diff options
Diffstat (limited to 'kernel')
41 files changed, 4488 insertions, 1140 deletions
diff --git a/kernel/Makefile b/kernel/Makefile index 6c07f30fa9b7..c0cc67ad764c 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -5,12 +5,12 @@ obj-y = fork.o exec_domain.o panic.o printk.o \ cpu.o exit.o itimer.o time.o softirq.o resource.o \ sysctl.o sysctl_binary.o capability.o ptrace.o timer.o user.o \ - signal.o sys.o kmod.o workqueue.o pid.o \ + signal.o sys.o kmod.o workqueue.o pid.o task_work.o \ rcupdate.o extable.o params.o posix-timers.o \ kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \ hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \ notifier.o ksysfs.o cred.o \ - async.o range.o groups.o + async.o range.o groups.o lglock.o ifdef CONFIG_FUNCTION_TRACER # Do not trace debug files and internal ftrace files @@ -25,6 +25,9 @@ endif obj-y += sched/ obj-y += power/ +ifeq ($(CONFIG_CHECKPOINT_RESTORE),y) +obj-$(CONFIG_X86) += kcmp.o +endif obj-$(CONFIG_FREEZER) += freezer.o obj-$(CONFIG_PROFILING) += profile.o obj-$(CONFIG_STACKTRACE) += stacktrace.o diff --git a/kernel/cgroup.c b/kernel/cgroup.c index a0c6af34d500..0f3527d6184a 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -5132,7 +5132,7 @@ EXPORT_SYMBOL_GPL(css_depth); * @root: the css supporsed to be an ancestor of the child. * * Returns true if "root" is an ancestor of "child" in its hierarchy. Because - * this function reads css->id, this use rcu_dereference() and rcu_read_lock(). + * this function reads css->id, the caller must hold rcu_read_lock(). * But, considering usual usage, the csses should be valid objects after test. * Assuming that the caller will do some action to the child if this returns * returns true, the caller must take "child";s reference count. @@ -5144,18 +5144,18 @@ bool css_is_ancestor(struct cgroup_subsys_state *child, { struct css_id *child_id; struct css_id *root_id; - bool ret = true; - rcu_read_lock(); child_id = rcu_dereference(child->id); + if (!child_id) + return false; root_id = rcu_dereference(root->id); - if (!child_id - || !root_id - || (child_id->depth < root_id->depth) - || (child_id->stack[root_id->depth] != root_id->id)) - ret = false; - rcu_read_unlock(); - return ret; + if (!root_id) + return false; + if (child_id->depth < root_id->depth) + return false; + if (child_id->stack[root_id->depth] != root_id->id) + return false; + return true; } void free_css_id(struct cgroup_subsys *ss, struct cgroup_subsys_state *css) diff --git a/kernel/cpu.c b/kernel/cpu.c index 0e6353cf147a..a4eb5227a19e 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -10,7 +10,10 @@ #include <linux/sched.h> #include <linux/unistd.h> #include <linux/cpu.h> +#include <linux/oom.h> +#include <linux/rcupdate.h> #include <linux/export.h> +#include <linux/bug.h> #include <linux/kthread.h> #include <linux/stop_machine.h> #include <linux/mutex.h> @@ -173,6 +176,47 @@ void __ref unregister_cpu_notifier(struct notifier_block *nb) } EXPORT_SYMBOL(unregister_cpu_notifier); +/** + * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU + * @cpu: a CPU id + * + * This function walks all processes, finds a valid mm struct for each one and + * then clears a corresponding bit in mm's cpumask. While this all sounds + * trivial, there are various non-obvious corner cases, which this function + * tries to solve in a safe manner. + * + * Also note that the function uses a somewhat relaxed locking scheme, so it may + * be called only for an already offlined CPU. + */ +void clear_tasks_mm_cpumask(int cpu) +{ + struct task_struct *p; + + /* + * This function is called after the cpu is taken down and marked + * offline, so its not like new tasks will ever get this cpu set in + * their mm mask. -- Peter Zijlstra + * Thus, we may use rcu_read_lock() here, instead of grabbing + * full-fledged tasklist_lock. + */ + WARN_ON(cpu_online(cpu)); + rcu_read_lock(); + for_each_process(p) { + struct task_struct *t; + + /* + * Main thread might exit, but other threads may still have + * a valid mm. Find one. + */ + t = find_lock_task_mm(p); + if (!t) + continue; + cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); + task_unlock(t); + } + rcu_read_unlock(); +} + static inline void check_for_tasks(int cpu) { struct task_struct *p; diff --git a/kernel/cpu_pm.c b/kernel/cpu_pm.c index 249152e15308..9656a3c36503 100644 --- a/kernel/cpu_pm.c +++ b/kernel/cpu_pm.c @@ -81,7 +81,7 @@ int cpu_pm_unregister_notifier(struct notifier_block *nb) EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); /** - * cpm_pm_enter - CPU low power entry notifier + * cpu_pm_enter - CPU low power entry notifier * * Notifies listeners that a single CPU is entering a low power state that may * cause some blocks in the same power domain as the cpu to reset. @@ -89,7 +89,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_unregister_notifier); * Must be called on the affected CPU with interrupts disabled. Platform is * responsible for ensuring that cpu_pm_enter is not called twice on the same * CPU before cpu_pm_exit is called. Notified drivers can include VFP - * co-processor, interrupt controller and it's PM extensions, local CPU + * co-processor, interrupt controller and its PM extensions, local CPU * timers context save/restore which shouldn't be interrupted. Hence it * must be called with interrupts disabled. * @@ -115,13 +115,13 @@ int cpu_pm_enter(void) EXPORT_SYMBOL_GPL(cpu_pm_enter); /** - * cpm_pm_exit - CPU low power exit notifier + * cpu_pm_exit - CPU low power exit notifier * * Notifies listeners that a single CPU is exiting a low power state that may * have caused some blocks in the same power domain as the cpu to reset. * * Notified drivers can include VFP co-processor, interrupt controller - * and it's PM extensions, local CPU timers context save/restore which + * and its PM extensions, local CPU timers context save/restore which * shouldn't be interrupted. Hence it must be called with interrupts disabled. * * Return conditions are same as __raw_notifier_call_chain. @@ -139,7 +139,7 @@ int cpu_pm_exit(void) EXPORT_SYMBOL_GPL(cpu_pm_exit); /** - * cpm_cluster_pm_enter - CPU cluster low power entry notifier + * cpu_cluster_pm_enter - CPU cluster low power entry notifier * * Notifies listeners that all cpus in a power domain are entering a low power * state that may cause some blocks in the same power domain to reset. @@ -147,7 +147,7 @@ EXPORT_SYMBOL_GPL(cpu_pm_exit); * Must be called after cpu_pm_enter has been called on all cpus in the power * domain, and before cpu_pm_exit has been called on any cpu in the power * domain. Notified drivers can include VFP co-processor, interrupt controller - * and it's PM extensions, local CPU timers context save/restore which + * and its PM extensions, local CPU timers context save/restore which * shouldn't be interrupted. Hence it must be called with interrupts disabled. * * Must be called with interrupts disabled. @@ -174,7 +174,7 @@ int cpu_cluster_pm_enter(void) EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); /** - * cpm_cluster_pm_exit - CPU cluster low power exit notifier + * cpu_cluster_pm_exit - CPU cluster low power exit notifier * * Notifies listeners that all cpus in a power domain are exiting form a * low power state that may have caused some blocks in the same power domain @@ -183,7 +183,7 @@ EXPORT_SYMBOL_GPL(cpu_cluster_pm_enter); * Must be called after cpu_pm_exit has been called on all cpus in the power * domain, and before cpu_pm_exit has been called on any cpu in the power * domain. Notified drivers can include VFP co-processor, interrupt controller - * and it's PM extensions, local CPU timers context save/restore which + * and its PM extensions, local CPU timers context save/restore which * shouldn't be interrupted. Hence it must be called with interrupts disabled. * * Return conditions are same as __raw_notifier_call_chain. diff --git a/kernel/cred.c b/kernel/cred.c index 430557ea488f..de728ac50d82 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -207,13 +207,6 @@ void exit_creds(struct task_struct *tsk) validate_creds(cred); alter_cred_subscribers(cred, -1); put_cred(cred); - - cred = (struct cred *) tsk->replacement_session_keyring; - if (cred) { - tsk->replacement_session_keyring = NULL; - validate_creds(cred); - put_cred(cred); - } } /** @@ -396,8 +389,6 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags) struct cred *new; int ret; - p->replacement_session_keyring = NULL; - if ( #ifdef CONFIG_KEYS !p->cred->thread_keyring && diff --git a/kernel/events/Makefile b/kernel/events/Makefile index 22d901f9caf4..103f5d147b2f 100644 --- a/kernel/events/Makefile +++ b/kernel/events/Makefile @@ -3,4 +3,7 @@ CFLAGS_REMOVE_core.o = -pg endif obj-y := core.o ring_buffer.o callchain.o + obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o +obj-$(CONFIG_UPROBES) += uprobes.o + diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c new file mode 100644 index 000000000000..985be4d80fe8 --- /dev/null +++ b/kernel/events/uprobes.c @@ -0,0 +1,1667 @@ +/* + * User-space Probes (UProbes) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) IBM Corporation, 2008-2012 + * Authors: + * Srikar Dronamraju + * Jim Keniston + * Copyright (C) 2011-2012 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> + */ + +#include <linux/kernel.h> +#include <linux/highmem.h> +#include <linux/pagemap.h> /* read_mapping_page */ +#include <linux/slab.h> +#include <linux/sched.h> +#include <linux/rmap.h> /* anon_vma_prepare */ +#include <linux/mmu_notifier.h> /* set_pte_at_notify */ +#include <linux/swap.h> /* try_to_free_swap */ +#include <linux/ptrace.h> /* user_enable_single_step */ +#include <linux/kdebug.h> /* notifier mechanism */ + +#include <linux/uprobes.h> + +#define UINSNS_PER_PAGE (PAGE_SIZE/UPROBE_XOL_SLOT_BYTES) +#define MAX_UPROBE_XOL_SLOTS UINSNS_PER_PAGE + +static struct srcu_struct uprobes_srcu; +static struct rb_root uprobes_tree = RB_ROOT; + +static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */ + +#define UPROBES_HASH_SZ 13 + +/* serialize (un)register */ +static struct mutex uprobes_mutex[UPROBES_HASH_SZ]; + +#define uprobes_hash(v) (&uprobes_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ]) + +/* serialize uprobe->pending_list */ +static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ]; +#define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ]) + +/* + * uprobe_events allows us to skip the uprobe_mmap if there are no uprobe + * events active at this time. Probably a fine grained per inode count is + * better? + */ +static atomic_t uprobe_events = ATOMIC_INIT(0); + +/* + * Maintain a temporary per vma info that can be used to search if a vma + * has already been handled. This structure is introduced since extending + * vm_area_struct wasnt recommended. + */ +struct vma_info { + struct list_head probe_list; + struct mm_struct *mm; + loff_t vaddr; +}; + +struct uprobe { + struct rb_node rb_node; /* node in the rb tree */ + atomic_t ref; + struct rw_semaphore consumer_rwsem; + struct list_head pending_list; + struct uprobe_consumer *consumers; + struct inode *inode; /* Also hold a ref to inode */ + loff_t offset; + int flags; + struct arch_uprobe arch; +}; + +/* + * valid_vma: Verify if the specified vma is an executable vma + * Relax restrictions while unregistering: vm_flags might have + * changed after breakpoint was inserted. + * - is_register: indicates if we are in register context. + * - Return 1 if the specified virtual address is in an + * executable vma. + */ +static bool valid_vma(struct vm_area_struct *vma, bool is_register) +{ + if (!vma->vm_file) + return false; + + if (!is_register) + return true; + + if ((vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)) == (VM_READ|VM_EXEC)) + return true; + + return false; +} + +static loff_t vma_address(struct vm_area_struct *vma, loff_t offset) +{ + loff_t vaddr; + + vaddr = vma->vm_start + offset; + vaddr -= vma->vm_pgoff << PAGE_SHIFT; + + return vaddr; +} + +/** + * __replace_page - replace page in vma by new page. + * based on replace_page in mm/ksm.c + * + * @vma: vma that holds the pte pointing to page + * @page: the cowed page we are replacing by kpage + * @kpage: the modified page we replace page by + * + * Returns 0 on success, -EFAULT on failure. + */ +static int __replace_page(struct vm_area_struct *vma, struct page *page, struct page *kpage) +{ + struct mm_struct *mm = vma->vm_mm; + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *ptep; + spinlock_t *ptl; + unsigned long addr; + int err = -EFAULT; + + addr = page_address_in_vma(page, vma); + if (addr == -EFAULT) + goto out; + + pgd = pgd_offset(mm, addr); + if (!pgd_present(*pgd)) + goto out; + + pud = pud_offset(pgd, addr); + if (!pud_present(*pud)) + goto out; + + pmd = pmd_offset(pud, addr); + if (!pmd_present(*pmd)) + goto out; + + ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); + if (!ptep) + goto out; + + get_page(kpage); + page_add_new_anon_rmap(kpage, vma, addr); + + if (!PageAnon(page)) { + dec_mm_counter(mm, MM_FILEPAGES); + inc_mm_counter(mm, MM_ANONPAGES); + } + + flush_cache_page(vma, addr, pte_pfn(*ptep)); + ptep_clear_flush(vma, addr, ptep); + set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot)); + + page_remove_rmap(page); + if (!page_mapped(page)) + try_to_free_swap(page); + put_page(page); + pte_unmap_unlock(ptep, ptl); + err = 0; + +out: + return err; +} + +/** + * is_swbp_insn - check if instruction is breakpoint instruction. + * @insn: instruction to be checked. + * Default implementation of is_swbp_insn + * Returns true if @insn is a breakpoint instruction. + */ +bool __weak is_swbp_insn(uprobe_opcode_t *insn) +{ + return *insn == UPROBE_SWBP_INSN; +} + +/* + * NOTE: + * Expect the breakpoint instruction to be the smallest size instruction for + * the architecture. If an arch has variable length instruction and the + * breakpoint instruction is not of the smallest length instruction + * supported by that architecture then we need to modify read_opcode / + * write_opcode accordingly. This would never be a problem for archs that + * have fixed length instructions. + */ + +/* + * write_opcode - write the opcode at a given virtual address. + * @auprobe: arch breakpointing information. + * @mm: the probed process address space. + * @vaddr: the virtual address to store the opcode. + * @opcode: opcode to be written at @vaddr. + * + * Called with mm->mmap_sem held (for read and with a reference to + * mm). + * + * For mm @mm, write the opcode at @vaddr. + * Return 0 (success) or a negative errno. + */ +static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, + unsigned long vaddr, uprobe_opcode_t opcode) +{ + struct page *old_page, *new_page; + struct address_space *mapping; + void *vaddr_old, *vaddr_new; + struct vm_area_struct *vma; + struct uprobe *uprobe; + loff_t addr; + int ret; + + /* Read the page with vaddr into memory */ + ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &old_page, &vma); + if (ret <= 0) + return ret; + + ret = -EINVAL; + + /* + * We are interested in text pages only. Our pages of interest + * should be mapped for read and execute only. We desist from + * adding probes in write mapped pages since the breakpoints + * might end up in the file copy. + */ + if (!valid_vma(vma, is_swbp_insn(&opcode))) + goto put_out; + + uprobe = container_of(auprobe, struct uprobe, arch); + mapping = uprobe->inode->i_mapping; + if (mapping != vma->vm_file->f_mapping) + goto put_out; + + addr = vma_address(vma, uprobe->offset); + if (vaddr != (unsigned long)addr) + goto put_out; + + ret = -ENOMEM; + new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr); + if (!new_page) + goto put_out; + + __SetPageUptodate(new_page); + + /* + * lock page will serialize against do_wp_page()'s + * PageAnon() handling + */ + lock_page(old_page); + /* copy the page now that we've got it stable */ + vaddr_old = kmap_atomic(old_page); + vaddr_new = kmap_atomic(new_page); + + memcpy(vaddr_new, vaddr_old, PAGE_SIZE); + + /* poke the new insn in, ASSUMES we don't cross page boundary */ + vaddr &= ~PAGE_MASK; + BUG_ON(vaddr + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); + memcpy(vaddr_new + vaddr, &opcode, UPROBE_SWBP_INSN_SIZE); + + kunmap_atomic(vaddr_new); + kunmap_atomic(vaddr_old); + + ret = anon_vma_prepare(vma); + if (ret) + goto unlock_out; + + lock_page(new_page); + ret = __replace_page(vma, old_page, new_page); + unlock_page(new_page); + +unlock_out: + unlock_page(old_page); + page_cache_release(new_page); + +put_out: + put_page(old_page); + + return ret; +} + +/** + * read_opcode - read the opcode at a given virtual address. + * @mm: the probed process address space. + * @vaddr: the virtual address to read the opcode. + * @opcode: location to store the read opcode. + * + * Called with mm->mmap_sem held (for read and with a reference to + * mm. + * + * For mm @mm, read the opcode at @vaddr and store it in @opcode. + * Return 0 (success) or a negative errno. + */ +static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t *opcode) +{ + struct page *page; + void *vaddr_new; + int ret; + + ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &page, NULL); + if (ret <= 0) + return ret; + + lock_page(page); + vaddr_new = kmap_atomic(page); + vaddr &= ~PAGE_MASK; + memcpy(opcode, vaddr_new + vaddr, UPROBE_SWBP_INSN_SIZE); + kunmap_atomic(vaddr_new); + unlock_page(page); + + put_page(page); + + return 0; +} + +static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr) +{ + uprobe_opcode_t opcode; + int result; + + result = read_opcode(mm, vaddr, &opcode); + if (result) + return result; + + if (is_swbp_insn(&opcode)) + return 1; + + return 0; +} + +/** + * set_swbp - store breakpoint at a given address. + * @auprobe: arch specific probepoint information. + * @mm: the probed process address space. + * @vaddr: the virtual address to insert the opcode. + * + * For mm @mm, store the breakpoint instruction at @vaddr. + * Return 0 (success) or a negative errno. + */ +int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) +{ + int result; + + result = is_swbp_at_addr(mm, vaddr); + if (result == 1) + return -EEXIST; + + if (result) + return result; + + return write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN); +} + +/** + * set_orig_insn - Restore the original instruction. + * @mm: the probed process address space. + * @auprobe: arch specific probepoint information. + * @vaddr: the virtual address to insert the opcode. + * @verify: if true, verify existance of breakpoint instruction. + * + * For mm @mm, restore the original opcode (opcode) at @vaddr. + * Return 0 (success) or a negative errno. + */ +int __weak +set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, bool verify) +{ + if (verify) { + int result; + + result = is_swbp_at_addr(mm, vaddr); + if (!result) + return -EINVAL; + + if (result != 1) + return result; + } + return write_opcode(auprobe, mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); +} + +static int match_uprobe(struct uprobe *l, struct uprobe *r) +{ + if (l->inode < r->inode) + return -1; + + if (l->inode > r->inode) + return 1; + + if (l->offset < r->offset) + return -1; + + if (l->offset > r->offset) + return 1; + + return 0; +} + +static struct uprobe *__find_uprobe(struct inode *inode, loff_t offset) +{ + struct uprobe u = { .inode = inode, .offset = offset }; + struct rb_node *n = uprobes_tree.rb_node; + struct uprobe *uprobe; + int match; + + while (n) { + uprobe = rb_entry(n, struct uprobe, rb_node); + match = match_uprobe(&u, uprobe); + if (!match) { + atomic_inc(&uprobe->ref); + return uprobe; + } + + if (match < 0) + n = n->rb_left; + else + n = n->rb_right; + } + return NULL; +} + +/* + * Find a uprobe corresponding to a given inode:offset + * Acquires uprobes_treelock + */ +static struct uprobe *find_uprobe(struct inode *inode, loff_t offset) +{ + struct uprobe *uprobe; + unsigned long flags; + + spin_lock_irqsave(&uprobes_treelock, flags); + uprobe = __find_uprobe(inode, offset); + spin_unlock_irqrestore(&uprobes_treelock, flags); + + return uprobe; +} + +static struct uprobe *__insert_uprobe(struct uprobe *uprobe) +{ + struct rb_node **p = &uprobes_tree.rb_node; + struct rb_node *parent = NULL; + struct uprobe *u; + int match; + + while (*p) { + parent = *p; + u = rb_entry(parent, struct uprobe, rb_node); + match = match_uprobe(uprobe, u); + if (!match) { + atomic_inc(&u->ref); + return u; + } + + if (match < 0) + p = &parent->rb_left; + else + p = &parent->rb_right; + + } + + u = NULL; + rb_link_node(&uprobe->rb_node, parent, p); + rb_insert_color(&uprobe->rb_node, &uprobes_tree); + /* get access + creation ref */ + atomic_set(&uprobe->ref, 2); + + return u; +} + +/* + * Acquire uprobes_treelock. + * Matching uprobe already exists in rbtre |