ntdll: Process system APCs while the signals are blocked.

This makes sure that system APC, such as APC_BREAK_PROCESS do not get interrupted in the middle of their execution, and that the APC completion notification is always correctly sent back to the caller. Otherwise DbgBreakProcess sometimes did not return until WaitForDebugEvent/ContinueDebugEvent are called, because of a race condition between the APC servicing thread, and the newly created exception thread. Signed-off-by: Rémi Bernon <rbernon@codeweavers.com> Signed-off-by: Jacek Caban <jacek@codeweavers.com> Signed-off-by: Alexandre Julliard <julliard@winehq.org>

ntdll: Process system APCs while the signals are blocked.
544fd950 · Rémi Bernon · Alexandre Julliard · 2dc99bfb · 544fd950 · 544fd950
Commit 544fd950 authored Feb 05, 2020 by Rémi Bernon Committed by Alexandre Julliard Feb 05, 2020
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Showing with 8 additions and 2 deletions

server.c dlls/ntdll/server.c +4 -1

sync.c dlls/ntdll/sync.c +4 -1

No files found.
--- a/dlls/ntdll/server.c
+++ b/dlls/ntdll/server.c
@@ -601,11 +601,13 @@ unsigned int server_select( const select_op_t *select_op, data_size_t size, UINT
    apc_call_t call;
    apc_result_t result;
    timeout_t abs_timeout = timeout ? timeout->QuadPart : TIMEOUT_INFINITE;
+    sigset_t old_set;
    memset( &result, 0, sizeof(result) );
    do
    {
+        pthread_sigmask( SIG_BLOCK, &server_block_set, &old_set );
        for (;;)
        {
            SERVER_START_REQ( select )
@@ -616,7 +618,7 @@ unsigned int server_select( const select_op_t *select_op, data_size_t size, UINT
                req->timeout  = abs_timeout;
                wine_server_add_data( req, &result, sizeof(result) );
                wine_server_add_data( req, select_op, size );
-                ret = wine_server_call( req );
+                ret = server_call_unlocked( req );
                abs_timeout = reply->timeout;
                apc_handle  = reply->apc_handle;
                call        = reply->call;
@@ -630,6 +632,7 @@ unsigned int server_select( const select_op_t *select_op, data_size_t size, UINT
            if (ret != STATUS_KERNEL_APC) break;
            invoke_apc( &call, &result );
        }
+        pthread_sigmask( SIG_SETMASK, &old_set, NULL );
        if (ret == STATUS_USER_APC)
        {

--- a/dlls/ntdll/sync.c
+++ b/dlls/ntdll/sync.c
@@ -2457,6 +2457,7 @@ NTSTATUS WINAPI RtlWaitOnAddress( const void *addr, const void *cmp, SIZE_T size
    apc_call_t call;
    apc_result_t result;
    timeout_t abs_timeout = timeout ? timeout->QuadPart : TIMEOUT_INFINITE;
+    sigset_t old_set;
    if (size != 1 && size != 2 && size != 4 && size != 8)
        return STATUS_INVALID_PARAMETER;
@@ -2479,6 +2480,7 @@ NTSTATUS WINAPI RtlWaitOnAddress( const void *addr, const void *cmp, SIZE_T size
            return STATUS_SUCCESS;
        }
+        pthread_sigmask( SIG_BLOCK, &server_block_set, &old_set );
        for (;;)
        {
            SERVER_START_REQ( select )
@@ -2489,7 +2491,7 @@ NTSTATUS WINAPI RtlWaitOnAddress( const void *addr, const void *cmp, SIZE_T size
                req->timeout  = abs_timeout;
                wine_server_add_data( req, &result, sizeof(result) );
                wine_server_add_data( req, &select_op, sizeof(select_op.keyed_event) );
-                ret = wine_server_call( req );
+                ret = server_call_unlocked( req );
                abs_timeout = reply->timeout;
                apc_handle  = reply->apc_handle;
                call        = reply->call;
@@ -2499,6 +2501,7 @@ NTSTATUS WINAPI RtlWaitOnAddress( const void *addr, const void *cmp, SIZE_T size
            if (ret != STATUS_KERNEL_APC) break;
            invoke_apc( &call, &result );
        }
+        pthread_sigmask( SIG_SETMASK, &old_set, NULL );
        RtlLeaveCriticalSection( &addr_section );