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ev: stop event listeners during context destroy

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I think I've found a bug in libev backend, in function lws_libev_io(). I'm using latest version from master branch.

When deleting a context with active connections via lws_context_destroy(), context->being_destroyed is set to 1 early in the function, before the loop calling lws_close_free_wsi() on each active connection.
lws_close_free_wsi() calls remove_wsi_socket_from_fds(), which calls lws_libev_io(), and here is my problem :

lws_libev_io() returns without doing anything if context->being_destroyed is set, so libev callbacks for deleted connections file descriptors stay registered after context is destroyed, which may lead to segfault/undefined behaviour if these file descriptors get reused later (which would trigger the callbacks).

I think the "if (!pt->io_loop_ev || context->being_destroyed) return;" statement should be replaced with " if (!pt->io_loop_ev) return;"

This fixes the problem for me and I have not seen any side effect yet. Moreover, libuv backend does not have such a test.
This commit is contained in:
Olivier Basson 2017-03-29 08:20:42 +08:00 • committed by Andy Green
parent 7a0dead82a
commit 73e12e7b93
1 changed files with 1 additions and 1 deletions
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lib/libev.c
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@ -190,7 +190,7 @@ lws_libev_io(struct lws *wsi, int flags)
if (!LWS_LIBEV_ENABLED(context))
return;
if (!pt->io_loop_ev || context->being_destroyed)
if (!pt->io_loop_ev)
return;
assert((flags & (LWS_EV_START | LWS_EV_STOP)) &&