| Message ID | 20210715102813.106843-1-aleksei.kodanev@bell-sw.com |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | crypto/af_alg02: use pthread_tryjoin_np() instead of pthread_kill() | expand |
Hi Alexey, On Thu, Jul 15, 2021 at 6:29 PM Alexey Kodanev <aleksei.kodanev@bell-sw.com> wrote: > musl doesn't return ESRCH for pthread_kill() if thread id is not found. > > POSIX only recommends to return ESRCH, and also says that pthread_kill() > produces undefined behavior if tid lifetime has ended [1]. > > [1]: https://man7.org/linux/man-pages/man3/pthread_kill.3.html > > Signed-off-by: Alexey Kodanev <aleksei.kodanev@bell-sw.com> > --- > testcases/kernel/crypto/af_alg02.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/testcases/kernel/crypto/af_alg02.c > b/testcases/kernel/crypto/af_alg02.c > index 31d30777c..0f5793c16 100644 > --- a/testcases/kernel/crypto/af_alg02.c > +++ b/testcases/kernel/crypto/af_alg02.c > @@ -60,7 +60,7 @@ static void run(void) > > TST_CHECKPOINT_WAIT(0); > > - while (pthread_kill(thr, 0) != ESRCH) { > + while (pthread_tryjoin_np(thr, NULL) == EBUSY) { > I'm not sure if safe enough to use because it is nonstandard GNU extensions and the "_np" means nonportable. Maybe another workaround is to define a volatile flag 'thread_complete', initialize it to '0' when thread_B starts and reset to '1' while exit, and just do a value check in the while loop of thread_A should acquire thread_B status. Is this way a bit better?
> Hi Alexey, > On Thu, Jul 15, 2021 at 6:29 PM Alexey Kodanev <aleksei.kodanev@bell-sw.com> > wrote: > > musl doesn't return ESRCH for pthread_kill() if thread id is not found. Maybe ask on MUSL mailing list? > > POSIX only recommends to return ESRCH, and also says that pthread_kill() > > produces undefined behavior if tid lifetime has ended [1]. > > [1]: https://man7.org/linux/man-pages/man3/pthread_kill.3.html > > Signed-off-by: Alexey Kodanev <aleksei.kodanev@bell-sw.com> > > --- > > testcases/kernel/crypto/af_alg02.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/testcases/kernel/crypto/af_alg02.c > > b/testcases/kernel/crypto/af_alg02.c > > index 31d30777c..0f5793c16 100644 > > --- a/testcases/kernel/crypto/af_alg02.c > > +++ b/testcases/kernel/crypto/af_alg02.c > > @@ -60,7 +60,7 @@ static void run(void) > > TST_CHECKPOINT_WAIT(0); > > - while (pthread_kill(thr, 0) != ESRCH) { > > + while (pthread_tryjoin_np(thr, NULL) == EBUSY) { > I'm not sure if safe enough to use because it is nonstandard GNU extensions > and the "_np" means nonportable. Others please double check, but pthread_tryjoin_np() seems to be in uclibc-ng and musl (+ of course in glibc). It's only missing in bionic (it looks like people would like to have it [1]). > Maybe another workaround is to define a volatile flag 'thread_complete', > initialize it to '0' when thread_B starts and reset to '1' while exit, and > just > do a value check in the while loop of thread_A should acquire thread_B > status. > Is this way a bit better? Sounds as reasonable workaround for me. Kind regards, Petr [1] https://github.com/kito-cheng/android-checkpoint/blob/master/bionic/0003-bionic-Implement-pthread_tryjoin_np.patch
Hi Li, On 16.07.2021 10:06, Li Wang wrote: > Hi Alexey, > > On Thu, Jul 15, 2021 at 6:29 PM Alexey Kodanev <aleksei.kodanev@bell-sw.com <mailto:aleksei.kodanev@bell-sw.com>> wrote: > > musl doesn't return ESRCH for pthread_kill() if thread id is not found. > > POSIX only recommends to return ESRCH, and also says that pthread_kill() > produces undefined behavior if tid lifetime has ended [1]. > > [1]: https://man7.org/linux/man-pages/man3/pthread_kill.3.html <https://man7.org/linux/man-pages/man3/pthread_kill.3.html> > > Signed-off-by: Alexey Kodanev <aleksei.kodanev@bell-sw.com <mailto:aleksei.kodanev@bell-sw.com>> > --- > testcases/kernel/crypto/af_alg02.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/testcases/kernel/crypto/af_alg02.c b/testcases/kernel/crypto/af_alg02.c > index 31d30777c..0f5793c16 100644 > --- a/testcases/kernel/crypto/af_alg02.c > +++ b/testcases/kernel/crypto/af_alg02.c > @@ -60,7 +60,7 @@ static void run(void) > > TST_CHECKPOINT_WAIT(0); > > - while (pthread_kill(thr, 0) != ESRCH) { > + while (pthread_tryjoin_np(thr, NULL) == EBUSY) { > > > I'm not sure ifsafeenough to use because it is nonstandard GNU extensions > and the "_np" means nonportable. > > Maybe another workaround is to define a volatile flag 'thread_complete', > initialize it to '0' when thread_B starts and reset to '1' while exit, and just > do a value check in the while loop of thread_A should acquire thread_B status. > Is this way a bit better? OK, why not, so something like this: diff --git a/testcases/kernel/crypto/af_alg02.c b/testcases/kernel/crypto/af_alg02.c index 0f5793c16..1fe0f3bf0 100644 --- a/testcases/kernel/crypto/af_alg02.c +++ b/testcases/kernel/crypto/af_alg02.c @@ -18,11 +18,13 @@ #include "tst_test.h" #include "tst_af_alg.h" #include "tst_safe_pthread.h" +#include "tst_atomic.h" #include <pthread.h> #include <errno.h> #define SALSA20_IV_SIZE 8 #define SALSA20_MIN_KEY_SIZE 16 +static int completed; static void *verify_encrypt(void *arg) { @@ -48,6 +50,8 @@ static void *verify_encrypt(void *arg) tst_res(TPASS, "Successfully \"encrypted\" an empty message"); else tst_res(TFAIL, "read() didn't return 0"); + + tst_atomic_store(1, &completed); return arg; } @@ -60,7 +64,7 @@ static void run(void) TST_CHECKPOINT_WAIT(0); - while (pthread_tryjoin_np(thr, NULL) == EBUSY) { + while (!tst_atomic_load(&completed)) { if (tst_timeout_remaining() <= 10) { pthread_cancel(thr); tst_brk(TBROK,
Hi Petr, On 16.07.2021 12:51, Petr Vorel wrote: >> Hi Alexey, > >> On Thu, Jul 15, 2021 at 6:29 PM Alexey Kodanev <aleksei.kodanev@bell-sw.com> >> wrote: > >>> musl doesn't return ESRCH for pthread_kill() if thread id is not found. > Maybe ask on MUSL mailing list? It's not a musl issue, but I was going to send a few improvements (including this) when time permits. > >>> POSIX only recommends to return ESRCH, and also says that pthread_kill() >>> produces undefined behavior if tid lifetime has ended [1]. > >>> [1]: https://man7.org/linux/man-pages/man3/pthread_kill.3.html > >>> Signed-off-by: Alexey Kodanev <aleksei.kodanev@bell-sw.com> >>> --- >>> testcases/kernel/crypto/af_alg02.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>> diff --git a/testcases/kernel/crypto/af_alg02.c >>> b/testcases/kernel/crypto/af_alg02.c >>> index 31d30777c..0f5793c16 100644 >>> --- a/testcases/kernel/crypto/af_alg02.c >>> +++ b/testcases/kernel/crypto/af_alg02.c >>> @@ -60,7 +60,7 @@ static void run(void) > >>> TST_CHECKPOINT_WAIT(0); > >>> - while (pthread_kill(thr, 0) != ESRCH) { >>> + while (pthread_tryjoin_np(thr, NULL) == EBUSY) { > > >> I'm not sure if safe enough to use because it is nonstandard GNU extensions >> and the "_np" means nonportable. > Others please double check, but pthread_tryjoin_np() seems to be in uclibc-ng > and musl (+ of course in glibc). It's only missing in bionic (it looks like > people would like to have it [1]). > Yeah, I think it's quite useful. >> Maybe another workaround is to define a volatile flag 'thread_complete', >> initialize it to '0' when thread_B starts and reset to '1' while exit, and >> just >> do a value check in the while loop of thread_A should acquire thread_B >> status. >> Is this way a bit better? > Sounds as reasonable workaround for me. > > Kind regards, > Petr > > [1] https://github.com/kito-cheng/android-checkpoint/blob/master/bionic/0003-bionic-Implement-pthread_tryjoin_np.patch >
Alexey Kodanev <aleksei.kodanev@bell-sw.com> wrote: > > > Maybe another workaround is to define a volatile flag 'thread_complete', > > initialize it to '0' when thread_B starts and reset to '1' while exit, > and just > > do a value check in the while loop of thread_A should acquire thread_B > status. > > Is this way a bit better? > > OK, why not, so something like this: > > diff --git a/testcases/kernel/crypto/af_alg02.c > b/testcases/kernel/crypto/af_alg02.c > index 0f5793c16..1fe0f3bf0 100644 > --- a/testcases/kernel/crypto/af_alg02.c > +++ b/testcases/kernel/crypto/af_alg02.c > @@ -18,11 +18,13 @@ > #include "tst_test.h" > #include "tst_af_alg.h" > #include "tst_safe_pthread.h" > +#include "tst_atomic.h" > #include <pthread.h> > #include <errno.h> > > #define SALSA20_IV_SIZE 8 > #define SALSA20_MIN_KEY_SIZE 16 > +static int completed; > > static void *verify_encrypt(void *arg) > { > @@ -48,6 +50,8 @@ static void *verify_encrypt(void *arg) > tst_res(TPASS, "Successfully \"encrypted\" an empty > message"); > else > tst_res(TFAIL, "read() didn't return 0"); > + > + tst_atomic_store(1, &completed); > return arg; > } > > @@ -60,7 +64,7 @@ static void run(void) > > TST_CHECKPOINT_WAIT(0); > > - while (pthread_tryjoin_np(thr, NULL) == EBUSY) { > + while (!tst_atomic_load(&completed)) { > +1 The atomic method is quite awesome!
> #define SALSA20_IV_SIZE 8 >> #define SALSA20_MIN_KEY_SIZE 16 >> +static int completed; >> >> static void *verify_encrypt(void *arg) >> { >> > But we still need to initialize '0' at the start of thread_B, in case of test running with '-i xx' parameter. Isn't it? tst_atomic_store(0, &completed);
On 16.07.2021 16:21, Li Wang wrote: > > #define SALSA20_IV_SIZE 8 > #define SALSA20_MIN_KEY_SIZE 16 > +static int completed; > > static void *verify_encrypt(void *arg) > { > > > But we still need to initialize '0' at the start of thread_B, > in case of test running with '-i xx' parameter. Isn't it? > > tst_atomic_store(0, &completed); > Yeah, right, and that's another reason to use pthread_tryjoin_np() :) Because otherwise the thread resources not released... anyway we could add pthread_join in the end of the run()... > -- > Regards, > Li Wang
diff --git a/testcases/kernel/crypto/af_alg02.c b/testcases/kernel/crypto/af_alg02.c index 31d30777c..0f5793c16 100644 --- a/testcases/kernel/crypto/af_alg02.c +++ b/testcases/kernel/crypto/af_alg02.c @@ -60,7 +60,7 @@ static void run(void) TST_CHECKPOINT_WAIT(0); - while (pthread_kill(thr, 0) != ESRCH) { + while (pthread_tryjoin_np(thr, NULL) == EBUSY) { if (tst_timeout_remaining() <= 10) { pthread_cancel(thr); tst_brk(TBROK,
musl doesn't return ESRCH for pthread_kill() if thread id is not found. POSIX only recommends to return ESRCH, and also says that pthread_kill() produces undefined behavior if tid lifetime has ended [1]. [1]: https://man7.org/linux/man-pages/man3/pthread_kill.3.html Signed-off-by: Alexey Kodanev <aleksei.kodanev@bell-sw.com> --- testcases/kernel/crypto/af_alg02.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)