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| author | Signed-off-by: Darren Hart <dvhltc@us.ibm.com> | 2010-08-04 18:28:33 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2010-08-24 15:26:29 +1000 |
| commit | a7c2bb8279d20d853e43c34584eaf2b039de8026 (patch) | |
| tree | bba0120f1bfddbc1a1236a2d8b5a6823e9bc928b /arch/powerpc/kernel/idle.c | |
| parent | da9bef6735d3c5c1c0cd16717acee18d56dd59f5 (diff) | |
| download | lwn-a7c2bb8279d20d853e43c34584eaf2b039de8026.tar.gz lwn-a7c2bb8279d20d853e43c34584eaf2b039de8026.zip | |
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/powerpc/kernel/idle.c')
| -rw-r--r-- | arch/powerpc/kernel/idle.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/idle.c b/arch/powerpc/kernel/idle.c index 049dda60e475..39a2baa6ad58 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(); } |