From d4e6f7105b00ba2536d5d733b7c03116f28ce116 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 6 May 2024 15:06:21 -0400 Subject: [PATCH 2/5] Revert "monitor: use aio_co_reschedule_self()" RH-Author: Kevin Wolf RH-MergeRequest: 248: Revert "monitor: use aio_co_reschedule_self()" RH-Jira: RHEL-34618 RHEL-38697 RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Miroslav Rezanina RH-Commit: [1/2] b6a2ebd4a69dbcd2bd56c61e7c747f8f8f42337e (kmwolf/centos-qemu-kvm) Commit 1f25c172f837 ("monitor: use aio_co_reschedule_self()") was a code cleanup that uses aio_co_reschedule_self() instead of open coding coroutine rescheduling. Bug RHEL-34618 was reported and Kevin Wolf identified the root cause. I missed that aio_co_reschedule_self() -> qemu_get_current_aio_context() only knows about qemu_aio_context/IOThread AioContexts and not about iohandler_ctx. It does not function correctly when going back from the iohandler_ctx to qemu_aio_context. Go back to open coding the AioContext transitions to avoid this bug. This reverts commit 1f25c172f83704e350c0829438d832384084a74d. Cc: qemu-stable@nongnu.org Buglink: https://issues.redhat.com/browse/RHEL-34618 Signed-off-by: Stefan Hajnoczi Message-ID: <20240506190622.56095-2-stefanha@redhat.com> Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf (cherry picked from commit 719c6819ed9a9838520fa732f9861918dc693bda) Signed-off-by: Kevin Wolf --- qapi/qmp-dispatch.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/qapi/qmp-dispatch.c b/qapi/qmp-dispatch.c index f3488afeef..176b549473 100644 --- a/qapi/qmp-dispatch.c +++ b/qapi/qmp-dispatch.c @@ -212,7 +212,8 @@ QDict *coroutine_mixed_fn qmp_dispatch(const QmpCommandList *cmds, QObject *requ * executing the command handler so that it can make progress if it * involves an AIO_WAIT_WHILE(). */ - aio_co_reschedule_self(qemu_get_aio_context()); + aio_co_schedule(qemu_get_aio_context(), qemu_coroutine_self()); + qemu_coroutine_yield(); } monitor_set_cur(qemu_coroutine_self(), cur_mon); @@ -226,7 +227,9 @@ QDict *coroutine_mixed_fn qmp_dispatch(const QmpCommandList *cmds, QObject *requ * Move back to iohandler_ctx so that nested event loops for * qemu_aio_context don't start new monitor commands. */ - aio_co_reschedule_self(iohandler_get_aio_context()); + aio_co_schedule(iohandler_get_aio_context(), + qemu_coroutine_self()); + qemu_coroutine_yield(); } } else { /* -- 2.39.3