[PATCH] fix crash in entry.S restore_all

Fix the access-above-bottom-of-stack crash.

1. Allows to preserve the valueable optimization

2. Works for NMIs

3.  Doesn't care whether or not there are more of the like instances
   where the stack is left empty.

4. Seems to work for me without the crashes:) 

(akpm: this is still under discussion, although I _think_ it's OK.  You might
want to hold off)

Signed-off-by: Stas Sergeev <stsp@aknet.ru> 
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Stas Sergeev
2005-04-16 15:24:01 -07:00
committed by Linus Torvalds
parent e493073d8d
commit 5df240826c
2 changed files with 14 additions and 1 deletions

View File

@@ -245,6 +245,9 @@ syscall_exit:
restore_all:
movl EFLAGS(%esp), %eax # mix EFLAGS, SS and CS
# Warning: OLDSS(%esp) contains the wrong/random values if we
# are returning to the kernel.
# See comments in process.c:copy_thread() for details.
movb OLDSS(%esp), %ah
movb CS(%esp), %al
andl $(VM_MASK | (4 << 8) | 3), %eax