linux/arch/x86/lguest
Rusty Russell 4357bd9453 lguest: Revert 1ce70c4fac, fix real problem.
Ahmed managed to crash the Host in release_pgd(), which cannot be a Guest
bug, and indeed it wasn't.

The bug was that handing a 0 as the address of the toplevel page table
being manipulated can cause the lookup code in find_pgdir() to return
an uninitialized cache entry (we shadow up to 4 top level page tables
for each Guest).

Commit 37cc8d7f96 introduced this
behaviour in the Guest, uncovering the bug.

The patch which he submitted (which removed the /4 from the index
calculation) simply ensured that these high-indexed entries hit the
early exit path of guest_set_pmd().  But you get lots of segfaults in
guest userspace as the PMDs aren't being updated.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2008-03-11 09:35:58 +11:00
..
boot.c lguest: Revert 1ce70c4fac, fix real problem. 2008-03-11 09:35:58 +11:00
i386_head.S lguest: documentation update 2007-10-25 15:02:50 +10:00
Kconfig x86: remove depends on X86_32 from PARAVIRT & PARAVIRT_GUEST 2008-01-30 13:33:32 +01:00
Makefile