On Tue, May 7, 2019 at 5:00 AM <[email protected]> wrote: > > From: Ralph Campbell <[email protected]> > > The helper function hmm_vma_fault() calls hmm_range_register() but is > missing a call to hmm_range_unregister() in one of the error paths. > This leads to a reference count leak and ultimately a memory leak on > struct hmm. > > Always call hmm_range_unregister() if hmm_range_register() succeeded.
How about * Call hmm_range_unregister() in error path if hmm_range_register() succeeded* ? > > Signed-off-by: Ralph Campbell <[email protected]> > Cc: John Hubbard <[email protected]> > Cc: Ira Weiny <[email protected]> > Cc: Dan Williams <[email protected]> > Cc: Arnd Bergmann <[email protected]> > Cc: Balbir Singh <[email protected]> > Cc: Dan Carpenter <[email protected]> > Cc: Matthew Wilcox <[email protected]> > Cc: Souptick Joarder <[email protected]> > Cc: Andrew Morton <[email protected]> > --- > include/linux/hmm.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/linux/hmm.h b/include/linux/hmm.h > index 35a429621e1e..fa0671d67269 100644 > --- a/include/linux/hmm.h > +++ b/include/linux/hmm.h > @@ -559,6 +559,7 @@ static inline int hmm_vma_fault(struct hmm_range *range, > bool block) > return (int)ret; > > if (!hmm_range_wait_until_valid(range, HMM_RANGE_DEFAULT_TIMEOUT)) { > + hmm_range_unregister(range); > /* > * The mmap_sem was taken by driver we release it here and > * returns -EAGAIN which correspond to mmap_sem have been > @@ -570,13 +571,13 @@ static inline int hmm_vma_fault(struct hmm_range > *range, bool block) > > ret = hmm_range_fault(range, block); > if (ret <= 0) { > + hmm_range_unregister(range); what is the reason to moved it up ? > if (ret == -EBUSY || !ret) { > /* Same as above, drop mmap_sem to match old API. */ > up_read(&range->vma->vm_mm->mmap_sem); > ret = -EBUSY; > } else if (ret == -EAGAIN) > ret = -EBUSY; > - hmm_range_unregister(range); > return ret; > } > return 0; > -- > 2.20.1 >
