diff options
| author | Alexey Kardashevskiy <aik@ozlabs.ru> | 2021-02-02 18:23:26 +1100 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-02-02 09:32:02 -0500 |
| commit | c8b186a8d54d7e12d28e9f9686cb00ff18fc2ab2 (patch) | |
| tree | 80a96646eed83f2690c2d8ac596b04d009b69ace | |
| parent | 0188b87899ffc4a1d36a0badbe77d56c92fd91dc (diff) | |
| download | linux-c8b186a8d54d7e12d28e9f9686cb00ff18fc2ab2.tar.bz2 | |
tracepoint: Fix race between tracing and removing tracepoint
When executing a tracepoint, the tracepoint's func is dereferenced twice -
in __DO_TRACE() (where the returned pointer is checked) and later on in
__traceiter_##_name where the returned pointer is dereferenced without
checking which leads to races against tracepoint_removal_sync() and
crashes.
This adds a check before referencing the pointer in tracepoint_ptr_deref.
Link: https://lkml.kernel.org/r/20210202072326.120557-1-aik@ozlabs.ru
Cc: stable@vger.kernel.org
Fixes: d25e37d89dd2f ("tracepoint: Optimize using static_call()")
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
| -rw-r--r-- | include/linux/tracepoint.h | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 0f21617f1a66..966ed8980327 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -307,11 +307,13 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) \ it_func_ptr = \ rcu_dereference_raw((&__tracepoint_##_name)->funcs); \ - do { \ - it_func = (it_func_ptr)->func; \ - __data = (it_func_ptr)->data; \ - ((void(*)(void *, proto))(it_func))(__data, args); \ - } while ((++it_func_ptr)->func); \ + if (it_func_ptr) { \ + do { \ + it_func = (it_func_ptr)->func; \ + __data = (it_func_ptr)->data; \ + ((void(*)(void *, proto))(it_func))(__data, args); \ + } while ((++it_func_ptr)->func); \ + } \ return 0; \ } \ DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name); |