* Steven Rostedt <[email protected]> wrote:
> > ahh ... I would not be surprised if this caused actual problems on x64
> > in the upstream kernel too: using save_flags() over u32 will corrupt a
> > word on the stack ...
> >
>
> Actually, it's still safe upstream. The locks are taken via a function
> defined as:
>
> unsigned long acpi_os_acquire_lock(acpi_handle handle)
> {
> unsigned long flags;
> spin_lock_irqsave((spinlock_t *) handle, flags);
> return flags;
> }
>
> So a u32 flags with
>
> flags = acpi_os_acquire_lock(lock);
>
> would be safe, unless a 64 bit machine stored the value of IR in the
> upper word, which I don't know of any archs that do that.
ok. But this still looks very volatile. Nowhere do we guarantee (or can
we guarantee) that silently zeroing out the upper 32 bits of flags is
safe!
Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
