Acked-off-by: Steve French <stfre...@microsoft.com>
On Wed, Jul 26, 2023 at 8:56 AM David Hildenbrand <da...@redhat.com> wrote:
>
> On 26.07.23 12:57, David Howells wrote:
> >
> > Fix error handling in extract_iter_to_sg(). Pages need to be unpinned, not
> > put in extract_user_to_sg() when handling IOVEC/UBUF sources.
> >
> > The bug may result in a warning like the following:
> >
> > WARNING: CPU: 1 PID: 20384 at mm/gup.c:229 __lse_atomic_add
> > arch/arm64/include/asm/atomic_lse.h:27 [inline]
> > WARNING: CPU: 1 PID: 20384 at mm/gup.c:229 arch_atomic_add
> > arch/arm64/include/asm/atomic.h:28 [inline]
> > WARNING: CPU: 1 PID: 20384 at mm/gup.c:229 raw_atomic_add
> > include/linux/atomic/atomic-arch-fallback.h:537 [inline]
> > WARNING: CPU: 1 PID: 20384 at mm/gup.c:229 atomic_add
> > include/linux/atomic/atomic-instrumented.h:105 [inline]
> > WARNING: CPU: 1 PID: 20384 at mm/gup.c:229 try_grab_page+0x108/0x160
> > mm/gup.c:252
> > ...
> > pc : try_grab_page+0x108/0x160 mm/gup.c:229
> > lr : follow_page_pte+0x174/0x3e4 mm/gup.c:651
> > ...
> > Call trace:
> > __lse_atomic_add arch/arm64/include/asm/atomic_lse.h:27 [inline]
> > arch_atomic_add arch/arm64/include/asm/atomic.h:28 [inline]
> > raw_atomic_add include/linux/atomic/atomic-arch-fallback.h:537 [inline]
> > atomic_add include/linux/atomic/atomic-instrumented.h:105 [inline]
> > try_grab_page+0x108/0x160 mm/gup.c:252
> > follow_pmd_mask mm/gup.c:734 [inline]
> > follow_pud_mask mm/gup.c:765 [inline]
> > follow_p4d_mask mm/gup.c:782 [inline]
> > follow_page_mask+0x12c/0x2e4 mm/gup.c:839
> > __get_user_pages+0x174/0x30c mm/gup.c:1217
> > __get_user_pages_locked mm/gup.c:1448 [inline]
> > __gup_longterm_locked+0x94/0x8f4 mm/gup.c:2142
> > internal_get_user_pages_fast+0x970/0xb60 mm/gup.c:3140
> > pin_user_pages_fast+0x4c/0x60 mm/gup.c:3246
> > iov_iter_extract_user_pages lib/iov_iter.c:1768 [inline]
> > iov_iter_extract_pages+0xc8/0x54c lib/iov_iter.c:1831
> > extract_user_to_sg lib/scatterlist.c:1123 [inline]
> > extract_iter_to_sg lib/scatterlist.c:1349 [inline]
> > extract_iter_to_sg+0x26c/0x6fc lib/scatterlist.c:1339
> > hash_sendmsg+0xc0/0x43c crypto/algif_hash.c:117
> > sock_sendmsg_nosec net/socket.c:725 [inline]
> > sock_sendmsg+0x54/0x60 net/socket.c:748
> > ____sys_sendmsg+0x270/0x2ac net/socket.c:2494
> > ___sys_sendmsg+0x80/0xdc net/socket.c:2548
> > __sys_sendmsg+0x68/0xc4 net/socket.c:2577
> > __do_sys_sendmsg net/socket.c:2586 [inline]
> > __se_sys_sendmsg net/socket.c:2584 [inline]
> > __arm64_sys_sendmsg+0x24/0x30 net/socket.c:2584
> > __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
> > invoke_syscall+0x48/0x114 arch/arm64/kernel/syscall.c:52
> > el0_svc_common.constprop.0+0x44/0xe4 arch/arm64/kernel/syscall.c:142
> > do_el0_svc+0x38/0xa4 arch/arm64/kernel/syscall.c:191
> > el0_svc+0x2c/0xb0 arch/arm64/kernel/entry-common.c:647
> > el0t_64_sync_handler+0xc0/0xc4 arch/arm64/kernel/entry-common.c:665
> > el0t_64_sync+0x19c/0x1a0 arch/arm64/kernel/entry.S:591
> >
> > Fixes: 018584697533 ("netfs: Add a function to extract an iterator into a
> > scatterlist")
> > Reported-by: syzbot+9b82859567f2e50c1...@syzkaller.appspotmail.com
> > Link:
> > https://lore.kernel.org/linux-mm/000000000000273d0105ff97b...@google.com/
> > Signed-off-by: David Howells <dhowe...@redhat.com>
> > cc: Sven Schnelle <sv...@linux.ibm.com>
> > cc: a...@linux-foundation.org
> > cc: Herbert Xu <herb...@gondor.apana.org.au>
> > cc: "David S. Miller" <da...@davemloft.net>
> > cc: Jeff Layton <jlay...@kernel.org>
> > cc: Steve French <sfre...@samba.org>
> > cc: Shyam Prasad N <nspmangal...@gmail.com>
> > cc: Rohith Surabattula <rohiths.m...@gmail.com>
> > cc: Jens Axboe <ax...@kernel.dk>
> > cc: Herbert Xu <herb...@gondor.apana.org.au>
> > cc: "David S. Miller" <da...@davemloft.net>
> > cc: Eric Dumazet <eduma...@google.com>
> > cc: Jakub Kicinski <k...@kernel.org>
> > cc: Paolo Abeni <pab...@redhat.com>
> > cc: Matthew Wilcox <wi...@infradead.org>
> > cc: linux...@kvack.org
> > cc: linux-cry...@vger.kernel.org
> > cc: linux-cachefs@redhat.com
> > cc: linux-c...@vger.kernel.org
> > cc: linux-fsde...@vger.kernel.org
> > cc: net...@vger.kernel.org
> > ---
> > lib/scatterlist.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/lib/scatterlist.c b/lib/scatterlist.c
> > index e86231a44c3d..c65566b4dc66 100644
> > --- a/lib/scatterlist.c
> > +++ b/lib/scatterlist.c
> > @@ -1148,7 +1148,7 @@ static ssize_t extract_user_to_sg(struct iov_iter
> > *iter,
> >
> > failed:
> > while (sgtable->nents > sgtable->orig_nents)
> > - put_page(sg_page(&sgtable->sgl[--sgtable->nents]));
> > + unpin_user_page(sg_page(&sgtable->sgl[--sgtable->nents]));
> > return res;
> > }
> >
> >
>
> Reviewed-by: David Hildenbrand <da...@redhat.com>
>
> --
> Cheers,
>
> David / dhildenb
>
--
Thanks,
Steve
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