Hello,
Spin lock debuging got this on UP+preempt:
arch/i386/kernel/i8259.c:176:spin_lock(arch/i386/kernel/i8259.c:c03d4838)
already locked by include/asm-i386/mach-default/do_timer.h/50
include/asm-i386/mach-default/do_timer.h:56:
spin_unlock(arch/i386/kernel/i8259.c:c03d4838) not locked
arch/i386/kernel/i8259.c:176:spin_lock(arch/i386/kernel/i8259.c:c03d4838)
already locked by include/asm-i386/mach-default/do_timer.h/50
include/asm-i386/mach-default/do_timer.h:56:
spin_unlock(arch/i386/kernel/i8259.c:c03d4838) not locked
This due to do_timer_overflow expecting to be called with IRQs disabled,
the whole path used to do that until converted to xtime_lock, but
do_timer_overflow seems to be missed. Patch changes get_offset_pit to hold
i8253_lock while calling do_timer_overflow.
Is the hack with caching jiffies in get_offset_pit still needed,
according to comments there, it is not?
-- have fun, alexBK current:
===== arch/i386/kernel/timers/timer_pit.c 1.10 vs edited ===== --- 1.10/arch/i386/kernel/timers/timer_pit.c Mon Mar 31 19:03:54 2003 +++ edited/arch/i386/kernel/timers/timer_pit.c Wed Apr 16 09:27:03 2003 @@ -50,7 +50,7 @@ } -/* This function must be called with interrupts disabled +/* This function must be called with xtime_lock held. * It was inspired by Steve McCanne's microtime-i386 for BSD. -- jrs * * However, the pc-audio speaker driver changes the divisor so that @@ -90,7 +90,7 @@ static unsigned long jiffies_p = 0; /* - * cache volatile jiffies temporarily; we have IRQs turned off. + * cache volatile jiffies temporarily; we have xtime_lock. */ unsigned long jiffies_t; @@ -109,14 +109,12 @@ count |= inb_p(0x40) << 8; /* VIA686a test code... reset the latch if count > max + 1 */ - if (count > LATCH) { - outb_p(0x34, 0x43); - outb_p(LATCH & 0xff, 0x40); - outb(LATCH >> 8, 0x40); - count = LATCH - 1; - } - - spin_unlock_irqrestore(&i8253_lock, flags); + if (count > LATCH) { + outb_p(0x34, 0x43); + outb_p(LATCH & 0xff, 0x40); + outb(LATCH >> 8, 0x40); + count = LATCH - 1; + } /* * avoiding timer inconsistencies (they are rare, but they happen)... @@ -127,7 +125,6 @@ * (see c't 95/10 page 335 for Neptun bug.) */ - if( jiffies_t == jiffies_p ) { if( count > count_p ) { /* the nutcase */ @@ -135,6 +132,8 @@ } } else jiffies_p = jiffies_t; + + spin_unlock_irqrestore(&i8253_lock, flags); count_p = count; ===== include/asm-i386/mach-default/do_timer.h 1.8 vs edited ===== --- 1.8/include/asm-i386/mach-default/do_timer.h Tue Feb 25 11:39:08 2003 +++ edited/include/asm-i386/mach-default/do_timer.h Tue Apr 15 23:47:39 2003 @@ -47,14 +47,12 @@ { int i; - spin_lock(&i8259A_lock); /* * This is tricky when I/O APICs are used; * see do_timer_interrupt(). */ i = inb(0x20); - spin_unlock(&i8259A_lock); - + /* assumption about timer being IRQ0 */ if (i & 0x01) { /* ===== include/asm-i386/mach-pc9800/do_timer.h 1.1 vs edited ===== --- 1.1/include/asm-i386/mach-pc9800/do_timer.h Fri Mar 14 03:17:16 2003 +++ edited/include/asm-i386/mach-pc9800/do_timer.h Tue Apr 15 23:47:39 2003 @@ -47,14 +47,12 @@ { int i; - spin_lock(&i8259A_lock); /* * This is tricky when I/O APICs are used; * see do_timer_interrupt(). */ i = inb(0x00); - spin_unlock(&i8259A_lock); - + /* assumption about timer being IRQ0 */ if (i & 0x01) { /* ===== include/asm-i386/mach-visws/do_timer.h 1.6 vs edited ===== --- 1.6/include/asm-i386/mach-visws/do_timer.h Wed Feb 19 04:58:56 2003 +++ edited/include/asm-i386/mach-visws/do_timer.h Tue Apr 15 23:47:39 2003 @@ -26,14 +26,12 @@ { int i; - spin_lock(&i8259A_lock); /* * This is tricky when I/O APICs are used; * see do_timer_interrupt(). */ i = inb(0x20); - spin_unlock(&i8259A_lock); - + /* assumption about timer being IRQ0 */ if (i & 0x01) { /*
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This archive was generated by hypermail 2b29 : Wed Apr 23 2003 - 22:00:17 EST