From aa033810461ee56abbef6cef10aabd6b97f5caee Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Mon, 20 May 2013 17:57:16 -0700 Subject: ARM: smp: Drop RCU_NONIDLE usage in cpu_die() Before f7b861b7a6d9 ("arm: Use generic idle loop") ARM would kill the CPU within the rcu idle section. Now that the rcu_idle_enter()/exit() pair have been pushed lower down in the idle loop this is no longer true and so using RCU_NONIDLE here is no longer necessary and also harmful because RCU is not actually idle at this point. Cc: Russell King Acked-by: Paul E. McKenney Signed-off-by: Stephen Boyd Signed-off-by: Linus Torvalds --- arch/arm/kernel/smp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 47ab90563bf4..550d63cef68e 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -251,7 +251,7 @@ void __ref cpu_die(void) * this returns, power and/or clocks can be removed at any point * from this CPU and its cache by platform_cpu_kill(). */ - RCU_NONIDLE(complete(&cpu_died)); + complete(&cpu_died); /* * Ensure that the cache lines associated with that completion are -- cgit v1.2.3 From 4ca46c5e1f38e32c90247686e9e17dae213ecbdb Mon Sep 17 00:00:00 2001 From: Steven Capper Date: Thu, 16 May 2013 17:16:11 +0100 Subject: ARM: 7727/1: remove the .vm_mm value from gate_vma If one reads /proc/$PID/smaps, the mmap_sem belonging to the address space of the task being examined is locked for reading. All the pages of the vmas belonging to the task's address space are then walked with this lock held. If a gate_vma is present in the architecture, it too is examined by the fs/proc/task_mmu.c code. As gate_vma doesn't belong to the address space of the task though, its pages are not walked. A recent cleanup (commit f6604efe) of the gate_vma initialisation code set the vm_mm value to &init_mm. Unfortunately a non-NULL vm_mm value in the gate_vma will cause the task_mmu code to attempt to walk the pages of the gate_vma (with no mmap-sem lock held). If one enables Transparent Huge Page support and vm debugging, this will then cause OOPses as pmd_trans_huge_lock is called without mmap_sem being locked. This patch removes the .vm_mm value from gate_vma, restoring the original behaviour of the task_mmu code. Signed-off-by: Steve Capper Signed-off-by: Russell King --- arch/arm/kernel/process.c | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index f21970316836..282de4826abb 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -411,7 +411,6 @@ static struct vm_area_struct gate_vma = { .vm_start = 0xffff0000, .vm_end = 0xffff0000 + PAGE_SIZE, .vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYEXEC, - .vm_mm = &init_mm, }; static int __init gate_vma_init(void) -- cgit v1.2.3