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Have the DEADLOCK_AVOIDANCE macro warn when an unlock fails, to help catch potentially large software bugs.

Browse Source 
(closes issue #17407)
 Reported by: pdf
 Patches: 
       20100527__issue17407.diff.txt uploaded by tilghman (license 14)
 
Review: https://reviewboard.asterisk.org/r/751/


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@273793 65c4cc65-6c06-0410-ace0-fbb531ad65f3
1.4
Tilghman Lesher 15 years ago
parent 01af082769
commit 14550f93d0
9 changed files with 25652 additions and 12372 deletions
Show Stats Download Patch File Download Diff File

7
channels/chan_agent.c
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@ -707,7 +707,12 @@ static int agent_indicate(struct ast_channel *ast, int condition, const void *da
ast_mutex_lock(&p->lock);
if (p->chan && !ast_check_hangup(p->chan)) {
while (ast_channel_trylock(p->chan)) {
ast_channel_unlock(ast);
int res;
if ((res = ast_channel_unlock(ast))) {
ast_log(LOG_ERROR, "chan_agent bug! Channel was not locked upon entry to agent_indicate: %s\n", strerror(res));
ast_mutex_unlock(&p->lock);
return -1;
}
usleep(1);
ast_channel_lock(ast);
}

6
channels/chan_dahdi.c
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@ -4399,8 +4399,12 @@ static struct ast_frame *dahdi_handle_event(struct ast_channel *ast)
/* Here we have to retain the lock on both the main channel, the 3-way channel, and
the private structure -- not especially easy or clean */
while (p->subs[SUB_THREEWAY].owner && ast_mutex_trylock(&p->subs[SUB_THREEWAY].owner->lock)) {
int res;
/* Yuck, didn't get the lock on the 3-way, gotta release everything and re-grab! */
ast_mutex_unlock(&p->lock);
if ((res = ast_mutex_unlock(&p->lock))) {
ast_log(LOG_ERROR, "chan_dahdi bug! '&p->lock' was not locked upon entry to 'dahdi_handle_dtmfup': %s\n", strerror(res));
return NULL;
}
DEADLOCK_AVOIDANCE(&ast->lock);
/* We can grab ast and p in that order, without worry. We should make sure
nothing seriously bad has happened though like some sort of bizarre double

6
channels/chan_h323.c
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@ -313,10 +313,8 @@ static int oh323_simulate_dtmf_end(const void *data)
if (pvt) {
ast_mutex_lock(&pvt->lock);
/* Don't hold pvt lock while trying to lock the channel */
while(pvt->owner && ast_channel_trylock(pvt->owner)) {
ast_mutex_unlock(&pvt->lock);
usleep(1);
ast_mutex_lock(&pvt->lock);
while (pvt->owner && ast_channel_trylock(pvt->owner)) {
DEADLOCK_AVOIDANCE(&pvt->lock);
}
if (pvt->owner) {

12
channels/chan_local.c
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@ -183,10 +183,18 @@ static int local_queue_frame(struct local_pvt *p, int isoutbound, struct ast_fra
/* Ensure that we have both channels locked */
while (other && ast_channel_trylock(other)) {
ast_mutex_unlock(&p->lock);
int res;
if ((res = ast_mutex_unlock(&p->lock))) {
ast_log(LOG_ERROR, "chan_local bug! '&p->lock' was not locked when entering local_queue_frame! (%s)\n", strerror(res));
return -1;
}
if (us && us_locked) {
do {
ast_channel_unlock(us);
if (ast_channel_unlock(us)) {
ast_log(LOG_ERROR, "chan_local bug! Our channel was not locked, yet arguments indicated that it was!!\n");
ast_mutex_lock(&p->lock);
return -1;
}
usleep(1);
ast_channel_lock(us);
} while (ast_mutex_trylock(&p->lock));

37896
configure vendored
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File diff suppressed because it is too large Load Diff

1
configure.ac
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@ -450,6 +450,7 @@ AST_GCC_ATTRIBUTE(const)
AST_GCC_ATTRIBUTE(unused)
AST_GCC_ATTRIBUTE(always_inline)
AST_GCC_ATTRIBUTE(deprecated)
AST_GCC_ATTRIBUTE(warn_unused_result)
AC_MSG_CHECKING(for -ffunction-sections support)
saved_CFLAGS="${CFLAGS}"

55
include/asterisk/autoconfig.h.in
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@ -66,6 +66,10 @@
/* Define to 1 if your GCC C compiler supports the 'unused' attribute. */
#undef HAVE_ATTRIBUTE_unused
/* Define to 1 if your GCC C compiler supports the 'warn_unused_result'
attribute. */
#undef HAVE_ATTRIBUTE_warn_unused_result
/* Define to 1 if you have the `bzero' function. */
#undef HAVE_BZERO
@ -467,7 +471,7 @@
/* Define to 1 if you have the `strtoq' function. */
#undef HAVE_STRTOQ
/* Define to 1 if `st_blksize' is a member of `struct stat'. */
/* Define to 1 if `st_blksize' is member of `struct stat'. */
#undef HAVE_STRUCT_STAT_ST_BLKSIZE
/* Define to 1 if you have the mISDN Supplemental Services library. */
@ -656,12 +660,12 @@
/* Define to the one symbol short name of this package. */
#undef PACKAGE_TARNAME
/* Define to the home page for this package. */
#undef PACKAGE_URL
/* Define to the version of this package. */
#undef PACKAGE_VERSION
/* Define to 1 if the C compiler supports function prototypes. */
#undef PROTOTYPES
/* Define to necessary symbol if this constant uses a non-standard name on
your system. */
#undef PTHREAD_CREATE_JOINABLE
@ -681,6 +685,11 @@
/* Define to the type of arg 5 for `select'. */
#undef SELECT_TYPE_ARG5
/* Define to 1 if the `setvbuf' function takes the buffering type as its
second argument and the buffer pointer as the third, as on System V before
release 3. */
#undef SETVBUF_REVERSED
/* The size of `int', as computed by sizeof. */
#undef SIZEOF_INT
@ -701,30 +710,20 @@
/* Define to 1 if your <sys/time.h> declares `struct tm'. */
#undef TM_IN_SYS_TIME
/* Enable extensions on AIX 3, Interix. */
/* Define to 1 if on AIX 3.
System headers sometimes define this.
We just want to avoid a redefinition error message. */
#ifndef _ALL_SOURCE
# undef _ALL_SOURCE
#endif
/* Number of bits in a file offset, on hosts where this is settable. */
#undef _FILE_OFFSET_BITS
/* Enable GNU extensions on systems that have them. */
#ifndef _GNU_SOURCE
# undef _GNU_SOURCE
#endif
/* Enable threading extensions on Solaris. */
#ifndef _POSIX_PTHREAD_SEMANTICS
# undef _POSIX_PTHREAD_SEMANTICS
#endif
/* Enable extensions on HP NonStop. */
#ifndef _TANDEM_SOURCE
# undef _TANDEM_SOURCE
#endif
/* Enable general extensions on Solaris. */
#ifndef __EXTENSIONS__
# undef __EXTENSIONS__
#endif
/* Number of bits in a file offset, on hosts where this is settable. */
#undef _FILE_OFFSET_BITS
/* Define to 1 to make fseeko visible on some hosts (e.g. glibc 2.2). */
#undef _LARGEFILE_SOURCE
@ -742,6 +741,20 @@
/* Define to 1 if you need to in order for `stat' and other things to work. */
#undef _POSIX_SOURCE
/* Enable extensions on Solaris. */
#ifndef __EXTENSIONS__
# undef __EXTENSIONS__
#endif
#ifndef _POSIX_PTHREAD_SEMANTICS
# undef _POSIX_PTHREAD_SEMANTICS
#endif
#ifndef _TANDEM_SOURCE
# undef _TANDEM_SOURCE
#endif
/* Define like PROTOTYPES; this can be used by system headers. */
#undef __PROTOTYPES
/* Define to empty if `const' does not conform to ANSI C. */
#undef const

6
include/asterisk/compiler.h
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@ -59,4 +59,10 @@
#define attribute_deprecated
#endif
#ifdef HAVE_ATTRIBUTE_warn_unused_result
#define attribute_warn_unused_result __attribute__((warn_unused_result))
#else
#define attribute_warn_unused_result
#endif
#endif /* _ASTERISK_COMPILER_H */

35
include/asterisk/lock.h
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@ -55,6 +55,7 @@
#include "asterisk/time.h"
#endif
#include "asterisk/logger.h"
#include "asterisk/compiler.h"
/* internal macro to profile mutexes. Only computes the delay on
* non-blocking calls.
@ -204,13 +205,21 @@ int ast_find_lock_info(void *lock_addr, char *filename, size_t filename_size, in
do { \
char __filename[80], __func[80], __mutex_name[80]; \
int __lineno; \
int __res = ast_find_lock_info(lock, __filename, sizeof(__filename), &__lineno, __func, sizeof(__func), __mutex_name, sizeof(__mutex_name)); \
ast_mutex_unlock(lock); \
int __res2, __res = ast_find_lock_info(lock, __filename, sizeof(__filename), &__lineno, __func, sizeof(__func), __mutex_name, sizeof(__mutex_name)); \
__res2 = ast_mutex_unlock(lock); \
usleep(1); \
if (__res < 0) { /* Shouldn't ever happen, but just in case... */ \
ast_mutex_lock(lock); \
if (__res2 == 0) { \
ast_mutex_lock(lock); \
} else { \
ast_log(LOG_WARNING, "Could not unlock mutex '%s': %s and no lock info found! I will NOT try to relock.\n", #lock, strerror(__res2)); \
} \
} else { \
__ast_pthread_mutex_lock(__filename, __lineno, __func, __mutex_name, lock); \
if (__res2 == 0) { \
__ast_pthread_mutex_lock(__filename, __lineno, __func, __mutex_name, lock); \
} else { \
ast_log(LOG_WARNING, "Could not unlock mutex '%s': %s. {{{Originally locked at %s line %d: (%s) '%s'}}} I will NOT try to relock.\n", #lock, strerror(__res2), __filename, __lineno, __func, __mutex_name); \
} \
} \
} while (0)
@ -432,6 +441,8 @@ static inline int __ast_pthread_mutex_lock(const char *filename, int lineno, con
return res;
}
static inline int __ast_pthread_mutex_trylock(const char *filename, int lineno, const char *func,
const char* mutex_name, ast_mutex_t *t) attribute_warn_unused_result;
static inline int __ast_pthread_mutex_trylock(const char *filename, int lineno, const char *func,
const char* mutex_name, ast_mutex_t *t)
{
@ -712,9 +723,15 @@ static inline int __ast_cond_timedwait(const char *filename, int lineno, const c
#else /* !DEBUG_THREADS */
#define DEADLOCK_AVOIDANCE(lock) \
ast_mutex_unlock(lock); \
usleep(1); \
ast_mutex_lock(lock);
do { \
int __res; \
if (!(__res = ast_mutex_unlock(lock))) { \
usleep(1); \
ast_mutex_lock(lock); \
} else { \
ast_log(LOG_WARNING, "Failed to unlock mutex '%s' (%s). I will NOT try to relock. {{{ THIS IS A BUG. }}}\n", #lock, strerror(__res)); \
} \
} while (0)
typedef pthread_mutex_t ast_mutex_t;
@ -1367,7 +1384,7 @@ AST_INLINE_API(int ast_atomic_dec_and_test(volatile int *p),
#define ast_channel_lock(x) ast_mutex_lock(&x->lock)
/*! \brief Unlock a channel. If DEBUG_CHANNEL_LOCKS is defined
in the Makefile, print relevant output for debugging */
#define ast_channel_unlock(x) ast_mutex_unlock(&x->lock)
#define ast_channel_unlock(x) ast_mutex_unlock(&x->lock)
/*! \brief Try locking a channel. If DEBUG_CHANNEL_LOCKS is defined
in the Makefile, print relevant output for debugging */
#define ast_channel_trylock(x) ast_mutex_trylock(&x->lock)
@ -1389,7 +1406,7 @@ int __ast_channel_unlock(struct ast_channel *chan, const char *file, int lineno,
#define ast_channel_trylock(a) __ast_channel_trylock(a, __FILE__, __LINE__, __PRETTY_FUNCTION__)
/*! \brief Lock AST channel (and print debugging output)
\note You need to enable DEBUG_CHANNEL_LOCKS for this function */
int __ast_channel_trylock(struct ast_channel *chan, const char *file, int lineno, const char *func);
int __ast_channel_trylock(struct ast_channel *chan, const char *file, int lineno, const char *func) attribute_warn_unused_result;
#endif
#endif /* _ASTERISK_LOCK_H */

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