eal/windows: fix data race when creating threads
Checks
Commit Message
create lcore worker threads suspended and then subsequently resume to
allow &lcore_config[i].thread_id be stored before eal_thread_loop
execution.
Fixes: 53ffd9f080fc ("eal/windows: add minimum viable code")
Cc: anand.rawat@intel.com
Cc: stable@dpdk.org
Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
---
lib/eal/windows/eal_thread.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
Comments
Hi Tyler,
2022-03-09 23:35 (UTC-0800), Tyler Retzlaff:
> create lcore worker threads suspended and then subsequently resume to
> allow &lcore_config[i].thread_id be stored before eal_thread_loop
> execution.
>
> Fixes: 53ffd9f080fc ("eal/windows: add minimum viable code")
> Cc: anand.rawat@intel.com
> Cc: stable@dpdk.org
>
> Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
It takes some effort to correlate &lcore_config[i].thread_id
with the code in the patch and knowledge of CreateThread()
to understand the root cause.
I suggest prepending an explanation to your commit message:
eal_thread_loop() uses lcore_config[i].thread_id,
which is stored upon the return from CreateThread().
Per documentation, eal_thread_loop() can start
before CreateThread() returns and the ID is stored.
> ---
> lib/eal/windows/eal_thread.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/lib/eal/windows/eal_thread.c b/lib/eal/windows/eal_thread.c
> index 54fa93f..ff84cb4 100644
> --- a/lib/eal/windows/eal_thread.c
> +++ b/lib/eal/windows/eal_thread.c
> @@ -150,13 +150,18 @@
>
> th = CreateThread(NULL, 0,
> (LPTHREAD_START_ROUTINE)(ULONG_PTR)eal_thread_loop,
> - NULL, 0, (LPDWORD)thread);
> + NULL, CREATE_SUSPENDED, (LPDWORD)thread);
> if (!th)
> return -1;
>
> SetPriorityClass(GetCurrentProcess(), NORMAL_PRIORITY_CLASS);
> SetThreadPriority(th, THREAD_PRIORITY_NORMAL);
>
> + if (ResumeThread(th) == (DWORD)-1) {
> + (void)CloseHandle(th);
> + return -1;
> + }
> +
> return 0;
> }
>
10/03/2022 17:19, Dmitry Kozlyuk:
> Hi Tyler,
>
> 2022-03-09 23:35 (UTC-0800), Tyler Retzlaff:
> > create lcore worker threads suspended and then subsequently resume to
> > allow &lcore_config[i].thread_id be stored before eal_thread_loop
> > execution.
> >
> > Fixes: 53ffd9f080fc ("eal/windows: add minimum viable code")
> > Cc: anand.rawat@intel.com
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
>
> Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
>
> It takes some effort to correlate &lcore_config[i].thread_id
> with the code in the patch and knowledge of CreateThread()
> to understand the root cause.
> I suggest prepending an explanation to your commit message:
>
> eal_thread_loop() uses lcore_config[i].thread_id,
> which is stored upon the return from CreateThread().
> Per documentation, eal_thread_loop() can start
> before CreateThread() returns and the ID is stored.
There was now reply to this suggestion after 3 weeks,
so I've decided to include it.
Applied, thanks.
@@ -150,13 +150,18 @@
th = CreateThread(NULL, 0,
(LPTHREAD_START_ROUTINE)(ULONG_PTR)eal_thread_loop,
- NULL, 0, (LPDWORD)thread);
+ NULL, CREATE_SUSPENDED, (LPDWORD)thread);
if (!th)
return -1;
SetPriorityClass(GetCurrentProcess(), NORMAL_PRIORITY_CLASS);
SetThreadPriority(th, THREAD_PRIORITY_NORMAL);
+ if (ResumeThread(th) == (DWORD)-1) {
+ (void)CloseHandle(th);
+ return -1;
+ }
+
return 0;
}