diff options
Diffstat (limited to 'include/net/rose.h')
| -rw-r--r-- | include/net/rose.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/net/rose.h b/include/net/rose.h index 2b5491bbf39a..95d1f9c582dc 100644 --- a/include/net/rose.h +++ b/include/net/rose.h @@ -160,6 +160,18 @@ static inline void rose_neigh_hold(struct rose_neigh *rose_neigh) static inline void rose_neigh_put(struct rose_neigh *rose_neigh) { if (refcount_dec_and_test(&rose_neigh->use)) { + /* We are dropping the last reference, so we are about to free the + * neighbour. Its timers may still be armed -- t0timer in particular + * re-arms itself in rose_t0timer_expiry(). rose_remove_neigh() + * cancels them before its own put, but callers that drop the final + * reference without first calling rose_remove_neigh() (the socket + * heartbeat reaping path) would otherwise kfree() a neighbour with a + * live timer -> use-after-free. timer_delete_sync() (not the async + * variant) is required: it waits out a concurrently running handler + * and loops until the self-rearming timer stays stopped. + */ + timer_delete_sync(&rose_neigh->ftimer); + timer_delete_sync(&rose_neigh->t0timer); if (rose_neigh->ax25) ax25_cb_put(rose_neigh->ax25); kfree(rose_neigh->digipeat); |