From 13ea9cc82138691856d7cd855dff9aef1479adb9 Mon Sep 17 00:00:00 2001 From: Santosh Shilimkar Date: Fri, 30 Apr 2010 06:51:20 +0100 Subject: [PATCH] ARM: 6066/1: Fix "BUG: scheduling while atomic: swapper/0/0x00000002 This patch fixes the preempt leak in the cpuidle path invoked from cpu-hotplug. The fix is suggested by Russell King and is based on x86 idea of calling init_idle() on the idle task when it's re-used which also resets the preempt count amongst other things dump: BUG: scheduling while atomic: swapper/0/0x00000002 Modules linked in: Backtrace: [] (dump_backtrace+0x0/0x110) from [] (dump_stack+0x18/0x1c) r7:c02149e4 r6:c033df00 r5:c7836000 r4:00000000 [] (dump_stack+0x0/0x1c) from [] (__schedule_bug+0x60/0x70) [] (__schedule_bug+0x0/0x70) from [] (schedule+0x98/0x7b8) r5:c7836000 r4:c7836000 [] (schedule+0x0/0x7b8) from [] (cpu_idle+0xb4/0xd4) # [] (cpu_idle+0x0/0xd4) from [] (secondary_start_kernel+0xe0/0xf0) r5:c7836000 r4:c0205f40 [] (secondary_start_kernel+0x0/0xf0) from [] (prm_rmw_mod_reg_bits+0x88/0xa4) r7:c02149e4 r6:00000001 r5:00000001 r4:c7836000 Backtrace aborted due to bad frame pointer Cc: Catalin Marinas Signed-off-by: Santosh Shilimkar Signed-off-by: Russell King --- arch/arm/kernel/smp.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 577543f3857..a01194e583f 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -86,6 +86,12 @@ int __cpuinit __cpu_up(unsigned int cpu) return PTR_ERR(idle); } ci->idle = idle; + } else { + /* + * Since this idle thread is being re-used, call + * init_idle() to reinitialize the thread structure. + */ + init_idle(idle, cpu); } /* -- 2.39.5