| Message ID | 20171106190233.1175-1-stefanha@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | [for-2.11] tests-aio-multithread: fix /aio/multi/schedule race condition | expand |
On 06/11/2017 20:02, Stefan Hajnoczi wrote: > test_multi_co_schedule_entry() set to_schedule[id] in the final loop > iteration before terminating the coroutine. There is a race condition > where the main thread attempts to enter the terminating or terminated > coroutine when signalling coroutines to stop: > > atomic_mb_set(&now_stopping, true); > for (i = 0; i < NUM_CONTEXTS; i++) { > ctx_run(i, finish_cb, NULL); <--- enters dead coroutine! > to_schedule[i] = NULL; > } > > Make sure only to set to_schedule[id] if this coroutine really needs to > be scheduled! > > Reported-by: "R.Nageswara Sastry" <nasastry@in.ibm.com> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> > --- > This patch is appropriate for the QEMU 2.11 release to eliminate > spurious test failures. > > tests/test-aio-multithread.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/tests/test-aio-multithread.c b/tests/test-aio-multithread.c > index 549d784915..d396185972 100644 > --- a/tests/test-aio-multithread.c > +++ b/tests/test-aio-multithread.c > @@ -144,17 +144,16 @@ static void finish_cb(void *opaque) > static coroutine_fn void test_multi_co_schedule_entry(void *opaque) > { > g_assert(to_schedule[id] == NULL); > - atomic_mb_set(&to_schedule[id], qemu_coroutine_self()); > > while (!atomic_mb_read(&now_stopping)) { > int n; > > n = g_test_rand_int_range(0, NUM_CONTEXTS); > schedule_next(n); > + > + atomic_mb_set(&to_schedule[id], qemu_coroutine_self()); > qemu_coroutine_yield(); > - > g_assert(to_schedule[id] == NULL); > - atomic_mb_set(&to_schedule[id], qemu_coroutine_self()); > } > } > > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Thanks, Paolo
On Mon, Nov 06, 2017 at 07:02:33PM +0000, Stefan Hajnoczi wrote: > test_multi_co_schedule_entry() set to_schedule[id] in the final loop > iteration before terminating the coroutine. There is a race condition > where the main thread attempts to enter the terminating or terminated > coroutine when signalling coroutines to stop: > > atomic_mb_set(&now_stopping, true); > for (i = 0; i < NUM_CONTEXTS; i++) { > ctx_run(i, finish_cb, NULL); <--- enters dead coroutine! > to_schedule[i] = NULL; > } > > Make sure only to set to_schedule[id] if this coroutine really needs to > be scheduled! > > Reported-by: "R.Nageswara Sastry" <nasastry@in.ibm.com> > Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> > --- > This patch is appropriate for the QEMU 2.11 release to eliminate > spurious test failures. > > tests/test-aio-multithread.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) Thanks, applied to my block tree: https://github.com/stefanha/qemu/commits/block Stefan
diff --git a/tests/test-aio-multithread.c b/tests/test-aio-multithread.c index 549d784915..d396185972 100644 --- a/tests/test-aio-multithread.c +++ b/tests/test-aio-multithread.c @@ -144,17 +144,16 @@ static void finish_cb(void *opaque) static coroutine_fn void test_multi_co_schedule_entry(void *opaque) { g_assert(to_schedule[id] == NULL); - atomic_mb_set(&to_schedule[id], qemu_coroutine_self()); while (!atomic_mb_read(&now_stopping)) { int n; n = g_test_rand_int_range(0, NUM_CONTEXTS); schedule_next(n); + + atomic_mb_set(&to_schedule[id], qemu_coroutine_self()); qemu_coroutine_yield(); - g_assert(to_schedule[id] == NULL); - atomic_mb_set(&to_schedule[id], qemu_coroutine_self()); } }
test_multi_co_schedule_entry() set to_schedule[id] in the final loop iteration before terminating the coroutine. There is a race condition where the main thread attempts to enter the terminating or terminated coroutine when signalling coroutines to stop: atomic_mb_set(&now_stopping, true); for (i = 0; i < NUM_CONTEXTS; i++) { ctx_run(i, finish_cb, NULL); <--- enters dead coroutine! to_schedule[i] = NULL; } Make sure only to set to_schedule[id] if this coroutine really needs to be scheduled! Reported-by: "R.Nageswara Sastry" <nasastry@in.ibm.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> --- This patch is appropriate for the QEMU 2.11 release to eliminate spurious test failures. tests/test-aio-multithread.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)