diff options
| -rw-r--r-- | include/linux/ftrace.h | 7 | ||||
| -rw-r--r-- | kernel/trace/ftrace.c | 45 |
2 files changed, 46 insertions, 6 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index a842d96c634..61e757bd235 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -43,9 +43,10 @@ extern void mcount(void); # define FTRACE_HASHSIZE (1<<FTRACE_HASHBITS) enum { - FTRACE_FL_FAILED = (1 << 0), - FTRACE_FL_FILTER = (1 << 1), - FTRACE_FL_ENABLED = (1 << 2), + FTRACE_FL_FREE = (1 << 0), + FTRACE_FL_FAILED = (1 << 1), + FTRACE_FL_FILTER = (1 << 2), + FTRACE_FL_ENABLED = (1 << 3), }; struct dyn_ftrace { diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a15e068535f..8e02aa690b2 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -188,6 +188,8 @@ static int ftraced_suspend; static int ftrace_record_suspend; +static struct dyn_ftrace *ftrace_free_records; + static inline int notrace ftrace_ip_in_hash(unsigned long ip, unsigned long key) { @@ -211,8 +213,35 @@ ftrace_add_hash(struct dyn_ftrace *node, unsigned long key) hlist_add_head(&node->node, &ftrace_hash[key]); } +static notrace void ftrace_free_rec(struct dyn_ftrace *rec) +{ + /* no locking, only called from kstop_machine */ + + rec->ip = (unsigned long)ftrace_free_records; + ftrace_free_records = rec; + rec->flags |= FTRACE_FL_FREE; +} + static notrace struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip) { + struct dyn_ftrace *rec; + + /* First check for freed records */ + if (ftrace_free_records) { + rec = ftrace_free_records; + + /* todo, disable tracing altogether on this warning */ + if (unlikely(!(rec->flags & FTRACE_FL_FREE))) { + WARN_ON_ONCE(1); + ftrace_free_records = NULL; + return NULL; + } + + ftrace_free_records = (void *)rec->ip; + memset(rec, 0, sizeof(*rec)); + return rec; + } + if (ftrace_pages->index == ENTRIES_PER_PAGE) { if (!ftrace_pages->next) return NULL; @@ -356,8 +385,16 @@ __ftrace_replace_code(struct dyn_ftrace *rec, } failed = ftrace_modify_code(ip, old, new); - if (failed) - rec->flags |= FTRACE_FL_FAILED; + if (failed) { + unsigned long key; + /* It is possible that the function hasn't been converted yet */ + key = hash_long(ip, FTRACE_HASHBITS); + if (!ftrace_ip_in_hash(ip, key)) { + rec->flags |= FTRACE_FL_FAILED; + ftrace_free_rec(rec); + } + + } } static void notrace ftrace_replace_code(int enable) @@ -407,8 +444,10 @@ ftrace_code_disable(struct dyn_ftrace *rec) call = ftrace_call_replace(ip, MCOUNT_ADDR); failed = ftrace_modify_code(ip, call, nop); - if (failed) + if (failed) { rec->flags |= FTRACE_FL_FAILED; + ftrace_free_rec(rec); + } } static int notrace __ftrace_modify_code(void *data) |