// SPDX-License-Identifier: GPL-2.0-only/* * linux/kernel/fork.c * * Copyright (C) 1991, 1992 Linus Torvalds */ /* * 'fork.c' contains the help-routines for the 'fork' system call * (see also entry.S and others). * Fork is rather simple, once you get the hang of it, but the memory * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' */ #include <linux/anon_inodes.h>#include <linux/slab.h>#include <linux/sched/autogroup.h>#include <linux/sched/mm.h>#include <linux/sched/coredump.h>#include <linux/sched/user.h>#include <linux/sched/numa_balancing.h>#include <linux/sched/stat.h>#include <linux/sched/task.h>#include <linux/sched/task_stack.h>#include <linux/sched/cputime.h>#include <linux/seq_file.h>#include <linux/rtmutex.h>#include <linux/init.h>#include <linux/unistd.h>#include <linux/module.h>#include <linux/vmalloc.h>#include <linux/completion.h>#include <linux/personality.h>#include <linux/mempolicy.h>#include <linux/sem.h>#include <linux/file.h>#include <linux/fdtable.h>#include <linux/iocontext.h>#include <linux/key.h>#include <linux/binfmts.h>#include <linux/mman.h>#include <linux/mmu_notifier.h>#include <linux/hmm.h>#include <linux/fs.h>#include <linux/mm.h>#include <linux/vmacache.h>#include <linux/nsproxy.h>#include <linux/capability.h>#include <linux/cpu.h>#include <linux/cgroup.h>#include <linux/security.h>#include <linux/hugetlb.h>#include <linux/seccomp.h>#include <linux/swap.h>#include <linux/syscalls.h>#include <linux/jiffies.h>#include <linux/futex.h>#include <linux/compat.h>#include <linux/kthread.h>#include <linux/task_io_accounting_ops.h>#include <linux/rcupdate.h>#include <linux/ptrace.h>#include <linux/mount.h>#include <linux/audit.h>#include <linux/memcontrol.h>#include <linux/ftrace.h>#include <linux/proc_fs.h>#include <linux/profile.h>#include <linux/rmap.h>#include <linux/ksm.h>#include <linux/acct.h>#include <linux/userfaultfd_k.h>#include <linux/tsacct_kern.h>#include <linux/cn_proc.h>#include <linux/freezer.h>#include <linux/delayacct.h>#include <linux/taskstats_kern.h>#include <linux/random.h>#include <linux/tty.h>#include <linux/blkdev.h>#include <linux/fs_struct.h>#include <linux/magic.h>#include <linux/perf_event.h>#include <linux/posix-timers.h>#include <linux/user-return-notifier.h>#include <linux/oom.h>#include <linux/khugepaged.h>#include <linux/signalfd.h>#include <linux/uprobes.h>#include <linux/aio.h>#include <linux/compiler.h>#include <linux/sysctl.h>#include <linux/kcov.h>#include <linux/livepatch.h>#include <linux/thread_info.h>#include <linux/stackleak.h> #include <asm/pgtable.h>#include <asm/pgalloc.h>#include <linux/uaccess.h>#include <asm/mmu_context.h>#include <asm/cacheflush.h>#include <asm/tlbflush.h> #include <trace/events/sched.h> #define CREATE_TRACE_POINTS#include <trace/events/task.h> /* * Minimum number of threads to boot the kernel */#define MIN_THREADS 20 /* * Maximum number of threads */#define MAX_THREADS FUTEX_TID_MASK /* * Protected counters by write_lock_irq(&tasklist_lock) */unsigned long total_forks; /* Handle normal Linux uptimes. */int nr_threads; /* The idle threads do not count.. */ int max_threads; /* tunable limit on nr_threads */ DEFINE_PER_CPU(unsigned long, process_counts) = 0; __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ #ifdef CONFIG_PROVE_RCUint lockdep_tasklist_lock_is_held(void){ return lockdep_is_held(&tasklist_lock);}EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held);#endif /* #ifdef CONFIG_PROVE_RCU */ int nr_processes(void){ int cpu; int total = 0; for_each_possible_cpu(cpu) total += per_cpu(process_counts, cpu); return total;} void __weak arch_release_task_struct(struct task_struct *tsk){} #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATORstatic struct kmem_cache *task_struct_cachep; static inline struct task_struct *alloc_task_struct_node(int node){ return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node);} static inline void free_task_struct(struct task_struct *tsk){ kmem_cache_free(task_struct_cachep, tsk);}#endif #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR /* * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a * kmemcache based allocator. */# if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) #ifdef CONFIG_VMAP_STACK/* * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB * flush. Try to minimize the number of calls by caching stacks. */#define NR_CACHED_STACKS 2static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]); static int free_vm_stack_cache(unsigned int cpu){ struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu); int i; for (i = 0; i < NR_CACHED_STACKS; i++) { struct vm_struct *vm_stack = cached_vm_stacks[i]; if (!vm_stack) continue; vfree(vm_stack->addr); cached_vm_stacks[i] = NULL; } return 0;}#endif static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node){#ifdef CONFIG_VMAP_STACK void *stack; int i; for (i = 0; i < NR_CACHED_STACKS; i++) { struct vm_struct *s; s = this_cpu_xchg(cached_stacks[i], NULL); if (!s) continue; /* Clear stale pointers from reused stack. */ memset(s->addr, 0, THREAD_SIZE); tsk->stack_vm_area = s; tsk->stack = s->addr; return s->addr; } /* * Allocated stacks are cached and later reused by new threads, * so memcg accounting is performed manually on assigning/releasing * stacks to tasks. Drop __GFP_ACCOUNT. */ stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN, VMALLOC_START, VMALLOC_END, THREADINFO_GFP & ~__GFP_ACCOUNT, PAGE_KERNEL, 0, node, __builtin_return_address(0)); /* * We can't call find_vm_area() in interrupt context, and * free_thread_stack() can be called in interrupt context, * so cache the vm_struct. */ if (stack) { tsk->stack_vm_area = find_vm_area(stack); tsk->stack = stack; } return stack;#else struct page *page = alloc_pages_node(node, THREADINFO_GFP, THREAD_SIZE_ORDER); return page ? page_address(page) : NULL;#endif} static inline void free_thread_stack(struct task_struct *tsk){#ifdef CONFIG_VMAP_STACK struct vm_struct *vm = task_stack_vm_area(tsk); if (vm) { int i; for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { mod_memcg_page_state(vm->pages[i], MEMCG_KERNEL_STACK_KB, -(int)(PAGE_SIZE / 1024)); memcg_kmem_uncharge(vm->pages[i], 0); } for (i = 0; i < NR_CACHED_STACKS; i++) { if (this_cpu_cmpxchg(cached_stacks[i], NULL, tsk->stack_vm_area) != NULL) continue; return; } vfree_atomic(tsk->stack); return; }#endif __free_pages(virt_to_page(tsk->stack), THREAD_SIZE_ORDER);}# elsestatic struct kmem_cache *thread_stack_cache; static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node){ unsigned long *stack; stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node); tsk->stack = stack; return stack;} static void free_thread_stack(struct task_struct *tsk){ kmem_cache_free(thread_stack_cache, tsk->stack);} void thread_stack_cache_init(void){ thread_stack_cache = kmem_cache_create_usercopy("thread_stack", THREAD_SIZE, THREAD_SIZE, 0, 0, THREAD_SIZE, NULL); BUG_ON(thread_stack_cache == NULL);}# endif#endif /* SLAB cache for signal_struct structures (tsk->signal) */static struct kmem_cache *signal_cachep; /* SLAB cache for sighand_struct structures (tsk->sighand) */struct kmem_cache *sighand_cachep; /* SLAB cache for files_struct structures (tsk->files) */struct kmem_cache *files_cachep; /* SLAB cache for fs_struct structures (tsk->fs) */struct kmem_cache *fs_cachep; /* SLAB cache for vm_area_struct structures */static struct kmem_cache *vm_area_cachep; /* SLAB cache for mm_struct structures (tsk->mm) */static struct kmem_cache *mm_cachep; struct vm_area_struct *vm_area_alloc(struct mm_struct *mm){ struct vm_area_struct *vma; vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); if (vma) vma_init(vma, mm); return vma;} struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig){ struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); if (new) { *new = *orig; INIT_LIST_HEAD(&new->anon_vma_chain); } return new;} void vm_area_free(struct vm_area_struct *vma){ kmem_cache_free(vm_area_cachep, vma);} static void account_kernel_stack(struct task_struct *tsk, int account){ void *stack = task_stack_page(tsk); struct vm_struct *vm = task_stack_vm_area(tsk); BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0); if (vm) { int i; BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE); for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { mod_zone_page_state(page_zone(vm->pages[i]), NR_KERNEL_STACK_KB, PAGE_SIZE / 1024 * account); } } else { /* * All stack pages are in the same zone and belong to the * same memcg. */ struct page *first_page = virt_to_page(stack); mod_zone_page_state(page_zone(first_page), NR_KERNEL_STACK_KB, THREAD_SIZE / 1024 * account); mod_memcg_page_state(first_page, MEMCG_KERNEL_STACK_KB, account * (THREAD_SIZE / 1024)); }} static int memcg_charge_kernel_stack(struct task_struct *tsk){#ifdef CONFIG_VMAP_STACK struct vm_struct *vm = task_stack_vm_area(tsk); int ret; if (vm) { int i; for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { /* * If memcg_kmem_charge() fails, page->mem_cgroup * pointer is NULL, and both memcg_kmem_uncharge() * and mod_memcg_page_state() in free_thread_stack() * will ignore this page. So it's safe. */ ret = memcg_kmem_charge(vm->pages[i], GFP_KERNEL, 0); if (ret) return ret; mod_memcg_page_state(vm->pages[i], MEMCG_KERNEL_STACK_KB, PAGE_SIZE / 1024); } }#endif return 0;} static void release_task_stack(struct task_struct *tsk){ if (WARN_ON(tsk->state != TASK_DEAD)) return; /* Better to leak the stack than to free prematurely */ account_kernel_stack(tsk, -1); free_thread_stack(tsk); tsk->stack = NULL;#ifdef CONFIG_VMAP_STACK tsk->stack_vm_area = NULL;#endif} #ifdef CONFIG_THREAD_INFO_IN_TASKvoid put_task_stack(struct task_struct *tsk){ if (refcount_dec_and_test(&tsk->stack_refcount)) release_task_stack(tsk);}#endif void free_task(struct task_struct *tsk){#ifndef CONFIG_THREAD_INFO_IN_TASK /* * The task is finally done with both the stack and thread_info, * so free both. */ release_task_stack(tsk);#else /* * If the task had a separate stack allocation, it should be gone * by now. */ WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0);#endif rt_mutex_debug_task_free(tsk); ftrace_graph_exit_task(tsk); put_seccomp_filter(tsk); arch_release_task_struct(tsk); if (tsk->flags & PF_KTHREAD) free_kthread_struct(tsk); free_task_struct(tsk);}EXPORT_SYMBOL(free_task); #ifdef CONFIG_MMUstatic __latent_entropy int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm){ struct vm_area_struct *mpnt, *tmp, *prev, **pprev; struct rb_node **rb_link, *rb_parent; int retval; unsigned long charge; LIST_HEAD(uf); uprobe_start_dup_mmap(); if (down_write_killable(&oldmm->mmap_sem)) { retval = -EINTR; goto fail_uprobe_end; } flush_cache_dup_mm(oldmm); uprobe_dup_mmap(oldmm, mm); /* * Not linked in yet - no deadlock potential: */ down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); /* No ordering required: file already has been exposed. */ RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm)); mm->total_vm = oldmm->total_vm; mm->data_vm = oldmm->data_vm; mm->exec_vm = oldmm->exec_vm; mm->stack_vm = oldmm->stack_vm; rb_link = &mm->mm_rb.rb_node; rb_parent = NULL; pprev = &mm->mmap; retval = ksm_fork(mm, oldmm); if (retval) goto out; retval = khugepaged_fork(mm, oldmm);Lines 1–500 of 2808. 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// SPDX-License-Identifier: GPL-2.0-only /* * linux/kernel/fork.c * * Copyright (C) 1991, 1992 Linus Torvalds */ /* * 'fork.c' contains the help-routines for the 'fork' system call * (see also entry.S and others). * Fork is rather simple, once you get the hang of it, but the memory * management can be a bitch. See 'mm/memory.c': 'copy_page_range()' */ #include <linux/anon_inodes.h> #include <linux/slab.h> #include <linux/sched/autogroup.h> #include <linux/sched/mm.h> #include <linux/sched/coredump.h> #include <linux/sched/user.h> #include <linux/sched/numa_balancing.h> #include <linux/sched/stat.h> #include <linux/sched/task.h> #include <linux/sched/task_stack.h> #include <linux/sched/cputime.h> #include <linux/seq_file.h> #include <linux/rtmutex.h> #include <linux/init.h> #include <linux/unistd.h> #include <linux/module.h> #include <linux/vmalloc.h> #include <linux/completion.h> #include <linux/personality.h> #include <linux/mempolicy.h> #include <linux/sem.h> #include <linux/file.h> #include <linux/fdtable.h> #include <linux/iocontext.h> #include <linux/key.h> #include <linux/binfmts.h> #include <linux/mman.h> #include <linux/mmu_notifier.h> #include <linux/hmm.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/vmacache.h> #include <linux/nsproxy.h> #include <linux/capability.h> #include <linux/cpu.h> #include <linux/cgroup.h> #include <linux/security.h> #include <linux/hugetlb.h> #include <linux/seccomp.h> #include <linux/swap.h> #include <linux/syscalls.h> #include <linux/jiffies.h> #include <linux/futex.h> #include <linux/compat.h> #include <linux/kthread.h> #include <linux/task_io_accounting_ops.h> #include <linux/rcupdate.h> #include <linux/ptrace.h> #include <linux/mount.h> #include <linux/audit.h> #include <linux/memcontrol.h> #include <linux/ftrace.h> #include <linux/proc_fs.h> #include <linux/profile.h> #include <linux/rmap.h> #include <linux/ksm.h> #include <linux/acct.h> #include <linux/userfaultfd_k.h> #include <linux/tsacct_kern.h> #include <linux/cn_proc.h> #include <linux/freezer.h> #include <linux/delayacct.h> #include <linux/taskstats_kern.h> #include <linux/random.h> #include <linux/tty.h> #include <linux/blkdev.h> #include <linux/fs_struct.h> #include <linux/magic.h> #include <linux/perf_event.h> #include <linux/posix-timers.h> #include <linux/user-return-notifier.h> #include <linux/oom.h> #include <linux/khugepaged.h> #include <linux/signalfd.h> #include <linux/uprobes.h> #include <linux/aio.h> #include <linux/compiler.h> #include <linux/sysctl.h> #include <linux/kcov.h> #include <linux/livepatch.h> #include <linux/thread_info.h> #include <linux/stackleak.h> #include <asm/pgtable.h> #include <asm/pgalloc.h> #include <linux/uaccess.h> #include <asm/mmu_context.h> #include <asm/cacheflush.h> #include <asm/tlbflush.h> #include <trace/events/sched.h> #define CREATE_TRACE_POINTS #include <trace/events/task.h> /* * Minimum number of threads to boot the kernel */ #define MIN_THREADS 20 /* * Maximum number of threads */ #define MAX_THREADS FUTEX_TID_MASK /* * Protected counters by write_lock_irq(&tasklist_lock) */ unsigned long total_forks; /* Handle normal Linux uptimes. */ int nr_threads; /* The idle threads do not count.. */ int max_threads; /* tunable limit on nr_threads */ DEFINE_PER_CPU(unsigned long, process_counts) = 0; __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ #ifdef CONFIG_PROVE_RCU int lockdep_tasklist_lock_is_held(void) { return lockdep_is_held(&tasklist_lock); } EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held); #endif /* #ifdef CONFIG_PROVE_RCU */ int nr_processes(void) { int cpu; int total = 0; for_each_possible_cpu(cpu) total += per_cpu(process_counts, cpu); return total; } void __weak arch_release_task_struct(struct task_struct *tsk) { } #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR static struct kmem_cache *task_struct_cachep; static inline struct task_struct *alloc_task_struct_node(int node) { return kmem_cache_alloc_node(task_struct_cachep, GFP_KERNEL, node); } static inline void free_task_struct(struct task_struct *tsk) { kmem_cache_free(task_struct_cachep, tsk); } #endif #ifndef CONFIG_ARCH_THREAD_STACK_ALLOCATOR /* * Allocate pages if THREAD_SIZE is >= PAGE_SIZE, otherwise use a * kmemcache based allocator. */ # if THREAD_SIZE >= PAGE_SIZE || defined(CONFIG_VMAP_STACK) #ifdef CONFIG_VMAP_STACK /* * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB * flush. Try to minimize the number of calls by caching stacks. */ #define NR_CACHED_STACKS 2 static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]); static int free_vm_stack_cache(unsigned int cpu) { struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu); int i; for (i = 0; i < NR_CACHED_STACKS; i++) { struct vm_struct *vm_stack = cached_vm_stacks[i]; if (!vm_stack) continue; vfree(vm_stack->addr); cached_vm_stacks[i] = NULL; } return 0; } #endif static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node) { #ifdef CONFIG_VMAP_STACK void *stack; int i; for (i = 0; i < NR_CACHED_STACKS; i++) { struct vm_struct *s; s = this_cpu_xchg(cached_stacks[i], NULL); if (!s) continue; /* Clear stale pointers from reused stack. */ memset(s->addr, 0, THREAD_SIZE); tsk->stack_vm_area = s; tsk->stack = s->addr; return s->addr; } /* * Allocated stacks are cached and later reused by new threads, * so memcg accounting is performed manually on assigning/releasing * stacks to tasks. Drop __GFP_ACCOUNT. */ stack = __vmalloc_node_range(THREAD_SIZE, THREAD_ALIGN, VMALLOC_START, VMALLOC_END, THREADINFO_GFP & ~__GFP_ACCOUNT, PAGE_KERNEL, 0, node, __builtin_return_address(0)); /* * We can't call find_vm_area() in interrupt context, and * free_thread_stack() can be called in interrupt context, * so cache the vm_struct. */ if (stack) { tsk->stack_vm_area = find_vm_area(stack); tsk->stack = stack; } return stack; #else struct page *page = alloc_pages_node(node, THREADINFO_GFP, THREAD_SIZE_ORDER); return page ? page_address(page) : NULL; #endif } static inline void free_thread_stack(struct task_struct *tsk) { #ifdef CONFIG_VMAP_STACK struct vm_struct *vm = task_stack_vm_area(tsk); if (vm) { int i; for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { mod_memcg_page_state(vm->pages[i], MEMCG_KERNEL_STACK_KB, -(int)(PAGE_SIZE / 1024)); memcg_kmem_uncharge(vm->pages[i], 0); } for (i = 0; i < NR_CACHED_STACKS; i++) { if (this_cpu_cmpxchg(cached_stacks[i], NULL, tsk->stack_vm_area) != NULL) continue; return; } vfree_atomic(tsk->stack); return; } #endif __free_pages(virt_to_page(tsk->stack), THREAD_SIZE_ORDER); } # else static struct kmem_cache *thread_stack_cache; static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node) { unsigned long *stack; stack = kmem_cache_alloc_node(thread_stack_cache, THREADINFO_GFP, node); tsk->stack = stack; return stack; } static void free_thread_stack(struct task_struct *tsk) { kmem_cache_free(thread_stack_cache, tsk->stack); } void thread_stack_cache_init(void) { thread_stack_cache = kmem_cache_create_usercopy("thread_stack", THREAD_SIZE, THREAD_SIZE, 0, 0, THREAD_SIZE, NULL); BUG_ON(thread_stack_cache == NULL); } # endif #endif /* SLAB cache for signal_struct structures (tsk->signal) */ static struct kmem_cache *signal_cachep; /* SLAB cache for sighand_struct structures (tsk->sighand) */ struct kmem_cache *sighand_cachep; /* SLAB cache for files_struct structures (tsk->files) */ struct kmem_cache *files_cachep; /* SLAB cache for fs_struct structures (tsk->fs) */ struct kmem_cache *fs_cachep; /* SLAB cache for vm_area_struct structures */ static struct kmem_cache *vm_area_cachep; /* SLAB cache for mm_struct structures (tsk->mm) */ static struct kmem_cache *mm_cachep; struct vm_area_struct *vm_area_alloc(struct mm_struct *mm) { struct vm_area_struct *vma; vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); if (vma) vma_init(vma, mm); return vma; } struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) { struct vm_area_struct *new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); if (new) { *new = *orig; INIT_LIST_HEAD(&new->anon_vma_chain); } return new; } void vm_area_free(struct vm_area_struct *vma) { kmem_cache_free(vm_area_cachep, vma); } static void account_kernel_stack(struct task_struct *tsk, int account) { void *stack = task_stack_page(tsk); struct vm_struct *vm = task_stack_vm_area(tsk); BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0); if (vm) { int i; BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE); for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { mod_zone_page_state(page_zone(vm->pages[i]), NR_KERNEL_STACK_KB, PAGE_SIZE / 1024 * account); } } else { /* * All stack pages are in the same zone and belong to the * same memcg. */ struct page *first_page = virt_to_page(stack); mod_zone_page_state(page_zone(first_page), NR_KERNEL_STACK_KB, THREAD_SIZE / 1024 * account); mod_memcg_page_state(first_page, MEMCG_KERNEL_STACK_KB, account * (THREAD_SIZE / 1024)); } } static int memcg_charge_kernel_stack(struct task_struct *tsk) { #ifdef CONFIG_VMAP_STACK struct vm_struct *vm = task_stack_vm_area(tsk); int ret; if (vm) { int i; for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) { /* * If memcg_kmem_charge() fails, page->mem_cgroup * pointer is NULL, and both memcg_kmem_uncharge() * and mod_memcg_page_state() in free_thread_stack() * will ignore this page. So it's safe. */ ret = memcg_kmem_charge(vm->pages[i], GFP_KERNEL, 0); if (ret) return ret; mod_memcg_page_state(vm->pages[i], MEMCG_KERNEL_STACK_KB, PAGE_SIZE / 1024); } } #endif return 0; } static void release_task_stack(struct task_struct *tsk) { if (WARN_ON(tsk->state != TASK_DEAD)) return; /* Better to leak the stack than to free prematurely */ account_kernel_stack(tsk, -1); free_thread_stack(tsk); tsk->stack = NULL; #ifdef CONFIG_VMAP_STACK tsk->stack_vm_area = NULL; #endif } #ifdef CONFIG_THREAD_INFO_IN_TASK void put_task_stack(struct task_struct *tsk) { if (refcount_dec_and_test(&tsk->stack_refcount)) release_task_stack(tsk); } #endif void free_task(struct task_struct *tsk) { #ifndef CONFIG_THREAD_INFO_IN_TASK /* * The task is finally done with both the stack and thread_info, * so free both. */ release_task_stack(tsk); #else /* * If the task had a separate stack allocation, it should be gone * by now. */ WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0); #endif rt_mutex_debug_task_free(tsk); ftrace_graph_exit_task(tsk); put_seccomp_filter(tsk); arch_release_task_struct(tsk); if (tsk->flags & PF_KTHREAD) free_kthread_struct(tsk); free_task_struct(tsk); } EXPORT_SYMBOL(free_task); #ifdef CONFIG_MMU static __latent_entropy int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) { struct vm_area_struct *mpnt, *tmp, *prev, **pprev; struct rb_node **rb_link, *rb_parent; int retval; unsigned long charge; LIST_HEAD(uf); uprobe_start_dup_mmap(); if (down_write_killable(&oldmm->mmap_sem)) { retval = -EINTR; goto fail_uprobe_end; } flush_cache_dup_mm(oldmm); uprobe_dup_mmap(oldmm, mm); /* * Not linked in yet - no deadlock potential: */ down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); /* No ordering required: file already has been exposed. */ RCU_INIT_POINTER(mm->exe_file, get_mm_exe_file(oldmm)); mm->total_vm = oldmm->total_vm; mm->data_vm = oldmm->data_vm; mm->exec_vm = oldmm->exec_vm; mm->stack_vm = oldmm->stack_vm; rb_link = &mm->mm_rb.rb_node; rb_parent = NULL; pprev = &mm->mmap; retval = ksm_fork(mm, oldmm); if (retval) goto out; retval = khugepaged_fork(mm, oldmm);