mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git
synced 2026-10-31 14:23:49 +01:00
Eric Dumazet
cd5dd68267
Callers that only reserve ETH_HLEN or less (such as llc_alloc_frame()),
or skbs allocated before dynamic device/headroom changes (e.g. toggling
VLAN_FLAG_REORDER_HDR or bonding/team switching slaves), can reach
vlan_dev_hard_header() with insufficient headroom and trigger
skb_under_panic().
Use skb_cow_head() in vlan_dev_hard_header() when VLAN_FLAG_REORDER_HDR
is not set to ensure sufficient headroom for the VLAN header(s) and the
underlying device hard header.
Use READ_ONCE() to read dev->hard_header_len and dev->needed_headroom as
they can be updated concurrently under RTNL (e.g. in
vlan_transfer_features()) while vlan_dev_hard_header() runs locklessly on
the transmit path. Also avoid LL_RESERVED_SPACE(dev) here so that the
extra HH_DATA_MOD alignment padding does not trigger unnecessary
pskb_expand_head() reallocations on inner stacked VLAN devices after the
outer VLAN header has been pushed.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Zixuan Chai <[email protected]>
Closes: https://lore.kernel.org/netdev/[email protected]/
Link: https://lore.kernel.org/netdev/[email protected]/
Cc: Hangbin Liu <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>