Fix dio_bio_alloc() to set BIO_PAGE_PINNED, not BIO_PAGE_REFFED, so that
the bio code unpins the pinned pages rather than putting a ref on them.
The issue was causing:
WARNING: CPU: 6 PID: 2220 at mm/gup.c:76 try_get_folio
This can be caused by creating a file on a loopback UDF filesystem, opening
it O_DIRECT and making two writes to it from the same source buffer.
Fixes: 1ccf164ec866 ("block: Use iov_iter_extract_pages() and page pinning in direct-io.c")
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-lkp/[email protected]
Signed-off-by: David Howells <[email protected]>
cc: Christoph Hellwig <[email protected]>
cc: David Hildenbrand <[email protected]>
cc: Andrew Morton <[email protected]>
cc: Jens Axboe <[email protected]>
cc: Al Viro <[email protected]>
cc: Matthew Wilcox <[email protected]>
cc: Jan Kara <[email protected]>
cc: Jeff Layton <[email protected]>
cc: Jason Gunthorpe <[email protected]>
cc: Logan Gunthorpe <[email protected]>
cc: Hillf Danton <[email protected]>
cc: Christian Brauner <[email protected]>
cc: Linus Torvalds <[email protected]>
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
---
Notes:
ver #2)
- Remove comment on requiring references for all pages.
fs/direct-io.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 14049204cac8..5d4c5be0fb41 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -414,8 +414,8 @@ dio_bio_alloc(struct dio *dio, struct dio_submit *sdio,
bio->bi_end_io = dio_bio_end_aio;
else
bio->bi_end_io = dio_bio_end_io;
- /* for now require references for all pages */
- bio_set_flag(bio, BIO_PAGE_REFFED);
+ if (dio->need_unpin)
+ bio_set_flag(bio, BIO_PAGE_PINNED);
sdio->bio = bio;
sdio->logical_offset_in_bio = sdio->cur_page_fs_offset;
}
Looks good:
Reviewed-by: Christoph Hellwig <[email protected]>
On 12.06.23 22:24, David Howells wrote:
>
> Fix dio_bio_alloc() to set BIO_PAGE_PINNED, not BIO_PAGE_REFFED, so that
> the bio code unpins the pinned pages rather than putting a ref on them.
>
> The issue was causing:
>
> WARNING: CPU: 6 PID: 2220 at mm/gup.c:76 try_get_folio
>
> This can be caused by creating a file on a loopback UDF filesystem, opening
> it O_DIRECT and making two writes to it from the same source buffer.
>
> Fixes: 1ccf164ec866 ("block: Use iov_iter_extract_pages() and page pinning in direct-io.c")
> Reported-by: kernel test robot <[email protected]>
> Closes: https://lore.kernel.org/oe-lkp/[email protected]
> Signed-off-by: David Howells <[email protected]>
> cc: Christoph Hellwig <[email protected]>
> cc: David Hildenbrand <[email protected]>
> cc: Andrew Morton <[email protected]>
> cc: Jens Axboe <[email protected]>
> cc: Al Viro <[email protected]>
> cc: Matthew Wilcox <[email protected]>
> cc: Jan Kara <[email protected]>
> cc: Jeff Layton <[email protected]>
> cc: Jason Gunthorpe <[email protected]>
> cc: Logan Gunthorpe <[email protected]>
> cc: Hillf Danton <[email protected]>
> cc: Christian Brauner <[email protected]>
> cc: Linus Torvalds <[email protected]>
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> ---
>
> Notes:
> ver #2)
> - Remove comment on requiring references for all pages.
>
> fs/direct-io.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/direct-io.c b/fs/direct-io.c
> index 14049204cac8..5d4c5be0fb41 100644
> --- a/fs/direct-io.c
> +++ b/fs/direct-io.c
> @@ -414,8 +414,8 @@ dio_bio_alloc(struct dio *dio, struct dio_submit *sdio,
> bio->bi_end_io = dio_bio_end_aio;
> else
> bio->bi_end_io = dio_bio_end_io;
> - /* for now require references for all pages */
> - bio_set_flag(bio, BIO_PAGE_REFFED);
> + if (dio->need_unpin)
> + bio_set_flag(bio, BIO_PAGE_PINNED);
> sdio->bio = bio;
> sdio->logical_offset_in_bio = sdio->cur_page_fs_offset;
> }
>
Reviewed-by: David Hildenbrand <[email protected]>
--
Cheers,
David / dhildenb
Jens Axboe <[email protected]> wrote:
> What is this against?
It's against the branch I posted. I should rebase it on your tree, but I'm in
a conference at the moment, so that may have to wait till Thursday.
David
On 6/12/23 2:24 PM, David Howells wrote:
>
> Fix dio_bio_alloc() to set BIO_PAGE_PINNED, not BIO_PAGE_REFFED, so that
> the bio code unpins the pinned pages rather than putting a ref on them.
>
> The issue was causing:
>
> WARNING: CPU: 6 PID: 2220 at mm/gup.c:76 try_get_folio
>
> This can be caused by creating a file on a loopback UDF filesystem, opening
> it O_DIRECT and making two writes to it from the same source buffer.
What is this against?
--
Jens Axboe
David Howells <[email protected]> wrote:
> > What is this against?
>
> It's against the branch I posted.
Actually, it's not. It's against an old version of the patch on a different
branch. The patches you have applied already have that change - so the issue
must be something else:-/
David