diff options
40 files changed, 65 insertions, 43 deletions
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c index 46bf263c3153..acb4b146a607 100644 --- a/arch/alpha/kernel/smp.c +++ b/arch/alpha/kernel/smp.c @@ -144,7 +144,7 @@ smp_callin(void) alpha_mv.smp_callin(); /* All kernel threads share the same mm context. */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; /* inform the notifiers about the new cpu */ diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c index 2afbafadb6ab..695624181682 100644 --- a/arch/arc/kernel/smp.c +++ b/arch/arc/kernel/smp.c @@ -140,7 +140,7 @@ void start_kernel_secondary(void) setup_processor(); atomic_inc(&mm->mm_users); - atomic_inc(&mm->mm_count); + mmgrab(mm); current->active_mm = mm; cpumask_set_cpu(cpu, mm_cpumask(mm)); diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 7dd14e8395e6..c6514ce0fcbc 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -371,7 +371,7 @@ asmlinkage void secondary_start_kernel(void) * reference and switch to it. */ cpu = smp_processor_id(); - atomic_inc(&mm->mm_count); + mmgrab(mm); current->active_mm = mm; cpumask_set_cpu(cpu, mm_cpumask(mm)); diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index a8ec5da530af..827d52d78b67 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -222,7 +222,7 @@ asmlinkage void secondary_start_kernel(void) * All kernel threads share the same mm context; grab a * reference and switch to it. */ - atomic_inc(&mm->mm_count); + mmgrab(mm); current->active_mm = mm; /* diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c index 23c4ef5f8bdc..bc5617ef7128 100644 --- a/arch/blackfin/mach-common/smp.c +++ b/arch/blackfin/mach-common/smp.c @@ -308,7 +308,7 @@ void secondary_start_kernel(void) /* Attach the new idle task to the global mm. */ atomic_inc(&mm->mm_users); - atomic_inc(&mm->mm_count); + mmgrab(mm); current->active_mm = mm; preempt_disable(); diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c index 983bae7d2665..c02a6455839e 100644 --- a/arch/hexagon/kernel/smp.c +++ b/arch/hexagon/kernel/smp.c @@ -162,7 +162,7 @@ void start_secondary(void) ); /* Set the memory struct */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; cpu = smp_processor_id(); diff --git a/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c index c483ece3eb84..d68322966f33 100644 --- a/arch/ia64/kernel/setup.c +++ b/arch/ia64/kernel/setup.c @@ -994,7 +994,7 @@ cpu_init (void) */ ia64_setreg(_IA64_REG_CR_DCR, ( IA64_DCR_DP | IA64_DCR_DK | IA64_DCR_DX | IA64_DCR_DR | IA64_DCR_DA | IA64_DCR_DD | IA64_DCR_LC)); - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; BUG_ON(current->mm); diff --git a/arch/m32r/kernel/setup.c b/arch/m32r/kernel/setup.c index 136c69f1fb8a..b18bc0bd6544 100644 --- a/arch/m32r/kernel/setup.c +++ b/arch/m32r/kernel/setup.c @@ -403,7 +403,7 @@ void __init cpu_init (void) printk(KERN_INFO "Initializing CPU#%d\n", cpu_id); /* Set up and load the per-CPU TSS and LDT */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; if (current->mm) BUG(); diff --git a/arch/metag/kernel/smp.c b/arch/metag/kernel/smp.c index bad13232de51..af9cff547a19 100644 --- a/arch/metag/kernel/smp.c +++ b/arch/metag/kernel/smp.c @@ -345,7 +345,7 @@ asmlinkage void secondary_start_kernel(void) * reference and switch to it. */ atomic_inc(&mm->mm_users); - atomic_inc(&mm->mm_count); + mmgrab(mm); current->active_mm = mm; cpumask_set_cpu(cpu, mm_cpumask(mm)); enter_lazy_tlb(mm, current); diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index cb479be31a50..49c6df20672a 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -2232,7 +2232,7 @@ void per_cpu_trap_init(bool is_boot_cpu) if (!cpu_data[cpu].asid_cache) cpu_data[cpu].asid_cache = asid_first_version(cpu); - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; BUG_ON(current->mm); enter_lazy_tlb(&init_mm, current); diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c index 426173c4b0b9..e65b5cc2fa67 100644 --- a/arch/mn10300/kernel/smp.c +++ b/arch/mn10300/kernel/smp.c @@ -589,7 +589,7 @@ static void __init smp_cpu_init(void) } printk(KERN_INFO "Initializing CPU#%d\n", cpu_id); - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; BUG_ON(current->mm); diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c index 75dab2871346..67b452b41ff6 100644 --- a/arch/parisc/kernel/smp.c +++ b/arch/parisc/kernel/smp.c @@ -279,7 +279,7 @@ smp_cpu_init(int cpunum) set_cpu_online(cpunum, true); /* Initialise the idle task for this CPU */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; BUG_ON(current->mm); enter_lazy_tlb(&init_mm, current); diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 893bd7f79be6..573fb3a461b5 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -707,7 +707,7 @@ void start_secondary(void *unused) unsigned int cpu = smp_processor_id(); int i, base; - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; smp_store_cpu_info(cpu); diff --git a/arch/s390/kernel/processor.c b/arch/s390/kernel/processor.c index 21004aaac69b..bc2b60dcb178 100644 --- a/arch/s390/kernel/processor.c +++ b/arch/s390/kernel/processor.c @@ -73,7 +73,7 @@ void cpu_init(void) get_cpu_id(id); if (machine_has_cpu_mhz) update_cpu_mhz(NULL); - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; BUG_ON(current->mm); enter_lazy_tlb(&init_mm, current); diff --git a/arch/score/kernel/traps.c b/arch/score/kernel/traps.c index 2b22bcf02c27..569ac02f68df 100644 --- a/arch/score/kernel/traps.c +++ b/arch/score/kernel/traps.c @@ -336,7 +336,7 @@ void __init trap_init(void) set_except_vector(18, handle_dbe); flush_icache_range(DEBUG_VECTOR_BASE_ADDR, IRQ_VECTOR_BASE_ADDR); - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; cpu_cache_init(); } diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c index 38e7860845db..ee379c699c08 100644 --- a/arch/sh/kernel/smp.c +++ b/arch/sh/kernel/smp.c @@ -178,7 +178,7 @@ asmlinkage void start_secondary(void) struct mm_struct *mm = &init_mm; enable_mmu(); - atomic_inc(&mm->mm_count); + mmgrab(mm); atomic_inc(&mm->mm_users); current->active_mm = mm; #ifdef CONFIG_MMU diff --git a/arch/sparc/kernel/leon_smp.c b/arch/sparc/kernel/leon_smp.c index 71e16f2241c2..b99d33797e1d 100644 --- a/arch/sparc/kernel/leon_smp.c +++ b/arch/sparc/kernel/leon_smp.c @@ -93,7 +93,7 @@ void leon_cpu_pre_online(void *arg) : "memory" /* paranoid */); /* Attach to the address space of init_task. */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; while (!cpumask_test_cpu(cpuid, &smp_commenced_mask)) diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c index 90a02cb64e20..8e3e13924594 100644 --- a/arch/sparc/kernel/smp_64.c +++ b/arch/sparc/kernel/smp_64.c @@ -122,7 +122,7 @@ void smp_callin(void) current_thread_info()->new_child = 0; /* Attach to the address space of init_task. */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; /* inform the notifiers about the new cpu */ diff --git a/arch/sparc/kernel/sun4d_smp.c b/arch/sparc/kernel/sun4d_smp.c index 9d98e5002a09..7b55c50eabe5 100644 --- a/arch/sparc/kernel/sun4d_smp.c +++ b/arch/sparc/kernel/sun4d_smp.c @@ -93,7 +93,7 @@ void sun4d_cpu_pre_online(void *arg) show_leds(cpuid); /* Attach to the address space of init_task. */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; local_ops->cache_all(); diff --git a/arch/sparc/kernel/sun4m_smp.c b/arch/sparc/kernel/sun4m_smp.c index 278c40abce82..633c4cf6fdb0 100644 --- a/arch/sparc/kernel/sun4m_smp.c +++ b/arch/sparc/kernel/sun4m_smp.c @@ -59,7 +59,7 @@ void sun4m_cpu_pre_online(void *arg) : "memory" /* paranoid */); /* Attach to the address space of init_task. */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; while (!cpumask_test_cpu(cpuid, &smp_commenced_mask)) diff --git a/arch/sparc/kernel/traps_32.c b/arch/sparc/kernel/traps_32.c index 4f21df7d4f13..ecddac5a4c96 100644 --- a/arch/sparc/kernel/traps_32.c +++ b/arch/sparc/kernel/traps_32.c @@ -448,7 +448,7 @@ void trap_init(void) thread_info_offsets_are_bolixed_pete(); /* Attach to the address space of init_task. */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; /* NOTE: Other cpus have this done as they are started diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c index dfc97a47c9a0..e022d7b00390 100644 --- a/arch/sparc/kernel/traps_64.c +++ b/arch/sparc/kernel/traps_64.c @@ -2837,6 +2837,6 @@ void __init trap_init(void) /* Attach to the address space of init_task. On SMP we * do this in smp.c:smp_callin for other cpus. */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; } diff --git a/arch/tile/kernel/smpboot.c b/arch/tile/kernel/smpboot.c index 6c0abaacec33..53ce940a5016 100644 --- a/arch/tile/kernel/smpboot.c +++ b/arch/tile/kernel/smpboot.c @@ -160,7 +160,7 @@ static void start_secondary(void) __this_cpu_write(current_asid, min_asid); /* Set up this thread as another owner of the init_mm */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); current->active_mm = &init_mm; if (current->mm) BUG(); diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index f07005e6f461..c64ca5929cb5 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1510,7 +1510,7 @@ void cpu_init(void) for (i = 0; i <= IO_BITMAP_LONGS; i++) t->io_bitmap[i] = ~0UL; - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); me->active_mm = &init_mm; BUG_ON(me->mm); enter_lazy_tlb(&init_mm, me); @@ -1561,7 +1561,7 @@ void cpu_init(void) /* * Set up and load the per-CPU TSS and LDT */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); curr->active_mm = &init_mm; BUG_ON(curr->mm); enter_lazy_tlb(&init_mm, curr); diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c index fc4ad21a5ed4..9bf5cea3bae4 100644 --- a/arch/xtensa/kernel/smp.c +++ b/arch/xtensa/kernel/smp.c @@ -136,7 +136,7 @@ void secondary_start_kernel(void) /* All kernel threads share the same mm context. */ atomic_inc(&mm->mm_users); - atomic_inc(&mm->mm_count); + mmgrab(mm); current->active_mm = mm; cpumask_set_cpu(cpu, mm_cpumask(mm)); enter_lazy_tlb(mm, current); diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c index ef7c8de7060e..ca5f2aa7232d 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c @@ -262,7 +262,7 @@ static void kfd_process_notifier_release(struct mmu_notifier *mn, * and because the mmu_notifier_unregister function also drop * mm_count we need to take an extra count here. */ - atomic_inc(&p->mm->mm_count); + mmgrab(p->mm); mmu_notifier_unregister_no_release(&p->mmu_notifier, p->mm); mmu_notifier_call_srcu(&p->rcu, &kfd_process_destroy_delayed); } diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c index 6a8fa085b74e..65802d93fdc1 100644 --- a/drivers/gpu/drm/i915/i915_gem_userptr.c +++ b/drivers/gpu/drm/i915/i915_gem_userptr.c @@ -334,7 +334,7 @@ i915_gem_userptr_init__mm_struct(struct drm_i915_gem_object *obj) mm->i915 = to_i915(obj->base.dev); mm->mm = current->mm; - atomic_inc(¤t->mm->mm_count); + mmgrab(current->mm); mm->mn = NULL; diff --git a/drivers/infiniband/hw/hfi1/file_ops.c b/drivers/infiniband/hw/hfi1/file_ops.c index f46033984d07..3b19c16a9e45 100644 --- a/drivers/infiniband/hw/hfi1/file_ops.c +++ b/drivers/infiniband/hw/hfi1/file_ops.c @@ -185,7 +185,7 @@ static int hfi1_file_open(struct inode *inode, struct file *fp) if (fd) { fd->rec_cpu_num = -1; /* no cpu affinity by default */ fd->mm = current->mm; - atomic_inc(&fd->mm->mm_count); + mmgrab(fd->mm); fp->private_data = fd; } else { fp->private_data = NULL; diff --git a/fs/proc/base.c b/fs/proc/base.c index b8f06273353e..5d51a188871b 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -766,7 +766,7 @@ struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode) if (!IS_ERR_OR_NULL(mm)) { /* ensure this mm_struct can't be freed */ - atomic_inc(&mm->mm_count); + mmgrab(mm); /* but do not pin its memory */ mmput(mm); } @@ -1064,7 +1064,7 @@ static int __set_oom_adj(struct file *file, int oom_adj, bool legacy) if (p) { if (atomic_read(&p->mm->mm_users) > 1) { mm = p->mm; - atomic_inc(&mm->mm_count); + mmgrab(mm); } task_unlock(p); } diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index e6e0a619cb3a..3c421d06a18e 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1847,7 +1847,7 @@ static struct file *userfaultfd_file_create(int flags) ctx->released = false; ctx->mm = current->mm; /* prevent the mm struct to be freed */ - atomic_inc(&ctx->mm->mm_count); + mmgrab(ctx->mm); file = anon_inode_getfile("[userfaultfd]", &userfaultfd_fops, ctx, O_RDWR | (flags & UFFD_SHARED_FCNTL_FLAGS)); diff --git a/include/linux/sched.h b/include/linux/sched.h index 451e241f32c5..7cfa5546c840 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2904,6 +2904,28 @@ static inline unsigned long sigsp(unsigned long sp, struct ksignal *ksig) */ extern struct mm_struct * mm_alloc(void); +/** + * mmgrab() - Pin a &struct mm_struct. + * @mm: The &struct mm_struct to pin. + * + * Make sure that @mm will not get freed even after the owning task + * exits. This doesn't guarantee that the associated address space + * will still exist later on and mmget_not_zero() has to be used before + * accessing it. + * + * This is a preferred way to to pin @mm for a longer/unbounded amount + * of time. + * + * Use mmdrop() to release the reference acquired by mmgrab(). + * + * See also <Documentation/vm/active_mm.txt> for an in-depth explanation + * of &mm_struct.mm_count vs &mm_struct.mm_users. + */ +static inline void mmgrab(struct mm_struct *mm) +{ + atomic_inc(&mm->mm_count); +} + /* mmdrop drops the mm and the page tables */ extern void __mmdrop(struct mm_struct *); static inline void mmdrop(struct mm_struct *mm) diff --git a/kernel/exit.c b/kernel/exit.c index 90b09ca35c84..8a768a3672a5 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -539,7 +539,7 @@ static void exit_mm(void) __set_current_state(TASK_RUNNING); down_read(&mm->mmap_sem); } - atomic_inc(&mm->mm_count); + mmgrab(mm); BUG_ON(mm != current->active_mm); /* more a memory barrier than a real lock */ task_lock(current); diff --git a/kernel/futex.c b/kernel/futex.c index cdf365036141..b687cb22301c 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -338,7 +338,7 @@ static inline bool should_fail_futex(bool fshared) static inline void futex_get_mm(union futex_key *key) { - atomic_inc(&key->private.mm->mm_count); + mmgrab(key->private.mm); /* * Ensure futex_get_mm() implies a full barrier such that * get_futex_key() implies a full barrier. This is relied upon diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e1ae6ac15eac..6ea1925ac5c0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2847,7 +2847,7 @@ context_switch(struct rq *rq, struct task_struct *prev, if (!mm) { next->active_mm = oldmm; - atomic_inc(&oldmm->mm_count); + mmgrab(oldmm); enter_lazy_tlb(oldmm, next); } else switch_mm_irqs_off(oldmm, mm, next); @@ -6098,7 +6098,7 @@ void __init sched_init(void) /* * The boot idle thread does lazy MMU switching as well: */ - atomic_inc(&init_mm.mm_count); + mmgrab(&init_mm); enter_lazy_tlb(&init_mm, current); /* diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 77ae3239c3de..34bce5c308e3 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -420,7 +420,7 @@ int __khugepaged_enter(struct mm_struct *mm) list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); spin_unlock(&khugepaged_mm_lock); - atomic_inc(&mm->mm_count); + mmgrab(mm); if (wakeup) wake_up_interruptible(&khugepaged_wait); @@ -1854,7 +1854,7 @@ int __ksm_enter(struct mm_struct *mm) spin_unlock(&ksm_mmlist_lock); set_bit(MMF_VM_MERGEABLE, &mm->flags); - atomic_inc(&mm->mm_count); + mmgrab(mm); if (needs_wakeup) wake_up_interruptible(&ksm_thread_wait); diff --git a/mm/mmu_context.c b/mm/mmu_context.c index 6f4d27c5bb32..daf67bb02b4a 100644 --- a/mm/mmu_context.c +++ b/mm/mmu_context.c @@ -25,7 +25,7 @@ void use_mm(struct mm_struct *mm) task_lock(tsk); active_mm = tsk->active_mm; if (active_mm != mm) { - atomic_inc(&mm->mm_count); + mmgrab(mm); tsk->active_mm = mm; } tsk->mm = mm; diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index f4259e496f83..32bc9f2ff7eb 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -275,7 +275,7 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn, mm->mmu_notifier_mm = mmu_notifier_mm; mmu_notifier_mm = NULL; } - atomic_inc(&mm->mm_count); + mmgrab(mm); /* * Serialize the update against mmu_notifier_unregister. A diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 578321f1c070..51c091849dcb 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -653,7 +653,7 @@ static void mark_oom_victim(struct task_struct *tsk) /* oom_mm is bound to the signal struct life time. */ if (!cmpxchg(&tsk->signal->oom_mm, NULL, mm)) - atomic_inc(&tsk->signal->oom_mm->mm_count); + mmgrab(tsk->signal->oom_mm); /* * Make sure that the task is woken up from uninterruptible sleep @@ -870,7 +870,7 @@ static void oom_kill_process(struct oom_control *oc, const char *message) /* Get a reference to safely compare mm after task_unlock(victim) */ mm = victim->mm; - atomic_inc(&mm->mm_count); + mmgrab(mm); /* * We should send SIGKILL before setting TIF_MEMDIE in order to prevent * the OOM victim from depleting the memory reserves from the user diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 5b0dd4a9b2cb..35f71409d9ee 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -611,7 +611,7 @@ static struct kvm *kvm_create_vm(unsigned long type) return ERR_PTR(-ENOMEM); spin_lock_init(&kvm->mmu_lock); - atomic_inc(¤t->mm->mm_count); + mmgrab(current->mm); kvm->mm = current->mm; kvm_eventfd_init(kvm); mutex_init(&kvm->lock); |