Hi Davidlohr,
On Wed, Feb 06, 2019 at 09:37:40PM -0800, Davidlohr Bueso wrote:
> It is well known that because the mm can internally
> call the regular gup_unlocked if the lockless approach
> fails and take the sem there, the caller must not hold
> the mmap_sem already.
>
> Fixes: e523f289fe4d (MIPS: c-r4k: Fix sigtramp SMP call to use kmap)
> Cc: Ralf Baechle <[email protected]>
> Cc: Paul Burton <[email protected]>
> Cc: James Hogan <[email protected]>
> Cc: [email protected]
> Signed-off-by: Davidlohr Bueso <[email protected]>
Thanks - this looks good, but:
1) The problem it fixes was introduced in v4.8.
2) Commit adcc81f148d7 ("MIPS: math-emu: Write-protect delay slot
emulation pages") actually left flush_cache_sigtramp unused, and has
been backported to stable kernels also as far as v4.8.
Therefore this will just fix code that never gets called, and I'll go
delete the whole thing instead.
Thanks,
Paul
