Commit-ID: dc1dd184c2f0016bec35c0d7a48c057e0ad763d3 Gitweb: https://git.kernel.org/tip/dc1dd184c2f0016bec35c0d7a48c057e0ad763d3 Author: Josh Poimboeuf <jpoim...@redhat.com> AuthorDate: Tue, 20 Feb 2018 11:37:52 -0600 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Wed, 21 Feb 2018 16:54:06 +0100
jump_label: Warn on failed jump_label patching attempt Currently when the jump label code encounters an address which isn't recognized by kernel_text_address(), it just silently fails. This can be dangerous because jump labels are used in a variety of places, and are generally expected to work. Convert the silent failure to a warning. This won't warn about attempted writes to tracepoints in __init code after initmem has been freed, as those are already guarded by the entry->code check. Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com> Acked-by: Peter Zijlstra <pet...@infradead.org> Cc: Borislav Petkov <b...@suse.de> Cc: Jason Baron <jba...@akamai.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Steven Rostedt <rost...@goodmis.org> Cc: Thomas Gleixner <t...@linutronix.de> Link: http://lkml.kernel.org/r/de3a271c93807adb7ed48f4e946b4f9156617680.1519051220.git.jpoim...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/jump_label.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/kernel/jump_label.c b/kernel/jump_label.c index b717765..b2f0b47 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -367,12 +367,15 @@ static void __jump_label_update(struct static_key *key, { for (; (entry < stop) && (jump_entry_key(entry) == key); entry++) { /* - * entry->code set to 0 invalidates module init text sections - * kernel_text_address() verifies we are not in core kernel - * init code, see jump_label_invalidate_module_init(). + * An entry->code of 0 indicates an entry which has been + * disabled because it was in an init text area. */ - if (entry->code && kernel_text_address(entry->code)) - arch_jump_label_transform(entry, jump_label_type(entry)); + if (entry->code) { + if (kernel_text_address(entry->code)) + arch_jump_label_transform(entry, jump_label_type(entry)); + else + WARN_ONCE(1, "can't patch jump_label at %pS", (void *)entry->code); + } } }
