mainline inclusion
from mainline-v5.14-rc3
commit 2cc3aeb5
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4CVS3
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2cc3aeb5eccc

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As Alexander points out, when we are trying to recycle a cloned/expanded
SKB we might trigger a race.  The recycling code relies on the
pp_recycle bit to trigger,  which we carry over to cloned SKBs.
If that cloned SKB gets expanded or if we get references to the frags,
call skb_release_data() and overwrite skb->head, we are creating separate
instances accessing the same page frags.  Since the skb_release_data()
will first try to recycle the frags,  there's a potential race between
the original and cloned SKB, since both will have the pp_recycle bit set.

Fix this by explicitly those SKBs not recyclable.
The atomic_sub_return effectively limits us to a single release case,
and when we are calling skb_release_data we are also releasing the
option to perform the recycling, or releasing the pages from the page pool.

Fixes: 6a5bcd84 ("page_pool: Allow drivers to hint on SKB recycling")
Reported-by: NAlexander Duyck <alexanderduyck@fb.com>
Suggested-by: NAlexander Duyck <alexanderduyck@fb.com>
Reviewed-by: NAlexander Duyck <alexanderduyck@fb.com>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: NIlias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Reviewed-by: NYongxin Li <liyongxin1@huawei.com>
Signed-off-by: NJunxin Chen <chenjunxin1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>