diff options
| author | Jesper Dangaard Brouer <brouer@redhat.com> | 2023-01-20 13:34:44 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-01-24 08:39:04 +0300 |
| commit | f72ff8b81ebc6a0a25e41b7e6c1dc42e3aa33e7e (patch) | |
| tree | 01ee397cacc792536ff11e16429b2694215adfa2 /net | |
| parent | 3bee9b573af515a8f15db70e7875ac96f87d57b5 (diff) | |
| download | linux-f72ff8b81ebc6a0a25e41b7e6c1dc42e3aa33e7e.tar.xz | |
net: fix kfree_skb_list use of skb_mark_not_on_list
A bug was introduced by commit eedade12f4cb ("net: kfree_skb_list use
kmem_cache_free_bulk"). It unconditionally unlinked the SKB list via
invoking skb_mark_not_on_list().
In this patch we choose to remove the skb_mark_not_on_list() call as it
isn't necessary. It would be possible and correct to call
skb_mark_not_on_list() only when __kfree_skb_reason() returns true,
meaning the SKB is ready to be free'ed, as it calls/check skb_unref().
This fix is needed as kfree_skb_list() is also invoked on skb_shared_info
frag_list (skb_drop_fraglist() calling kfree_skb_list()). A frag_list can
have SKBs with elevated refcnt due to cloning via skb_clone_fraglist(),
which takes a reference on all SKBs in the list. This implies the
invariant that all SKBs in the list must have the same refcnt, when using
kfree_skb_list().
Reported-by: syzbot+c8a2e66e37eee553c4fd@syzkaller.appspotmail.com
Reported-and-tested-by: syzbot+c8a2e66e37eee553c4fd@syzkaller.appspotmail.com
Fixes: eedade12f4cb ("net: kfree_skb_list use kmem_cache_free_bulk")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/167421088417.1125894.9761158218878962159.stgit@firesoul
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/skbuff.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 4e73ab3482b8..180df58e85c7 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -999,8 +999,6 @@ kfree_skb_list_reason(struct sk_buff *segs, enum skb_drop_reason reason) while (segs) { struct sk_buff *next = segs->next; - skb_mark_not_on_list(segs); - if (__kfree_skb_reason(segs, reason)) kfree_skb_add_bulk(segs, &sa, reason); |