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. Not reserving
image->dm_crypt_keys_addr makes it implicitly to disallow using this
API. 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")
Reviewed-by: Sourabh Jain <[email protected]>
Signed-off-by: Coiby Xu <[email protected]>
---
Documentation/admin-guide/kdump/kdump.rst | 16 ++++++++++------
kernel/crash_dump_dm_crypt.c | 12 ++++++++----
2 files changed, 18 insertions(+), 10 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 bc70fbb79e0f..666c1f0c9e3b 100644
--- a/kernel/crash_dump_dm_crypt.c
+++ b/kernel/crash_dump_dm_crypt.c
@@ -324,7 +324,7 @@ static ssize_t config_keys_reuse_store(struct config_item
*item,
r = -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");
+ pr_debug("dm-crypt keys haven't be saved to crash-reserved
memory or crash hotplug supported\n");
goto unlock;
}
@@ -522,14 +522,18 @@ int crash_load_dm_crypt_keys(struct kimage *image)
void crash_dm_crypt_cleanup(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);
keys_header = NULL;
}
+#ifdef CONFIG_CRASH_HOTPLUG
+ if (image->hotplug_support)
+ image->dm_crypt_keys_addr = 0;
+#endif
}
static int __init configfs_dmcrypt_keys_init(void)
--
2.55.0
