Re: [dpdk-dev] [PATCH v4] eal/windows: fix thread handle

[Ranjit Menon <ranjit.menon@intel.com>]

Hi, Tasnim...

On 6/24/2020 4:10 PM, Tasnim Bashar wrote:
> Casting thread ID to handle is not accurate way to get thread handle.
> Need to use OpenThread function to get thread handle from thread ID.
>
> pthread_setaffinity_np and pthread_getaffinity_np functions
> for Windows are affected because of it.
>
> Signed-off-by: Tasnim Bashar <tbashar@mellanox.com>
> ---
> v3: WA to remove warning(-Wmaybe-uninitialized)
> v4: Directly used function name instead of #define
> ---
>   lib/librte_eal/windows/include/pthread.h     | 84 +++++++++++++++-----
>   lib/librte_eal/windows/include/rte_windows.h |  1 +
>   2 files changed, 67 insertions(+), 18 deletions(-)
>
> diff --git a/lib/librte_eal/windows/include/pthread.h b/lib/librte_eal/windows/include/pthread.h
> index e2274cf4e9..2553c0890a 100644
> --- a/lib/librte_eal/windows/include/pthread.h
> +++ b/lib/librte_eal/windows/include/pthread.h
> @@ -6,6 +6,7 @@
>   #define _PTHREAD_H_
>   
>   #include <stdint.h>
> +#include <sched.h>
>   
>   /**
>    * This file is required to support the common code in eal_common_proc.c,
> @@ -16,8 +17,8 @@
>   extern "C" {
>   #endif
>   
> -#include <windows.h>
>   #include <rte_common.h>
> +#include <rte_windows.h>
>   
>   #define PTHREAD_BARRIER_SERIAL_THREAD TRUE
>   
> @@ -40,37 +41,84 @@ typedef SYNCHRONIZATION_BARRIER pthread_barrier_t;
>   /* pthread function overrides */
>   #define pthread_self() \
>   	((pthread_t)GetCurrentThreadId())
> -#define pthread_setaffinity_np(thread, size, cpuset) \
> -	eal_set_thread_affinity_mask(thread, (unsigned long *) cpuset)
> -#define pthread_getaffinity_np(thread, size, cpuset) \
> -	eal_get_thread_affinity_mask(thread, (unsigned long *) cpuset)
> -#define pthread_create(threadid, threadattr, threadfunc, args) \
> -	eal_create_thread(threadid, threadattr, threadfunc, args)
>   
>   static inline int
> -eal_set_thread_affinity_mask(pthread_t threadid, unsigned long *cpuset)
> +pthread_setaffinity_np(pthread_t threadid, size_t cpuset_size,
> +			rte_cpuset_t *cpuset)
>   {
> -	SetThreadAffinityMask((HANDLE) threadid, *cpuset);
> -	return 0;
> +	DWORD_PTR ret;
> +	HANDLE thread_handle;
> +
> +	if (cpuset == NULL || cpuset_size == 0)
> +		return -1;
> +
> +	thread_handle = OpenThread(THREAD_ALL_ACCESS, FALSE, threadid);
> +	if (thread_handle == NULL) {
> +		RTE_LOG_WIN32_ERR("OpenThread()");
> +		return -1;
> +	}
> +
> +	ret = SetThreadAffinityMask(thread_handle, *cpuset->_bits);
> +	if (ret == 0) {
> +		RTE_LOG_WIN32_ERR("SetThreadAffinityMask()");
> +		goto close_handle;
> +	}
> +
> +close_handle:
> +	if (CloseHandle(thread_handle) == 0) {
> +		RTE_LOG_WIN32_ERR("CloseHandle()");
> +		return -1;
> +	}
> +	return (ret == 0) ? -1 : 0;
>   }
>   
>   static inline int
> -eal_get_thread_affinity_mask(pthread_t threadid, unsigned long *cpuset)
> +pthread_getaffinity_np(pthread_t threadid, size_t cpuset_size,
> +			rte_cpuset_t *cpuset)
>   {
>   	/* Workaround for the lack of a GetThreadAffinityMask()
>   	 *API in Windows
>   	 */
> -		/* obtain previous mask by setting dummy mask */
> -	DWORD dwprevaffinitymask =
> -		SetThreadAffinityMask((HANDLE) threadid, 0x1);
> +	DWORD_PTR prev_affinity_mask;
> +	HANDLE thread_handle;
> +	DWORD_PTR ret;
Initialize ret to 0 here, otherwise... (see below)
> +
> +	if (cpuset == NULL || cpuset_size == 0)
> +		return -1;
> +
> +	thread_handle = OpenThread(THREAD_ALL_ACCESS, FALSE, threadid);
> +	if (thread_handle == NULL) {
> +		RTE_LOG_WIN32_ERR("OpenThread()");
> +		return -1;
> +	}
> +
> +	/* obtain previous mask by setting dummy mask */
> +	prev_affinity_mask = SetThreadAffinityMask(thread_handle, 0x1);
> +	if (prev_affinity_mask == 0) {
> +		RTE_LOG_WIN32_ERR("SetThreadAffinityMask()");
> +		goto close_handle;
...after this jump, ret is uninitialized and will produce random results 
at the check at the end of the function.
> +	}
> +
>   	/* set it back! */
> -	SetThreadAffinityMask((HANDLE) threadid, dwprevaffinitymask);
> -	*cpuset = dwprevaffinitymask;
> -	return 0;
> +	ret = SetThreadAffinityMask(thread_handle, prev_affinity_mask);
> +	if (ret == 0) {
> +		RTE_LOG_WIN32_ERR("SetThreadAffinityMask()");
> +		goto close_handle;
> +	}
> +
> +	memset(cpuset, 0, cpuset_size);
> +	*cpuset->_bits = prev_affinity_mask;
> +
> +close_handle:
> +	if (CloseHandle(thread_handle) == 0) {
> +		RTE_LOG_WIN32_ERR("SetThreadAffinityMask()");
> +		return -1;
> +	}
> +	return (ret == 0) ? -1 : 0;
>   }
>   
>   static inline int
> -eal_create_thread(void *threadid, const void *threadattr, void *threadfunc,
> +pthread_create(void *threadid, const void *threadattr, void *threadfunc,
>   		void *args)
>   {
>   	RTE_SET_USED(threadattr);
> diff --git a/lib/librte_eal/windows/include/rte_windows.h b/lib/librte_eal/windows/include/rte_windows.h
> index 899ed7d874..d013b50241 100644
> --- a/lib/librte_eal/windows/include/rte_windows.h
> +++ b/lib/librte_eal/windows/include/rte_windows.h
> @@ -31,6 +31,7 @@
>   #define INITGUID
>   #endif
>   #include <initguid.h>
> +#include <rte_log.h>
>   
>   /**
>    * Log GetLastError() with context, usually a Win32 API function and arguments.


ranjit m.