tyler.durden
/
kernel
mirror of https://github.com/FDOS/kernel.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

avoid race condition that could corrupt user stack if DOS re-entered too soon 

apply suggested fix from SF bug 215 (https://sourceforge.net/p/freedos/bugs/215/), InDOS cleared but small chance DOS re-entered before user stack restored thus corrupting user stack
This commit is contained in:
Kenneth J Davis 2024-08-19 16:31:22 -04:00
parent dabfaf7d54
commit 1cc00e194d
No known key found for this signature in database
GPG Key ID: 59D5F216C38F11FD
1 changed files with 5 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
kernel/entry.asm
View File

@ -406,7 +406,7 @@ int21_normalentry:
push bp push bp
call _int21_service call _int21_service
int21_exit: dec byte [_InDOS] int21_exit:
%IFDEF WIN31SUPPORT %IFDEF WIN31SUPPORT
call end_dos_crit_sect ; release all critical sections call end_dos_crit_sect ; release all critical sections
%if 0 %if 0
@ -417,6 +417,10 @@ int21_exit: dec byte [_InDOS]
%endif %endif
%ENDIF ; WIN31SUPPORT %ENDIF ; WIN31SUPPORT
; tiny chance DOS re-entered between clearing InDOS and restoring user stack,
; so we disable interrupts until user stack restored; see SF bug# 215
cli
dec byte [_InDOS]
; ;
; Recover registers from system call. Registers and flags ; Recover registers from system call. Registers and flags
; were modified by the system call. ; were modified by the system call.