diff options
| author | Miroslav Benes <mbenes@suse.cz> | 2018-01-10 13:01:28 +0300 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2018-01-11 12:58:03 +0300 |
| commit | d0807da78e11d46f18399cbf8c4028c731346766 (patch) | |
| tree | 7421d9d68ae0d159c816995564984a0c0cfcc26a /include/linux/livepatch.h | |
| parent | c99a2be790b07752d8cc694434d3450afd4c5a00 (diff) | |
| download | linux-d0807da78e11d46f18399cbf8c4028c731346766.tar.xz | |
livepatch: Remove immediate feature
Immediate flag has been used to disable per-task consistency and patch
all tasks immediately. It could be useful if the patch doesn't change any
function or data semantics.
However, it causes problems on its own. The consistency problem is
currently broken with respect to immediate patches.
func a
patches 1i
2i
3
When the patch 3 is applied, only 2i function is checked (by stack
checking facility). There might be a task sleeping in 1i though. Such
task is migrated to 3, because we do not check 1i in
klp_check_stack_func() at all.
Coming atomic replace feature would be easier to implement and more
reliable without immediate.
Thus, remove immediate feature completely and save us from the problems.
Note that force feature has the similar problem. However it is
considered as a last resort. If used, administrator should not apply any
new live patches and should plan for reboot into an updated kernel.
The architectures would now need to provide HAVE_RELIABLE_STACKTRACE to
fully support livepatch.
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'include/linux/livepatch.h')
| -rw-r--r-- | include/linux/livepatch.h | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h index fc5c1be3f6f4..4754f01c1abb 100644 --- a/include/linux/livepatch.h +++ b/include/linux/livepatch.h @@ -40,7 +40,6 @@ * @new_func: pointer to the patched function code * @old_sympos: a hint indicating which symbol position the old function * can be found (optional) - * @immediate: patch the func immediately, bypassing safety mechanisms * @old_addr: the address of the function being patched * @kobj: kobject for sysfs resources * @stack_node: list node for klp_ops func_stack list @@ -76,7 +75,6 @@ struct klp_func { * in kallsyms for the given object is used. */ unsigned long old_sympos; - bool immediate; /* internal */ unsigned long old_addr; @@ -137,7 +135,6 @@ struct klp_object { * struct klp_patch - patch structure for live patching * @mod: reference to the live patch module * @objs: object entries for kernel objects to be patched - * @immediate: patch all funcs immediately, bypassing safety mechanisms * @list: list node for global list of registered patches * @kobj: kobject for sysfs resources * @enabled: the patch is enabled (but operation may be incomplete) @@ -147,7 +144,6 @@ struct klp_patch { /* external */ struct module *mod; struct klp_object *objs; - bool immediate; /* internal */ struct list_head list; |