For compatibility KPI functions like if_addr_rlock() that used to have

mutexes but now are converted to epoch(9) use thread-private epoch_tracker.
Embedding tracker into ifnet(9) or ifnet derived structures creates a non
reentrable function, that will fail miserably if called simultaneously from
two different contexts.
A thread private tracker will provide a single tracker that would allow to
call these functions safely. It doesn't allow nested call, but this is not
expected from compatibility KPIs.

Reviewed by:	markj

1 files changed, 2 insertions, 0 deletions

diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c
index b60c2d5b40ef..03da844f652c 100644
--- a/sys/kern/kern_thread.c
+++ b/sys/kern/kern_thread.c
@@ -272,6 +272,7 @@ thread_init(void *mem, int size, int flags)
 	td->td_rlqe = NULL;
 	EVENTHANDLER_DIRECT_INVOKE(thread_init, td);
 	umtx_thread_init(td);
+	epoch_thread_init(td);
 	td->td_kstack = 0;
 	td->td_sel = NULL;
 	return (0);
@@ -291,6 +292,7 @@ thread_fini(void *mem, int size)
 	turnstile_free(td->td_turnstile);
 	sleepq_free(td->td_sleepqueue);
 	umtx_thread_fini(td);
+	epoch_thread_fini(td);
 	seltdfini(td);
 }