Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
py/objexcept: Prevent infinite recursion when allocating exceptions.
The aim of this patch is to rewrite the functions that create exception instances (mp_obj_exception_make_new and mp_obj_new_exception_msg_varg) so that they do not call any functions that may raise an exception. Otherwise it's possible to create infinite recursion with an exception being raised while trying to create an exception object. The two main things that are done to accomplish this are: 1. Change mp_obj_new_exception_msg_varg to just format the string, then call mp_obj_exception_make_new to actually create the exception object. 2. In mp_obj_exception_make_new and mp_obj_new_exception_msg_varg try to allocate all memory first using functions that don't raise exceptions If any of the memory allocations fail (return NULL) then degrade gracefully by trying other options for memory allocation, eg using the emergency exception buffer. 3. Use a custom printer backend to conservatively format strings: if it can't allocate memory then it just truncates the string. As part of this rewrite, raising an exception without a message, like KeyError(123), will now use the emergency buffer to store the arg and traceback data if there is no heap memory available. Memory use with this patch is unchanged. Code size is increased by: bare-arm: +136 minimal x86: +124 unix x64: +72 unix nanbox: +96 stm32: +88 esp8266: +92 cc3200: +80
- Loading branch information
Showing
4 changed files
with
176 additions
and
89 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -1 +1,4 @@ | ||
ValueError: | ||
Traceback (most recent call last): | ||
, line 20, in f | ||
ValueError: 1 | ||
|
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters