kernel/linux.git/include/net/inet_frag.h, branch v6.19.11

inet: frags: flush pending skbs in fqdir_pre_exit()

2025-12-10T09:15:27+00:00

We have been seeing occasional deadlocks on pernet_ops_rwsem since September in NIPA. The stuck task was usually modprobe (often loading a driver like ipvlan), trying to take the lock as a Writer. lockdep does not track readers for rwsems so the read wasn't obvious from the reports. On closer inspection the Reader holding the lock was conntrack looping forever in nf_conntrack_cleanup_net_list(). Based on past experience with occasional NIPA crashes I looked thru the tests which run before the crash and noticed that the crash follows ip_defrag.sh. An immediate red flag. Scouring thru (de)fragmentation queues reveals skbs sitting around, holding conntrack references. The problem is that since conntrack depends on nf_defrag_ipv6, nf_defrag_ipv6 will load first. Since nf_defrag_ipv6 loads first its netns exit hooks run _after_ conntrack's netns exit hook. Flush all fragment queue SKBs during fqdir_pre_exit() to release conntrack references before conntrack cleanup runs. Also flush the queues in timer expiry handlers when they discover fqdir->dead is set, in case packet sneaks in while we're running the pre_exit flush. The commit under Fixes is not exactly the culprit, but I think previously the timer firing would eventually unblock the spinning conntrack. Fixes: d5dd88794a13 ("inet: fix various use-after-free in defrags units") Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20251207010942.1672972-4-kuba@kernel.org Signed-off-by: Jakub Kicinski

inet: frags: add inet_frag_queue_flush()

2025-12-10T09:15:27+00:00

Instead of exporting inet_frag_rbtree_purge() which requires that caller takes care of memory accounting, add a new helper. We will need to call it from a few places in the next patch. Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20251207010942.1672972-3-kuba@kernel.org Signed-off-by: Jakub Kicinski

inet: frags: change inet_frag_kill() to defer refcount updates

2025-03-18T12:18:36+00:00

In the following patch, we no longer assume inet_frag_kill() callers own a reference. Consuming two refcounts from inet_frag_kill() would lead in UAF. Propagate the pointer to the refs that will be consumed later by the final inet_frag_putn() call. Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20250312082250.1803501-4-edumazet@google.com Signed-off-by: Paolo Abeni

inet: frags: add inet_frag_putn() helper

2025-03-18T12:18:36+00:00

inet_frag_putn() can release multiple references in one step. Use it in inet_frags_free_cb(). Replace inet_frag_put(X) with inet_frag_putn(X, 1) Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20250312082250.1803501-2-edumazet@google.com Signed-off-by: Paolo Abeni

net: Rename mono_delivery_time to tstamp_type for scalabilty

2024-05-23T21:14:23+00:00

mono_delivery_time was added to check if skb->tstamp has delivery time in mono clock base (i.e. EDT) otherwise skb->tstamp has timestamp in ingress and delivery_time at egress. Renaming the bitfield from mono_delivery_time to tstamp_type is for extensibilty for other timestamps such as userspace timestamp (i.e. SO_TXTIME) set via sock opts. As we are renaming the mono_delivery_time to tstamp_type, it makes sense to start assigning tstamp_type based on enum defined in this commit. Earlier we used bool arg flag to check if the tstamp is mono in function skb_set_delivery_time, Now the signature of the functions accepts tstamp_type to distinguish between mono and real time. Also skb_set_delivery_type_by_clockid is a new function which accepts clockid to determine the tstamp_type. In future tstamp_type:1 can be extended to support userspace timestamp by increasing the bitfield. Signed-off-by: Abhishek Chauhan Reviewed-by: Willem de Bruijn Reviewed-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20240509211834.3235191-2-quic_abchauha@quicinc.com Signed-off-by: Martin KaFai Lau

inet: frags: eliminate kernel-doc warning

2023-07-15T03:39:29+00:00

Modify the anonymous enum kernel-doc content so that it doesn't cause a kernel-doc warning. inet_frag.h:33: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst Fixes: 1ab1934ed80a ("inet: frags: enum the flag definitions and add descriptions") Signed-off-by: Randy Dunlap Cc: Nikolay Aleksandrov Link: https://lore.kernel.org/r/20230714045127.18752-6-rdunlap@infradead.org Signed-off-by: Jakub Kicinski

net: move dropreason.h to dropreason-core.h

2023-04-21T03:20:49+00:00

This will, after the next patch, hold only the core drop reasons and minimal infrastructure. Fix a small kernel-doc issue while at it, to avoid the move triggering a checker. Signed-off-by: Johannes Berg Signed-off-by: Jakub Kicinski

net: dropreason: add SKB_DROP_REASON_FRAG_REASM_TIMEOUT

2022-11-01T03:14:27+00:00

Used to track skbs freed after a timeout happened in a reassmbly unit. Passing a @reason argument to inet_frag_rbtree_purge() allows to use correct consumed status for frags that have been successfully re-assembled. Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski

net: add missing includes and forward declarations under net/

2022-07-22T11:53:22+00:00

This patch adds missing includes to headers under include/net. All these problems are currently masked by the existing users including the missing dependency before the broken header. Signed-off-by: Jakub Kicinski Signed-off-by: David S. Miller

net: ip: Handle delivery_time in ip defrag

2022-03-03T14:38:48+00:00

A latter patch will postpone the delivery_time clearing until the stack knows the skb is being delivered locally. That will allow other kernel forwarding path (e.g. ip[6]_forward) to keep the delivery_time also. An earlier attempt was to do skb_clear_delivery_time() in ip_local_deliver() and ip6_input(). The discussion [0] requested to move it one step later into ip_local_deliver_finish() and ip6_input_finish() so that the delivery_time can be kept for the ip_vs forwarding path also. To do that, this patch also needs to take care of the (rcv) timestamp usecase in ip_is_fragment(). It needs to expect delivery_time in the skb->tstamp, so it needs to save the mono_delivery_time bit in inet_frag_queue such that the delivery_time (if any) can be restored in the final defragmented skb. [Note that it will only happen when the locally generated skb is looping from egress to ingress over a virtual interface (e.g. veth, loopback...), skb->tstamp may have the delivery time before it is known that it will be delivered locally and received by another sk.] [0]: https://lore.kernel.org/netdev/ca728d81-80e8-3767-d5e-d44f6ad96e43@ssi.bg/ Signed-off-by: Martin KaFai Lau Signed-off-by: David S. Miller