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unix: zero epoll_event before use

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Valgrind will emit the following error on a system where `int` is 32
bits:

==21616== Syscall param epoll_ctl(event) points to uninitialised byte(s)
==21616==    at 0x693E06A: epoll_ctl (syscall-template.S:84)
==21616==    by 0x529F35B: uv__io_poll (in .../libuv/libuv.so)
==21616==    by 0x528AE62: uv_run (in .../libuv/libuv.so)
[...]
==21616==  Address 0x1ffeffc8ec is on thread 1's stack
==21616==  in frame #1, created by uv__io_poll (???:)

We only initialise e.events and e.data.fd, meaning half of
e.data (the 32 bits not covered by the 4-byte `fd`) is
uninitialised.

PR-URL: https://github.com/libuv/libuv/pull/1996
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
This commit is contained in:
Ashe Connor 2018-09-19 16:36:47 +10:00 committed by cjihrig
parent a24e8a17e5
commit 0813f5b97a
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1 changed files with 3 additions and 0 deletions
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3
src/unix/linux-core.c
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@ -170,6 +170,7 @@ int uv__io_check_fd(uv_loop_t* loop, int fd) {
struct epoll_event e;
int rc;
memset(&e, 0, sizeof(e));
e.events = POLLIN;
e.data.fd = -1;
@ -218,6 +219,8 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
return;
}
memset(&e, 0, sizeof(e));
while (!QUEUE_EMPTY(&loop->watcher_queue)) {
q = QUEUE_HEAD(&loop->watcher_queue);
QUEUE_REMOVE(q);