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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2018-02-20 20:37:51 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2018-02-21 18:54:05 +0300 |
| commit | 33352244706369ea6736781ae41fe41692eb69bb (patch) | |
| tree | c3ea4269b95e89e4594b2023e7167a2ba8b0fa59 /init | |
| parent | f3d415ea46968ae1f9cbb9e201601d7207ce74c7 (diff) | |
| download | linux-33352244706369ea6736781ae41fe41692eb69bb.tar.xz | |
jump_label: Explicitly disable jump labels in __init code
After initmem has been freed, any jump labels in __init code are
prevented from being written to by the kernel_text_address() check in
__jump_label_update(). However, this check is quite broad. If
kernel_text_address() were to return false for any other reason, the
jump label write would fail silently with no warning.
For jump labels in module init code, entry->code is set to zero to
indicate that the entry is disabled. Do the same thing for core kernel
init code. This makes the behavior more consistent, and will also make
it more straightforward to detect non-init jump label write failures in
the next patch.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/c52825c73f3a174e8398b6898284ec20d4deb126.1519051220.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'init')
| -rw-r--r-- | init/main.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/init/main.c b/init/main.c index a8100b954839..969eaf140ef0 100644 --- a/init/main.c +++ b/init/main.c @@ -89,6 +89,7 @@ #include <linux/io.h> #include <linux/cache.h> #include <linux/rodata_test.h> +#include <linux/jump_label.h> #include <asm/io.h> #include <asm/bugs.h> @@ -1000,6 +1001,7 @@ static int __ref kernel_init(void *unused) /* need to finish all async __init code before freeing the memory */ async_synchronize_full(); ftrace_free_init_mem(); + jump_label_invalidate_init(); free_initmem(); mark_readonly(); system_state = SYSTEM_RUNNING; |