diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 5d78b6a..2feab13 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -997,7 +997,7 @@ static void __init reserve_crashkernel(void)
 	total_mem = get_total_mem();
 	ret = parse_crashkernel(boot_command_line, total_mem,
 				&crash_size, &crash_base);
-	if (ret)
+	if (ret < 0)
 		return;
 
 	if (crash_base <= 0) {
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 6bc1350..240918c 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -79,7 +79,7 @@ static void __init reserve_crashkernel(void)
 	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
 				&crash_size, &crash_base);
 	/* no crashkernel= or invalid value specified */
-	if (ret || !crash_size)
+	if (ret < 0)
 		return;
 
 	crash_size = PAGE_ALIGN(crash_size);
diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c
index 583a374..99cae33 100644
--- a/arch/ia64/kernel/setup.c
+++ b/arch/ia64/kernel/setup.c
@@ -277,7 +277,7 @@ static void __init setup_crashkernel(unsigned long total, int *n)
 
 	ret = parse_crashkernel(boot_command_line, total,
 			&size, &base);
-	if (ret == 0 && size > 0) {
+	if (ret >= 0) {
 		if (!base) {
 			sort_regions(rsvd_region, *n);
 			*n = merge_regions(rsvd_region, *n);
diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 8d1dc6c..168571b 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -715,7 +715,7 @@ static void __init mips_parse_crashkernel(void)
 	total_mem = get_total_mem();
 	ret = parse_crashkernel(boot_command_line, total_mem,
 				&crash_size, &crash_base);
-	if (ret != 0 || crash_size <= 0)
+	if (ret < 0)
 		return;
 
 	if (!memory_region_available(crash_base, crash_size)) {
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 45a8d0b..0b626e2 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -376,7 +376,7 @@ static inline unsigned long fadump_calculate_reserve_size(void)
 	 */
 	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
 				&size, &base);
-	if (ret == 0 && size > 0) {
+	if (ret >= 0) {
 		unsigned long max_size;
 
 		if (fw_dump.reserve_bootvar)
diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index 63f5a93..9f3e61a 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -122,7 +122,7 @@ void __init reserve_crashkernel(void)
 	/* use common parsing */
 	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
 			&crash_size, &crash_base);
-	if (ret == 0 && crash_size > 0) {
+	if (ret >= 0) {
 		crashk_res.start = crash_base;
 		crashk_res.end = crash_base + crash_size - 1;
 	}
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 2c642af..d4bd61b 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -671,7 +671,7 @@ static void __init reserve_crashkernel(void)
 
 	crash_base = ALIGN(crash_base, KEXEC_CRASH_MEM_ALIGN);
 	crash_size = ALIGN(crash_size, KEXEC_CRASH_MEM_ALIGN);
-	if (rc || crash_size == 0)
+	if (rc < 0)
 		return;
 
 	if (memblock.memory.regions[0].size < crash_size) {
diff --git a/arch/sh/kernel/machine_kexec.c b/arch/sh/kernel/machine_kexec.c
index 63d63a3..612b21e 100644
--- a/arch/sh/kernel/machine_kexec.c
+++ b/arch/sh/kernel/machine_kexec.c
@@ -157,7 +157,7 @@ void __init reserve_crashkernel(void)
 
 	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
 			&crash_size, &crash_base);
-	if (ret == 0 && crash_size > 0) {
+	if (ret >= 0) {
 		crashk_res.start = crash_base;
 		crashk_res.end = crash_base + crash_size - 1;
 	}
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 3d872a5..62d07d4 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -526,11 +526,11 @@ static void __init reserve_crashkernel(void)
 
 	/* crashkernel=XM */
 	ret = parse_crashkernel(boot_command_line, total_mem, &crash_size, &crash_base);
-	if (ret != 0 || crash_size <= 0) {
+	if (ret == -EINVAL) {
 		/* crashkernel=X,high */
 		ret = parse_crashkernel_high(boot_command_line, total_mem,
 					     &crash_size, &crash_base);
-		if (ret != 0 || crash_size <= 0)
+		if (ret < 0)
 			return;
 		high = true;
 	}
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 093c9f9..563d86d 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -87,7 +87,7 @@ static int __init parse_crashkernel_mem(char *cmdline,
 		cur = tmp;
 		if (size >= system_ram) {
 			pr_warn("crashkernel: invalid size\n");
-			return -EINVAL;
+			return -1;
 		}
 
 		/* match ? */
@@ -108,8 +108,10 @@ static int __init parse_crashkernel_mem(char *cmdline,
 				return -EINVAL;
 			}
 		}
-	} else
+	} else {
 		pr_info("crashkernel size resulted in zero bytes\n");
+		return -1;
+	}
 
 	return 0;
 }
@@ -139,6 +141,8 @@ static int __init parse_crashkernel_simple(char *cmdline,
 		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
 		return -EINVAL;
 	}
+	if (*crash_size == 0)
+		return -1;
 
 	return 0;
 }
@@ -181,6 +185,8 @@ static int __init parse_crashkernel_suffix(char *cmdline,
 		pr_warn("crashkernel: unrecognized char: %c\n", *cur);
 		return -EINVAL;
 	}
+	if (*crash_size == 0)
+		return -1;
 
 	return 0;
 }
@@ -266,6 +272,8 @@ static int __init __parse_crashkernel(char *cmdline,
 /*
  * That function is the entry point for command line parsing and should be
  * called from the arch-specific code.
+ * On success 0 or 1 if @offset is given. On error -EINVAL if bad syntax,
+ * or -1 if the parsing results in crash_size=0.
  */
 int __init parse_crashkernel(char *cmdline,
 			     unsigned long long system_ram,
