Messages in this thread Patch in this message | | | Date | Mon, 24 Aug 2009 11:26:59 -0700 | From | Ravikiran G Thirumalai <> | Subject | [patch] x86: 2.6.31-rc7 crash due to buggy flat_phys_pkg_id |
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2.6.31-rc7 does not boot on vSMPowered systems. The sched domains seem to build incorrectly with error messages of the sort:
[ 8.501108] CPU31: Thermal monitoring enabled (TM1) [ 8.501127] CPU 31 MCA banks SHD:2 SHD:3 SHD:5 SHD:6 SHD:8 [ 8.650254] CPU31: Intel(R) Xeon(R) CPU E5540 @ 2.53GHz stepping 04 [ 8.710324] Brought up 32 CPUs [ 8.713916] Total of 32 processors activated (162314.96 BogoMIPS). [ 8.721489] ERROR: parent span is not a superset of domain->span [ 8.727686] ERROR: domain->groups does not contain CPU0 [ 8.733091] ERROR: groups don't span domain->span [ 8.737975] ERROR: domain->cpu_power not set [ 8.742416]
This is followed by oopsen in the scheduler code with NULL pointer deference in find_busiest_group.
Git bisection pointed to the following commit:
commit 2759c3287de27266e06f1f4e82cbd2d65f6a044c x86: don't call read_apic_id if !cpu_has_apic
Upon examining the history of the commit, the above commit seems to be a fix for:
commit 4797f6b021a3fa399942245d07a1feb30df81bb8 x86: read apic ID in the !acpi_lapic case
However, there appears to be bug in the commit 2759c3287de27266e06f1f4e82cbd2d65f6a044c, where flat_phys_pkg_id uses initial apic id instead of hard_smp_processor_id() on SMP machines. http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=2759c3287de27266e06f1f4e82cbd2d65f6a044c
This patch fixes the bug and causes vSMPowered systems to boot up correctly,
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Cc: Yinghai Lu <yinghai@kernel.org>
Index: linux-2.6.31-rc6/arch/x86/kernel/apic/apic_flat_64.c =================================================================== --- linux-2.6.31-rc6.orig/arch/x86/kernel/apic/apic_flat_64.c 2009-08-21 12:42:16.000000000 -0700 +++ linux-2.6.31-rc6/arch/x86/kernel/apic/apic_flat_64.c 2009-08-21 14:12:21.654837472 -0700 @@ -161,7 +161,8 @@ static int flat_apic_id_registered(void) static int flat_phys_pkg_id(int initial_apic_id, int index_msb) { - return initial_apic_id >> index_msb; + return cpu_has_apic ? hard_smp_processor_id() >> index_msb : + initial_apic_id >> index_msb; } struct apic apic_flat = {
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