| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Sun, 22 Mar 2009 19:00:13 +0100
From: Frederic Weisbecker <fweisbec@...il.com>
To: Ingo Molnar <mingo@...e.hu>
Cc: Tom Zanussi <tzanussi@...il.com>,
linux-kernel <linux-kernel@...r.kernel.org>,
Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCH 1/4] tracing: add run-time field descriptions for event
filtering
On Sun, Mar 22, 2009 at 06:44:43PM +0100, Ingo Molnar wrote:
>
> * Frederic Weisbecker <fweisbec@...il.com> wrote:
>
> > Hi Tom,
> >
> >
> > On Sun, Mar 22, 2009 at 03:30:39AM -0500, Tom Zanussi wrote:
> > > This patch makes the field descriptions defined for event tracing
> > > available at run-time, for the event-filtering mechanism introduced in a
> > > subsequent patch.
> > >
> > > The common event fields are prepended with 'common_' in the format
> > > display, allowing them to be distinguished from the other fields that
> > > might internally have same name and can therefore be unambiguously used
> > > in filters.
> > >
> > > Signed-off-by: Tom Zanussi <tzanussi@...il.com>
> > >
> > > ---
> > > kernel/trace/trace.h | 30 ++++++++++++++++-------
> > > kernel/trace/trace_events.c | 40 ++++++++++++++++++++++++++++++-
> > > kernel/trace/trace_events_stage_2.h | 45 +++++++++++++++++++++++++++++++++++
> > > kernel/trace/trace_events_stage_3.h | 2 +
> > > 4 files changed, 107 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> > > index 7cfb741..9288dc7 100644
> > > --- a/kernel/trace/trace.h
> > > +++ b/kernel/trace/trace.h
> > > @@ -775,16 +775,26 @@ enum {
> > > TRACE_EVENT_TYPE_RAW = 2,
> > > };
> > >
> > > +struct ftrace_event_field {
> > > + struct list_head link;
> > > + char *name;
> > > + char *type;
> > > + int offset;
> > > + int size;
> > > +};
> > > +
> > > struct ftrace_event_call {
> > > - char *name;
> > > - char *system;
> > > - struct dentry *dir;
> > > - int enabled;
> > > - int (*regfunc)(void);
> > > - void (*unregfunc)(void);
> > > - int id;
> > > - int (*raw_init)(void);
> > > - int (*show_format)(struct trace_seq *s);
> > > + char *name;
> > > + char *system;
> > > + struct dentry *dir;
> > > + int enabled;
> > > + int (*regfunc)(void);
> > > + void (*unregfunc)(void);
> > > + int id;
> > > + int (*raw_init)(void);
> > > + int (*show_format)(struct trace_seq *s);
> > > + int (*define_fields)(void);
> > > + struct list_head fields;
> > >
> > > #ifdef CONFIG_EVENT_PROFILE
> > > atomic_t profile_count;
> > > @@ -793,6 +803,8 @@ struct ftrace_event_call {
> > > #endif
> > > };
> > >
> > > +int trace_define_field(struct ftrace_event_call *call, char *type,
> > > + char *name, int offset, int size);
> > > void event_trace_printk(unsigned long ip, const char *fmt, ...);
> > > extern struct ftrace_event_call __start_ftrace_events[];
> > > extern struct ftrace_event_call __stop_ftrace_events[];
> > > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
> > > index 3047b56..961b057 100644
> > > --- a/kernel/trace/trace_events.c
> > > +++ b/kernel/trace/trace_events.c
> > > @@ -19,6 +19,34 @@
> > >
> > > static DEFINE_MUTEX(event_mutex);
> > >
> > > +int trace_define_field(struct ftrace_event_call *call, char *type,
> > > + char *name, int offset, int size)
> > > +{
> > > + struct ftrace_event_field *field;
> > > +
> > > + field = kmalloc(sizeof(*field), GFP_KERNEL);
> > > + if (!field)
> > > + goto err;
> > > + field->name = kstrdup(name, GFP_KERNEL);
> > > + if (!field->name)
> > > + goto err;
> > > + field->type = kstrdup(type, GFP_KERNEL);
> > > + if (!field->type)
> > > + goto err;
> > > + field->offset = offset;
> > > + field->size = size;
> > > + list_add(&field->link, &call->fields);
> > > +
> > > + return 0;
> > > +err:
> > > + if (field) {
> > > + kfree(field->name);
> > > + kfree(field->type);
> >
> >
> > You need kzalloc to allocate field.
> > With kmalloc, field will point to random filled memory
> > after a fresh allocation.
> >
> > Imagine this path:
> >
> > if (!field->name)
> > goto err;
> > ...
> > err:
> > kfree(field->name) <- field->name = NULL, correct
> > kfree(field->type) <- field->type = ?
> >
> >
> > > + }
> > > + kfree(field);
> > > + return -ENOMEM;
> > > +}
> > > +
> > > static void ftrace_clear_events(void)
> > > {
> > > struct ftrace_event_call *call = (void *)__start_ftrace_events;
> > > @@ -343,7 +371,8 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt,
> > >
> > > #undef FIELD
> > > #define FIELD(type, name) \
> > > - #type, #name, offsetof(typeof(field), name), sizeof(field.name)
> > > + #type, "common_" #name, offsetof(typeof(field), name), \
> > > + sizeof(field.name)
> > >
> > > static int trace_write_header(struct trace_seq *s)
> > > {
> > > @@ -581,6 +610,15 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events)
> > > call->name);
> > > }
> > >
> > > + if (call->define_fields) {
> > > + ret = call->define_fields();
> > > + if (ret < 0) {
> > > + pr_warning("Could not initialize trace point"
> > > + " events/%s\n", call->name);
> > > + return ret;
> > > + }
> > > + }
> > > +
> > > /* A trace may not want to export its format */
> > > if (!call->show_format)
> > > return 0;
> > > diff --git a/kernel/trace/trace_events_stage_2.h b/kernel/trace/trace_events_stage_2.h
> > > index 5117c43..30743f7 100644
> > > --- a/kernel/trace/trace_events_stage_2.h
> > > +++ b/kernel/trace/trace_events_stage_2.h
> > > @@ -129,3 +129,48 @@ ftrace_format_##call(struct trace_seq *s) \
> > > }
> > >
> > > #include <trace/trace_event_types.h>
> > > +
> > > +#undef __field
> > > +#define __field(type, item) \
> > > + ret = trace_define_field(event_call, #type, #item, \
> > > + offsetof(typeof(field), item), \
> > > + sizeof(field.item)); \
> > > + if (ret) \
> > > + return ret;
> > > +
> > > +#undef __array
> > > +#define __array(type, item, len) \
> > > + ret = trace_define_field(event_call, #type "[" #len "]", #item, \
> > > + offsetof(typeof(field), item), \
> > > + sizeof(field.item)); \
> > > + if (ret) \
> > > + return ret;
> > > +
> > > +#define __common_field(type, item) \
> > > + ret = trace_define_field(event_call, #type, "common_" #item, \
> > > + offsetof(typeof(field.ent), item), \
> > > + sizeof(field.ent.item)); \
> > > + if (ret) \
> > > + return ret;
> > > +
> > > +#undef TRACE_EVENT
> > > +#define TRACE_EVENT(call, proto, args, tstruct, func, print) \
> > > +int \
> > > +ftrace_define_fields_##call(void) \
> > > +{ \
> > > + struct ftrace_raw_##call field; \
> > > + struct ftrace_event_call *event_call = &event_##call; \
> > > + int ret; \
> > > + \
> > > + __common_field(unsigned char, type); \
> > > + __common_field(unsigned char, flags); \
> > > + __common_field(unsigned char, preempt_count); \
> > > + __common_field(int, pid); \
> > > + __common_field(int, tgid); \
> > > + \
> > > + tstruct; \
> > > + \
> > > + return ret; \
> > > +}
> > > +
> > > +#include <trace/trace_event_types.h>
> > > diff --git a/kernel/trace/trace_events_stage_3.h b/kernel/trace/trace_events_stage_3.h
> > > index 6b3261c..468938f 100644
> > > --- a/kernel/trace/trace_events_stage_3.h
> > > +++ b/kernel/trace/trace_events_stage_3.h
> > > @@ -252,6 +252,7 @@ static int ftrace_raw_init_event_##call(void) \
> > > if (!id) \
> > > return -ENODEV; \
> > > event_##call.id = id; \
> > > + INIT_LIST_HEAD(&event_##call.fields); \
> > > return 0; \
> > > } \
> > > \
> > > @@ -264,6 +265,7 @@ __attribute__((section("_ftrace_events"))) event_##call = { \
> > > .regfunc = ftrace_raw_reg_event_##call, \
> > > .unregfunc = ftrace_raw_unreg_event_##call, \
> > > .show_format = ftrace_format_##call, \
> > > + .define_fields = ftrace_define_fields_##call, \
> > > _TRACE_PROFILE_INIT(call) \
> > > }
> > >
> >
> > Other than the small possible memory leak, it looks good.
>
> it's not a memory leak but an incorrect kfree(), which can crash the
> box.
Yeah, indeed.
> >
> > Acked-by: Frederic Weisbecker <fweisbec@...il.com>
>
> thanks - i also queued up a fix for the kfree() bug.
>
> Ingo
Thanks.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists