From patchwork Mon Nov 19 06:16:39 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [RFC,powerpc] Protect smp_processor_id() in arch_spin_unlock_wait() Date: Sun, 18 Nov 2012 20:16:39 -0000 From: Li Zhong X-Patchwork-Id: 199930 Message-Id: <1353305799.3694.9.camel@ThinkPad-T5421.cn.ibm.com> To: PowerPC email list Cc: "Paul E. McKenney" , Paul Mackerras This patch tries to disable preemption for using smp_processor_id() in arch_spin_unlock_wait(), to avoid following report: [ 17.279377] BUG: using smp_processor_id() in preemptible [00000000] code: autorun/1024 [ 17.279407] caller is .arch_spin_unlock_wait+0x34/0x80 [ 17.279415] Call Trace: [ 17.279423] [c00000000911fb30] [c000000000015230] .show_stack+0x70/0x1c0 (unreliable) [ 17.279441] [c00000000911fbe0] [c0000000003e13b0] .debug_smp_processor_id+0x110/0x130 [ 17.279455] [c00000000911fc80] [c00000000004c2b4] .arch_spin_unlock_wait+0x34/0x80 [ 17.279470] [c00000000911fd00] [c0000000000b0e50] .task_work_run+0x80/0x160 [ 17.279482] [c00000000911fdb0] [c000000000018744] .do_notify_resume+0x94/0xa0 [ 17.279495] [c00000000911fe30] [c000000000009d1c] .ret_from_except_lite+0x48/0x4c Reported-by: Paul E. McKenney Signed-off-by: Li Zhong --- arch/powerpc/lib/locks.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c index bb7cfec..7a7c31b 100644 --- a/arch/powerpc/lib/locks.c +++ b/arch/powerpc/lib/locks.c @@ -72,8 +72,10 @@ void arch_spin_unlock_wait(arch_spinlock_t *lock) { while (lock->slock) { HMT_low(); + preempt_disable(); if (SHARED_PROCESSOR) __spin_yield(lock); + preempt_enable(); } HMT_medium(); }