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tracing/uprobe: Fix to make trace_uprobe_filter alignment safe

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Commit 99c9a923e9 ("tracing/uprobe: Fix double perf_event
linking on multiprobe uprobe") moved trace_uprobe_filter on
trace_probe_event. However, since it introduced a flexible
data structure with char array and type casting, the
alignment of trace_uprobe_filter can be broken.

This changes the type of the array to trace_uprobe_filter
data strucure to fix it.

Link: http://lore.kernel.org/r/20200120124022.GA14897@hirez.programming.kicks-ass.net
Link: http://lkml.kernel.org/r/157966340499.5107.10978352478952144902.stgit@devnote2

Fixes: 99c9a923e9 ("tracing/uprobe: Fix double perf_event linking on multiprobe uprobe")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu 2020-01-22 12:23:25 +09:00 committed by Steven Rostedt (VMware)
parent bf24daac8f
commit b61387cb73
4 changed files with 22 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/trace/trace_kprobe.c
View File

@ -290,7 +290,7 @@ static struct trace_kprobe *alloc_trace_kprobe(const char *group,
INIT_HLIST_NODE(&tk->rp.kp.hlist);
INIT_LIST_HEAD(&tk->rp.kp.list);
ret = trace_probe_init(&tk->tp, event, group, 0);
ret = trace_probe_init(&tk->tp, event, group, false);
if (ret < 0)
goto error;

9
kernel/trace/trace_probe.c
View File

@ -984,16 +984,19 @@ void trace_probe_cleanup(struct trace_probe *tp)
}
int trace_probe_init(struct trace_probe *tp, const char *event,
const char *group, size_t event_data_size)
const char *group, bool alloc_filter)
{
struct trace_event_call *call;
size_t size = sizeof(struct trace_probe_event);
int ret = 0;
if (!event || !group)
return -EINVAL;
tp->event = kzalloc(sizeof(struct trace_probe_event) + event_data_size,
GFP_KERNEL);
if (alloc_filter)
size += sizeof(struct trace_uprobe_filter);
tp->event = kzalloc(size, GFP_KERNEL);
if (!tp->event)
return -ENOMEM;

10
kernel/trace/trace_probe.h
View File

@ -223,6 +223,12 @@ struct probe_arg {
const struct fetch_type *type; /* Type of this argument */
};
struct trace_uprobe_filter {
rwlock_t rwlock;
int nr_systemwide;
struct list_head perf_events;
};
/* Event call and class holder */
struct trace_probe_event {
unsigned int flags; /* For TP_FLAG_* */
@ -230,7 +236,7 @@ struct trace_probe_event {
struct trace_event_call call;
struct list_head files;
struct list_head probes;
char data[0];
struct trace_uprobe_filter filter[0];
};
struct trace_probe {
@ -323,7 +329,7 @@ static inline bool trace_probe_has_single_file(struct trace_probe *tp)
}
int trace_probe_init(struct trace_probe *tp, const char *event,
const char *group, size_t event_data_size);
const char *group, bool alloc_filter);
void trace_probe_cleanup(struct trace_probe *tp);
int trace_probe_append(struct trace_probe *tp, struct trace_probe *to);
void trace_probe_unlink(struct trace_probe *tp);

29
kernel/trace/trace_uprobe.c
View File

@ -34,12 +34,6 @@ struct uprobe_trace_entry_head {
#define DATAOF_TRACE_ENTRY(entry, is_return) \
((void*)(entry) + SIZEOF_TRACE_ENTRY(is_return))
struct trace_uprobe_filter {
rwlock_t rwlock;
int nr_systemwide;
struct list_head perf_events;
};
static int trace_uprobe_create(int argc, const char **argv);
static int trace_uprobe_show(struct seq_file *m, struct dyn_event *ev);
static int trace_uprobe_release(struct dyn_event *ev);
@ -263,14 +257,6 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest,
}
NOKPROBE_SYMBOL(process_fetch_insn)
static struct trace_uprobe_filter *
trace_uprobe_get_filter(struct trace_uprobe *tu)
{
struct trace_probe_event *event = tu->tp.event;
return (struct trace_uprobe_filter *)&event->data[0];
}
static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter)
{
rwlock_init(&filter->rwlock);
@ -358,8 +344,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
if (!tu)
return ERR_PTR(-ENOMEM);
ret = trace_probe_init(&tu->tp, event, group,
sizeof(struct trace_uprobe_filter));
ret = trace_probe_init(&tu->tp, event, group, true);
if (ret < 0)
goto error;
@ -367,7 +352,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
tu->consumer.handler = uprobe_dispatcher;
if (is_ret)
tu->consumer.ret_handler = uretprobe_dispatcher;
init_trace_uprobe_filter(trace_uprobe_get_filter(tu));
init_trace_uprobe_filter(tu->tp.event->filter);
return tu;
error:
@ -1076,7 +1061,7 @@ static void __probe_event_disable(struct trace_probe *tp)
struct trace_uprobe *tu;
tu = container_of(tp, struct trace_uprobe, tp);
WARN_ON(!uprobe_filter_is_empty(trace_uprobe_get_filter(tu)));
WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter));
list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
tu = container_of(pos, struct trace_uprobe, tp);
@ -1117,7 +1102,7 @@ static int probe_event_enable(struct trace_event_call *call,
}
tu = container_of(tp, struct trace_uprobe, tp);
WARN_ON(!uprobe_filter_is_empty(trace_uprobe_get_filter(tu)));
WARN_ON(!uprobe_filter_is_empty(tu->tp.event->filter));
if (enabled)
return 0;
@ -1281,7 +1266,7 @@ static int uprobe_perf_close(struct trace_event_call *call,
return -ENODEV;
tu = container_of(tp, struct trace_uprobe, tp);
if (trace_uprobe_filter_remove(trace_uprobe_get_filter(tu), event))
if (trace_uprobe_filter_remove(tu->tp.event->filter, event))
return 0;
list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
@ -1306,7 +1291,7 @@ static int uprobe_perf_open(struct trace_event_call *call,
return -ENODEV;
tu = container_of(tp, struct trace_uprobe, tp);
if (trace_uprobe_filter_add(trace_uprobe_get_filter(tu), event))
if (trace_uprobe_filter_add(tu->tp.event->filter, event))
return 0;
list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
@ -1328,7 +1313,7 @@ static bool uprobe_perf_filter(struct uprobe_consumer *uc,
int ret;
tu = container_of(uc, struct trace_uprobe, consumer);
filter = trace_uprobe_get_filter(tu);
filter = tu->tp.event->filter;
read_lock(&filter->rwlock);
ret = __uprobe_perf_filter(filter, mm);