Re: Re: [PATCH] tools/liblockdep: change current_obj from thread-local storage to non thread-local storage
> On 04/23/2015 02:55 AM, Eunbong Song wrote: >> current_obj is declared as a thread-local storage. >> This prevent to detect locking problem between multiple threads because >> each thread has it's own current_obj. liblockdep can only detect locking >> problem in a single >> thread. However, pthread_mutex_xxx, pthread_rwlock_xxx functions are mainly >> used for synchro >> nization of data between multiple threads. >> This patch changes current_obj to non thread-local storage. and >> current_obj.pid is getting >> from getpid system call. > um... It always worked with threads: I am sorry for confusing you. I did some mistake with my test. Thanks for your reply. > $ cat tests/ABBA_threads.c > #include > #include "common.h" > pthread_mutex_t a, b; > void *thread_a(void *arg) > { > LOCK_UNLOCK_2(a, b); > return NULL; > } void *thread_b(void *arg) { LOCK_UNLOCK_2(b, a); return NULL; } void main(void) { pthread_t ta, tb; pthread_mutex_init(&a, NULL); pthread_mutex_init(&b, NULL); pthread_create(&ta, NULL, thread_a, NULL); pthread_create(&tb, NULL, thread_b, NULL); pthread_join(ta, NULL); pthread_join(tb, NULL); } $ tests/ABBA_threads == [ INFO: possible circular locking dependency detected ] liblockdep 4.0.0 --- ABBA_threads/12101 is trying to acquire lock: (0x10bb700){..}, at: tests/ABBA_threads() [0x401333] but task is already holding lock: (0x10bb680){..}, at: tests/ABBA_threads() [0x401333] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (0x10bb680){..}: tests/ABBA_threads[0x4019d3] tests/ABBA_threads[0x4036f6] tests/ABBA_threads[0x4039c2] tests/ABBA_threads[0x403fde] tests/ABBA_threads[0x404aa7] tests/ABBA_threads[0x405250] tests/ABBA_threads[0x4053d3] tests/ABBA_threads[0x4055cd] tests/ABBA_threads[0x40135d] tests/ABBA_threads[0x401395] /lib/x86_64-linux-gnu/libpthread.so.0(+0x80a5)[0x7f8e6e1dc0a5] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f8e6df09cfd] -> #0 (0x10bb700){..}: tests/ABBA_threads[0x4019d3] tests/ABBA_threads[0x402f51] tests/ABBA_threads[0x4035c4] tests/ABBA_threads[0x4039c2] tests/ABBA_threads[0x403fde] tests/ABBA_threads[0x404aa7] tests/ABBA_threads[0x405565] tests/ABBA_threads(pthread_mutex_lock+0x51)[0x4063fd] tests/ABBA_threads[0x401333] tests/ABBA_threads[0x4013c6] /lib/x86_64-linux-gnu/libpthread.so.0(+0x80a5)[0x7f8e6e1dc0a5] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f8e6df09cfd] other info that might help us debug this: Possible unsafe locking scenario: CPU0CPU1 lock(0x10bb680); lock(0x10bb700); lock(0x10bb680); lock(0x10bb700); *** DEADLOCK *** 2 locks held by ABBA_threads/12101: #0: (&b){..}, at: tests/ABBA_threads() [0x4013bc] #1: (0x10bb680){..}, at: tests/ABBA_threads() [0x401333] stack backtrace: tests/ABBA_threads[0x4016dd] tests/ABBA_threads[0x40300b] tests/ABBA_threads[0x4035c4] tests/ABBA_threads[0x4039c2] tests/ABBA_threads[0x403fde] tests/ABBA_threads[0x404aa7] tests/ABBA_threads[0x405565] tests/ABBA_threads(pthread_mutex_lock+0x51)[0x4063fd] tests/ABBA_threads[0x401333] tests/ABBA_threads[0x4013c6] /lib/x86_64-linux-gnu/libpthread.so.0(+0x80a5)[0x7f8e6e1dc0a5] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f8e6df09cfd] Thanks, Sasha
Re: [PATCH] tools/liblockdep: change current_obj from thread-local storage to non thread-local storage
On 04/23/2015 02:55 AM, Eunbong Song wrote: > current_obj is declared as a thread-local storage. > This prevent to detect locking problem between multiple threads because > each thread has it's own current_obj. liblockdep can only detect locking > problem in a single > thread. However, pthread_mutex_xxx, pthread_rwlock_xxx functions are mainly > used for synchro > nization of data between multiple threads. > This patch changes current_obj to non thread-local storage. and > current_obj.pid is getting > from getpid system call. um... It always worked with threads: $ cat tests/ABBA_threads.c #include #include "common.h" pthread_mutex_t a, b; void *thread_a(void *arg) { LOCK_UNLOCK_2(a, b); return NULL; } void *thread_b(void *arg) { LOCK_UNLOCK_2(b, a); return NULL; } void main(void) { pthread_t ta, tb; pthread_mutex_init(&a, NULL); pthread_mutex_init(&b, NULL); pthread_create(&ta, NULL, thread_a, NULL); pthread_create(&tb, NULL, thread_b, NULL); pthread_join(ta, NULL); pthread_join(tb, NULL); } $ tests/ABBA_threads == [ INFO: possible circular locking dependency detected ] liblockdep 4.0.0 --- ABBA_threads/12101 is trying to acquire lock: (0x10bb700){..}, at: tests/ABBA_threads() [0x401333] but task is already holding lock: (0x10bb680){..}, at: tests/ABBA_threads() [0x401333] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (0x10bb680){..}: tests/ABBA_threads[0x4019d3] tests/ABBA_threads[0x4036f6] tests/ABBA_threads[0x4039c2] tests/ABBA_threads[0x403fde] tests/ABBA_threads[0x404aa7] tests/ABBA_threads[0x405250] tests/ABBA_threads[0x4053d3] tests/ABBA_threads[0x4055cd] tests/ABBA_threads[0x40135d] tests/ABBA_threads[0x401395] /lib/x86_64-linux-gnu/libpthread.so.0(+0x80a5)[0x7f8e6e1dc0a5] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f8e6df09cfd] -> #0 (0x10bb700){..}: tests/ABBA_threads[0x4019d3] tests/ABBA_threads[0x402f51] tests/ABBA_threads[0x4035c4] tests/ABBA_threads[0x4039c2] tests/ABBA_threads[0x403fde] tests/ABBA_threads[0x404aa7] tests/ABBA_threads[0x405565] tests/ABBA_threads(pthread_mutex_lock+0x51)[0x4063fd] tests/ABBA_threads[0x401333] tests/ABBA_threads[0x4013c6] /lib/x86_64-linux-gnu/libpthread.so.0(+0x80a5)[0x7f8e6e1dc0a5] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f8e6df09cfd] other info that might help us debug this: Possible unsafe locking scenario: CPU0CPU1 lock(0x10bb680); lock(0x10bb700); lock(0x10bb680); lock(0x10bb700); *** DEADLOCK *** 2 locks held by ABBA_threads/12101: #0: (&b){..}, at: tests/ABBA_threads() [0x4013bc] #1: (0x10bb680){..}, at: tests/ABBA_threads() [0x401333] stack backtrace: tests/ABBA_threads[0x4016dd] tests/ABBA_threads[0x40300b] tests/ABBA_threads[0x4035c4] tests/ABBA_threads[0x4039c2] tests/ABBA_threads[0x403fde] tests/ABBA_threads[0x404aa7] tests/ABBA_threads[0x405565] tests/ABBA_threads(pthread_mutex_lock+0x51)[0x4063fd] tests/ABBA_threads[0x401333] tests/ABBA_threads[0x4013c6] /lib/x86_64-linux-gnu/libpthread.so.0(+0x80a5)[0x7f8e6e1dc0a5] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f8e6df09cfd] Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] tools/liblockdep: change current_obj from thread-local storage to non thread-local storage
current_obj is declared as a thread-local storage. This prevent to detect locking problem between multiple threads because each thread has it's own current_obj. liblockdep can only detect locking problem in a single thread. However, pthread_mutex_xxx, pthread_rwlock_xxx functions are mainly used for synchro nization of data between multiple threads. This patch changes current_obj to non thread-local storage. and current_obj.pid is getting from getpid system call. Signed-off-by: Eunbong Song --- tools/lib/lockdep/common.c |4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/lib/lockdep/common.c b/tools/lib/lockdep/common.c index 8ef602f..6b9a6eb 100644 --- a/tools/lib/lockdep/common.c +++ b/tools/lib/lockdep/common.c @@ -5,7 +5,7 @@ #include #include -static __thread struct task_struct current_obj; +static struct task_struct current_obj; /* lockdep wants these */ bool debug_locks = true; @@ -26,7 +26,7 @@ struct task_struct *__curr(void) if (current_obj.pid == 0) { /* Makes lockdep output pretty */ prctl(PR_GET_NAME, current_obj.comm); - current_obj.pid = syscall(__NR_gettid); + current_obj.pid = syscall(__NR_getpid); } return ¤t_obj; -- 1.7.0.1 N떑꿩�r툤y鉉싕b쾊Ф푤v�^�)頻{.n�+돴쪐{콗喩zX㎍썳變}찠꼿쟺�&j:+v돣�쳭喩zZ+�+zf"톒쉱�~넮녬i鎬z�췿ⅱ�?솳鈺�&�)刪f뷌^j푹y쬶끷@A첺뛴 0띠h��뭝