If crash hotplug is supported, dm-crypt keys saved to reserved memory
will be taken care of automatically. Thus it doesn't make sense to use
configfs/crash_dm_crypt_key/reuse. Reserving image->dm_crypt_keys_addr
is also unnecessary. Currently x86_64 and ppc64le have implemented
crash hotplug feature.
Also update the doc accordingly. Note two doc issues are fixed as well.
Fixes: 9ebfa8dcaea7 ("crash_dump: reuse saved dm crypt keys for CPU/memory
hot-plugging")
Signed-off-by: Coiby Xu <[email protected]>
---
Documentation/admin-guide/kdump/kdump.rst | 16 ++++++++++------
kernel/crash_dump_dm_crypt.c | 23 ++++++++++++++++++++---
2 files changed, 30 insertions(+), 9 deletions(-)
diff --git a/Documentation/admin-guide/kdump/kdump.rst
b/Documentation/admin-guide/kdump/kdump.rst
index 7587caadbae1..0bf2eb100a05 100644
--- a/Documentation/admin-guide/kdump/kdump.rst
+++ b/Documentation/admin-guide/kdump/kdump.rst
@@ -577,9 +577,10 @@ with /sys/kernel/config/crash_dm_crypt_keys for setup,
1. Tell the first kernel what logon keys are needed to unlock the disk volumes,
# Add key #1
- mkdir
/sys/kernel/config/crash_dm_crypt_keys/7d26b7b4-e342-4d2d-b660-7426b0996720
+ VOL1_UUID=7d26b7b4-e342-4d2d-b660-7426b0996720
+ mkdir /sys/kernel/config/crash_dm_crypt_keys/$VOL1_UUID
# Add key #1's description
- echo cryptsetup:7d26b7b4-e342-4d2d-b660-7426b0996720 >
/sys/kernel/config/crash_dm_crypt_keys/description
+ echo cryptsetup:$VOL1_UUID >
/sys/kernel/config/crash_dm_crypt_keys/$VOL1_UUID/description
# how many keys do we have now?
cat /sys/kernel/config/crash_dm_crypt_keys/count
@@ -591,15 +592,18 @@ with /sys/kernel/config/crash_dm_crypt_keys for setup,
cat /sys/kernel/config/crash_dm_crypt_keys/count
2
- # To support CPU/memory hot-plugging, reuse keys already saved to reserved
- # memory
- echo true > /sys/kernel/config/crash_dm_crypt_key/reuse
-
2. Load the dump-capture kernel
3. After the dump-capture kerne get booted, restore the keys to user keyring
echo yes > /sys/kernel/crash_dm_crypt_keys/restore
+For CPU/memory hot-plugging, you can reuse keys already saved to reserved
+memory before reloading the kdump image,
+ echo true > /sys/kernel/config/crash_dm_crypt_keys/reuse
+
+Note if crash hotplug is supported, this API is totally unnecessary thus will
+be disabled automatically.
+
Contact
=======
diff --git a/kernel/crash_dump_dm_crypt.c b/kernel/crash_dump_dm_crypt.c
index b5b78656cf06..46d6b31c3ca4 100644
--- a/kernel/crash_dump_dm_crypt.c
+++ b/kernel/crash_dump_dm_crypt.c
@@ -310,6 +310,15 @@ static ssize_t config_keys_reuse_show(struct config_item
*item, char *page)
return sysfs_emit(page, "%d\n", is_dm_key_reused);
}
+static bool crash_hotplug_support(struct kimage *image)
+{
+#ifdef CONFIG_CRASH_HOTPLUG
+ return image->hotplug_support;
+#else
+ return false;
+#endif
+}
+
static ssize_t config_keys_reuse_store(struct config_item *item,
const char *page, size_t count)
{
@@ -317,6 +326,11 @@ static ssize_t config_keys_reuse_store(struct config_item
*item,
bool val;
int r;
+ if (kexec_crash_image && crash_hotplug_support(kexec_crash_image)) {
+ pr_debug("Crash hotplug supported\n");
+ return -EINVAL;
+ }
+
if (!kexec_crash_image || !kexec_crash_image->dm_crypt_keys_addr) {
pr_debug("dm-crypt keys haven't be saved to crash-reserved
memory\n");
return -EINVAL;
@@ -513,9 +527,9 @@ int crash_load_dm_crypt_keys(struct kimage *image)
void kexec_file_post_load_cleanup_dm_crypt(struct kimage *image)
{
/*
- * For CPU/memory hot-plugging, the kdump image will be reloaded.
Prevent
- * keys_header from being cleaned up during unloading when
- * is_dm_key_reused=true
+ * For CPU/memory hot-plugging without CONFIG_CRASH_HOTPLUG, the whole
kdump
+ * image will be reloaded. Prevent keys_header from being cleaned up
during
+ * unloading when is_dm_key_reused=true
*/
if (!is_dm_key_reused) {
kfree_sensitive(keys_header);
@@ -526,6 +540,9 @@ void kexec_file_post_load_cleanup_dm_crypt(struct kimage
*image)
mutex_unlock(&config_keys_subsys.su_mutex);
mutex_acquired = false;
}
+
+ if (crash_hotplug_support(image))
+ image->dm_crypt_keys_addr = 0;
}
static int __init configfs_dmcrypt_keys_init(void)
--
2.55.0
