From: Ingo Molnar Date: Wed, 9 Jul 2008 13:42:09 +0000 (+0200) Subject: x86, paravirt-spinlocks: fix boot hang X-Git-Tag: v2.6.27-rc1~955^2^2~3 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=34646bca474142e1424e5f6c4a33cb2ba0930ea1;p=linux-2.6 x86, paravirt-spinlocks: fix boot hang the paravirt-spinlock patches caused a boot hang with this config: http://redhat.com/~mingo/misc/config-Wed_Jul__9_14_47_04_CEST_2008.bad i have bisected it down to: | commit e17b58c2e85bc2ad2afc07fb8d898017c2b75ed1 | Author: Jeremy Fitzhardinge | Date: Mon Jul 7 12:07:53 2008 -0700 | | xen: implement Xen-specific spinlocks i.e. applying that patch alone causes the hang. The hang happens in the ftrace self-test: initcall utsname_sysctl_init+0x0/0x19 returned 0 after 0 msecs calling init_sched_switch_trace+0x0/0x4c Testing tracer sched_switch: PASSED initcall init_sched_switch_trace+0x0/0x4c returned 0 after 167 msecs calling init_function_trace+0x0/0x12 Testing tracer ftrace: [hard hang] it should have continued like this: Testing tracer ftrace: PASSED initcall init_function_trace+0x0/0x12 returned 0 after 198 msecs calling init_irqsoff_tracer+0x0/0x14 Testing tracer irqsoff: PASSED initcall init_irqsoff_tracer+0x0/0x14 returned 0 after 3 msecs calling init_mmio_trace+0x0/0x12 initcall init_mmio_trace+0x0/0x12 returned 0 after 0 msecs the problem is that such lowlevel primitives as spinlocks should never be built with -pg (which ftrace does). Marking paravirt.o as non-pg and marking all spinlock ops as always-inline solve the hang. Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 5112c84f54..78d5217140 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -7,10 +7,11 @@ extra-y := head_$(BITS).o head$(BITS).o head.o init_task.o vmlinu CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE) ifdef CONFIG_FTRACE -# Do not profile debug utilities +# Do not profile debug and lowlevel utilities CFLAGS_REMOVE_tsc_64.o = -pg CFLAGS_REMOVE_tsc_32.o = -pg CFLAGS_REMOVE_rtc.o = -pg +CFLAGS_REMOVE_paravirt.o = -pg endif #