linux_dsm_epyc7002/include/trace/events/module.h
Mathieu Desnoyers 66cc69e34e Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE
Users have reported being unable to trace non-signed modules loaded
within a kernel supporting module signature.

This is caused by tracepoint.c:tracepoint_module_coming() refusing to
take into account tracepoints sitting within force-loaded modules
(TAINT_FORCED_MODULE). The reason for this check, in the first place, is
that a force-loaded module may have a struct module incompatible with
the layout expected by the kernel, and can thus cause a kernel crash
upon forced load of that module on a kernel with CONFIG_TRACEPOINTS=y.

Tracepoints, however, specifically accept TAINT_OOT_MODULE and
TAINT_CRAP, since those modules do not lead to the "very likely system
crash" issue cited above for force-loaded modules.

With kernels having CONFIG_MODULE_SIG=y (signed modules), a non-signed
module is tainted re-using the TAINT_FORCED_MODULE taint flag.
Unfortunately, this means that Tracepoints treat that module as a
force-loaded module, and thus silently refuse to consider any tracepoint
within this module.

Since an unsigned module does not fit within the "very likely system
crash" category of tainting, add a new TAINT_UNSIGNED_MODULE taint flag
to specifically address this taint behavior, and accept those modules
within Tracepoints. We use the letter 'X' as a taint flag character for
a module being loaded that doesn't know how to sign its name (proposed
by Steven Rostedt).

Also add the missing 'O' entry to trace event show_module_flags() list
for the sake of completeness.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
NAKed-by: Ingo Molnar <mingo@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: David Howells <dhowells@redhat.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-03-13 12:11:51 +10:30

134 lines
2.8 KiB
C

/*
* Because linux/module.h has tracepoints in the header, and ftrace.h
* used to include this file, define_trace.h includes linux/module.h
* But we do not want the module.h to override the TRACE_SYSTEM macro
* variable that define_trace.h is processing, so we only set it
* when module events are being processed, which would happen when
* CREATE_TRACE_POINTS is defined.
*/
#ifdef CREATE_TRACE_POINTS
#undef TRACE_SYSTEM
#define TRACE_SYSTEM module
#endif
#if !defined(_TRACE_MODULE_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_MODULE_H
#include <linux/tracepoint.h>
#ifdef CONFIG_MODULES
struct module;
#define show_module_flags(flags) __print_flags(flags, "", \
{ (1UL << TAINT_PROPRIETARY_MODULE), "P" }, \
{ (1UL << TAINT_OOT_MODULE), "O" }, \
{ (1UL << TAINT_FORCED_MODULE), "F" }, \
{ (1UL << TAINT_CRAP), "C" }, \
{ (1UL << TAINT_UNSIGNED_MODULE), "X" })
TRACE_EVENT(module_load,
TP_PROTO(struct module *mod),
TP_ARGS(mod),
TP_STRUCT__entry(
__field( unsigned int, taints )
__string( name, mod->name )
),
TP_fast_assign(
__entry->taints = mod->taints;
__assign_str(name, mod->name);
),
TP_printk("%s %s", __get_str(name), show_module_flags(__entry->taints))
);
TRACE_EVENT(module_free,
TP_PROTO(struct module *mod),
TP_ARGS(mod),
TP_STRUCT__entry(
__string( name, mod->name )
),
TP_fast_assign(
__assign_str(name, mod->name);
),
TP_printk("%s", __get_str(name))
);
#ifdef CONFIG_MODULE_UNLOAD
/* trace_module_get/put are only used if CONFIG_MODULE_UNLOAD is defined */
DECLARE_EVENT_CLASS(module_refcnt,
TP_PROTO(struct module *mod, unsigned long ip),
TP_ARGS(mod, ip),
TP_STRUCT__entry(
__field( unsigned long, ip )
__field( int, refcnt )
__string( name, mod->name )
),
TP_fast_assign(
__entry->ip = ip;
__entry->refcnt = __this_cpu_read(mod->refptr->incs) + __this_cpu_read(mod->refptr->decs);
__assign_str(name, mod->name);
),
TP_printk("%s call_site=%pf refcnt=%d",
__get_str(name), (void *)__entry->ip, __entry->refcnt)
);
DEFINE_EVENT(module_refcnt, module_get,
TP_PROTO(struct module *mod, unsigned long ip),
TP_ARGS(mod, ip)
);
DEFINE_EVENT(module_refcnt, module_put,
TP_PROTO(struct module *mod, unsigned long ip),
TP_ARGS(mod, ip)
);
#endif /* CONFIG_MODULE_UNLOAD */
TRACE_EVENT(module_request,
TP_PROTO(char *name, bool wait, unsigned long ip),
TP_ARGS(name, wait, ip),
TP_STRUCT__entry(
__field( unsigned long, ip )
__field( bool, wait )
__string( name, name )
),
TP_fast_assign(
__entry->ip = ip;
__entry->wait = wait;
__assign_str(name, name);
),
TP_printk("%s wait=%d call_site=%pf",
__get_str(name), (int)__entry->wait, (void *)__entry->ip)
);
#endif /* CONFIG_MODULES */
#endif /* _TRACE_MODULE_H */
/* This part must be outside protection */
#include <trace/define_trace.h>