Date: Sat, 23 May 2015 23:08:17 +0000 (UTC) From: Andrew Turner <andrew@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r283337 - head/sys/arm/arm Message-ID: <201505232308.t4NN8H66052464@svn.freebsd.org>
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Author: andrew Date: Sat May 23 23:08:16 2015 New Revision: 283337 URL: https://svnweb.freebsd.org/changeset/base/283337 Log: Fix a lock up where we enter swapper() with interrupts disabled. In smp_rendezvous_cpus we expect to wait for all cpus to enter smp_rendezvous_action. If we call this holding a proc lock swapper may attempt to also lock it, however as interrupts are disabled the cpu never handles the ipi. Because smp_rendezvous_action waits for all signaled cpus before contining it may get caught waiting for the cpu running swapper as the proc mutex will be unlocked after smp_rendezvous_cpus finishes. The fix is to enable interrupts in the configure stage as we should be doing. MFC after: 1 week Modified: head/sys/arm/arm/autoconf.c Modified: head/sys/arm/arm/autoconf.c ============================================================================== --- head/sys/arm/arm/autoconf.c Sat May 23 23:05:31 2015 (r283336) +++ head/sys/arm/arm/autoconf.c Sat May 23 23:08:16 2015 (r283337) @@ -94,6 +94,7 @@ static void configure_final(void *dummy) { + enable_interrupts(PSR_I | PSR_F); cninit_finish(); cold = 0; }
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