From 977c1f9c8c022d0173181766b34a0db3705265a4 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Mon, 7 Nov 2016 15:14:20 -0800 Subject: [PATCH 1/2] ftrace: Ignore FTRACE_FL_DISABLED while walking dyn_ftrace records ftrace_shutdown() checks for sanity of ftrace records and if dyn_ftrace->flags is not zero, it will warn. It can happen that 'flags' are set to FTRACE_FL_DISABLED at this point, since some module was loaded, but before ftrace_module_enable() cleared the flags for this module. In other words the module.c is doing: ftrace_module_init(mod); // calls ftrace_update_code() that sets flags=FTRACE_FL_DISABLED ... // here ftrace_shutdown() is called that warns, since err = prepare_coming_module(mod); // didn't have a chance to clear FTRACE_FL_DISABLED Fix it by ignoring disabled records. It's similar to what __ftrace_hash_rec_update() is already doing. Link: http://lkml.kernel.org/r/1478560460-3818619-1-git-send-email-ast@fb.com Cc: stable@vger.kernel.org Fixes: b7ffffbb46f2 "ftrace: Add infrastructure for delayed enabling of module functions" Signed-off-by: Alexei Starovoitov Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 2050a7652a86..326498baab83 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2763,7 +2763,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) struct dyn_ftrace *rec; do_for_each_ftrace_rec(pg, rec) { - if (FTRACE_WARN_ON_ONCE(rec->flags)) + if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED)) pr_warn(" %pS flags:%lx\n", (void *)rec->ip, rec->flags); } while_for_each_ftrace_rec(); From 546fece4eae871f033925ccf0ff2b740725ae915 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 14 Nov 2016 16:31:49 -0500 Subject: [PATCH 2/2] ftrace: Add more checks for FTRACE_FL_DISABLED in processing ip records When a module is first loaded and its function ip records are added to the ftrace list of functions to modify, they are set to DISABLED, as their text is still in a read only state. When the module is fully loaded, and can be updated, the flag is cleared, and if their's any functions that should be tracing them, it is updated at that moment. But there's several locations that do record accounting and should ignore records that are marked as disabled, or they can cause issues. Alexei already fixed one location, but others need to be addressed. Cc: stable@vger.kernel.org Fixes: b7ffffbb46f2 "ftrace: Add infrastructure for delayed enabling of module functions" Reported-by: Alexei Starovoitov Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 326498baab83..da87b3cba5b3 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1862,6 +1862,10 @@ static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops, /* Update rec->flags */ do_for_each_ftrace_rec(pg, rec) { + + if (rec->flags & FTRACE_FL_DISABLED) + continue; + /* We need to update only differences of filter_hash */ in_old = !!ftrace_lookup_ip(old_hash, rec->ip); in_new = !!ftrace_lookup_ip(new_hash, rec->ip); @@ -1884,6 +1888,10 @@ rollback: /* Roll back what we did above */ do_for_each_ftrace_rec(pg, rec) { + + if (rec->flags & FTRACE_FL_DISABLED) + continue; + if (rec == end) goto err_out; @@ -2397,6 +2405,10 @@ void __weak ftrace_replace_code(int enable) return; do_for_each_ftrace_rec(pg, rec) { + + if (rec->flags & FTRACE_FL_DISABLED) + continue; + failed = __ftrace_replace_code(rec, enable); if (failed) { ftrace_bug(failed, rec); @@ -3598,6 +3610,10 @@ match_records(struct ftrace_hash *hash, char *func, int len, char *mod) goto out_unlock; do_for_each_ftrace_rec(pg, rec) { + + if (rec->flags & FTRACE_FL_DISABLED) + continue; + if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) { ret = enter_record(hash, rec, clear_filter); if (ret < 0) { @@ -3793,6 +3809,9 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops, do_for_each_ftrace_rec(pg, rec) { + if (rec->flags & FTRACE_FL_DISABLED) + continue; + if (!ftrace_match_record(rec, &func_g, NULL, 0)) continue; @@ -4685,6 +4704,9 @@ ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer) do_for_each_ftrace_rec(pg, rec) { + if (rec->flags & FTRACE_FL_DISABLED) + continue; + if (ftrace_match_record(rec, &func_g, NULL, 0)) { /* if it is in the array */ exists = false;