Author: jhb
Date: Thu Dec 23 15:17:28 2010
New Revision: 216679
URL: http://svn.freebsd.org/changeset/base/216679
Log:
Drop the icu_lock spinlock while pausing briefly after masking the
interrupt in the I/O APIC before moving it to a different CPU. If the
interrupt had been triggered by the I/O APIC after locking icu_lock but
before we masked the pin in the I/O APIC, then this could cause the
interrupt to be pending on the "old" CPU and it would finally trigger
after we had moved the interrupt to the new CPU. This could cause us to
panic as there was no interrupt source associated with the old IDT vector
on the old CPU. Dropping the lock after the interrupt is masked but
before it is moved allows the interrupt to fire and be handled in this
case before it is moved.
Tested by: Daniel Braniss danny of cs huji ac il
MFC after: 1 week
Modified:
head/sys/x86/x86/io_apic.c
Modified: head/sys/x86/x86/io_apic.c
==============================================================================
--- head/sys/x86/x86/io_apic.c Thu Dec 23 03:12:03 2010 (r216678)
+++ head/sys/x86/x86/io_apic.c Thu Dec 23 15:17:28 2010 (r216679)
@@ -359,7 +359,9 @@ ioapic_assign_cpu(struct intsrc *isrc, u
if (!intpin->io_masked && !intpin->io_edgetrigger) {
ioapic_write(io->io_addr, IOAPIC_REDTBL_LO(intpin->io_intpin),
intpin->io_lowreg | IOART_INTMSET);
+ mtx_unlock_spin(&icu_lock);
DELAY(100);
+ mtx_lock_spin(&icu_lock);
}
intpin->io_cpu = apic_id;
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
