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authorSigned-off-by: Darren Hart <dvhltc@us.ibm.com>2010-08-04 18:28:33 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2010-08-24 15:26:29 +1000
commita7c2bb8279d20d853e43c34584eaf2b039de8026 (patch)
treebba0120f1bfddbc1a1236a2d8b5a6823e9bc928b /arch
parentda9bef6735d3c5c1c0cd16717acee18d56dd59f5 (diff)
powerpc: Re-enable preemption before cpu_die()
start_secondary() is called shortly after _start and also via cpu_idle()->cpu_die()->pseries_mach_cpu_die() start_secondary() expects a preempt_count() of 0. pseries_mach_cpu_die() is called via the cpu_idle() routine with preemption disabled, resulting in the following repeating message during rapid cpu offline/online tests with CONFIG_PREEMPT=y: BUG: scheduling while atomic: swapper/0/0x00000002 Modules linked in: autofs4 binfmt_misc dm_mirror dm_region_hash dm_log [last unloaded: scsi_wait_scan] Call Trace: [c00000010e7079c0] [c0000000000133ec] .show_stack+0xd8/0x218 (unreliable) [c00000010e707aa0] [c0000000006a47f0] .dump_stack+0x28/0x3c [c00000010e707b20] [c00000000006e7a4] .__schedule_bug+0x7c/0x9c [c00000010e707bb0] [c000000000699d9c] .schedule+0x104/0x800 [c00000010e707cd0] [c000000000015b24] .cpu_idle+0x1c4/0x1d8 [c00000010e707d70] [c0000000006aa1b4] .start_secondary+0x398/0x3d4 [c00000010e707e30] [c000000000008278] .start_secondary_resume+0x10/0x14 Move the cpu_die() call inside the existing preemption enabled block of cpu_idle(). This is safe as the idle task is affined to a single CPU so the debug_smp_processor_id() tests (from cpu_should_die()) won't trigger as we are in a "migration disabled" region. Signed-off-by: Darren Hart <dvhltc@us.ibm.com> Acked-by: Will Schmidt <will_schmidt@vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Nathan Fontenot <nfont@austin.ibm.com> Cc: Robert Jennings <rcj@linux.vnet.ibm.com> Cc: Brian King <brking@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kernel/idle.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c
index 049dda60e47..39a2baa6ad5 100644
--- a/arch/powerpc/kernel/idle.c
+++ b/arch/powerpc/kernel/idle.c
@@ -94,9 +94,9 @@ void cpu_idle(void)
HMT_medium();
ppc64_runlatch_on();
tick_nohz_restart_sched_tick();
+ preempt_enable_no_resched();
if (cpu_should_die())
cpu_die();
- preempt_enable_no_resched();
schedule();
preempt_disable();
}