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Both are ARPHRD_ETHER and share > the same lockdep class, creating an ABBA deadlock: > > sch_direct_xmit [lock erspan] -> erspan_xmit -> ip_tunnel_xmit -> > ip_output -> __dev_queue_xmit -> sch_direct_xmit [lock underlay] Sashiko complains that this is not accurate. Clarify that both the overlay and underlay devices are of the same type (both erspan or both ip6erspan). Not erspan and some Ethernet device in the underlay. See: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260730082238.676845-1-yun.zhou%40windriver.com And: https://lore.kernel.org/all/83360de7addb13a3b5f4d5e722148f248fdb2ae0.1784884817.git.pabeni@redhat.com/ > > Set dev->lltx = true so HARD_TX_LOCK() skips the spinlock for ERSPAN. > This is safe as erspan_xmit() has no shared mutable state: o_seqno is > atomic, stats use atomic_long_inc, and dst_cache is per-CPU. GRETAP, > the sibling device with identical xmit structure, already sets lltx. This is still not safe and in v2 I asked to wait for Eric's patch to be accepted: https://lore.kernel.org/netdev/20260720075352.GA2233846@shredder/ And it's still WIP: https://lore.kernel.org/netdev/20260720135132.3957146-1-edumazet@google.com/ > > Closes: https://syzkaller.appspot.com/bug?extid=9bda1b9fbb7fbdf9b62b > Reported-by: syzbot+9bda1b9fbb7fbdf9b62b@syzkaller.appspotmail.com > Fixes: 84e54fe0a5ea ("gre: introduce native tunnel support for ERSPAN") > Fixes: 5a963eb61b7c ("ip6_gre: Add ERSPAN native tunnel support") > Cc: stable@vger.kernel.org > Signed-off-by: Yun Zhou > --- > v3: > - add fix for IPv6 The commit message doesn't mention the ip6erspan fix.