shadps4-emu/archived-ext-libusb
1
0
Fork 0
mirror of https://github.com/shadps4-emu/ext-libusb.git synced 2026-01-31 00:55:21 +01:00
Code Issues Packages Projects Releases Wiki Activity

core: Avoid possible data race in log_v()

Browse Source 
The logging function usbi_dbg() called from udev event thread needs to
safely get the log level of the default context or the fallback context.
This is not trivial because udev thread may log events while contexts
are created and destroyed. Locking the default context mutex is not an
option because usbi_dbg() may be called from code that already holds
this mutex, which would lead to a deadlock. The solution implemented in
this commit is to maintain a separate atomic global variable with the
default debug level.

The issue was found with ThreadSanitizer, although no actual bugs have
been observed.

libusb_set_debug() was also changed to call libusb_set_option() instead
of doing its own option setting which had fewer checks.

Closes #1332
This commit is contained in:
SomeAlphabetGuy
2023-10-27 23:57:54 +00:00
committed by Tormod Volden
parent dfed0d1695
commit 9de0fefb31
2 changed files with 23 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
libusb/core.c
View File

@@ -43,6 +43,9 @@ static libusb_log_cb log_handler;
struct libusb_context *usbi_default_context;
struct libusb_context *usbi_fallback_context;
static int default_context_refcnt;
#if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
static usbi_atomic_t default_debug_level = -1;
#endif
static usbi_mutex_static_t default_context_lock = USBI_MUTEX_INITIALIZER;
static struct usbi_option default_context_options[LIBUSB_OPTION_MAX];
@@ -2207,16 +2210,7 @@ int API_EXPORTED libusb_set_auto_detach_kernel_driver(
*/
void API_EXPORTED libusb_set_debug(libusb_context *ctx, int level)
{
#if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
ctx = usbi_get_context(ctx);
if (!ctx->debug_fixed) {
level = CLAMP(level, LIBUSB_LOG_LEVEL_NONE, LIBUSB_LOG_LEVEL_DEBUG);
ctx->debug = (enum libusb_log_level)level;
}
#else
UNUSED(ctx);
UNUSED(level);
#endif
libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, level);
}
static void libusb_set_log_cb_internal(libusb_context *ctx, libusb_log_cb cb,
@@ -2300,6 +2294,7 @@ int API_EXPORTEDV libusb_set_option(libusb_context *ctx,
int arg = 0, r = LIBUSB_SUCCESS;
libusb_log_cb log_cb = NULL;
va_list ap;
int is_default_context = (NULL == ctx);
va_start(ap, option);
@@ -2343,8 +2338,11 @@ int API_EXPORTEDV libusb_set_option(libusb_context *ctx,
switch (option) {
case LIBUSB_OPTION_LOG_LEVEL:
#if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
if (!ctx->debug_fixed)
if (!ctx->debug_fixed) {
ctx->debug = (enum libusb_log_level)arg;
if (is_default_context)
usbi_atomic_store(&default_debug_level, CLAMP(arg, LIBUSB_LOG_LEVEL_NONE, LIBUSB_LOG_LEVEL_DEBUG));
}
#endif
break;
@@ -2503,6 +2501,9 @@ int API_EXPORTED libusb_init_context(libusb_context **ctx, const struct libusb_i
if (!ctx) {
usbi_default_context = _ctx;
default_context_refcnt = 1;
#if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
usbi_atomic_store(&default_debug_level, _ctx->debug);
#endif
usbi_dbg(usbi_default_context, "created default context");
}
@@ -2530,6 +2531,10 @@ int API_EXPORTED libusb_init_context(libusb_context **ctx, const struct libusb_i
*ctx = _ctx;
if (!usbi_fallback_context) {
#if defined(ENABLE_LOGGING) && !defined(ENABLE_DEBUG_LOGGING)
if (usbi_atomic_load(&default_debug_level) == -1)
usbi_atomic_store(&default_debug_level, _ctx->debug);
#endif
usbi_fallback_context = _ctx;
usbi_dbg(usbi_fallback_context, "installing new context as implicit default");
}
@@ -2756,13 +2761,14 @@ static void log_v(struct libusb_context *ctx, enum libusb_log_level level,
UNUSED(ctx);
#else
enum libusb_log_level ctx_level;
long default_level_value;
ctx = ctx ? ctx : usbi_default_context;
ctx = ctx ? ctx : usbi_fallback_context;
if (ctx)
if (ctx) {
ctx_level = ctx->debug;
else
ctx_level = get_env_debug_level();
} else {
default_level_value = usbi_atomic_load(&default_debug_level);
ctx_level = default_level_value < 0 ? get_env_debug_level() : (enum libusb_log_level)default_level_value;
}
if (ctx_level < level)
return;

2
libusb/version_nano.h
View File

@@ -1 +1 @@
#define LIBUSB_NANO 11825
#define LIBUSB_NANO 11826