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authorVivek Goyal <vgoyal@in.ibm.com>2006-03-31 02:30:05 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-31 12:18:50 -0800
commit1a75a3f0680d9c4bc4761512658b6fd664032e18 (patch)
tree8d3d7fe266740f58961b43ecf144503f36e88dc4 /kernel/power/process.c
parent3ccfb81e871b45e4af6ebb3282f3cfa0f98f1b80 (diff)
[PATCH] i386 kdump timer vector lockup fix
Porting the patch I posted for x86_64 to i386. http://marc.theaimsgroup.com/?l=linux-kernel&m=114178139610707&w=2 o While using kdump, after a system crash when second kernel boots, timer vector gets (0x31) locked and CPU does not see timer interrupts travelling from IOAPIC to APIC. Currently it does not lead to boot failure in second kernel as timer interrupts continues to come as ExtInt through LAPIC directly, but fixing it is good in case some boards do not support the other mode. o After a system crash, it is not safe to service interrupts any more, hence interrupts are disabled. This leads to pending interrupts at LAPIC. LAPIC sends these interrupts to the CPU during early boot of second kernel. Other pending interrupts are discarded saying unexpected trap but timer interrupt is serviced and CPU does not issue an LAPIC EOI because it think this interrupt came from i8259 and sends ack to 8259. This leads to vector 0x31 locking as LAPIC does not clear respective ISR and keeps on waiting for EOI. o This patch issues extra EOI for the pending interrupts who have ISR set. o Though today only timer seems to be the special case because in early boot it thinks interrupts are coming from i8259 and uses mask_and_ack_8259A() as ack handler and does not issue LAPIC EOI. But probably doing it in generic manner for all vectors makes sense. Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/power/process.c')
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