Commit-ID: c3fb3dfce2ad4e17e6f1d090b56e3d9f09a3f509
Gitweb: https://git.kernel.org/tip/c3fb3dfce2ad4e17e6f1d090b56e3d9f09a3f509
Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Mon, 19 Mar 2018 13:18:57 -0500
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 20 Mar 2018 10:51:25 +0100
jump_label: Disable jump labels in __exit code
With the following commit:
333522447063 ("jump_label: Explicitly disable jump labels in __init code")
... we explicitly disabled jump labels in __init code, so they could be
detected and not warned about in the following commit:
dc1dd184c2f0 ("jump_label: Warn on failed jump_label patching attempt")
In-kernel __exit code has the same issue. It's never used, so it's
freed along with the rest of initmem. But jump label entries in __exit
code aren't explicitly disabled, so we get the following warning when
enabling pr_debug() in __exit code:
can't patch jump_label at dmi_sysfs_exit+0x0/0x2d
WARNING: CPU: 0 PID: 22572 at kernel/jump_label.c:376 __jump_label_update+0x9d/0xb0
Fix the warning by disabling all jump labels in initmem (which includes
both __init and __exit code).
Fixes: dc1dd184c2f0 ("jump_label: Warn on failed jump_label patching attempt")
Reported-and-tested-by: Li Wang <liwang@xxxxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Jason Baron <jbaron@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Link: https://lkml.kernel.org/r/7121e6e595374f06616c505b6e690e275c0054d1.1521483452.git.jpoimboe@xxxxxxxxxx
---
include/linux/jump_label.h | 4 ++--
init/main.c | 2 +-
kernel/jump_label.c | 7 ++++---
3 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h
index 2168cc6b8b30..b46b541c67c4 100644
--- a/include/linux/jump_label.h
+++ b/include/linux/jump_label.h
@@ -151,7 +151,7 @@ extern struct jump_entry __start___jump_table[];
extern struct jump_entry __stop___jump_table[];
extern void jump_label_init(void);
-extern void jump_label_invalidate_init(void);
+extern void jump_label_invalidate_initmem(void);
extern void jump_label_lock(void);
extern void jump_label_unlock(void);
extern void arch_jump_label_transform(struct jump_entry *entry,
@@ -199,7 +199,7 @@ static __always_inline void jump_label_init(void)
static_key_initialized = true;
}
-static inline void jump_label_invalidate_init(void) {}
+static inline void jump_label_invalidate_initmem(void) {}
static __always_inline bool static_key_false(struct static_key *key)
{
diff --git a/init/main.c b/init/main.c
index 969eaf140ef0..21efbf6ace93 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1001,7 +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();
+ jump_label_invalidate_initmem();
free_initmem();
mark_readonly();
system_state = SYSTEM_RUNNING;
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index e7214093dcd1..01ebdf1f9f40 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -16,6 +16,7 @@
#include <linux/jump_label_ratelimit.h>
#include <linux/bug.h>
#include <linux/cpu.h>
+#include <asm/sections.h>
#ifdef HAVE_JUMP_LABEL
@@ -421,15 +422,15 @@ void __init jump_label_init(void)
cpus_read_unlock();
}
-/* Disable any jump label entries in __init code */
-void __init jump_label_invalidate_init(void)
+/* Disable any jump label entries in __init/__exit code */
+void __init jump_label_invalidate_initmem(void)
{
struct jump_entry *iter_start = __start___jump_table;
struct jump_entry *iter_stop = __stop___jump_table;
struct jump_entry *iter;
for (iter = iter_start; iter < iter_stop; iter++) {
- if (init_kernel_text(iter->code))
+ if (init_section_contains((void *)(unsigned long)iter->code, 1))
iter->code = 0;
}
}
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