frr: fix segfault zebra on finish #227
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The zebra dplane shutdown logic has two steps. First, zebra_dplane_pre_finish() is called with early == true. In this phase, the dataplane thread and its event loop are still running, and event_cancel_async() must be used to safely cancel timers. Later, zebra_dplane_shutdown() is called with early == false. At this point, the dataplane thread has exited, its event loop has been freed, and its pointer has been set to NULL. Calling event_cancel_async() in the second phase dereferences a NULL pointer, causing a SIGSEGV. This commit ensures that event_cancel_async() is only called during the early shutdown phase. The second timer (dg_t_zebra_update) runs on the main thread. It is canceled in the early phase using event_cancel(), which is safe from the main context. There's no need to cancel it again in the final phase. Signed-off-by: Maxime Leroy <[email protected]>
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LGTM. Very good analysis from the commit log. |
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Didn't have time to reproduce the crash. But it fixes a real bug for sure.