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authorFrederic Weisbecker <fweisbec@gmail.com>2013-05-02 17:37:49 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2013-05-02 17:54:19 +0200
commitc032862fba51a3ca504752d3a25186b324c5ce83 (patch)
tree955dc2ba4ab3df76ecc2bb780ee84aca04967e8d /kernel/events
parentfda76e074c7737fc57855dd17c762e50ed526052 (diff)
parent8700c95adb033843fc163d112b9d21d4fda78018 (diff)
downloadvexpress-lsk-c032862fba51a3ca504752d3a25186b324c5ce83.tar.gz
Merge commit '8700c95adb03' into timers/nohz
The full dynticks tree needs the latest RCU and sched upstream updates in order to fix some dependencies. Merge a common upstream merge point that has these updates. Conflicts: include/linux/perf_event.h kernel/rcutree.h kernel/rcutree_plugin.h Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c70
-rw-r--r--kernel/events/internal.h2
-rw-r--r--kernel/events/ring_buffer.c22
-rw-r--r--kernel/events/uprobes.c300
4 files changed, 328 insertions, 66 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index ddb993b5219..6b41c1899a8 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -38,6 +38,7 @@
#include <linux/ftrace_event.h>
#include <linux/hw_breakpoint.h>
#include <linux/mm_types.h>
+#include <linux/cgroup.h>
#include "internal.h"
@@ -235,6 +236,20 @@ static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
#ifdef CONFIG_CGROUP_PERF
/*
+ * perf_cgroup_info keeps track of time_enabled for a cgroup.
+ * This is a per-cpu dynamically allocated data structure.
+ */
+struct perf_cgroup_info {
+ u64 time;
+ u64 timestamp;
+};
+
+struct perf_cgroup {
+ struct cgroup_subsys_state css;
+ struct perf_cgroup_info __percpu *info;
+};
+
+/*
* Must ensure cgroup is pinned (css_get) before calling
* this function. In other words, we cannot call this function
* if there is no cgroup event for the current CPU context.
@@ -252,7 +267,22 @@ perf_cgroup_match(struct perf_event *event)
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
- return !event->cgrp || event->cgrp == cpuctx->cgrp;
+ /* @event doesn't care about cgroup */
+ if (!event->cgrp)
+ return true;
+
+ /* wants specific cgroup scope but @cpuctx isn't associated with any */
+ if (!cpuctx->cgrp)
+ return false;
+
+ /*
+ * Cgroup scoping is recursive. An event enabled for a cgroup is
+ * also enabled for all its descendant cgroups. If @cpuctx's
+ * cgroup is a descendant of @event's (the test covers identity
+ * case), it's a match.
+ */
+ return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
+ event->cgrp->css.cgroup);
}
static inline bool perf_tryget_cgroup(struct perf_event *event)
@@ -966,9 +996,15 @@ static void perf_event__header_size(struct perf_event *event)
if (sample_type & PERF_SAMPLE_PERIOD)
size += sizeof(data->period);
+ if (sample_type & PERF_SAMPLE_WEIGHT)
+ size += sizeof(data->weight);
+
if (sample_type & PERF_SAMPLE_READ)
size += event->read_size;
+ if (sample_type & PERF_SAMPLE_DATA_SRC)
+ size += sizeof(data->data_src.val);
+
event->header_size = size;
}
@@ -4193,6 +4229,12 @@ void perf_output_sample(struct perf_output_handle *handle,
perf_output_sample_ustack(handle,
data->stack_user_size,
data->regs_user.regs);
+
+ if (sample_type & PERF_SAMPLE_WEIGHT)
+ perf_output_put(handle, data->weight);
+
+ if (sample_type & PERF_SAMPLE_DATA_SRC)
+ perf_output_put(handle, data->data_src.val);
}
void perf_prepare_sample(struct perf_event_header *header,
@@ -4449,12 +4491,15 @@ static void perf_event_task_event(struct perf_task_event *task_event)
if (ctxn < 0)
goto next;
ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
+ if (ctx)
+ perf_event_task_ctx(ctx, task_event);
}
- if (ctx)
- perf_event_task_ctx(ctx, task_event);
next:
put_cpu_ptr(pmu->pmu_cpu_context);
}
+ if (task_event->task_ctx)
+ perf_event_task_ctx(task_event->task_ctx, task_event);
+
rcu_read_unlock();
}
@@ -4608,6 +4653,7 @@ void perf_event_comm(struct task_struct *task)
struct perf_event_context *ctx;
int ctxn;
+ rcu_read_lock();
for_each_task_context_nr(ctxn) {
ctx = task->perf_event_ctxp[ctxn];
if (!ctx)
@@ -4615,6 +4661,7 @@ void perf_event_comm(struct task_struct *task)
perf_event_enable_on_exec(ctx);
}
+ rcu_read_unlock();
if (!atomic_read(&nr_comm_events))
return;
@@ -4749,7 +4796,8 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
} else {
if (arch_vma_name(mmap_event->vma)) {
name = strncpy(tmp, arch_vma_name(mmap_event->vma),
- sizeof(tmp));
+ sizeof(tmp) - 1);
+ tmp[sizeof(tmp) - 1] = '\0';
goto got_name;
}
@@ -4776,6 +4824,9 @@ got_name:
mmap_event->file_name = name;
mmap_event->file_size = size;
+ if (!(vma->vm_flags & VM_EXEC))
+ mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
+
mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
rcu_read_lock();
@@ -5342,7 +5393,7 @@ static void sw_perf_event_destroy(struct perf_event *event)
static int perf_swevent_init(struct perf_event *event)
{
- int event_id = event->attr.config;
+ u64 event_id = event->attr.config;
if (event->attr.type != PERF_TYPE_SOFTWARE)
return -ENOENT;
@@ -5662,6 +5713,7 @@ static void perf_swevent_init_hrtimer(struct perf_event *event)
event->attr.sample_period = NSEC_PER_SEC / freq;
hwc->sample_period = event->attr.sample_period;
local64_set(&hwc->period_left, hwc->sample_period);
+ hwc->last_period = hwc->sample_period;
event->attr.freq = 0;
}
}
@@ -5997,6 +6049,7 @@ skip_type:
if (pmu->pmu_cpu_context)
goto got_cpu_context;
+ ret = -ENOMEM;
pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
if (!pmu->pmu_cpu_context)
goto free_dev;
@@ -7524,12 +7577,5 @@ struct cgroup_subsys perf_subsys = {
.css_free = perf_cgroup_css_free,
.exit = perf_cgroup_exit,
.attach = perf_cgroup_attach,
-
- /*
- * perf_event cgroup doesn't handle nesting correctly.
- * ctx->nr_cgroups adjustments should be propagated through the
- * cgroup hierarchy. Fix it and remove the following.
- */
- .broken_hierarchy = true,
};
#endif /* CONFIG_CGROUP_PERF */
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index d56a64c99a8..eb675c4d59d 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -16,7 +16,7 @@ struct ring_buffer {
int page_order; /* allocation order */
#endif
int nr_pages; /* nr of data pages */
- int writable; /* are we writable */
+ int overwrite; /* can overwrite itself */
atomic_t poll; /* POLL_ for wakeups */
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 23cb34ff397..97fddb09762 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -18,12 +18,24 @@
static bool perf_output_space(struct ring_buffer *rb, unsigned long tail,
unsigned long offset, unsigned long head)
{
- unsigned long mask;
+ unsigned long sz = perf_data_size(rb);
+ unsigned long mask = sz - 1;
- if (!rb->writable)
+ /*
+ * check if user-writable
+ * overwrite : over-write its own tail
+ * !overwrite: buffer possibly drops events.
+ */
+ if (rb->overwrite)
return true;
- mask = perf_data_size(rb) - 1;
+ /*
+ * verify that payload is not bigger than buffer
+ * otherwise masking logic may fail to detect
+ * the "not enough space" condition
+ */
+ if ((head - offset) > sz)
+ return false;
offset = (offset - tail) & mask;
head = (head - tail) & mask;
@@ -212,7 +224,9 @@ ring_buffer_init(struct ring_buffer *rb, long watermark, int flags)
rb->watermark = max_size / 2;
if (flags & RING_BUFFER_WRITABLE)
- rb->writable = 1;
+ rb->overwrite = 0;
+ else
+ rb->overwrite = 1;
atomic_set(&rb->refcount, 1);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index a567c8c7ef3..f3569747d62 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -75,6 +75,15 @@ struct uprobe {
struct arch_uprobe arch;
};
+struct return_instance {
+ struct uprobe *uprobe;
+ unsigned long func;
+ unsigned long orig_ret_vaddr; /* original return address */
+ bool chained; /* true, if instance is nested */
+
+ struct return_instance *next; /* keep as stack */
+};
+
/*
* valid_vma: Verify if the specified vma is an executable vma
* Relax restrictions while unregistering: vm_flags might have
@@ -173,10 +182,31 @@ bool __weak is_swbp_insn(uprobe_opcode_t *insn)
return *insn == UPROBE_SWBP_INSN;
}
-static void copy_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *opcode)
+/**
+ * is_trap_insn - check if instruction is breakpoint instruction.
+ * @insn: instruction to be checked.
+ * Default implementation of is_trap_insn
+ * Returns true if @insn is a breakpoint instruction.
+ *
+ * This function is needed for the case where an architecture has multiple
+ * trap instructions (like powerpc).
+ */
+bool __weak is_trap_insn(uprobe_opcode_t *insn)
+{
+ return is_swbp_insn(insn);
+}
+
+static void copy_from_page(struct page *page, unsigned long vaddr, void *dst, int len)
{
void *kaddr = kmap_atomic(page);
- memcpy(opcode, kaddr + (vaddr & ~PAGE_MASK), UPROBE_SWBP_INSN_SIZE);
+ memcpy(dst, kaddr + (vaddr & ~PAGE_MASK), len);
+ kunmap_atomic(kaddr);
+}
+
+static void copy_to_page(struct page *page, unsigned long vaddr, const void *src, int len)
+{
+ void *kaddr = kmap_atomic(page);
+ memcpy(kaddr + (vaddr & ~PAGE_MASK), src, len);
kunmap_atomic(kaddr);
}
@@ -185,7 +215,16 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
uprobe_opcode_t old_opcode;
bool is_swbp;
- copy_opcode(page, vaddr, &old_opcode);
+ /*
+ * Note: We only check if the old_opcode is UPROBE_SWBP_INSN here.
+ * We do not check if it is any other 'trap variant' which could
+ * be conditional trap instruction such as the one powerpc supports.
+ *
+ * The logic is that we do not care if the underlying instruction
+ * is a trap variant; uprobes always wins over any other (gdb)
+ * breakpoint.
+ */
+ copy_from_page(page, vaddr, &old_opcode, UPROBE_SWBP_INSN_SIZE);
is_swbp = is_swbp_insn(&old_opcode);
if (is_swbp_insn(new_opcode)) {
@@ -204,7 +243,7 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t
* 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 is_swbp_at_addr and
+ * supported by that architecture then we need to modify is_trap_at_addr and
* write_opcode accordingly. This would never be a problem for archs that
* have fixed length instructions.
*/
@@ -225,7 +264,6 @@ static int write_opcode(struct mm_struct *mm, unsigned long vaddr,
uprobe_opcode_t opcode)
{
struct page *old_page, *new_page;
- void *vaddr_old, *vaddr_new;
struct vm_area_struct *vma;
int ret;
@@ -246,15 +284,8 @@ retry:
__SetPageUptodate(new_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);
- memcpy(vaddr_new + (vaddr & ~PAGE_MASK), &opcode, UPROBE_SWBP_INSN_SIZE);
-
- kunmap_atomic(vaddr_new);
- kunmap_atomic(vaddr_old);
+ copy_highpage(new_page, old_page);
+ copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
ret = anon_vma_prepare(vma);
if (ret)
@@ -477,30 +508,18 @@ __copy_insn(struct address_space *mapping, struct file *filp, char *insn,
unsigned long nbytes, loff_t offset)
{
struct page *page;
- void *vaddr;
- unsigned long off;
- pgoff_t idx;
-
- if (!filp)
- return -EINVAL;
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
* populated and in page-cache.
*/
- page = read_mapping_page(mapping, idx, filp);
+ page = read_mapping_page(mapping, offset >> PAGE_CACHE_SHIFT, filp);
if (IS_ERR(page))
return PTR_ERR(page);
- vaddr = kmap_atomic(page);
- memcpy(insn, vaddr + off, nbytes);
- kunmap_atomic(vaddr);
+ copy_from_page(page, offset, insn, nbytes);
page_cache_release(page);
return 0;
@@ -550,7 +569,7 @@ static int prepare_uprobe(struct uprobe *uprobe, struct file *file,
goto out;
ret = -ENOTSUPP;
- if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn))
+ if (is_trap_insn((uprobe_opcode_t *)uprobe->arch.insn))
goto out;
ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr);
@@ -758,7 +777,7 @@ register_for_each_vma(struct uprobe *uprobe, struct uprobe_consumer *new)
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)
+ file_inode(vma->vm_file) != uprobe->inode)
goto unlock;
if (vma->vm_start > info->vaddr ||
@@ -828,6 +847,10 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *
struct uprobe *uprobe;
int ret;
+ /* Uprobe must have at least one set consumer */
+ if (!uc->handler && !uc->ret_handler)
+ return -EINVAL;
+
/* Racy, just to catch the obvious mistakes */
if (offset > i_size_read(inode))
return -EINVAL;
@@ -917,7 +940,7 @@ static int unapply_uprobe(struct uprobe *uprobe, struct mm_struct *mm)
loff_t offset;
if (!valid_vma(vma, false) ||
- vma->vm_file->f_mapping->host != uprobe->inode)
+ file_inode(vma->vm_file) != uprobe->inode)
continue;
offset = (loff_t)vma->vm_pgoff << PAGE_SHIFT;
@@ -1010,7 +1033,7 @@ int uprobe_mmap(struct vm_area_struct *vma)
if (no_uprobe_events() || !valid_vma(vma, true))
return 0;
- inode = vma->vm_file->f_mapping->host;
+ inode = file_inode(vma->vm_file);
if (!inode)
return 0;
@@ -1041,7 +1064,7 @@ vma_has_uprobes(struct vm_area_struct *vma, unsigned long start, unsigned long e
struct inode *inode;
struct rb_node *n;
- inode = vma->vm_file->f_mapping->host;
+ inode = file_inode(vma->vm_file);
min = vaddr_to_offset(vma, start);
max = min + (end - start) - 1;
@@ -1114,6 +1137,7 @@ static struct xol_area *get_xol_area(void)
{
struct mm_struct *mm = current->mm;
struct xol_area *area;
+ uprobe_opcode_t insn = UPROBE_SWBP_INSN;
area = mm->uprobes_state.xol_area;
if (area)
@@ -1131,7 +1155,12 @@ static struct xol_area *get_xol_area(void)
if (!area->page)
goto free_bitmap;
+ /* allocate first slot of task's xol_area for the return probes */
+ set_bit(0, area->bitmap);
+ copy_to_page(area->page, 0, &insn, UPROBE_SWBP_INSN_SIZE);
+ atomic_set(&area->slot_count, 1);
init_waitqueue_head(&area->wq);
+
if (!xol_add_vma(area))
return area;
@@ -1216,9 +1245,7 @@ static unsigned long xol_take_insn_slot(struct xol_area *area)
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();
if (!area)
@@ -1229,10 +1256,7 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe)
return 0;
/* 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);
+ copy_to_page(area->page, xol_vaddr, uprobe->arch.insn, MAX_UINSN_BYTES);
/*
* We probably need flush_icache_user_range() but it needs vma.
* This should work on supported architectures too.
@@ -1298,6 +1322,7 @@ unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs)
void uprobe_free_utask(struct task_struct *t)
{
struct uprobe_task *utask = t->utask;
+ struct return_instance *ri, *tmp;
if (!utask)
return;
@@ -1305,6 +1330,15 @@ void uprobe_free_utask(struct task_struct *t)
if (utask->active_uprobe)
put_uprobe(utask->active_uprobe);
+ ri = utask->return_instances;
+ while (ri) {
+ tmp = ri;
+ ri = ri->next;
+
+ put_uprobe(tmp->uprobe);
+ kfree(tmp);
+ }
+
xol_free_insn_slot(t);
kfree(utask);
t->utask = NULL;
@@ -1333,6 +1367,93 @@ static struct uprobe_task *get_utask(void)
return current->utask;
}
+/*
+ * Current area->vaddr notion assume the trampoline address is always
+ * equal area->vaddr.
+ *
+ * Returns -1 in case the xol_area is not allocated.
+ */
+static unsigned long get_trampoline_vaddr(void)
+{
+ struct xol_area *area;
+ unsigned long trampoline_vaddr = -1;
+
+ area = current->mm->uprobes_state.xol_area;
+ smp_read_barrier_depends();
+ if (area)
+ trampoline_vaddr = area->vaddr;
+
+ return trampoline_vaddr;
+}
+
+static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs)
+{
+ struct return_instance *ri;
+ struct uprobe_task *utask;
+ unsigned long orig_ret_vaddr, trampoline_vaddr;
+ bool chained = false;
+
+ if (!get_xol_area())
+ return;
+
+ utask = get_utask();
+ if (!utask)
+ return;
+
+ if (utask->depth >= MAX_URETPROBE_DEPTH) {
+ printk_ratelimited(KERN_INFO "uprobe: omit uretprobe due to"
+ " nestedness limit pid/tgid=%d/%d\n",
+ current->pid, current->tgid);
+ return;
+ }
+
+ ri = kzalloc(sizeof(struct return_instance), GFP_KERNEL);
+ if (!ri)
+ goto fail;
+
+ trampoline_vaddr = get_trampoline_vaddr();
+ orig_ret_vaddr = arch_uretprobe_hijack_return_addr(trampoline_vaddr, regs);
+ if (orig_ret_vaddr == -1)
+ goto fail;
+
+ /*
+ * We don't want to keep trampoline address in stack, rather keep the
+ * original return address of first caller thru all the consequent
+ * instances. This also makes breakpoint unwrapping easier.
+ */
+ if (orig_ret_vaddr == trampoline_vaddr) {
+ if (!utask->return_instances) {
+ /*
+ * This situation is not possible. Likely we have an
+ * attack from user-space.
+ */
+ pr_warn("uprobe: unable to set uretprobe pid/tgid=%d/%d\n",
+ current->pid, current->tgid);
+ goto fail;
+ }
+
+ chained = true;
+ orig_ret_vaddr = utask->return_instances->orig_ret_vaddr;
+ }
+
+ atomic_inc(&uprobe->ref);
+ ri->uprobe = uprobe;
+ ri->func = instruction_pointer(regs);
+ ri->orig_ret_vaddr = orig_ret_vaddr;
+ ri->chained = chained;
+
+ utask->depth++;
+
+ /* add instance to the stack */
+ ri->next = utask->return_instances;
+ utask->return_instances = ri;
+
+ return;
+
+ fail:
+ kfree(ri);
+}
+
/* Prepare to single-step probed instruction out of line. */
static int
pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long bp_vaddr)
@@ -1431,7 +1552,7 @@ static void mmf_recalc_uprobes(struct mm_struct *mm)
clear_bit(MMF_HAS_UPROBES, &mm->flags);
}
-static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr)
+static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr)
{
struct page *page;
uprobe_opcode_t opcode;
@@ -1449,10 +1570,11 @@ static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr)
if (result < 0)
return result;
- copy_opcode(page, vaddr, &opcode);
+ copy_from_page(page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);
put_page(page);
out:
- return is_swbp_insn(&opcode);
+ /* This needs to return true for any variant of the trap insn */
+ return is_trap_insn(&opcode);
}
static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
@@ -1465,14 +1587,14 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
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;
+ struct inode *inode = file_inode(vma->vm_file);
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);
+ *is_swbp = is_trap_at_addr(mm, bp_vaddr);
} else {
*is_swbp = -EFAULT;
}
@@ -1488,16 +1610,27 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
{
struct uprobe_consumer *uc;
int remove = UPROBE_HANDLER_REMOVE;
+ bool need_prep = false; /* prepare return uprobe, when needed */
down_read(&uprobe->register_rwsem);
for (uc = uprobe->consumers; uc; uc = uc->next) {
- int rc = uc->handler(uc, regs);
+ int rc = 0;
+
+ if (uc->handler) {
+ rc = uc->handler(uc, regs);
+ WARN(rc & ~UPROBE_HANDLER_MASK,
+ "bad rc=0x%x from %pf()\n", rc, uc->handler);
+ }
+
+ if (uc->ret_handler)
+ need_prep = true;
- WARN(rc & ~UPROBE_HANDLER_MASK,
- "bad rc=0x%x from %pf()\n", rc, uc->handler);
remove &= rc;
}
+ if (need_prep && !remove)
+ prepare_uretprobe(uprobe, regs); /* put bp at return */
+
if (remove && uprobe->consumers) {
WARN_ON(!uprobe_is_active(uprobe));
unapply_uprobe(uprobe, current->mm);
@@ -1505,6 +1638,64 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
up_read(&uprobe->register_rwsem);
}
+static void
+handle_uretprobe_chain(struct return_instance *ri, struct pt_regs *regs)
+{
+ struct uprobe *uprobe = ri->uprobe;
+ struct uprobe_consumer *uc;
+
+ down_read(&uprobe->register_rwsem);
+ for (uc = uprobe->consumers; uc; uc = uc->next) {
+ if (uc->ret_handler)
+ uc->ret_handler(uc, ri->func, regs);
+ }
+ up_read(&uprobe->register_rwsem);
+}
+
+static bool handle_trampoline(struct pt_regs *regs)
+{
+ struct uprobe_task *utask;
+ struct return_instance *ri, *tmp;
+ bool chained;
+
+ utask = current->utask;
+ if (!utask)
+ return false;
+
+ ri = utask->return_instances;
+ if (!ri)
+ return false;
+
+ /*
+ * TODO: we should throw out return_instance's invalidated by
+ * longjmp(), currently we assume that the probed function always
+ * returns.
+ */
+ instruction_pointer_set(regs, ri->orig_ret_vaddr);
+
+ for (;;) {
+ handle_uretprobe_chain(ri, regs);
+
+ chained = ri->chained;
+ put_uprobe(ri->uprobe);
+
+ tmp = ri;
+ ri = ri->next;
+ kfree(tmp);
+
+ if (!chained)
+ break;
+
+ utask->depth--;
+
+ BUG_ON(!ri);
+ }
+
+ utask->return_instances = ri;
+
+ return true;
+}
+
/*
* Run handler and ask thread to singlestep.
* Ensure all non-fatal signals cannot interrupt thread while it singlesteps.
@@ -1516,8 +1707,15 @@ static void handle_swbp(struct pt_regs *regs)
int uninitialized_var(is_swbp);
bp_vaddr = uprobe_get_swbp_addr(regs);
- uprobe = find_active_uprobe(bp_vaddr, &is_swbp);
+ if (bp_vaddr == get_trampoline_vaddr()) {
+ if (handle_trampoline(regs))
+ return;
+
+ pr_warn("uprobe: unable to handle uretprobe pid/tgid=%d/%d\n",
+ current->pid, current->tgid);
+ }
+ uprobe = find_active_uprobe(bp_vaddr, &is_swbp);
if (!uprobe) {
if (is_swbp > 0) {
/* No matching uprobe; signal SIGTRAP. */
@@ -1616,7 +1814,11 @@ void uprobe_notify_resume(struct pt_regs *regs)
*/
int uprobe_pre_sstep_notifier(struct pt_regs *regs)
{
- if (!current->mm || !test_bit(MMF_HAS_UPROBES, &current->mm->flags))
+ if (!current->mm)
+ return 0;
+
+ if (!test_bit(MMF_HAS_UPROBES, &current->mm->flags) &&
+ (!current->utask || !current->utask->return_instances))
return 0;
set_thread_flag(TIF_UPROBE);