Avoid a deadlock when registering FDEs at runtime

koute · koute · commit eb4097e27c36 · 2021-06-10T16:56:16.000+09:00
diff --git a/preload/src/api.rs b/preload/src/api.rs
@@ -559,7 +559,9 @@ pub unsafe extern "C" fn __register_frame( fde: *const u8 ) {
         error!( "__register_frame call ignored since we couldn't find the original symbol" );
     }
 
+    let thread = StrongThreadHandle::acquire();
     unwind::register_frame_by_pointer( fde );
+    std::mem::drop( thread );
 }
 
 #[cfg_attr(not(test), no_mangle)]
@@ -572,5 +574,7 @@ pub unsafe extern "C" fn __deregister_frame( fde: *const u8 ) {
         error!( "__deregister_frame call ignored since we couldn't find the original symbol" );
     }
 
+    let thread = StrongThreadHandle::acquire();
     unwind::deregister_frame_by_pointer( fde );
+    std::mem::drop( thread );
 }

Original file line number	Diff line number	Diff line change
`@@ -559,7 +559,9 @@ pub unsafe extern "C" fn __register_frame( fde: *const u8 ) {`
`559`	`559`	`error!( "__register_frame call ignored since we couldn't find the original symbol" );`
`560`	`560`	`}`
`561`	`561`
	`562`	`+ let thread = StrongThreadHandle::acquire();`
`562`	`563`	`unwind::register_frame_by_pointer( fde );`
	`564`	`+ std::mem::drop( thread );`
`563`	`565`	`}`
`564`	`566`
`565`	`567`	`#[cfg_attr(not(test), no_mangle)]`
`@@ -572,5 +574,7 @@ pub unsafe extern "C" fn __deregister_frame( fde: *const u8 ) {`
`572`	`574`	`error!( "__deregister_frame call ignored since we couldn't find the original symbol" );`
`573`	`575`	`}`
`574`	`576`
	`577`	`+ let thread = StrongThreadHandle::acquire();`
`575`	`578`	`unwind::deregister_frame_by_pointer( fde );`
	`579`	`+ std::mem::drop( thread );`
`576`	`580`	`}`