From 91bad2f8d3057482b9afb599f14421b007136960 Mon Sep 17 00:00:00 2001 From: Jason Baron Date: Fri, 1 Oct 2010 17:23:48 -0400 Subject: jump label: Fix deadlock b/w jump_label_mutex vs. text_mutex register_kprobe() downs the 'text_mutex' and then calls jump_label_text_reserved(), which downs the 'jump_label_mutex'. However, the jump label code takes those mutexes in the reverse order. Fix by requiring the caller of jump_label_text_reserved() to do the jump label locking via the newly added: jump_label_lock(), jump_label_unlock(). Currently, kprobes is the only user of jump_label_text_reserved(). Reported-by: Ingo Molnar Acked-by: Masami Hiramatsu Signed-off-by: Jason Baron LKML-Reference: <759032c48d5e30c27f0bba003d09bffa8e9f28bb.1285965957.git.jbaron@redhat.com> Signed-off-by: Steven Rostedt --- kernel/kprobes.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel/kprobes.c') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 99865c33a60..9437e14f36b 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1146,13 +1146,16 @@ int __kprobes register_kprobe(struct kprobe *p) return ret; preempt_disable(); + jump_label_lock(); if (!kernel_text_address((unsigned long) p->addr) || in_kprobes_functions((unsigned long) p->addr) || ftrace_text_reserved(p->addr, p->addr) || jump_label_text_reserved(p->addr, p->addr)) { preempt_enable(); + jump_label_unlock(); return -EINVAL; } + jump_label_unlock(); /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ p->flags &= KPROBE_FLAG_DISABLED; @@ -1187,6 +1190,8 @@ int __kprobes register_kprobe(struct kprobe *p) INIT_LIST_HEAD(&p->list); mutex_lock(&kprobe_mutex); + jump_label_lock(); /* needed to call jump_label_text_reserved() */ + get_online_cpus(); /* For avoiding text_mutex deadlock. */ mutex_lock(&text_mutex); @@ -1214,6 +1219,7 @@ int __kprobes register_kprobe(struct kprobe *p) out: mutex_unlock(&text_mutex); put_online_cpus(); + jump_label_unlock(); mutex_unlock(&kprobe_mutex); if (probed_mod) -- cgit v1.2.3