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authorIngo Molnar <mingo@kernel.org>2013-02-11 10:41:53 +0100
committerIngo Molnar <mingo@kernel.org>2013-02-11 10:41:53 +0100
commita3d4fd7a2d81604fedfa270d29c824b8d3380c2e (patch)
tree1bd1defbfe3f285dfa7c77f94bc5523ac4a82679
parent661e591525ffbb0439270bf2a4d165c04f87543d (diff)
parentb2fe8ba674e8acbb9e8e63510b802c6d054d88a3 (diff)
downloadvexpress-lsk-a3d4fd7a2d81604fedfa270d29c824b8d3380c2e.tar.gz
Merge branch 'uprobes/core' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc into perf/core
Improve uprobes performance by adding 'pre-filtering' support, by Oleg Nesterov: # time perl -e 'syscall -1 for 1..100_000' real 0m0.040s user 0m0.027s sys 0m0.010s # perf probe -x /lib/libc.so.6 syscall # perf record -e probe_libc:syscall sleep 100 & Before this series: # time perl -e 'syscall -1 for 1..100_000' real 0m1.714s user 0m0.103s sys 0m1.607s After: # time perl -e 'syscall -1 for 1..100_000' real 0m0.037s user 0m0.013s sys 0m0.023s Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/kernel/uprobes.c4
-rw-r--r--include/linux/perf_event.h9
-rw-r--r--include/linux/uprobes.h23
-rw-r--r--kernel/events/core.c5
-rw-r--r--kernel/events/uprobes.c465
-rw-r--r--kernel/ptrace.c6
-rw-r--r--kernel/trace/trace_probe.h1
-rw-r--r--kernel/trace/trace_uprobe.c217
8 files changed, 456 insertions, 274 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index c71025b6746..0ba4cfb4f41 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -680,8 +680,10 @@ static bool __skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
if (auprobe->insn[i] == 0x66)
continue;
- if (auprobe->insn[i] == 0x90)
+ if (auprobe->insn[i] == 0x90) {
+ regs->ip += i + 1;
return true;
+ }
break;
}
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 42adf012145..e47ee462c2f 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -135,16 +135,21 @@ struct hw_perf_event {
struct { /* software */
struct hrtimer hrtimer;
};
+ struct { /* tracepoint */
+ struct task_struct *tp_target;
+ /* for tp_event->class */
+ struct list_head tp_list;
+ };
#ifdef CONFIG_HAVE_HW_BREAKPOINT
struct { /* breakpoint */
- struct arch_hw_breakpoint info;
- struct list_head bp_list;
/*
* Crufty hack to avoid the chicken and egg
* problem hw_breakpoint has with context
* creation and event initalization.
*/
struct task_struct *bp_target;
+ struct arch_hw_breakpoint info;
+ struct list_head bp_list;
};
#endif
};
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 4f628a6fc5b..02b83db8e2c 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -35,13 +35,20 @@ struct inode;
# include <asm/uprobes.h>
#endif
+#define UPROBE_HANDLER_REMOVE 1
+#define UPROBE_HANDLER_MASK 1
+
+enum uprobe_filter_ctx {
+ UPROBE_FILTER_REGISTER,
+ UPROBE_FILTER_UNREGISTER,
+ UPROBE_FILTER_MMAP,
+};
+
struct uprobe_consumer {
int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs);
- /*
- * filter is optional; If a filter exists, handler is run
- * if and only if filter returns true.
- */
- bool (*filter)(struct uprobe_consumer *self, struct task_struct *task);
+ bool (*filter)(struct uprobe_consumer *self,
+ enum uprobe_filter_ctx ctx,
+ struct mm_struct *mm);
struct uprobe_consumer *next;
};
@@ -94,6 +101,7 @@ extern int __weak set_swbp(struct arch_uprobe *aup, struct mm_struct *mm, unsign
extern int __weak set_orig_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long vaddr);
extern bool __weak is_swbp_insn(uprobe_opcode_t *insn);
extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
+extern int uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool);
extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
extern int uprobe_mmap(struct vm_area_struct *vma);
extern void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end);
@@ -117,6 +125,11 @@ uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
{
return -ENOSYS;
}
+static inline int
+uprobe_apply(struct inode *inode, loff_t offset, struct uprobe_consumer *uc, bool add)
+{
+ return -ENOSYS;
+}
static inline void
uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
{
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 301079d06f2..e2d4323c6ae 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6162,11 +6162,14 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
if (task) {
event->attach_state = PERF_ATTACH_TASK;
+
+ if (attr->type == PERF_TYPE_TRACEPOINT)
+ event->hw.tp_target = task;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
/*
* hw_breakpoint is a bit difficult here..
*/
- if (attr->type == PERF_TYPE_BREAKPOINT)
+ else if (attr->type == PERF_TYPE_BREAKPOINT)
event->hw.bp_target = task;
#endif
}
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 30ea9a4f4ab..a567c8c7ef3 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -27,6 +27,7 @@
#include <linux/pagemap.h> /* read_mapping_page */
#include <linux/slab.h>
#include <linux/sched.h>
+#include <linux/export.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 */
@@ -41,58 +42,31 @@
#define MAX_UPROBE_XOL_SLOTS UINSNS_PER_PAGE
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.
+ * 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?
*/
+#define no_uprobe_events() RB_EMPTY_ROOT(&uprobes_tree)
-/* serialize (un)register */
-static struct mutex uprobes_mutex[UPROBES_HASH_SZ];
-
-#define uprobes_hash(v) (&uprobes_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ])
+static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */
+#define UPROBES_HASH_SZ 13
/* 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])
static struct percpu_rw_semaphore dup_mmap_sem;
-/*
- * 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);
-
/* Have a copy of original instruction */
#define UPROBE_COPY_INSN 0
-/* Dont run handlers when first register/ last unregister in progress*/
-#define UPROBE_RUN_HANDLER 1
/* Can skip singlestep */
-#define UPROBE_SKIP_SSTEP 2
+#define UPROBE_SKIP_SSTEP 1
struct uprobe {
struct rb_node rb_node; /* node in the rb tree */
atomic_t ref;
+ struct rw_semaphore register_rwsem;
struct rw_semaphore consumer_rwsem;
- struct mutex copy_mutex; /* TODO: kill me and UPROBE_COPY_INSN */
struct list_head pending_list;
struct uprobe_consumer *consumers;
struct inode *inode; /* Also hold a ref to inode */
@@ -430,9 +404,6 @@ static struct uprobe *insert_uprobe(struct uprobe *uprobe)
u = __insert_uprobe(uprobe);
spin_unlock(&uprobes_treelock);
- /* For now assume that the instruction need not be single-stepped */
- __set_bit(UPROBE_SKIP_SSTEP, &uprobe->flags);
-
return u;
}
@@ -452,8 +423,10 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
uprobe->inode = igrab(inode);
uprobe->offset = offset;
+ init_rwsem(&uprobe->register_rwsem);
init_rwsem(&uprobe->consumer_rwsem);
- mutex_init(&uprobe->copy_mutex);
+ /* For now assume that the instruction need not be single-stepped */
+ __set_bit(UPROBE_SKIP_SSTEP, &uprobe->flags);
/* add to uprobes_tree, sorted on inode:offset */
cur_uprobe = insert_uprobe(uprobe);
@@ -463,38 +436,17 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
kfree(uprobe);
uprobe = cur_uprobe;
iput(inode);
- } else {
- atomic_inc(&uprobe_events);
}
return uprobe;
}
-static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
-{
- struct uprobe_consumer *uc;
-
- if (!test_bit(UPROBE_RUN_HANDLER, &uprobe->flags))
- return;
-
- down_read(&uprobe->consumer_rwsem);
- for (uc = uprobe->consumers; uc; uc = uc->next) {
- if (!uc->filter || uc->filter(uc, current))
- uc->handler(uc, regs);
- }
- up_read(&uprobe->consumer_rwsem);
-}
-
-/* Returns the previous consumer */
-static struct uprobe_consumer *
-consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc)
+static void consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc)
{
down_write(&uprobe->consumer_rwsem);
uc->next = uprobe->consumers;
uprobe->consumers = uc;
up_write(&uprobe->consumer_rwsem);
-
- return uc->next;
}
/*
@@ -588,7 +540,8 @@ static int prepare_uprobe(struct uprobe *uprobe, struct file *file,
if (test_bit(UPROBE_COPY_INSN, &uprobe->flags))
return ret;
- mutex_lock(&uprobe->copy_mutex);
+ /* TODO: move this into _register, until then we abuse this sem. */
+ down_write(&uprobe->consumer_rwsem);
if (test_bit(UPROBE_COPY_INSN, &uprobe->flags))
goto out;
@@ -612,7 +565,30 @@ static int prepare_uprobe(struct uprobe *uprobe, struct file *file,
set_bit(UPROBE_COPY_INSN, &uprobe->flags);
out:
- mutex_unlock(&uprobe->copy_mutex);
+ up_write(&uprobe->consumer_rwsem);
+
+ return ret;
+}
+
+static inline bool consumer_filter(struct uprobe_consumer *uc,
+ enum uprobe_filter_ctx ctx, struct mm_struct *mm)
+{
+ return !uc->filter || uc->filter(uc, ctx, mm);
+}
+
+static bool filter_chain(struct uprobe *uprobe,
+ enum uprobe_filter_ctx ctx, struct mm_struct *mm)
+{
+ struct uprobe_consumer *uc;
+ bool ret = false;
+
+ down_read(&uprobe->consumer_rwsem);
+ for (uc = uprobe->consumers; uc; uc = uc->next) {
+ ret = consumer_filter(uc, ctx, mm);
+ if (ret)
+ break;
+ }
+ up_read(&uprobe->consumer_rwsem);
return ret;
}
@@ -624,16 +600,6 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
bool first_uprobe;
int ret;
- /*
- * If probe is being deleted, unregister thread could be done with
- * the vma-rmap-walk through. Adding a probe now can be fatal since
- * nobody will be able to cleanup. Also we could be from fork or
- * mremap path, where the probe might have already been inserted.
- * Hence behave as if probe already existed.
- */
- if (!uprobe->consumers)
- return 0;
-
ret = prepare_uprobe(uprobe, vma->vm_file, mm, vaddr);
if (ret)
return ret;
@@ -658,14 +624,14 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
static int
remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr)
{
- /* can happen if uprobe_register() fails */
- if (!test_bit(MMF_HAS_UPROBES, &mm->flags))
- return 0;
-
set_bit(MMF_RECALC_UPROBES, &mm->flags);
return set_orig_insn(&uprobe->arch, mm, vaddr);
}
+static inline bool uprobe_is_active(struct uprobe *uprobe)
+{
+ return !RB_EMPTY_NODE(&uprobe->rb_node);
+}
/*
* There could be threads that have already hit the breakpoint. They
* will recheck the current insn and restart if find_uprobe() fails.
@@ -673,12 +639,15 @@ remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vad
*/
static void delete_uprobe(struct uprobe *uprobe)
{
+ if (WARN_ON(!uprobe_is_active(uprobe)))
+ return;
+
spin_lock(&uprobes_treelock);
rb_erase(&uprobe->rb_node, &uprobes_tree);
spin_unlock(&uprobes_treelock);
+ RB_CLEAR_NODE(&uprobe->rb_node); /* for uprobe_is_active() */
iput(uprobe->inode);
put_uprobe(uprobe);
- atomic_dec(&uprobe_events);
}
struct map_info {
@@ -764,8 +733,10 @@ build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
return curr;
}
-static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
+static int
+register_for_each_vma(struct uprobe *uprobe, struct uprobe_consumer *new)
{
+ bool is_register = !!new;
struct map_info *info;
int err = 0;
@@ -794,10 +765,16 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
vaddr_to_offset(vma, info->vaddr) != uprobe->offset)
goto unlock;
- if (is_register)
- err = install_breakpoint(uprobe, mm, vma, info->vaddr);
- else
- err |= remove_breakpoint(uprobe, mm, info->vaddr);
+ if (is_register) {
+ /* consult only the "caller", new consumer. */
+ if (consumer_filter(new,
+ UPROBE_FILTER_REGISTER, mm))
+ err = install_breakpoint(uprobe, mm, vma, info->vaddr);
+ } else if (test_bit(MMF_HAS_UPROBES, &mm->flags)) {
+ if (!filter_chain(uprobe,
+ UPROBE_FILTER_UNREGISTER, mm))
+ err |= remove_breakpoint(uprobe, mm, info->vaddr);
+ }
unlock:
up_write(&mm->mmap_sem);
@@ -810,17 +787,23 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
return err;
}
-static int __uprobe_register(struct uprobe *uprobe)
+static int __uprobe_register(struct uprobe *uprobe, struct uprobe_consumer *uc)
{
- return register_for_each_vma(uprobe, true);
+ consumer_add(uprobe, uc);
+ return register_for_each_vma(uprobe, uc);
}
-static void __uprobe_unregister(struct uprobe *uprobe)
+static void __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc)
{
- if (!register_for_each_vma(uprobe, false))
- delete_uprobe(uprobe);
+ int err;
+
+ if (!consumer_del(uprobe, uc)) /* WARN? */
+ return;
+ err = register_for_each_vma(uprobe, NULL);
/* TODO : cant unregister? schedule a worker thread */
+ if (!uprobe->consumers && !err)
+ delete_uprobe(uprobe);
}
/*
@@ -845,31 +828,59 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *
struct uprobe *uprobe;
int ret;
- if (!inode || !uc || uc->next)
- return -EINVAL;
-
+ /* Racy, just to catch the obvious mistakes */
if (offset > i_size_read(inode))
return -EINVAL;
- ret = 0;
- mutex_lock(uprobes_hash(inode));
+ retry:
uprobe = alloc_uprobe(inode, offset);
-
- if (!uprobe) {
- ret = -ENOMEM;
- } else if (!consumer_add(uprobe, uc)) {
- ret = __uprobe_register(uprobe);
- if (ret) {
- uprobe->consumers = NULL;
- __uprobe_unregister(uprobe);
- } else {
- set_bit(UPROBE_RUN_HANDLER, &uprobe->flags);
- }
+ if (!uprobe)
+ return -ENOMEM;
+ /*
+ * We can race with uprobe_unregister()->delete_uprobe().
+ * Check uprobe_is_active() and retry if it is false.
+ */
+ down_write(&uprobe->register_rwsem);
+ ret = -EAGAIN;
+ if (likely(uprobe_is_active(uprobe))) {
+ ret = __uprobe_register(uprobe, uc);
+ if (ret)
+ __uprobe_unregister(uprobe, uc);
}
+ up_write(&uprobe->register_rwsem);
+ put_uprobe(uprobe);
- mutex_unlock(uprobes_hash(inode));
- if (uprobe)
- put_uprobe(uprobe);
+ if (unlikely(ret == -EAGAIN))
+ goto retry;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(uprobe_register);
+
+/*
+ * uprobe_apply - unregister a already registered probe.
+ * @inode: the file in which the probe has to be removed.
+ * @offset: offset from the start of the file.
+ * @uc: consumer which wants to add more or remove some breakpoints
+ * @add: add or remove the breakpoints
+ */
+int uprobe_apply(struct inode *inode, loff_t offset,
+ struct uprobe_consumer *uc, bool add)
+{
+ struct uprobe *uprobe;
+ struct uprobe_consumer *con;
+ int ret = -ENOENT;
+
+ uprobe = find_uprobe(inode, offset);
+ if (!uprobe)
+ return ret;
+
+ down_write(&uprobe->register_rwsem);
+ for (con = uprobe->consumers; con && con != uc ; con = con->next)
+ ;
+ if (con)
+ ret = register_for_each_vma(uprobe, add ? uc : NULL);
+ up_write(&uprobe->register_rwsem);
+ put_uprobe(uprobe);
return ret;
}
@@ -884,24 +895,42 @@ void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consume
{
struct uprobe *uprobe;
- if (!inode || !uc)
- return;
-
uprobe = find_uprobe(inode, offset);
if (!uprobe)
return;
- mutex_lock(uprobes_hash(inode));
+ down_write(&uprobe->register_rwsem);
+ __uprobe_unregister(uprobe, uc);
+ up_write(&uprobe->register_rwsem);
+ put_uprobe(uprobe);
+}
+EXPORT_SYMBOL_GPL(uprobe_unregister);
- if (consumer_del(uprobe, uc)) {
- if (!uprobe->consumers) {
- __uprobe_unregister(uprobe);
- clear_bit(UPROBE_RUN_HANDLER, &uprobe->flags);
- }
+static int unapply_uprobe(struct uprobe *uprobe, struct mm_struct *mm)
+{
+ struct vm_area_struct *vma;
+ int err = 0;
+
+ down_read(&mm->mmap_sem);
+ for (vma = mm->mmap; vma; vma = vma->vm_next) {
+ unsigned long vaddr;
+ loff_t offset;
+
+ if (!valid_vma(vma, false) ||
+ vma->vm_file->f_mapping->host != uprobe->inode)
+ continue;
+
+ offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
+ if (uprobe->offset < offset ||
+ uprobe->offset >= offset + vma->vm_end - vma->vm_start)
+ continue;
+
+ vaddr = offset_to_vaddr(vma, uprobe->offset);
+ err |= remove_breakpoint(uprobe, mm, vaddr);
}
+ up_read(&mm->mmap_sem);
- mutex_unlock(uprobes_hash(inode));
- put_uprobe(uprobe);
+ return err;
}
static struct rb_node *
@@ -978,7 +1007,7 @@ int uprobe_mmap(struct vm_area_struct *vma)
struct uprobe *uprobe, *u;
struct inode *inode;
- if (!atomic_read(&uprobe_events) || !valid_vma(vma, true))
+ if (no_uprobe_events() || !valid_vma(vma, true))
return 0;
inode = vma->vm_file->f_mapping->host;
@@ -987,9 +1016,14 @@ int uprobe_mmap(struct vm_area_struct *vma)
mutex_lock(uprobes_mmap_hash(inode));
build_probe_list(inode, vma, vma->vm_start, vma->vm_end, &tmp_list);
-
+ /*
+ * We can race with uprobe_unregister(), this uprobe can be already
+ * removed. But in this case filter_chain() must return false, all
+ * consumers have gone away.
+ */
list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
- if (!fatal_signal_pending(current)) {
+ if (!fatal_signal_pending(current) &&
+ filter_chain(uprobe, UPROBE_FILTER_MMAP, vma->vm_mm)) {
unsigned long vaddr = offset_to_vaddr(vma, uprobe->offset);
install_breakpoint(uprobe, vma->vm_mm, vma, vaddr);
}
@@ -1024,7 +1058,7 @@ vma_has_uprobes(struct vm_area_struct *vma, unsigned long start, unsigned long e
*/
void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
- if (!atomic_read(&uprobe_events) || !valid_vma(vma, false))
+ if (no_uprobe_events() || !valid_vma(vma, false))
return;
if (!atomic_read(&vma->vm_mm->mm_users)) /* called by mmput() ? */
@@ -1041,22 +1075,14 @@ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned lon
/* Slot allocation for XOL */
static int xol_add_vma(struct xol_area *area)
{
- struct mm_struct *mm;
- int ret;
-
- area->page = alloc_page(GFP_HIGHUSER);
- if (!area->page)
- return -ENOMEM;
-
- ret = -EALREADY;
- mm = current->mm;
+ struct mm_struct *mm = current->mm;
+ int ret = -EALREADY;
down_write(&mm->mmap_sem);
if (mm->uprobes_state.xol_area)
goto fail;
ret = -ENOMEM;
-
/* Try to map as high as possible, this is only a hint. */
area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0);
if (area->vaddr & ~PAGE_MASK) {
@@ -1072,54 +1098,53 @@ static int xol_add_vma(struct xol_area *area)
smp_wmb(); /* pairs with get_xol_area() */
mm->uprobes_state.xol_area = area;
ret = 0;
-
-fail:
+ fail:
up_write(&mm->mmap_sem);
- if (ret)
- __free_page(area->page);
return ret;
}
-static struct xol_area *get_xol_area(struct mm_struct *mm)
-{
- struct xol_area *area;
-
- area = mm->uprobes_state.xol_area;
- smp_read_barrier_depends(); /* pairs with wmb in xol_add_vma() */
-
- return area;
-}
-
/*
- * xol_alloc_area - Allocate process's xol_area.
- * This area will be used for storing instructions for execution out of
- * line.
+ * get_xol_area - Allocate process's xol_area if necessary.
+ * This area will be used for storing instructions for execution out of line.
*
* Returns the allocated area or NULL.
*/
-static struct xol_area *xol_alloc_area(void)
+static struct xol_area *get_xol_area(void)
{
+ struct mm_struct *mm = current->mm;
struct xol_area *area;
+ area = mm->uprobes_state.xol_area;
+ if (area)
+ goto ret;
+
area = kzalloc(sizeof(*area), GFP_KERNEL);
if (unlikely(!area))
- return NULL;
+ goto out;
area->bitmap = kzalloc(BITS_TO_LONGS(UINSNS_PER_PAGE) * sizeof(long), GFP_KERNEL);
-
if (!area->bitmap)
- goto fail;
+ goto free_area;
+
+ area->page = alloc_page(GFP_HIGHUSER);
+ if (!area->page)
+ goto free_bitmap;
init_waitqueue_head(&area->wq);
if (!xol_add_vma(area))
return area;
-fail:
+ __free_page(area->page);
+ free_bitmap:
kfree(area->bitmap);
+ free_area:
kfree(area);
-
- return get_xol_area(current->mm);
+ out:
+ area = mm->uprobes_state.xol_area;
+ ret:
+ smp_read_barrier_depends(); /* pairs with wmb in xol_add_vma() */
+ return area;
}
/*
@@ -1185,33 +1210,26 @@ static unsigned long xol_take_insn_slot(struct xol_area *area)
}
/*
- * xol_get_insn_slot - If was not allocated a slot, then
- * allocate a slot.
+ * xol_get_insn_slot - allocate a slot for xol.
* Returns the allocated slot address or 0.
*/
-static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot_addr)
+static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
{
struct xol_area *area;
unsigned long offset;
+ unsigned long xol_vaddr;
void *vaddr;
- area = get_xol_area(current->mm);
- if (!area) {
- area = xol_alloc_area();
- if (!area)
- return 0;
- }
- current->utask->xol_vaddr = xol_take_insn_slot(area);
+ area = get_xol_area();
+ if (!area)
+ return 0;
- /*
- * Initialize the slot if xol_vaddr points to valid
- * instruction slot.
- */
- if (unlikely(!current->utask->xol_vaddr))
+ xol_vaddr = xol_take_insn_slot(area);
+ if (unlikely(!xol_vaddr))
return 0;
- current->utask->vaddr = slot_addr;
- offset = current->utask->xol_vaddr & ~PAGE_MASK;
+ /* Initialize the slot */
+ offset = xol_vaddr & ~PAGE_MASK;
vaddr = kmap_atomic(area->page);
memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES);
kunmap_atomic(vaddr);
@@ -1221,7 +1239,7 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot
*/
flush_dcache_page(area->page);
- return current->utask->xol_vaddr;
+ return xol_vaddr;
}
/*
@@ -1239,8 +1257,7 @@ static void xol_free_insn_slot(struct task_struct *tsk)
return;
slot_addr = tsk->utask->xol_vaddr;
-
- if (unlikely(!slot_addr || IS_ERR_VALUE(slot_addr)))
+ if (unlikely(!slot_addr))
return;
area = tsk->mm->uprobes_state.xol_area;
@@ -1302,33 +1319,48 @@ void uprobe_copy_process(struct task_struct *t)
}
/*
- * Allocate a uprobe_task object for the task.
- * Called when the thread hits a breakpoint for the first time.
+ * Allocate a uprobe_task object for the task if if necessary.
+ * Called when the thread hits a breakpoint.
*
* Returns:
* - pointer to new uprobe_task on success
* - NULL otherwise
*/
-static struct uprobe_task *add_utask(void)
+static struct uprobe_task *get_utask(void)
{
- struct uprobe_task *utask;
-
- utask = kzalloc(sizeof *utask, GFP_KERNEL);
- if (unlikely(!utask))
- return NULL;
-
- current->utask = utask;
- return utask;
+ if (!current->utask)
+ current->utask = kzalloc(sizeof(struct uprobe_task), GFP_KERNEL);
+ return current->utask;
}
/* Prepare to single-step probed instruction out of line. */
static int
-pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long vaddr)
+pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr)
{
- if (xol_get_insn_slot(uprobe, vaddr) && !arch_uprobe_pre_xol(&uprobe->arch, regs))
- return 0;
+ struct uprobe_task *utask;
+ unsigned long xol_vaddr;
+ int err;
+
+ utask = get_utask();
+ if (!utask)
+ return -ENOMEM;
+
+ xol_vaddr = xol_get_insn_slot(uprobe);
+ if (!xol_vaddr)
+ return -ENOMEM;
+
+ utask->xol_vaddr = xol_vaddr;
+ utask->vaddr = bp_vaddr;
+
+ err = arch_uprobe_pre_xol(&uprobe->arch, regs);
+ if (unlikely(err)) {
+ xol_free_insn_slot(current);
+ return err;
+ }
- return -EFAULT;
+ utask->active_uprobe = uprobe;
+ utask->state = UTASK_SSTEP;
+ return 0;
}
/*
@@ -1390,6 +1422,7 @@ static void mmf_recalc_uprobes(struct mm_struct *mm)
* This is not strictly accurate, we can race with
* uprobe_unregister() and see the already removed
* uprobe if delete_uprobe() was not yet called.
+ * Or this uprobe can be filtered out.
*/
if (vma_has_uprobes(vma, vma->vm_start, vma->vm_end))
return;
@@ -1451,13 +1484,33 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
return uprobe;
}
+static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
+{
+ struct uprobe_consumer *uc;
+ int remove = UPROBE_HANDLER_REMOVE;
+
+ down_read(&uprobe->register_rwsem);
+ for (uc = uprobe->consumers; uc; uc = uc->next) {
+ int rc = uc->handler(uc, regs);
+
+ WARN(rc & ~UPROBE_HANDLER_MASK,
+ "bad rc=0x%x from %pf()\n", rc, uc->handler);
+ remove &= rc;
+ }
+
+ if (remove && uprobe->consumers) {
+ WARN_ON(!uprobe_is_active(uprobe));
+ unapply_uprobe(uprobe, current->mm);
+ }
+ up_read(&uprobe->register_rwsem);
+}
+
/*
* 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 uprobe_task *utask;
struct uprobe *uprobe;
unsigned long bp_vaddr;
int uninitialized_var(is_swbp);
@@ -1482,6 +1535,10 @@ static void handle_swbp(struct pt_regs *regs)
}
return;
}
+
+ /* change it in advance for ->handler() and restart */
+ instruction_pointer_set(regs, bp_vaddr);
+
/*
* TODO: move copy_insn/etc into _register and remove this hack.
* After we hit the bp, _unregister + _register can install the
@@ -1489,32 +1546,16 @@ static void handle_swbp(struct pt_regs *regs)
*/
smp_rmb(); /* pairs with wmb() in install_breakpoint() */
if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags)))
- goto restart;
-
- utask = current->utask;
- if (!utask) {
- utask = add_utask();
- /* Cannot allocate; re-execute the instruction. */
- if (!utask)
- goto restart;
- }
+ goto out;
handler_chain(uprobe, regs);
if (can_skip_sstep(uprobe, regs))
goto out;
- if (!pre_ssout(uprobe, regs, bp_vaddr)) {
- utask->active_uprobe = uprobe;
- utask->state = UTASK_SSTEP;
+ if (!pre_ssout(uprobe, regs, bp_vaddr))
return;
- }
-restart:
- /*
- * cannot singlestep; cannot skip instruction;
- * re-execute the instruction.
- */
- instruction_pointer_set(regs, bp_vaddr);
+ /* can_skip_sstep() succeeded, or restart if can't singlestep */
out:
put_uprobe(uprobe);
}
@@ -1608,10 +1649,8 @@ static int __init init_uprobes(void)
{
int i;
- for (i = 0; i < UPROBES_HASH_SZ; i++) {
- mutex_init(&uprobes_mutex[i]);
+ for (i = 0; i < UPROBES_HASH_SZ; i++)
mutex_init(&uprobes_mmap_mutex[i]);
- }
if (percpu_init_rwsem(&dup_mmap_sem))
return -ENOMEM;
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 6cbeaae4406..acbd28424d8 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -712,6 +712,12 @@ static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
kiov->iov_len, kiov->iov_base);
}
+/*
+ * This is declared in linux/regset.h and defined in machine-dependent
+ * code. We put the export here, near the primary machine-neutral use,
+ * to ensure no machine forgets it.
+ */
+EXPORT_SYMBOL_GPL(task_user_regset_view);
#endif
int ptrace_request(struct task_struct *child, long request,
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 93370867781..5c7e09d10d7 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -66,7 +66,6 @@
#define TP_FLAG_TRACE 1
#define TP_FLAG_PROFILE 2
#define TP_FLAG_REGISTERED 4
-#define TP_FLAG_UPROBE 8
/* data_rloc: data relative location, compatible with u32 */
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 87b6db4ccbc..8dad2a92dee 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -28,20 +28,21 @@
#define UPROBE_EVENT_SYSTEM "uprobes"
+struct trace_uprobe_filter {
+ rwlock_t rwlock;
+ int nr_systemwide;
+ struct list_head perf_events;
+};
+
/*
* uprobe event core functions
*/
-struct trace_uprobe;
-struct uprobe_trace_consumer {
- struct uprobe_consumer cons;
- struct trace_uprobe *tu;
-};
-
struct trace_uprobe {
struct list_head list;
struct ftrace_event_class class;
struct ftrace_event_call call;
- struct uprobe_trace_consumer *consumer;
+ struct trace_uprobe_filter filter;
+ struct uprobe_consumer consumer;
struct inode *inode;
char *filename;
unsigned long offset;
@@ -64,6 +65,18 @@ static LIST_HEAD(uprobe_list);
static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
+static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
+{
+ rwlock_init(&filter->rwlock);
+ filter->nr_systemwide = 0;
+ INIT_LIST_HEAD(&filter->perf_events);
+}
+
+static inline bool uprobe_filter_is_empty(struct trace_uprobe_filter *filter)
+{
+ return !filter->nr_systemwide && list_empty(&filter->perf_events);
+}
+
/*
* Allocate new trace_uprobe and initialize it (including uprobes).
*/
@@ -92,6 +105,8 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs)
goto error;
INIT_LIST_HEAD(&tu->list);
+ tu->consumer.handler = uprobe_dispatcher;
+ init_trace_uprobe_filter(&tu->filter);
return tu;
error:
@@ -253,16 +268,18 @@ static int create_trace_uprobe(int argc, char **argv)
if (ret)
goto fail_address_parse;
- ret = kstrtoul(arg, 0, &offset);
- if (ret)
- goto fail_address_parse;
-
inode = igrab(path.dentry->d_inode);
- if (!S_ISREG(inode->i_mode)) {
+ path_put(&path);
+
+ if (!inode || !S_ISREG(inode->i_mode)) {
ret = -EINVAL;
goto fail_address_parse;
}
+ ret = kstrtoul(arg, 0, &offset);
+ if (ret)
+ goto fail_address_parse;
+
argc -= 2;
argv += 2;
@@ -469,7 +486,7 @@ static const struct file_operations uprobe_profile_ops = {
};
/* uprobe handler */
-static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
+static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
{
struct uprobe_trace_entry_head *entry;
struct ring_buffer_event *event;
@@ -479,8 +496,6 @@ static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
unsigned long irq_flags;
struct ftrace_event_call *call = &tu->call;
- tu->nhit++;
-
local_save_flags(irq_flags);
pc = preempt_count();
@@ -489,16 +504,18 @@ static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
size, irq_flags, pc);
if (!event)
- return;
+ return 0;
entry = ring_buffer_event_data(event);
- entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
+ entry->ip = instruction_pointer(task_pt_regs(current));
data = (u8 *)&entry[1];
for (i = 0; i < tu->nr_args; i++)
call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
if (!filter_current_check_discard(buffer, call, entry, event))
trace_buffer_unlock_commit(buffer, event, irq_flags, pc);
+
+ return 0;
}
/* Event entry printers */
@@ -537,42 +554,43 @@ partial:
return TRACE_TYPE_PARTIAL_LINE;
}
-static int probe_event_enable(struct trace_uprobe *tu, int flag)
+static inline bool is_trace_uprobe_enabled(struct trace_uprobe *tu)
{
- struct uprobe_trace_consumer *utc;
- int ret = 0;
+ return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE);
+}
- if (!tu->inode || tu->consumer)
- return -EINTR;
+typedef bool (*filter_func_t)(struct uprobe_consumer *self,
+ enum uprobe_filter_ctx ctx,
+ struct mm_struct *mm);
+
+static int
+probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
+{
+ int ret = 0;
- utc = kzalloc(sizeof(struct uprobe_trace_consumer), GFP_KERNEL);
- if (!utc)
+ if (is_trace_uprobe_enabled(tu))
return -EINTR;
- utc->cons.handler = uprobe_dispatcher;
- utc->cons.filter = NULL;
- ret = uprobe_register(tu->inode, tu->offset, &utc->cons);
- if (ret) {
- kfree(utc);
- return ret;
- }
+ WARN_ON(!uprobe_filter_is_empty(&tu->filter));
tu->flags |= flag;
- utc->tu = tu;
- tu->consumer = utc;
+ tu->consumer.filter = filter;
+ ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
+ if (ret)
+ tu->flags &= ~flag;
- return 0;
+ return ret;
}
static void probe_event_disable(struct trace_uprobe *tu, int flag)
{
- if (!tu->inode || !tu->consumer)
+ if (!is_trace_uprobe_enabled(tu))
return;
- uprobe_unregister(tu->inode, tu->offset, &tu->consumer->cons);
+ WARN_ON(!uprobe_filter_is_empty(&tu->filter));
+
+ uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
tu->flags &= ~flag;
- kfree(tu->consumer);
- tu->consumer = NULL;
}
static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
@@ -646,8 +664,96 @@ static int set_print_fmt(struct trace_uprobe *tu)
}
#ifdef CONFIG_PERF_EVENTS
+static bool
+__uprobe_perf_filter(struct trace_uprobe_filter *filter, struct mm_struct *mm)
+{
+ struct perf_event *event;
+
+ if (filter->nr_systemwide)
+ return true;
+
+ list_for_each_entry(event, &filter->perf_events, hw.tp_list) {
+ if (event->hw.tp_target->mm == mm)
+ return true;
+ }
+
+ return false;
+}
+
+static inline bool
+uprobe_filter_event(struct trace_uprobe *tu, struct perf_event *event)
+{
+ return __uprobe_perf_filter(&tu->filter, event->hw.tp_target->mm);
+}
+
+static int uprobe_perf_open(struct trace_uprobe *tu, struct perf_event *event)
+{
+ bool done;
+
+ write_lock(&tu->filter.rwlock);
+ if (event->hw.tp_target) {
+ /*
+ * event->parent != NULL means copy_process(), we can avoid
+ * uprobe_apply(). current->mm must be probed and we can rely
+ * on dup_mmap() which preserves the already installed bp's.
+ *
+ * attr.enable_on_exec means that exec/mmap will install the
+ * breakpoints we need.
+ */
+ done = tu->filter.nr_systemwide ||
+ event->parent || event->attr.enable_on_exec ||
+ uprobe_filter_event(tu, event);
+ list_add(&event->hw.tp_list, &tu->filter.perf_events);
+ } else {
+ done = tu->filter.nr_systemwide;
+ tu->filter.nr_systemwide++;
+ }
+ write_unlock(&tu->filter.rwlock);
+
+ if (!done)
+ uprobe_apply(tu->inode, tu->offset, &tu->consumer, true);
+
+ return 0;
+}
+
+static int uprobe_perf_close(struct trace_uprobe *tu, struct perf_event *event)
+{
+ bool done;
+
+ write_lock(&tu->filter.rwlock);
+ if (event->hw.tp_target) {
+ list_del(&event->hw.tp_list);
+ done = tu->filter.nr_systemwide ||
+ (event->hw.tp_target->flags & PF_EXITING) ||
+ uprobe_filter_event(tu, event);
+ } else {
+ tu->filter.nr_systemwide--;
+ done = tu->filter.nr_systemwide;
+ }
+ write_unlock(&tu->filter.rwlock);
+
+ if (!done)
+ uprobe_apply(tu->inode, tu->offset, &tu->consumer, false);
+
+ return 0;
+}
+
+static bool uprobe_perf_filter(struct uprobe_consumer *uc,
+ enum uprobe_filter_ctx ctx, struct mm_struct *mm)
+{
+ struct trace_uprobe *tu;
+ int ret;
+
+ tu = container_of(uc, struct trace_uprobe, consumer);
+ read_lock(&tu->filter.rwlock);
+ ret = __uprobe_perf_filter(&tu->filter, mm);
+ read_unlock(&tu->filter.rwlock);
+
+ return ret;
+}
+
/* uprobe profile handler */
-static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
+static int uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
{
struct ftrace_event_call *call = &tu->call;
struct uprobe_trace_entry_head *entry;
@@ -656,11 +762,14 @@ static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
int size, __size, i;
int rctx;
+ if (!uprobe_perf_filter(&tu->consumer, 0, current->mm))
+ return UPROBE_HANDLER_REMOVE;
+
__size = sizeof(*entry) + tu->size;
size = ALIGN(__size + sizeof(u32), sizeof(u64));
size -= sizeof(u32);
if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE, "profile buffer not large enough"))
- return;
+ return 0;
preempt_disable();
@@ -668,7 +777,7 @@ static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
if (!entry)
goto out;
- entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
+ entry->ip = instruction_pointer(task_pt_regs(current));
data = (u8 *)&entry[1];
for (i = 0; i < tu->nr_args; i++)
call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
@@ -678,6 +787,7 @@ static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
out:
preempt_enable();
+ return 0;
}
#endif /* CONFIG_PERF_EVENTS */
@@ -688,7 +798,7 @@ int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type,
switch (type) {
case TRACE_REG_REGISTER:
- return probe_event_enable(tu, TP_FLAG_TRACE);
+ return probe_event_enable(tu, TP_FLAG_TRACE, NULL);
case TRACE_REG_UNREGISTER:
probe_event_disable(tu, TP_FLAG_TRACE);
@@ -696,11 +806,18 @@ int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type,
#ifdef CONFIG_PERF_EVENTS
case TRACE_REG_PERF_REGISTER:
- return probe_event_enable(tu, TP_FLAG_PROFILE);
+ return probe_event_enable(tu, TP_FLAG_PROFILE, uprobe_perf_filter);
case TRACE_REG_PERF_UNREGISTER:
probe_event_disable(tu, TP_FLAG_PROFILE);
return 0;
+
+ case TRACE_REG_PERF_OPEN:
+ return uprobe_perf_open(tu, data);
+
+ case TRACE_REG_PERF_CLOSE:
+ return uprobe_perf_close(tu, data);
+
#endif
default:
return 0;
@@ -710,22 +827,20 @@ int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type,
static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
{
- struct uprobe_trace_consumer *utc;
struct trace_uprobe *tu;
+ int ret = 0;
- utc = container_of(con, struct uprobe_trace_consumer, cons);
- tu = utc->tu;
- if (!tu || tu->consumer != utc)
- return 0;
+ tu = container_of(con, struct trace_uprobe, consumer);
+ tu->nhit++;
if (tu->flags & TP_FLAG_TRACE)
- uprobe_trace_func(tu, regs);
+ ret |= uprobe_trace_func(tu, regs);
#ifdef CONFIG_PERF_EVENTS
if (tu->flags & TP_FLAG_PROFILE)
- uprobe_perf_func(tu, regs);
+ ret |= uprobe_perf_func(tu, regs);
#endif
- return 0;
+ return ret;
}
static struct trace_event_functions uprobe_funcs = {