Re: [Qemu-devel] [PATCH for-1.1] user-exec.c: Don't assert on segfaults for non-valid addresses

[Alexander Graf]

On 03.05.2012, at 20:32, Peter Maydell wrote:

> h2g() will assert if passed an address that's not a valid guest address,
> so handle_cpu_signal() needs to check before passing "data address
> which caused a segfault" to it, since for a misbehaving guest
> that could be anything. If the address isn't a valid guest address
> then we can simply skip the attempt to unprotect a guest page
> which was made read-only to catch self-modifying code.
> 
> This assertion probably fires more readily now than it used to
> do because of recent changes to default to reserving guest address
> space.
> 
> Signed-off-by: Peter Maydell <address@hidden>

Yup, just wrote the same thing a few hours ago.

Acked-by: Alexander Graf <address@hidden>

> ---
> I've tentatively marked this as for-1.1 as it's pretty safe, although
> it doesn't buy you a great deal: misbehaving guest binaries will
> die cleanly with a segfault rather than qemu asserting and then
> locking up (assert() in qemu's linux-user code doesn't really behave
> very nicely...)

It's definitely 1.1 material.


Alex