Date: Wed, 24 Jan 2018 07:54:05 +0000 (UTC) From: Wojciech Macek <wma@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r328320 - head/sys/kern Message-ID: <201801240754.w0O7s57E063486@repo.freebsd.org>
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Author: wma Date: Wed Jan 24 07:54:05 2018 New Revision: 328320 URL: https://svnweb.freebsd.org/changeset/base/328320 Log: ULE: provide defaults to ts_cpu Fix a bug when the system has no CPU 0. When created, threads were implicitly assigned to CPU 0. This had no practical effect since a real CPU was chosen immediately by the scheduler. However, on systems without a CPU 0, sched_ule attempted to access the scheduler queue of the "old" CPU when assigned the initial choice of the old one. This caused an attempt to use illegal memory and a crash (or, more usually, a deadlock). Fix this by assigned new threads to the BSP explicitly and add some asserts to see that this problem does not recur. Authored by: Nathan Whitehorn <nwhitehorn@freebsd.org> Submitted by: Wojciech Macek <wma@semihalf.com> Obtained from: Semihalf Differential revision: https://reviews.freebsd.org/D13932 Modified: head/sys/kern/sched_ule.c Modified: head/sys/kern/sched_ule.c ============================================================================== --- head/sys/kern/sched_ule.c Wed Jan 24 07:01:44 2018 (r328319) +++ head/sys/kern/sched_ule.c Wed Jan 24 07:54:05 2018 (r328320) @@ -1405,6 +1405,7 @@ sched_setup(void *dummy) /* Add thread0's load since it's running. */ TDQ_LOCK(tdq); + td_get_sched(&thread0)->ts_cpu = curcpu; /* Something valid to start */ thread0.td_lock = TDQ_LOCKPTR(TDQ_SELF()); tdq_load_add(tdq, &thread0); tdq->tdq_lowpri = thread0.td_priority; @@ -2454,6 +2455,7 @@ sched_add(struct thread *td, int flags) * Pick the destination cpu and if it isn't ours transfer to the * target cpu. */ + td_get_sched(td)->ts_cpu = curcpu; /* Pick something valid to start */ cpu = sched_pickcpu(td, flags); tdq = sched_setcpu(td, cpu, flags); tdq_add(tdq, td, flags);
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