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When multiple threads are involved receiving completion events in LibUSB

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make sure there is always a master polling thread, by setting the "ctx_handler"
field in the context. Else the reception of completion events can stop.
This happens if event threads are created and destroyed during runtime.

Found by:		Ludovic Rousseau <ludovic.rousseau+freebsd@gmail.com>
PR:			231742
MFC after:		1 week
Approved by:		re (kib)
Sponsored by:		Mellanox Technologies
This commit is contained in:
Hans Petter Selasky 2018-09-28 10:28:22 +00:00
parent d0addc700e
commit 2682992483
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=338993
1 changed files with 6 additions and 0 deletions
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6
lib/libusb/libusb10_io.c
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@ -312,6 +312,9 @@ libusb_wait_for_event(libusb_context *ctx, struct timeval *tv)
if (tv == NULL) {
pthread_cond_wait(&ctx->ctx_cond,
&ctx->ctx_lock);
/* try to grab polling of actual events, if any */
if (ctx->ctx_handler == NO_THREAD)
ctx->ctx_handler = pthread_self();
return (0);
}
err = clock_gettime(CLOCK_MONOTONIC, &ts);
@ -330,6 +333,9 @@ libusb_wait_for_event(libusb_context *ctx, struct timeval *tv)
}
err = pthread_cond_timedwait(&ctx->ctx_cond,
&ctx->ctx_lock, &ts);
/* try to grab polling of actual events, if any */
if (ctx->ctx_handler == NO_THREAD)
ctx->ctx_handler = pthread_self();
if (err == ETIMEDOUT)
return (1);