Hi Ingo et all.
Ingo Molnar wrote:
the crashes below happen when PAGEALLOC is enabled. It's this instruction:
movb OLDSS(%esp), %ah
I am really sorry about that screwup :( I can't do too much right now as I am reading the mail in a batch mode, and the next time I'll be reading it will be 24 hours from now.
Attached is a quick fix, which I'll be
testing to death tomorrow at work.
I had DEBUG_PAGEALLOC disabled, so I
haven't noticed that stupid bug while
optimizing my checks...
Let me know how it goes.
--- entry.S.old 2005-04-05 20:08:07.000000000 +0400 +++ entry.S 2005-04-05 22:54:43.000000000 +0400 @@ -244,11 +244,12 @@ jne syscall_exit_work restore_all: - movl EFLAGS(%esp), %eax # mix EFLAGS, SS and CS - movb OLDSS(%esp), %ah - movb CS(%esp), %al - andl $(VM_MASK | (4 << 8) | 3), %eax - cmpl $((4 << 8) | 3), %eax + testl $3, CS(%esp) + jz restore_nocheck # return to kernel or v86 + movl EFLAGS(%esp), %eax # mix EFLAGS and SS + movb OLDSS(%esp), %al + andl $(VM_MASK | 4), %eax + cmpl $4, %eax je ldt_ss # returning to user-space with LDT SS restore_nocheck: RESTORE_REGS
