[PATCH v3 1/3] crash: Exclude crash kernel memory in crash core
Jinjie Ruan
ruanjinjie at huawei.com
Wed Feb 4 01:37:26 PST 2026
The exclude of crashk_res, crashk_low_res and crashk_cma memory
are almost identical across different architectures, so handling them
in the crash core would eliminate a lot of duplication, so do
them in the common code.
Signed-off-by: Jinjie Ruan <ruanjinjie at huawei.com>
---
arch/arm64/kernel/machine_kexec_file.c | 12 -------
arch/loongarch/kernel/machine_kexec_file.c | 12 -------
arch/powerpc/kexec/ranges.c | 16 ++-------
arch/riscv/kernel/machine_kexec_file.c | 5 +--
arch/x86/kernel/crash.c | 39 ++--------------------
kernel/crash_core.c | 28 ++++++++++++++++
6 files changed, 34 insertions(+), 78 deletions(-)
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index 410060ebd86d..ed2c45007158 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -64,20 +64,8 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
cmem->nr_ranges++;
}
- /* Exclude crashkernel region */
- ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
- if (ret)
- goto out;
-
- if (crashk_low_res.end) {
- ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
- if (ret)
- goto out;
- }
-
ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
-out:
kfree(cmem);
return ret;
}
diff --git a/arch/loongarch/kernel/machine_kexec_file.c b/arch/loongarch/kernel/machine_kexec_file.c
index fb57026f5f25..26f867e53955 100644
--- a/arch/loongarch/kernel/machine_kexec_file.c
+++ b/arch/loongarch/kernel/machine_kexec_file.c
@@ -80,20 +80,8 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
cmem->nr_ranges++;
}
- /* Exclude crashkernel region */
- ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
- if (ret < 0)
- goto out;
-
- if (crashk_low_res.end) {
- ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
- if (ret < 0)
- goto out;
- }
-
ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
-out:
kfree(cmem);
return ret;
}
diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c
index 867135560e5c..3f76dd266b1f 100644
--- a/arch/powerpc/kexec/ranges.c
+++ b/arch/powerpc/kexec/ranges.c
@@ -553,9 +553,7 @@ int get_usable_memory_ranges(struct crash_mem **mem_ranges)
#endif /* CONFIG_KEXEC_FILE */
#ifdef CONFIG_CRASH_DUMP
-static int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges,
- unsigned long long mstart,
- unsigned long long mend)
+static int crash_realloc_mem_range_guarded(struct crash_mem **mem_ranges)
{
struct crash_mem *tmem = *mem_ranges;
@@ -566,7 +564,7 @@ static int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges,
return -ENOMEM;
}
- return crash_exclude_mem_range(tmem, mstart, mend);
+ return 0;
}
/**
@@ -604,18 +602,10 @@ int get_crash_memory_ranges(struct crash_mem **mem_ranges)
sort_memory_ranges(*mem_ranges, true);
}
- /* Exclude crashkernel region */
- ret = crash_exclude_mem_range_guarded(mem_ranges, crashk_res.start, crashk_res.end);
+ ret = crash_realloc_mem_range_guarded(mem_ranges);
if (ret)
goto out;
- for (i = 0; i < crashk_cma_cnt; ++i) {
- ret = crash_exclude_mem_range_guarded(mem_ranges, crashk_cma_ranges[i].start,
- crashk_cma_ranges[i].end);
- if (ret)
- goto out;
- }
-
/*
* FIXME: For now, stay in parity with kexec-tools but if RTAS/OPAL
* regions are exported to save their context at the time of
diff --git a/arch/riscv/kernel/machine_kexec_file.c b/arch/riscv/kernel/machine_kexec_file.c
index dd9d92a96517..fec3622a13c9 100644
--- a/arch/riscv/kernel/machine_kexec_file.c
+++ b/arch/riscv/kernel/machine_kexec_file.c
@@ -74,10 +74,7 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
if (ret)
goto out;
- /* Exclude crashkernel region */
- ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
- if (!ret)
- ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
+ ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
out:
kfree(cmem);
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index 335fd2ee9766..d8341a48f6b3 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -186,41 +186,6 @@ static struct crash_mem *fill_up_crash_elf_data(void)
return cmem;
}
-/*
- * Look for any unwanted ranges between mstart, mend and remove them. This
- * might lead to split and split ranges are put in cmem->ranges[] array
- */
-static int elf_header_exclude_ranges(struct crash_mem *cmem)
-{
- int ret = 0;
- int i;
-
- /* Exclude the low 1M because it is always reserved */
- ret = crash_exclude_mem_range(cmem, 0, SZ_1M - 1);
- if (ret)
- return ret;
-
- /* Exclude crashkernel region */
- ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
- if (ret)
- return ret;
-
- if (crashk_low_res.end)
- ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
- crashk_low_res.end);
- if (ret)
- return ret;
-
- for (i = 0; i < crashk_cma_cnt; ++i) {
- ret = crash_exclude_mem_range(cmem, crashk_cma_ranges[i].start,
- crashk_cma_ranges[i].end);
- if (ret)
- return ret;
- }
-
- return 0;
-}
-
static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
{
struct crash_mem *cmem = arg;
@@ -247,8 +212,8 @@ static int prepare_elf_headers(void **addr, unsigned long *sz,
if (ret)
goto out;
- /* Exclude unwanted mem ranges */
- ret = elf_header_exclude_ranges(cmem);
+ /* Exclude the low 1M because it is always reserved */
+ ret = crash_exclude_mem_range(cmem, 0, SZ_1M - 1);
if (ret)
goto out;
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 99dac1aa972a..5c0de111ddc3 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -18,6 +18,7 @@
#include <linux/memblock.h>
#include <linux/kmemleak.h>
#include <linux/crash_core.h>
+#include <linux/crash_reserve.h>
#include <linux/reboot.h>
#include <linux/btf.h>
#include <linux/objtool.h>
@@ -161,8 +162,30 @@ static inline resource_size_t crash_resource_size(const struct resource *res)
return !res->end ? 0 : resource_size(res);
}
+static int crash_exclude_mem_ranges(struct crash_mem *cmem)
+{
+ int ret, i;
+
+ /* Exclude crashkernel region */
+ ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
+ if (ret)
+ return ret;
+
+ if (crashk_low_res.end) {
+ ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
+ if (ret)
+ return ret;
+ }
+ for (i = 0; i < crashk_cma_cnt; ++i) {
+ ret = crash_exclude_mem_range(cmem, crashk_cma_ranges[i].start,
+ crashk_cma_ranges[i].end);
+ if (ret)
+ return ret;
+ }
+ return ret;
+}
int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
void **addr, unsigned long *sz)
@@ -174,6 +197,11 @@ int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
unsigned int cpu, i;
unsigned long long notes_addr;
unsigned long mstart, mend;
+ int ret;
+
+ ret = crash_exclude_mem_ranges(mem);
+ if (ret)
+ return ret;
/* extra phdr for vmcoreinfo ELF note */
nr_phdr = nr_cpus + 1;
--
2.34.1
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