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f5f99309fa
Do not set sk_err when dequeuing errors from the error queue. Doing so results in: a) Bugs: By overwriting existing sk_err values, it possibly hides legitimate errors. It is also incorrect when local errors are queued with ip_local_error. That happens in the context of a system call, which already returns the error code. b) Inconsistent behavior: When there are pending errors on the error queue, sk_err is sometimes 0 (e.g., for the first timestamp on the error queue) and sometimes set to an error code (after dequeuing the first timestamp). c) Suboptimality: Setting sk_err to ENOMSG on simple TX timestamps can abort parallel reads and writes. Removing this line doesn't break userspace. This is because userspace code cannot rely on sk_err for detecting whether there is something on the error queue. Except for ICMP messages received for UDP and RAW, sk_err is not set at enqueue time, and as a result sk_err can be 0 while there are plenty of errors on the error queue. For ICMP packets in UDP and RAW, sk_err is set when they are enqueued on the error queue, but that does not result in aborting reads and writes. For such cases, sk_err is only readable via getsockopt(SO_ERROR) which will reset the value of sk_err on its own. More importantly, prior to this patch, recvmsg(MSG_ERRQUEUE) has a race on setting sk_err (i.e., sk_err is set by sock_dequeue_err_skb without atomic ops or locks) which can store 0 in sk_err even when we have ICMP messages pending. Removing this line from sock_dequeue_err_skb eliminates that race. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| 802 | ||
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| appletalk | ||
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| batman-adv | ||
| bluetooth | ||
| bridge | ||
| caif | ||
| can | ||
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| core | ||
| dcb | ||
| dccp | ||
| decnet | ||
| dns_resolver | ||
| dsa | ||
| ethernet | ||
| hsr | ||
| ieee802154 | ||
| ipv4 | ||
| ipv6 | ||
| ipx | ||
| irda | ||
| iucv | ||
| kcm | ||
| key | ||
| l2tp | ||
| l3mdev | ||
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| mac80211 | ||
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| mpls | ||
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| netfilter | ||
| netlabel | ||
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| netrom | ||
| nfc | ||
| openvswitch | ||
| packet | ||
| phonet | ||
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| rds | ||
| rfkill | ||
| rose | ||
| rxrpc | ||
| sched | ||
| sctp | ||
| strparser | ||
| sunrpc | ||
| switchdev | ||
| tipc | ||
| unix | ||
| vmw_vsock | ||
| wimax | ||
| wireless | ||
| x25 | ||
| xfrm | ||
| compat.c | ||
| Kconfig | ||
| Makefile | ||
| socket.c | ||
| sysctl_net.c | ||