +++ b/makedumpfile-1.7.0/Makefile
+ @@ -45,7 +45,7 @@ CFLAGS_ARCH += -m32
+ endif
+
+ SRC_BASE = makedumpfile.c makedumpfile.h diskdump_mod.h sadump_mod.h sadump_info.h
+ -SRC_PART = print_info.c dwarf_info.c elf_info.c erase_info.c sadump_info.c cache.c tools.c printk.c
+ +SRC_PART = print_info.c dwarf_info.c elf_info.c erase_info.c sadump_info.c cache.c tools.c printk.c detect_cycle.c
+ OBJ_PART=$(patsubst %.c,%.o,$(SRC_PART))
+ SRC_ARCH = arch/arm.c arch/arm64.c arch/x86.c arch/x86_64.c arch/ia64.c arch/ppc64.c arch/s390x.c arch/ppc.c arch/sparc64.c arch/mips64.c
+ OBJ_ARCH=$(patsubst %.c,%.o,$(SRC_ARCH))
+ diff --git a/makedumpfile-1.7.0/detect_cycle.c b/makedumpfile-1.7.0/detect_cycle.c
+ new file mode 100644
+ index 0000000000000000000000000000000000000000..6b551a75d1c83d64fba2c078be8133efbc791fbe
+ --- /dev/null
+ +++ b/makedumpfile-1.7.0/detect_cycle.c
+ @@ -0,0 +1,99 @@
+ +/*
+ + * detect_cycle.c -- Generic cycle detection using Brent's algorithm
+ + *
+ + * Created by: Philipp Rudo <prudo@redhat.com>
+ + *
+ + * Copyright (c) 2022 Red Hat, Inc. All rights reserved.
+ + *
+ + * This program is free software; you can redistribute it and/or modify
+ + * it under the terms of the GNU General Public License as published by
+ + * the Free Software Foundation; either version 2 of the License, or
+ + * (at your option) any later version.
+ + *
+ + * This program is distributed in the hope that it will be useful,
+ + * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ + * GNU General Public License for more details.
+ + */
+ +
+ +#include <stdlib.h>
+ +
+ +#include "detect_cycle.h"
+ +
+ +struct detect_cycle {
+ + /* First entry of the list */
+ + void *head;
+ +
+ + /* Variables required by Brent's algorithm */
+ + void *fast_p;
+ + void *slow_p;
+ + unsigned long length;
+ + unsigned long power;
+ +
+ + /* Function to get the next entry in the list */
+ + dc_next_t next;
+ +
+ + /* Private data passed to next */
+ + void *data;
+ +};
+ +
+ +struct detect_cycle *dc_init(void *head, void *data, dc_next_t next)
+ +{
+ + struct detect_cycle *new;
+ +
+ + new = malloc(sizeof(*new));
+ + if (!new)
+ + return NULL;
+ +
+ + new->next = next;
+ + new->data = data;
+ +
+ + new->head = head;
+ + new->slow_p = head;
+ + new->fast_p = head;
+ + new->length = 0;
+ + new->power = 2;
+ +
+ + return new;
+ +}
+ +
+ +int dc_next(struct detect_cycle *dc, void **next)
+ +{
+ +
+ + if (dc->length == dc->power) {
+ + dc->length = 0;
+ + dc->power *= 2;
+ + dc->slow_p = dc->fast_p;
+ + }
+ +
+ + dc->fast_p = dc->next(dc->fast_p, dc->data);
+ + dc->length++;
+ +
+ + if (dc->slow_p == dc->fast_p)
+ + return 1;
+ +
+ + *next = dc->fast_p;
+ + return 0;
+ +}
+ +
+ +void dc_find_start(struct detect_cycle *dc, void **first, unsigned long *len)
+ +{
+ + void *slow_p, *fast_p;
+ + unsigned long tmp;
+ +
+ + slow_p = fast_p = dc->head;
+ + tmp = dc->length;
+ +
+ + while (tmp) {
+ + fast_p = dc->next(fast_p, dc->data);
+ + tmp--;
+ + }
+ +
+ + while (slow_p != fast_p) {
+ + slow_p = dc->next(slow_p, dc->data);
+ + fast_p = dc->next(fast_p, dc->data);
+ + }
+ +
+ + *first = slow_p;
+ + *len = dc->length;
+ +}
+ diff --git a/makedumpfile-1.7.0/detect_cycle.h b/makedumpfile-1.7.0/detect_cycle.h
+ new file mode 100644
+ index 0000000000000000000000000000000000000000..2ca75c78b59a98274fc5a98666b1be74f7bbfc2c
+ --- /dev/null
+ +++ b/makedumpfile-1.7.0/detect_cycle.h
+ @@ -0,0 +1,40 @@
+ +/*
+ + * detect_cycle.h -- Generic cycle detection using Brent's algorithm
+ + *
+ + * Created by: Philipp Rudo <prudo@redhat.com>
+ + *
+ + * Copyright (c) 2022 Red Hat, Inc. All rights reserved.
+ + *
+ + * This program is free software; you can redistribute it and/or modify
+ + * it under the terms of the GNU General Public License as published by
+ + * the Free Software Foundation; either version 2 of the License, or
+ + * (at your option) any later version.
+ + *
+ + * This program is distributed in the hope that it will be useful,
+ + * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ + * GNU General Public License for more details.
+ + */
+ +
+ +struct detect_cycle;
+ +
+ +typedef void *(*dc_next_t)(void *prev, void *data);
+ +
+ +/*
+ + * Initialize cycle detection.
+ + * Returns a pointer to allocated struct detect_cycle. The caller is
+ + * responsible to free the memory after use.
+ + */
+ +struct detect_cycle *dc_init(void *head, void *data, dc_next_t next);
+ +
+ +/*
+ + * Get next entry in the list using dc->next.
+ + * Returns 1 when cycle was detected, 0 otherwise.
+ + */
+ +int dc_next(struct detect_cycle *dc, void **next);
+ +
+ +/*
+ + * Get the start and length of the cycle. Must only be called after cycle was
+ + * detected by dc_next.
+ + */
+ +void dc_find_start(struct detect_cycle *dc, void **first, unsigned long *len);
diff --git a/kexec-tools.spec b/kexec-tools.spec
index 8486a4d..75c52b7 100644
--- a/kexec-tools.spec
+++ b/kexec-tools.spec
@@ -113,6 +113,7 @@ Requires: systemd-udev%{?_isa}
#
Patch601: ./kexec-tools-2.0.22-01-s390_handle_R_390_PLT32DBL_reloc_entries_in_machine_apply_elf_rel_.patch
Patch602: ./kexec-tools-2.0.23-makedumpfile-sadump-kaslr-fix-failure-of-calculating-kaslr_.patch
+Patch603: ./kexec-tools-2.0.23-01-_PATCH_v2_1_3_add_generic_cycle_detection.patch
%description
kexec-tools provides /sbin/kexec binary that facilitates a new
@@ -130,6 +131,7 @@ tar -z -x -v -f %{SOURCE19}
%patch601 -p1
%patch602 -p1
+%patch603 -p1
%ifarch ppc
%define archdef ARCH=ppc