summaryrefslogtreecommitdiffstats
path: root/kernel/events
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/callchain.c9
-rw-r--r--kernel/events/core.c143
-rw-r--r--kernel/events/hw_breakpoint.c11
-rw-r--r--kernel/events/internal.h3
-rw-r--r--kernel/events/uprobes.c622
5 files changed, 426 insertions, 362 deletions
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 6581a040f39..98d4597f43d 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -153,7 +153,8 @@ put_callchain_entry(int rctx)
put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
}
-struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
+struct perf_callchain_entry *
+perf_callchain(struct perf_event *event, struct pt_regs *regs)
{
int rctx;
struct perf_callchain_entry *entry;
@@ -178,6 +179,12 @@ struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
}
if (regs) {
+ /*
+ * Disallow cross-task user callchains.
+ */
+ if (event->ctx->task && event->ctx->task != current)
+ goto exit_put;
+
perf_callchain_store(entry, PERF_CONTEXT_USER);
perf_callchain_user(entry, regs);
}
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d7d71d6ec97..7fee567153f 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1253,7 +1253,7 @@ retry:
/*
* Cross CPU call to disable a performance event
*/
-static int __perf_event_disable(void *info)
+int __perf_event_disable(void *info)
{
struct perf_event *event = info;
struct perf_event_context *ctx = event->ctx;
@@ -1645,6 +1645,8 @@ perf_install_in_context(struct perf_event_context *ctx,
lockdep_assert_held(&ctx->mutex);
event->ctx = ctx;
+ if (event->cpu != -1)
+ event->cpu = cpu;
if (!task) {
/*
@@ -2933,12 +2935,12 @@ EXPORT_SYMBOL_GPL(perf_event_release_kernel);
/*
* Called when the last reference to the file is gone.
*/
-static int perf_release(struct inode *inode, struct file *file)
+static void put_event(struct perf_event *event)
{
- struct perf_event *event = file->private_data;
struct task_struct *owner;
- file->private_data = NULL;
+ if (!atomic_long_dec_and_test(&event->refcount))
+ return;
rcu_read_lock();
owner = ACCESS_ONCE(event->owner);
@@ -2973,7 +2975,13 @@ static int perf_release(struct inode *inode, struct file *file)
put_task_struct(owner);
}
- return perf_event_release_kernel(event);
+ perf_event_release_kernel(event);
+}
+
+static int perf_release(struct inode *inode, struct file *file)
+{
+ put_event(file->private_data);
+ return 0;
}
u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
@@ -3225,7 +3233,7 @@ unlock:
static const struct file_operations perf_fops;
-static struct perf_event *perf_fget_light(int fd, int *fput_needed)
+static struct file *perf_fget_light(int fd, int *fput_needed)
{
struct file *file;
@@ -3239,7 +3247,7 @@ static struct perf_event *perf_fget_light(int fd, int *fput_needed)
return ERR_PTR(-EBADF);
}
- return file->private_data;
+ return file;
}
static int perf_event_set_output(struct perf_event *event,
@@ -3271,19 +3279,21 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case PERF_EVENT_IOC_SET_OUTPUT:
{
+ struct file *output_file = NULL;
struct perf_event *output_event = NULL;
int fput_needed = 0;
int ret;
if (arg != -1) {
- output_event = perf_fget_light(arg, &fput_needed);
- if (IS_ERR(output_event))
- return PTR_ERR(output_event);
+ output_file = perf_fget_light(arg, &fput_needed);
+ if (IS_ERR(output_file))
+ return PTR_ERR(output_file);
+ output_event = output_file->private_data;
}
ret = perf_event_set_output(event, output_event);
if (output_event)
- fput_light(output_event->filp, fput_needed);
+ fput_light(output_file, fput_needed);
return ret;
}
@@ -4037,7 +4047,7 @@ void perf_prepare_sample(struct perf_event_header *header,
if (sample_type & PERF_SAMPLE_CALLCHAIN) {
int size = 1;
- data->callchain = perf_callchain(regs);
+ data->callchain = perf_callchain(event, regs);
if (data->callchain)
size += data->callchain->nr;
@@ -5207,7 +5217,8 @@ static int perf_tp_event_match(struct perf_event *event,
}
void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
- struct pt_regs *regs, struct hlist_head *head, int rctx)
+ struct pt_regs *regs, struct hlist_head *head, int rctx,
+ struct task_struct *task)
{
struct perf_sample_data data;
struct perf_event *event;
@@ -5226,6 +5237,31 @@ void perf_tp_event(u64 addr, u64 count, void *record, int entry_size,
perf_swevent_event(event, count, &data, regs);
}
+ /*
+ * If we got specified a target task, also iterate its context and
+ * deliver this event there too.
+ */
+ if (task && task != current) {
+ struct perf_event_context *ctx;
+ struct trace_entry *entry = record;
+
+ rcu_read_lock();
+ ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
+ if (!ctx)
+ goto unlock;
+
+ list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
+ if (event->attr.type != PERF_TYPE_TRACEPOINT)
+ continue;
+ if (event->attr.config != entry->type)
+ continue;
+ if (perf_tp_event_match(event, &data, regs))
+ perf_swevent_event(event, count, &data, regs);
+ }
+unlock:
+ rcu_read_unlock();
+ }
+
perf_swevent_put_recursion_context(rctx);
}
EXPORT_SYMBOL_GPL(perf_tp_event);
@@ -5922,6 +5958,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
mutex_init(&event->mmap_mutex);
+ atomic_long_set(&event->refcount, 1);
event->cpu = cpu;
event->attr = *attr;
event->group_leader = group_leader;
@@ -6232,12 +6269,12 @@ SYSCALL_DEFINE5(perf_event_open,
return event_fd;
if (group_fd != -1) {
- group_leader = perf_fget_light(group_fd, &fput_needed);
- if (IS_ERR(group_leader)) {
- err = PTR_ERR(group_leader);
+ group_file = perf_fget_light(group_fd, &fput_needed);
+ if (IS_ERR(group_file)) {
+ err = PTR_ERR(group_file);
goto err_fd;
}
- group_file = group_leader->filp;
+ group_leader = group_file->private_data;
if (flags & PERF_FLAG_FD_OUTPUT)
output_event = group_leader;
if (flags & PERF_FLAG_FD_NO_GROUP)
@@ -6252,6 +6289,8 @@ SYSCALL_DEFINE5(perf_event_open,
}
}
+ get_online_cpus();
+
event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
NULL, NULL);
if (IS_ERR(event)) {
@@ -6304,7 +6343,7 @@ SYSCALL_DEFINE5(perf_event_open,
/*
* Get the target context (task or percpu):
*/
- ctx = find_get_context(pmu, task, cpu);
+ ctx = find_get_context(pmu, task, event->cpu);
if (IS_ERR(ctx)) {
err = PTR_ERR(ctx);
goto err_alloc;
@@ -6372,25 +6411,27 @@ SYSCALL_DEFINE5(perf_event_open,
put_ctx(gctx);
}
- event->filp = event_file;
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
if (move_group) {
- perf_install_in_context(ctx, group_leader, cpu);
+ synchronize_rcu();
+ perf_install_in_context(ctx, group_leader, event->cpu);
get_ctx(ctx);
list_for_each_entry(sibling, &group_leader->sibling_list,
group_entry) {
- perf_install_in_context(ctx, sibling, cpu);
+ perf_install_in_context(ctx, sibling, event->cpu);
get_ctx(ctx);
}
}
- perf_install_in_context(ctx, event, cpu);
+ perf_install_in_context(ctx, event, event->cpu);
++ctx->generation;
perf_unpin_context(ctx);
mutex_unlock(&ctx->mutex);
+ put_online_cpus();
+
event->owner = current;
mutex_lock(&current->perf_event_mutex);
@@ -6419,6 +6460,7 @@ err_context:
err_alloc:
free_event(event);
err_task:
+ put_online_cpus();
if (task)
put_task_struct(task);
err_group_fd:
@@ -6462,7 +6504,6 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
goto err_free;
}
- event->filp = NULL;
WARN_ON_ONCE(ctx->parent_ctx);
mutex_lock(&ctx->mutex);
perf_install_in_context(ctx, event, cpu);
@@ -6479,6 +6520,39 @@ err:
}
EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
+void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
+{
+ struct perf_event_context *src_ctx;
+ struct perf_event_context *dst_ctx;
+ struct perf_event *event, *tmp;
+ LIST_HEAD(events);
+
+ src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
+ dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
+
+ mutex_lock(&src_ctx->mutex);
+ list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
+ event_entry) {
+ perf_remove_from_context(event);
+ put_ctx(src_ctx);
+ list_add(&event->event_entry, &events);
+ }
+ mutex_unlock(&src_ctx->mutex);
+
+ synchronize_rcu();
+
+ mutex_lock(&dst_ctx->mutex);
+ list_for_each_entry_safe(event, tmp, &events, event_entry) {
+ list_del(&event->event_entry);
+ if (event->state >= PERF_EVENT_STATE_OFF)
+ event->state = PERF_EVENT_STATE_INACTIVE;
+ perf_install_in_context(dst_ctx, event, dst_cpu);
+ get_ctx(dst_ctx);
+ }
+ mutex_unlock(&dst_ctx->mutex);
+}
+EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
+
static void sync_child_event(struct perf_event *child_event,
struct task_struct *child)
{
@@ -6511,7 +6585,7 @@ static void sync_child_event(struct perf_event *child_event,
* Release the parent event, if this was the last
* reference to it.
*/
- fput(parent_event->filp);
+ put_event(parent_event);
}
static void
@@ -6587,9 +6661,8 @@ static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
*
* __perf_event_exit_task()
* sync_child_event()
- * fput(parent_event->filp)
- * perf_release()
- * mutex_lock(&ctx->mutex)
+ * put_event()
+ * mutex_lock(&ctx->mutex)
*
* But since its the parent context it won't be the same instance.
*/
@@ -6657,7 +6730,7 @@ static void perf_free_event(struct perf_event *event,
list_del_init(&event->child_list);
mutex_unlock(&parent->child_mutex);
- fput(parent->filp);
+ put_event(parent);
perf_group_detach(event);
list_del_event(event, ctx);
@@ -6737,6 +6810,12 @@ inherit_event(struct perf_event *parent_event,
NULL, NULL);
if (IS_ERR(child_event))
return child_event;
+
+ if (!atomic_long_inc_not_zero(&parent_event->refcount)) {
+ free_event(child_event);
+ return NULL;
+ }
+
get_ctx(child_ctx);
/*
@@ -6778,14 +6857,6 @@ inherit_event(struct perf_event *parent_event,
raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
/*
- * Get a reference to the parent filp - we will fput it
- * when the child event exits. This is safe to do because
- * we are in the parent and we know that the filp still
- * exists and has a nonzero count:
- */
- atomic_long_inc(&parent_event->filp->f_count);
-
- /*
* Link this into the parent event's child list
*/
WARN_ON_ONCE(parent_event->ctx->parent_ctx);
diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index bb38c4d3ee1..9a7b487c6fe 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -453,7 +453,16 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att
int old_type = bp->attr.bp_type;
int err = 0;
- perf_event_disable(bp);
+ /*
+ * modify_user_hw_breakpoint can be invoked with IRQs disabled and hence it
+ * will not be possible to raise IPIs that invoke __perf_event_disable.
+ * So call the function directly after making sure we are targeting the
+ * current task.
+ */
+ if (irqs_disabled() && bp->ctx && bp->ctx->task == current)
+ __perf_event_disable(bp);
+ else
+ perf_event_disable(bp);
bp->attr.bp_addr = attr->bp_addr;
bp->attr.bp_type = attr->bp_type;
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index b0b107f90af..a096c19f2c2 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -101,7 +101,8 @@ __output_copy(struct perf_output_handle *handle,
}
/* Callchain handling */
-extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
+extern struct perf_callchain_entry *
+perf_callchain(struct perf_event *event, struct pt_regs *regs);
extern int get_callchain_buffers(void);
extern void put_callchain_buffers(void);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 985be4d80fe..c08a22d02f7 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -32,19 +32,36 @@
#include <linux/swap.h> /* try_to_free_swap */
#include <linux/ptrace.h> /* user_enable_single_step */
#include <linux/kdebug.h> /* notifier mechanism */
+#include "../../mm/internal.h" /* munlock_vma_page */
#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
+/*
+ * We need separate register/unregister and mmap/munmap lock hashes because
+ * of mmap_sem nesting.
+ *
+ * uprobe_register() needs to install probes on (potentially) all processes
+ * and thus needs to acquire multiple mmap_sems (consequtively, not
+ * concurrently), whereas uprobe_mmap() is called while holding mmap_sem
+ * for the particular process doing the mmap.
+ *
+ * uprobe_register()->register_for_each_vma() needs to drop/acquire mmap_sem
+ * because of lock order against i_mmap_mutex. This means there's a hole in
+ * the register vma iteration where a mmap() can happen.
+ *
+ * Thus uprobe_register() can race with uprobe_mmap() and we can try and
+ * install a probe where one is already installed.
+ */
+
/* serialize (un)register */
static struct mutex uprobes_mutex[UPROBES_HASH_SZ];
@@ -61,17 +78,6 @@ static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
*/
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;
@@ -100,20 +106,21 @@ static bool valid_vma(struct vm_area_struct *vma, bool is_register)
if (!is_register)
return true;
- if ((vma->vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)) == (VM_READ|VM_EXEC))
+ if ((vma->vm_flags & (VM_HUGETLB|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)
+static unsigned long offset_to_vaddr(struct vm_area_struct *vma, loff_t offset)
{
- loff_t vaddr;
-
- vaddr = vma->vm_start + offset;
- vaddr -= vma->vm_pgoff << PAGE_SHIFT;
+ return vma->vm_start + offset - ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+}
- return vaddr;
+static loff_t vaddr_to_offset(struct vm_area_struct *vma, unsigned long vaddr)
+{
+ return ((loff_t)vma->vm_pgoff << PAGE_SHIFT) + (vaddr - vma->vm_start);
}
/**
@@ -121,41 +128,27 @@ static loff_t vma_address(struct vm_area_struct *vma, loff_t offset)
* based on replace_page in mm/ksm.c
*
* @vma: vma that holds the pte pointing to page
+ * @addr: address the old @page is mapped at
* @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)
+static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
+ 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;
+ pte_t *ptep;
+ int err;
- pmd = pmd_offset(pud, addr);
- if (!pmd_present(*pmd))
- goto out;
+ /* For try_to_free_swap() and munlock_vma_page() below */
+ lock_page(page);
- ptep = pte_offset_map_lock(mm, pmd, addr, &ptl);
+ err = -EAGAIN;
+ ptep = page_check_address(page, mm, addr, &ptl, 0);
if (!ptep)
- goto out;
+ goto unlock;
get_page(kpage);
page_add_new_anon_rmap(kpage, vma, addr);
@@ -172,11 +165,15 @@ static int __replace_page(struct vm_area_struct *vma, struct page *page, struct
page_remove_rmap(page);
if (!page_mapped(page))
try_to_free_swap(page);
- put_page(page);
pte_unmap_unlock(ptep, ptl);
- err = 0;
-out:
+ if (vma->vm_flags & VM_LOCKED)
+ munlock_vma_page(page);
+ put_page(page);
+
+ err = 0;
+ unlock:
+ unlock_page(page);
return err;
}
@@ -218,79 +215,46 @@ 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;
+retry:
/* 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;
+ goto put_old;
__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);
+ memcpy(vaddr_new + (vaddr & ~PAGE_MASK), &opcode, UPROBE_SWBP_INSN_SIZE);
kunmap_atomic(vaddr_new);
kunmap_atomic(vaddr_old);
ret = anon_vma_prepare(vma);
if (ret)
- goto unlock_out;
+ goto put_new;
- lock_page(new_page);
- ret = __replace_page(vma, old_page, new_page);
- unlock_page(new_page);
+ ret = __replace_page(vma, vaddr, old_page, new_page);
-unlock_out:
- unlock_page(old_page);
+put_new:
page_cache_release(new_page);
-
-put_out:
+put_old:
put_page(old_page);
+ if (unlikely(ret == -EAGAIN))
+ goto retry;
return ret;
}
@@ -312,7 +276,7 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_
void *vaddr_new;
int ret;
- ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &page, NULL);
+ ret = get_user_pages(NULL, mm, vaddr, 1, 0, 1, &page, NULL);
if (ret <= 0)
return ret;
@@ -333,10 +297,20 @@ static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr)
uprobe_opcode_t opcode;
int result;
+ if (current->mm == mm) {
+ pagefault_disable();
+ result = __copy_from_user_inatomic(&opcode, (void __user*)vaddr,
+ sizeof(opcode));
+ pagefault_enable();
+
+ if (likely(result == 0))
+ goto out;
+ }
+
result = read_opcode(mm, vaddr, &opcode);
if (result)
return result;
-
+out:
if (is_swbp_insn(&opcode))
return 1;
@@ -355,7 +329,9 @@ static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr)
int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
{
int result;
-
+ /*
+ * See the comment near uprobes_hash().
+ */
result = is_swbp_at_addr(mm, vaddr);
if (result == 1)
return -EEXIST;
@@ -520,7 +496,6 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
uprobe->inode = igrab(inode);
uprobe->offset = offset;
init_rwsem(&uprobe->consumer_rwsem);
- INIT_LIST_HEAD(&uprobe->pending_list);
/* add to uprobes_tree, sorted on inode:offset */
cur_uprobe = insert_uprobe(uprobe);
@@ -588,20 +563,22 @@ static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc)
}
static int
-__copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *insn,
- unsigned long nbytes, unsigned long offset)
+__copy_insn(struct address_space *mapping, struct file *filp, char *insn,
+ unsigned long nbytes, loff_t offset)
{
- struct file *filp = vma->vm_file;
struct page *page;
void *vaddr;
- unsigned long off1;
- unsigned long idx;
+ unsigned long off;
+ pgoff_t idx;
if (!filp)
return -EINVAL;
- idx = (unsigned long)(offset >> PAGE_CACHE_SHIFT);
- off1 = offset &= ~PAGE_MASK;
+ if (!mapping->a_ops->readpage)
+ return -EIO;
+
+ idx = offset >> PAGE_CACHE_SHIFT;
+ off = offset & ~PAGE_MASK;
/*
* Ensure that the page that has the original instruction is
@@ -612,22 +589,20 @@ __copy_insn(struct address_space *mapping, struct vm_area_struct *vma, char *ins
return PTR_ERR(page);
vaddr = kmap_atomic(page);
- memcpy(insn, vaddr + off1, nbytes);
+ memcpy(insn, vaddr + off, nbytes);
kunmap_atomic(vaddr);
page_cache_release(page);
return 0;
}
-static int
-copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr)
+static int copy_insn(struct uprobe *uprobe, struct file *filp)
{
struct address_space *mapping;
unsigned long nbytes;
int bytes;
- addr &= ~PAGE_MASK;
- nbytes = PAGE_SIZE - addr;
+ nbytes = PAGE_SIZE - (uprobe->offset & ~PAGE_MASK);
mapping = uprobe->inode->i_mapping;
/* Instruction at end of binary; copy only available bytes */
@@ -638,13 +613,13 @@ copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr)
/* Instruction at the page-boundary; copy bytes in second page */
if (nbytes < bytes) {
- if (__copy_insn(mapping, vma, uprobe->arch.insn + nbytes,
- bytes - nbytes, uprobe->offset + nbytes))
- return -ENOMEM;
-
+ int err = __copy_insn(mapping, filp, uprobe->arch.insn + nbytes,
+ bytes - nbytes, uprobe->offset + nbytes);
+ if (err)
+ return err;
bytes = nbytes;
}
- return __copy_insn(mapping, vma, uprobe->arch.insn, bytes, uprobe->offset);
+ return __copy_insn(mapping, filp, uprobe->arch.insn, bytes, uprobe->offset);
}
/*
@@ -672,9 +647,8 @@ copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned long addr)
*/
static int
install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
- struct vm_area_struct *vma, loff_t vaddr)
+ struct vm_area_struct *vma, unsigned long vaddr)
{
- unsigned long addr;
int ret;
/*
@@ -687,20 +661,22 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
if (!uprobe->consumers)
return -EEXIST;
- addr = (unsigned long)vaddr;
-
if (!(uprobe->flags & UPROBE_COPY_INSN)) {
- ret = copy_insn(uprobe, vma, addr);
+ ret = copy_insn(uprobe, vma->vm_file);
if (ret)
return ret;
if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn))
- return -EEXIST;
+ return -ENOTSUPP;
- ret = arch_uprobe_analyze_insn(&uprobe->arch, mm);
+ ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr);
if (ret)
return ret;
+ /* write_opcode() assumes we don't cross page boundary */
+ BUG_ON((uprobe->offset & ~PAGE_MASK) +
+ UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
+
uprobe->flags |= UPROBE_COPY_INSN;
}
@@ -713,7 +689,7 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
* Hence increment before and decrement on failure.
*/
atomic_inc(&mm->uprobes_state.count);
- ret = set_swbp(&uprobe->arch, mm, addr);
+ ret = set_swbp(&uprobe->arch, mm, vaddr);
if (ret)
atomic_dec(&mm->uprobes_state.count);
@@ -721,27 +697,21 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
}
static void
-remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, loff_t vaddr)
+remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr)
{
- if (!set_orig_insn(&uprobe->arch, mm, (unsigned long)vaddr, true))
+ if (!set_orig_insn(&uprobe->arch, mm, vaddr, true))
atomic_dec(&mm->uprobes_state.count);
}
/*
- * There could be threads that have hit the breakpoint and are entering the
- * notifier code and trying to acquire the uprobes_treelock. The thread
- * calling delete_uprobe() that is removing the uprobe from the rb_tree can
- * race with these threads and might acquire the uprobes_treelock compared
- * to some of the breakpoint hit threads. In such a case, the breakpoint
- * hit threads will not find the uprobe. The current unregistering thread
- * waits till all other threads have hit a breakpoint, to acquire the
- * uprobes_treelock before the uprobe is removed from the rbtree.
+ * There could be threads that have already hit the breakpoint. They
+ * will recheck the current insn and restart if find_uprobe() fails.
+ * See find_active_uprobe().
*/
static void delete_uprobe(struct uprobe *uprobe)
{
unsigned long flags;
- synchronize_srcu(&uprobes_srcu);
spin_lock_irqsave(&uprobes_treelock, flags);
rb_erase(&uprobe->rb_node, &uprobes_tree);
spin_unlock_irqrestore(&uprobes_treelock, flags);
@@ -750,139 +720,136 @@ static void delete_uprobe(struct uprobe *uprobe)
atomic_dec(&uprobe_events);
}
-static struct vma_info *
-__find_next_vma_info(struct address_space *mapping, struct list_head *head,
- struct vma_info *vi, loff_t offset, bool is_register)
+struct map_info {
+ struct map_info *next;
+ struct mm_struct *mm;
+ unsigned long vaddr;
+};
+
+static inline struct map_info *free_map_info(struct map_info *info)
+{
+ struct map_info *next = info->next;
+ kfree(info);
+ return next;
+}
+
+static struct map_info *
+build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
{
+ unsigned long pgoff = offset >> PAGE_SHIFT;
struct prio_tree_iter iter;
struct vm_area_struct *vma;
- struct vma_info *tmpvi;
- unsigned long pgoff;
- int existing_vma;
- loff_t vaddr;
-
- pgoff = offset >> PAGE_SHIFT;
+ struct map_info *curr = NULL;
+ struct map_info *prev = NULL;
+ struct map_info *info;
+ int more = 0;
+ again:
+ mutex_lock(&mapping->i_mmap_mutex);
vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
if (!valid_vma(vma, is_register))
continue;
- existing_vma = 0;
- vaddr = vma_address(vma, offset);
-
- list_for_each_entry(tmpvi, head, probe_list) {
- if (tmpvi->mm == vma->vm_mm && tmpvi->vaddr == vaddr) {
- existing_vma = 1;
- break;
- }
+ if (!prev && !more) {
+ /*
+ * Needs GFP_NOWAIT to avoid i_mmap_mutex recursion through
+ * reclaim. This is optimistic, no harm done if it fails.
+ */
+ prev = kmalloc(sizeof(struct map_info),
+ GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN);
+ if (prev)
+ prev->next = NULL;
}
-
- /*
- * Another vma needs a probe to be installed. However skip
- * installing the probe if the vma is about to be unlinked.
- */
- if (!existing_vma && atomic_inc_not_zero(&vma->vm_mm->mm_users)) {
- vi->mm = vma->vm_mm;
- vi->vaddr = vaddr;
- list_add(&vi->probe_list, head);
-
- return vi;
+ if (!prev) {
+ more++;
+ continue;
}
- }
-
- return NULL;
-}
-/*
- * Iterate in the rmap prio tree and find a vma where a probe has not
- * yet been inserted.
- */
-static struct vma_info *
-find_next_vma_info(struct address_space *mapping, struct list_head *head,
- loff_t offset, bool is_register)
-{
- struct vma_info *vi, *retvi;
+ if (!atomic_inc_not_zero(&vma->vm_mm->mm_users))
+ continue;
- vi = kzalloc(sizeof(struct vma_info), GFP_KERNEL);
- if (!vi)
- return ERR_PTR(-ENOMEM);
+ info = prev;
+ prev = prev->next;
+ info->next = curr;
+ curr = info;
- mutex_lock(&mapping->i_mmap_mutex);
- retvi = __find_next_vma_info(mapping, head, vi, offset, is_register);
+ info->mm = vma->vm_mm;
+ info->vaddr = offset_to_vaddr(vma, offset);
+ }
mutex_unlock(&mapping->i_mmap_mutex);
- if (!retvi)
- kfree(vi);
+ if (!more)
+ goto out;
+
+ prev = curr;
+ while (curr) {
+ mmput(curr->mm);
+ curr = curr->next;
+ }
- return retvi;
+ do {
+ info = kmalloc(sizeof(struct map_info), GFP_KERNEL);
+ if (!info) {
+ curr = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+ info->next = prev;
+ prev = info;
+ } while (--more);
+
+ goto again;
+ out:
+ while (prev)
+ prev = free_map_info(prev);
+ return curr;
}
static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
{
- struct list_head try_list;
- struct vm_area_struct *vma;
- struct address_space *mapping;
- struct vma_info *vi, *tmpvi;
- struct mm_struct *mm;
- loff_t vaddr;
- int ret;
-
- mapping = uprobe->inode->i_mapping;
- INIT_LIST_HEAD(&try_list);
+ struct map_info *info;
+ int err = 0;
- ret = 0;
+ info = build_map_info(uprobe->inode->i_mapping,
+ uprobe->offset, is_register);
+ if (IS_ERR(info))
+ return PTR_ERR(info);
- for (;;) {
- vi = find_next_vma_info(mapping, &try_list, uprobe->offset, is_register);
- if (!vi)
- break;
+ while (info) {
+ struct mm_struct *mm = info->mm;
+ struct vm_area_struct *vma;
- if (IS_ERR(vi)) {
- ret = PTR_ERR(vi);
- break;
- }
+ if (err)
+ goto free;
- mm = vi->mm;
- down_read(&mm->mmap_sem);
- vma = find_vma(mm, (unsigned long)vi->vaddr);
- if (!vma || !valid_vma(vma, is_register)) {
- list_del(&vi->probe_list);
- kfree(vi);
- up_read(&mm->mmap_sem);
- mmput(mm);
- continue;
- }
- vaddr = vma_address(vma, uprobe->offset);
- if (vma->vm_file->f_mapping->host != uprobe->inode ||
- vaddr != vi->vaddr) {
- list_del(&vi->probe_list);
- kfree(vi);
- up_read(&mm->mmap_sem);
- mmput(mm);
- continue;
- }
+ down_write(&mm->mmap_sem);
+ vma = find_vma(mm, info->vaddr);
+ if (!vma || !valid_vma(vma, is_register) ||
+ vma->vm_file->f_mapping->host != uprobe->inode)
+ goto unlock;
- if (is_register)
- ret = install_breakpoint(uprobe, mm, vma, vi->vaddr);
- else
- remove_breakpoint(uprobe, mm, vi->vaddr);
+ if (vma->vm_start > info->vaddr ||
+ vaddr_to_offset(vma, info->vaddr) != uprobe->offset)
+ goto unlock;
- up_read(&mm->mmap_sem);
- mmput(mm);
if (is_register) {
- if (ret && ret == -EEXIST)
- ret = 0;
- if (ret)
- break;
+ err = install_breakpoint(uprobe, mm, vma, info->vaddr);
+ /*
+ * We can race against uprobe_mmap(), see the
+ * comment near uprobe_hash().
+ */
+ if (err == -EEXIST)
+ err = 0;
+ } else {
+ remove_breakpoint(uprobe, mm, info->vaddr);
}
+ unlock:
+ up_write(&mm->mmap_sem);
+ free:
+ mmput(mm);
+ info = free_map_info(info);
}
- list_for_each_entry_safe(vi, tmpvi, &try_list, probe_list) {
- list_del(&vi->probe_list);
- kfree(vi);
- }
-
- return ret;
+ return err;
}
static int __uprobe_register(struct uprobe *uprobe)
@@ -977,59 +944,66 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume
put_uprobe(uprobe);
}
-/*
- * Of all the nodes that correspond to the given inode, return the node
- * with the least offset.
- */
-static struct rb_node *find_least_offset_node(struct inode *inode)
+static struct rb_node *
+find_node_in_range(struct inode *inode, loff_t min, loff_t max)
{
- struct uprobe u = { .inode = inode, .offset = 0};
struct rb_node *n = uprobes_tree.rb_node;
- struct rb_node *close_node = NULL;
- struct uprobe *uprobe;
- int match;
while (n) {
- uprobe = rb_entry(n, struct uprobe, rb_node);
- match = match_uprobe(&u, uprobe);
+ struct uprobe *u = rb_entry(n, struct uprobe, rb_node);
- if (uprobe->inode == inode)
- close_node = n;
-
- if (!match)
- return close_node;
-
- if (match < 0)
+ if (inode < u->inode) {
n = n->rb_left;
- else
+ } else if (inode > u->inode) {
n = n->rb_right;
+ } else {
+ if (max < u->offset)
+ n = n->rb_left;
+ else if (min > u->offset)
+ n = n->rb_right;
+ else
+ break;
+ }
}
- return close_node;
+ return n;
}
/*
- * For a given inode, build a list of probes that need to be inserted.
+ * For a given range in vma, build a list of probes that need to be inserted.
*/
-static void build_probe_list(struct inode *inode, struct list_head *head)
+static void build_probe_list(struct inode *inode,
+ struct vm_area_struct *vma,
+ unsigned long start, unsigned long end,
+ struct list_head *head)
{
- struct uprobe *uprobe;
+ loff_t min, max;
unsigned long flags;
- struct rb_node *n;
-
- spin_lock_irqsave(&uprobes_treelock, flags);
-
- n = find_least_offset_node(inode);
+ struct rb_node *n, *t;
+ struct uprobe *u;
- for (; n; n = rb_next(n)) {
- uprobe = rb_entry(n, struct uprobe, rb_node);
- if (uprobe->inode != inode)
- break;
+ INIT_LIST_HEAD(head);
+ min = vaddr_to_offset(vma, start);
+ max = min + (end - start) - 1;
- list_add(&uprobe->pending_list, head);
- atomic_inc(&uprobe->ref);
+ spin_lock_irqsave(&uprobes_treelock, flags);
+ n = find_node_in_range(inode, min, max);
+ if (n) {
+ for (t = n; t; t = rb_prev(t)) {
+ u = rb_entry(t, struct uprobe, rb_node);
+ if (u->inode != inode || u->offset < min)
+ break;
+ list_add(&u->pending_list, head);
+ atomic_inc(&u->ref);
+ }
+ for (t = n; (t = rb_next(t)); ) {
+ u = rb_entry(t, struct uprobe, rb_node);
+ if (u->inode != inode || u->offset > max)
+ break;
+ list_add(&u->pending_list, head);
+ atomic_inc(&u->ref);
+ }
}
-
spin_unlock_irqrestore(&uprobes_treelock, flags);
}
@@ -1059,28 +1033,21 @@ int uprobe_mmap(struct vm_area_struct *vma)
if (!inode)
return 0;
- INIT_LIST_HEAD(&tmp_list);
mutex_lock(uprobes_mmap_hash(inode));
- build_probe_list(inode, &tmp_list);
+ build_probe_list(inode, vma, vma->vm_start, vma->vm_end, &tmp_list);
ret = 0;
count = 0;
list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
- loff_t vaddr;
-
- list_del(&uprobe->pending_list);
if (!ret) {
- vaddr = vma_address(vma, uprobe->offset);
-
- if (vaddr < vma->vm_start || vaddr >= vma->vm_end) {
- put_uprobe(uprobe);
- continue;
- }
+ unsigned long vaddr = offset_to_vaddr(vma, uprobe->offset);
ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr);
-
- /* Ignore double add: */
+ /*
+ * We can race against uprobe_register(), see the
+ * comment near uprobe_hash().
+ */
if (ret == -EEXIST) {
ret = 0;
@@ -1121,6 +1088,9 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon
if (!atomic_read(&uprobe_events) || !valid_vma(vma, false))
return;
+ if (!atomic_read(&vma->vm_mm->mm_users)) /* called by mmput() ? */
+ return;
+
if (!atomic_read(&vma->vm_mm->uprobes_state.count))
return;
@@ -1128,24 +1098,17 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon
if (!inode)
return;
- INIT_LIST_HEAD(&tmp_list);
mutex_lock(uprobes_mmap_hash(inode));
- build_probe_list(inode, &tmp_list);
+ build_probe_list(inode, vma, start, end, &tmp_list);
list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
- loff_t vaddr;
-
- list_del(&uprobe->pending_list);
- vaddr = vma_address(vma, uprobe->offset);
-
- if (vaddr >= start && vaddr < end) {
- /*
- * An unregister could have removed the probe before
- * unmap. So check before we decrement the count.
- */
- if (is_swbp_at_addr(vma->vm_mm, vaddr) == 1)
- atomic_dec(&vma->vm_mm->uprobes_state.count);
- }
+ unsigned long vaddr = offset_to_vaddr(vma, uprobe->offset);
+ /*
+ * An unregister could have removed the probe before
+ * unmap. So check before we decrement the count.
+ */
+ if (is_swbp_at_addr(vma->vm_mm, vaddr) == 1)
+ atomic_dec(&vma->vm_mm->uprobes_state.count);
put_uprobe(uprobe);
}
mutex_unlock(uprobes_mmap_hash(inode));
@@ -1378,9 +1341,6 @@ void uprobe_free_utask(struct task_struct *t)
{
struct uprobe_task *utask = t->utask;
- if (t->uprobe_srcu_id != -1)
- srcu_read_unlock_raw(&uprobes_srcu, t->uprobe_srcu_id);
-
if (!utask)
return;
@@ -1398,7 +1358,6 @@ void uprobe_free_utask(struct task_struct *t)
void uprobe_copy_process(struct task_struct *t)
{
t->utask = NULL;
- t->uprobe_srcu_id = -1;
}
/*
@@ -1417,7 +1376,6 @@ static struct uprobe_task *add_utask(void)
if (unlikely(!utask))
return NULL;
- utask->active_uprobe = NULL;
current->utask = utask;
return utask;
}
@@ -1479,41 +1437,61 @@ static bool can_skip_sstep(struct uprobe *uprobe, struct pt_regs *regs)
return false;
}
+static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
+{
+ struct mm_struct *mm = current->mm;
+ struct uprobe *uprobe = NULL;
+ struct vm_area_struct *vma;
+
+ down_read(&mm->mmap_sem);
+ vma = find_vma(mm, bp_vaddr);
+ if (vma && vma->vm_start <= bp_vaddr) {
+ if (valid_vma(vma, false)) {
+ struct inode *inode = vma->vm_file->f_mapping->host;
+ loff_t offset = vaddr_to_offset(vma, bp_vaddr);
+
+ uprobe = find_uprobe(inode, offset);
+ }
+
+ if (!uprobe)
+ *is_swbp = is_swbp_at_addr(mm, bp_vaddr);
+ } else {
+ *is_swbp = -EFAULT;
+ }
+ up_read(&mm->mmap_sem);
+
+ return uprobe;
+}
+
/*
* Run handler and ask thread to singlestep.
* Ensure all non-fatal signals cannot interrupt thread while it singlesteps.
*/
static void handle_swbp(struct pt_regs *regs)
{
- struct vm_area_struct *vma;
struct uprobe_task *utask;
struct uprobe *uprobe;
- struct mm_struct *mm;
unsigned long bp_vaddr;
+ int uninitialized_var(is_swbp);
- uprobe = NULL;
bp_vaddr = uprobe_get_swbp_addr(regs);
- mm = current->mm;
- down_read(&mm->mmap_sem);
- vma = find_vma(mm, bp_vaddr);
-
- if (vma && vma->vm_start <= bp_vaddr && valid_vma(vma, false)) {
- struct inode *inode;
- loff_t offset;
-
- inode = vma->vm_file->f_mapping->host;
- offset = bp_vaddr - vma->vm_start;
- offset += (vma->vm_pgoff << PAGE_SHIFT);
- uprobe = find_uprobe(inode, offset);
- }
-
- srcu_read_unlock_raw(&uprobes_srcu, current->uprobe_srcu_id);
- current->uprobe_srcu_id = -1;
- up_read(&mm->mmap_sem);
+ uprobe = find_active_uprobe(bp_vaddr, &is_swbp);
if (!uprobe) {
- /* No matching uprobe; signal SIGTRAP. */
- send_sig(SIGTRAP, current, 0);
+ if (is_swbp > 0) {
+ /* No matching uprobe; signal SIGTRAP. */
+ send_sig(SIGTRAP, current, 0);
+ } else {
+ /*
+ * Either we raced with uprobe_unregister() or we can't
+ * access this memory. The latter is only possible if
+ * another thread plays with our ->mm. In both cases
+ * we can simply restart. If this vma was unmapped we
+ * can pretend this insn was not executed yet and get
+ * the (correct) SIGSEGV after restart.
+ */
+ instruction_pointer_set(regs, bp_vaddr);
+ }
return;
}
@@ -1620,7 +1598,6 @@ int uprobe_pre_sstep_notifier(struct pt_regs *regs)
utask->state = UTASK_BP_HIT;
set_thread_flag(TIF_UPROBE);
- current->uprobe_srcu_id = srcu_read_lock_raw(&uprobes_srcu);
return 1;
}
@@ -1655,7 +1632,6 @@ static int __init init_uprobes(void)
mutex_init(&uprobes_mutex[i]);
mutex_init(&uprobes_mmap_mutex[i]);
}
- init_srcu_struct(&uprobes_srcu);
return register_die_notifier(&uprobe_exception_nb);
}