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Mon, 22 Aug 2016 04:27:21 -0700 (PDT) Received: from ubuntu16.spreadtrum.com ([175.111.195.49]) by smtp.gmail.com with ESMTPSA id e2sm26639128pfd.45.2016.08.22.04.27.18 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 22 Aug 2016 04:27:20 -0700 (PDT) From: Chunyan Zhang To: rostedt@goodmis.org, mingo@redhat.com Cc: linux-kernel@vger.kernel.org, zhang.lyra@gmail.com Subject: [PATCH] trace: fix the errors caused by incompatible type of RCU variables Date: Mon, 22 Aug 2016 19:27:14 +0800 Message-Id: <1471865234-9859-1-git-send-email-zhang.chunyan@linaro.org> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The variables which are processed by RCU functions should be annotated as RCU, otherwise sparse will report the errors like below: "error: incompatible types in comparison expression (different address spaces)" Signed-off-by: Chunyan Zhang --- include/linux/ftrace.h | 6 +++--- include/linux/trace_events.h | 2 +- kernel/trace/ftrace.c | 36 ++++++++++++++++++++++-------------- kernel/trace/trace.h | 6 +++--- 4 files changed, 29 insertions(+), 21 deletions(-) -- 2.7.4 diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 7d565af..24f75ca 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -140,8 +140,8 @@ enum { #ifdef CONFIG_DYNAMIC_FTRACE /* The hash used to know what functions callbacks trace */ struct ftrace_ops_hash { - struct ftrace_hash *notrace_hash; - struct ftrace_hash *filter_hash; + struct ftrace_hash __rcu *notrace_hash; + struct ftrace_hash __rcu *filter_hash; struct mutex regex_lock; }; #endif @@ -159,7 +159,7 @@ struct ftrace_ops_hash { */ struct ftrace_ops { ftrace_func_t func; - struct ftrace_ops *next; + struct ftrace_ops __rcu *next; unsigned long flags; void *private; ftrace_func_t saved_func; diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index be00761..90e148c 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -331,7 +331,7 @@ enum { struct trace_event_file { struct list_head list; struct trace_event_call *event_call; - struct event_filter *filter; + struct event_filter __rcu *filter; struct dentry *dir; struct trace_array *tr; struct trace_subsystem_dir *system; diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 84752c8..088c4e7 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -111,7 +111,8 @@ static int ftrace_disabled __read_mostly; static DEFINE_MUTEX(ftrace_lock); -static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end; +static struct ftrace_ops __rcu * + ftrace_ops_list __read_mostly = &ftrace_list_end; ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; static struct ftrace_ops global_ops; @@ -167,8 +168,9 @@ int ftrace_nr_registered_ops(void) mutex_lock(&ftrace_lock); - for (ops = ftrace_ops_list; - ops != &ftrace_list_end; ops = ops->next) + for (ops = rcu_dereference_raw_notrace(ftrace_ops_list); + ops != &ftrace_list_end; + ops = rcu_dereference_raw_notrace(ops->next)) cnt++; mutex_unlock(&ftrace_lock); @@ -273,10 +275,10 @@ static void update_ftrace_function(void) * If there's only one ftrace_ops registered, the ftrace_ops_list * will point to the ops we want. */ - set_function_trace_op = ftrace_ops_list; + set_function_trace_op = rcu_dereference_raw_notrace(ftrace_ops_list); /* If there's no ftrace_ops registered, just call the stub function */ - if (ftrace_ops_list == &ftrace_list_end) { + if (set_function_trace_op == &ftrace_list_end) { func = ftrace_stub; /* @@ -284,7 +286,8 @@ static void update_ftrace_function(void) * recursion safe and not dynamic and the arch supports passing ops, * then have the mcount trampoline call the function directly. */ - } else if (ftrace_ops_list->next == &ftrace_list_end) { + } else if (rcu_dereference_raw_notrace(ftrace_ops_list->next) == + &ftrace_list_end) { func = ftrace_ops_get_list_func(ftrace_ops_list); } else { @@ -346,9 +349,11 @@ int using_ftrace_ops_list_func(void) return ftrace_trace_function == ftrace_ops_list_func; } -static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) +static void add_ftrace_ops(struct ftrace_ops __rcu **list, + struct ftrace_ops *ops) { - ops->next = *list; + rcu_assign_pointer(ops->next, *list); + /* * We are entering ops into the list but another * CPU might be walking that list. We need to make sure @@ -358,7 +363,8 @@ static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) rcu_assign_pointer(*list, ops); } -static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) +static int remove_ftrace_ops(struct ftrace_ops __rcu **list, + struct ftrace_ops *ops) { struct ftrace_ops **p; @@ -366,7 +372,8 @@ static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops) * If we are removing the last function, then simply point * to the ftrace_stub. */ - if (*list == ops && ops->next == &ftrace_list_end) { + if (rcu_dereference_raw_notrace(*list) == ops && + rcu_dereference_raw_notrace(ops->next) == &ftrace_list_end) { *list = &ftrace_list_end; return 0; } @@ -1493,8 +1500,8 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs) return 0; #endif - hash.filter_hash = rcu_dereference_raw_notrace(ops->func_hash->filter_hash); - hash.notrace_hash = rcu_dereference_raw_notrace(ops->func_hash->notrace_hash); + rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash); + rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash); if (hash_contains_ip(ip, &hash)) ret = 1; @@ -2752,7 +2759,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) * If there's no more ops registered with ftrace, run a * sanity check to make sure all rec flags are cleared. */ - if (ftrace_ops_list == &ftrace_list_end) { + if (rcu_dereference_raw_notrace(ftrace_ops_list) == &ftrace_list_end) { struct ftrace_page *pg; struct dyn_ftrace *rec; @@ -5642,7 +5649,8 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, if (ftrace_enabled) { /* we are starting ftrace again */ - if (ftrace_ops_list != &ftrace_list_end) + if (rcu_dereference_raw_notrace(ftrace_ops_list) != + &ftrace_list_end) update_ftrace_function(); ftrace_startup_sysctl(); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index f783df4..4538110 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1075,9 +1075,9 @@ struct ftrace_event_field { struct event_filter { int n_preds; /* Number assigned */ int a_preds; /* allocated */ - struct filter_pred *preds; - struct filter_pred *root; - char *filter_string; + struct filter_pred __rcu *preds; + struct filter_pred __rcu *root; + char *filter_string; }; struct event_subsystem {