Usually crash_image is defined statically via the crashkernel parameter
or DT.
But if the crash kernel is not used, or is smaller than then
area pre-allocated that memory is wasted.
Also, if the crash kernel was not defined at bootime, there is no way to
use the crash kernel.
Enable runtime allocation of the crash_image if the crash_image is not
defined statically. Following the same memory allocation/validation path
that for the reboot kexec kernel.
Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
---
kexec: Enable runtime allocation of crash_image
To: Eric Biederman <ebiederm@xxxxxxxxxxxx>
Cc: kexec@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: Ross Zwisler <zwisler@xxxxxxxxxx>
Cc: Philipp Rudo <prudo@xxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
---
include/linux/kexec.h | 1 +
kernel/kexec.c | 9 +++++----
kernel/kexec_core.c | 5 +++++
kernel/kexec_file.c | 7 ++++---
4 files changed, 15 insertions(+), 7 deletions(-)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 41a686996aaa..98ca9a32bc8e 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -427,6 +427,7 @@ extern int kexec_load_disabled;
extern bool kexec_in_progress;
int crash_shrink_memory(unsigned long new_size);
+bool __crash_memory_valid(void);
ssize_t crash_get_memory_size(void);
#ifndef arch_kexec_protect_crashkres
diff --git a/kernel/kexec.c b/kernel/kexec.c
index cb8e6e6f983c..b5c17db25e88 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -28,7 +28,7 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
struct kimage *image;
bool kexec_on_panic = flags & KEXEC_ON_CRASH;
- if (kexec_on_panic) {
+ if (kexec_on_panic && __crash_memory_valid()) {
/* Verify we have a valid entry point */
if ((entry < phys_to_boot_phys(crashk_res.start)) ||
(entry > phys_to_boot_phys(crashk_res.end)))
@@ -44,7 +44,7 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry,
image->nr_segments = nr_segments;
memcpy(image->segment, segments, nr_segments * sizeof(*segments));
- if (kexec_on_panic) {
+ if (kexec_on_panic && __crash_memory_valid()) {
/* Enable special crash kernel control page alloc policy. */
image->control_page = crashk_res.start;
image->type = KEXEC_TYPE_CRASH;
@@ -101,7 +101,7 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
if (flags & KEXEC_ON_CRASH) {
dest_image = &kexec_crash_image;
- if (kexec_crash_image)
+ if (kexec_crash_image && __crash_memory_valid())
arch_kexec_unprotect_crashkres();
} else {
dest_image = &kexec_image;
@@ -157,7 +157,8 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
image = xchg(dest_image, image);
out:
- if ((flags & KEXEC_ON_CRASH) && kexec_crash_image)
+ if ((flags & KEXEC_ON_CRASH) && kexec_crash_image &&
+ __crash_memory_valid())
arch_kexec_protect_crashkres();
kimage_free(image);
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index ca2743f9c634..77083c9760fb 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -1004,6 +1004,11 @@ void crash_kexec(struct pt_regs *regs)
}
}
+bool __crash_memory_valid(void)
+{
+ return crashk_res.end != crashk_res.start;
+}
+
ssize_t crash_get_memory_size(void)
{
ssize_t size = 0;
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 45637511e0de..0671f4f370ff 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -280,7 +280,7 @@ kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
image->file_mode = 1;
- if (kexec_on_panic) {
+ if (kexec_on_panic && __crash_memory_valid()) {
/* Enable special crash kernel control page alloc policy. */
image->control_page = crashk_res.start;
image->type = KEXEC_TYPE_CRASH;
@@ -345,7 +345,7 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
dest_image = &kexec_image;
if (flags & KEXEC_FILE_ON_CRASH) {
dest_image = &kexec_crash_image;
- if (kexec_crash_image)
+ if (kexec_crash_image && __crash_memory_valid())
arch_kexec_unprotect_crashkres();
}
@@ -408,7 +408,8 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
exchange:
image = xchg(dest_image, image);
out:
- if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image)
+ if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image &&
+ __crash_memory_valid())
arch_kexec_protect_crashkres();
kexec_unlock();
---
base-commit: 4312098baf37ee17a8350725e6e0d0e8590252d4
change-id: 20221124-kexec-noalloc-3cab3cbe000f
Best regards,
--
Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
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