On 04/28/2014 11:51 PM, Mauro Carvalho Chehab wrote: > Hi Hans, > > Could you please take a look at this patch? I was planning to do that, but I won't have time for it until Monday. > I remember you had to revert a > VB2 patch from Al Viro, as it caused some regressions. Not sure if this one > is similar to the one that was reverted. That was a patch for videobuf, not vb2. But this still needs to be reviewed carefully for pretty much the same reasons. Regards, Hans > > Thanks, > Mauro > > Forwarded message: > > Date: Mon, 28 Apr 2014 15:04:06 -0700 > From: akpm@xxxxxxxxxxxxxxxxxxxx > To: mm-commits@xxxxxxxxxxxxxxx, pawel@xxxxxxxxxx, m.szyprowski@xxxxxxxxxxx, m.chehab@xxxxxxxxxxx, kyungmin.park@xxxxxxxxxxx, davidlohr@xxxxxx > Subject: + media-videobuf2-dma-sg-call-find_vma-with-the-mmap_sem-held.patch added to -mm tree > > > Subject: + media-videobuf2-dma-sg-call-find_vma-with-the-mmap_sem-held.patch added to -mm tree > To: davidlohr@xxxxxx,kyungmin.park@xxxxxxxxxxx,m.chehab@xxxxxxxxxxx,m.szyprowski@xxxxxxxxxxx,pawel@xxxxxxxxxx > From: akpm@xxxxxxxxxxxxxxxxxxxx > Date: Mon, 28 Apr 2014 15:04:06 -0700 > > > The patch titled > Subject: drivers/media/v4l2-core/videobuf2-dma-sg.c: call find_vma with the mmap_sem held > has been added to the -mm tree. Its filename is > media-videobuf2-dma-sg-call-find_vma-with-the-mmap_sem-held.patch > > This patch should soon appear at > http://ozlabs.org/~akpm/mmots/broken-out/media-videobuf2-dma-sg-call-find_vma-with-the-mmap_sem-held.patch > and later at > http://ozlabs.org/~akpm/mmotm/broken-out/media-videobuf2-dma-sg-call-find_vma-with-the-mmap_sem-held.patch > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/SubmitChecklist when testing your code *** > > The -mm tree is included into linux-next and is updated > there every 3-4 working days > > ------------------------------------------------------ > From: Davidlohr Bueso <davidlohr@xxxxxx> > Subject: drivers/media/v4l2-core/videobuf2-dma-sg.c: call find_vma with the mmap_sem held > > Performing vma lookups without taking the mm->mmap_sem is asking for > trouble. While doing the search, the vma in question can be modified or > even removed before returning to the caller. Take the lock in order to > avoid races while iterating through the vmacache and/or rbtree. > > Also do some very minor cleanup changes. > > Signed-off-by: Davidlohr Bueso <davidlohr@xxxxxx> > Cc: Pawel Osciak <pawel@xxxxxxxxxx> > Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> > Cc: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> > Cc: Mauro Carvalho Chehab <m.chehab@xxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > --- > > drivers/media/v4l2-core/videobuf2-dma-sg.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff -puN drivers/media/v4l2-core/videobuf2-dma-sg.c~media-videobuf2-dma-sg-call-find_vma-with-the-mmap_sem-held drivers/media/v4l2-core/videobuf2-dma-sg.c > --- a/drivers/media/v4l2-core/videobuf2-dma-sg.c~media-videobuf2-dma-sg-call-find_vma-with-the-mmap_sem-held > +++ a/drivers/media/v4l2-core/videobuf2-dma-sg.c > @@ -168,8 +168,9 @@ static void *vb2_dma_sg_get_userptr(void > unsigned long first, last; > int num_pages_from_user; > struct vm_area_struct *vma; > + struct mm_struct *mm = current->mm; > > - buf = kzalloc(sizeof *buf, GFP_KERNEL); > + buf = kzalloc(sizeof(*buf), GFP_KERNEL); > if (!buf) > return NULL; > > @@ -178,7 +179,7 @@ static void *vb2_dma_sg_get_userptr(void > buf->offset = vaddr & ~PAGE_MASK; > buf->size = size; > > - first = (vaddr & PAGE_MASK) >> PAGE_SHIFT; > + first = (vaddr & PAGE_MASK) >> PAGE_SHIFT; > last = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT; > buf->num_pages = last - first + 1; > > @@ -187,7 +188,8 @@ static void *vb2_dma_sg_get_userptr(void > if (!buf->pages) > goto userptr_fail_alloc_pages; > > - vma = find_vma(current->mm, vaddr); > + down_write(&mm->mmap_sem); > + vma = find_vma(mm, vaddr); > if (!vma) { > dprintk(1, "no vma for address %lu\n", vaddr); > goto userptr_fail_find_vma; > @@ -218,7 +220,7 @@ static void *vb2_dma_sg_get_userptr(void > buf->pages[num_pages_from_user] = pfn_to_page(pfn); > } > } else > - num_pages_from_user = get_user_pages(current, current->mm, > + num_pages_from_user = get_user_pages(current, mm, > vaddr & PAGE_MASK, > buf->num_pages, > write, > @@ -233,6 +235,7 @@ static void *vb2_dma_sg_get_userptr(void > buf->num_pages, buf->offset, size, 0)) > goto userptr_fail_alloc_table_from_pages; > > + up_write(&mm->mmap_sem); > return buf; > > userptr_fail_alloc_table_from_pages: > @@ -244,6 +247,7 @@ userptr_fail_get_user_pages: > put_page(buf->pages[num_pages_from_user]); > vb2_put_vma(buf->vma); > userptr_fail_find_vma: > + up_write(&mm->mmap_sem); > kfree(buf->pages); > userptr_fail_alloc_pages: > kfree(buf); > _ > > Patches currently in -mm which might be from davidlohr@xxxxxx are > > mmvmacache-add-debug-data.patch > mmvmacache-optimize-overflow-system-wide-flushing.patch > mm-pass-vm_bug_on-reason-to-dump_page.patch > mm-pass-vm_bug_on-reason-to-dump_page-fix.patch > hugetlb-prep_compound_gigantic_page-drop-__init-marker.patch > hugetlb-add-hstate_is_gigantic.patch > hugetlb-update_and_free_page-dont-clear-pg_reserved-bit.patch > hugetlb-move-helpers-up-in-the-file.patch > hugetlb-add-support-for-gigantic-page-allocation-at-runtime.patch > m68k-call-find_vma-with-the-mmap_sem-held-in-sys_cacheflush.patch > mips-call-find_vma-with-the-mmap_sem-held.patch > arc-call-find_vma-with-the-mmap_sem-held.patch > arc-call-find_vma-with-the-mmap_sem-held-fix.patch > drm-exynos-call-find_vma-with-the-mmap_sem-held.patch > media-videobuf2-dma-sg-call-find_vma-with-the-mmap_sem-held.patch > ipc-constify-ipc_ops.patch > ipc-shmc-check-for-ulong-overflows-in-shmat.patch > ipc-shmc-check-for-overflows-of-shm_tot.patch > ipc-shmc-check-for-integer-overflow-during-shmget.patch > ipc-shmc-increase-the-defaults-for-shmall-shmmax.patch > blackfin-ptrace-call-find_vma-with-the-mmap_sem-held.patch > > > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
