f72ff8b81e
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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.