diff options
| -rw-r--r-- | kernel/trace/ftrace.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 5b372e3ed675..b867c647e5bc 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1492,6 +1492,26 @@ int ftrace_text_reserved(const void *start, const void *end) return (int)!!ret; } +/* Test if ops registered to this rec needs regs */ +static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec) +{ + struct ftrace_ops *ops; + bool keep_regs = false; + + for (ops = ftrace_ops_list; + ops != &ftrace_list_end; ops = ops->next) { + /* pass rec in as regs to have non-NULL val */ + if (ftrace_ops_test(ops, rec->ip, rec)) { + if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) { + keep_regs = true; + break; + } + } + } + + return keep_regs; +} + static void __ftrace_hash_rec_update(struct ftrace_ops *ops, int filter_hash, bool inc) @@ -1584,6 +1604,18 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0)) return; rec->flags--; + /* + * If the rec had REGS enabled and the ops that is + * being removed had REGS set, then see if there is + * still any ops for this record that wants regs. + * If not, we can stop recording them. + */ + if ((rec->flags & ~FTRACE_FL_MASK) > 0 && + rec->flags & FTRACE_FL_REGS && + ops->flags & FTRACE_OPS_FL_SAVE_REGS) { + if (!test_rec_ops_needs_regs(rec)) + rec->flags &= ~FTRACE_FL_REGS; + } } count++; /* Shortcut, if we handled all records, we are done. */ |