Shadow stacks are only available in the kernel, so disable SCS
instrumentation for the vDSO.
Bug: 145210207
Change-Id: I6e01b2c7788ba52d3b754b1fbd5bfb908b45741b
(am from https://lore.kernel.org/patchwork/patch/1149061/)
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
* This function is meant for cleaning up going from STA to AP mode
* On latest 18.1 builds deleting/deactivating AP interface causes
hotspot not to work, hostapd starts up and system says hotspot
is on, but due to a kernel error (vif type isn't set to AP anymore)
SSID isn't actually broadcasted and clients can't find nor connect
to the hotspot
* So let's remove this as removing it doesn't seem to have any
negative consequences but fixes hotspot, also disable an
ugly warning caused by this which isn't actually a problem
Change-Id: I5a656fd38697b9be09ecdc5f344bc343458aeaaf
PLB (Protective Load Balancing) is a host based mechanism for load
balancing across switch links. It leverages congestion signals(e.g. ECN)
from transport layer to randomly change the path of the connection
experiencing congestion. PLB changes the path of the connection by
changing the outgoing IPv6 flow label for IPv6 connections (implemented
in Linux by calling sk_rethink_txhash()). Because of this implementation
mechanism, PLB can currently only work for IPv6 traffic. For more
information, see the SIGCOMM 2022 paper:
https://doi.org/10.1145/3544216.3544226
This commit adds new sysctl knobs and sets their default values for
TCP PLB.
Signed-off-by: Mubashir Adnan Qureshi <mubashirq@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
PLB support is added to TCP DCTCP code. As DCTCP uses ECN as the
congestion signal, PLB also uses ECN to make decisions whether to change
the path or not upon sustained congestion.
Signed-off-by: Mubashir Adnan Qureshi <mubashirq@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
rcv_wnd can be useful to diagnose TCP performance where receiver window
becomes the bottleneck. rehash reports the PLB and timeout triggered
rehash attempts by the TCP connection.
Signed-off-by: Mubashir Adnan Qureshi <mubashirq@google.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
We had various bugs over the years with code
breaking the assumption that tp->snd_cwnd is greater
than zero.
Lately, syzbot reported the WARN_ON_ONCE(!tp->prior_cwnd) added
in commit 8b8a321ff72c ("tcp: fix zero cwnd in tcp_cwnd_reduction")
can trigger, and without a repro we would have to spend
considerable time finding the bug.
Instead of complaining too late, we want to catch where
and when tp->snd_cwnd is set to an illegal value.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Link: https://lore.kernel.org/r/20220405233538.947344-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
In order to track CE marks per rate sample (one round trip), TCP needs a
per-skb header field to record the tp->delivered_ce count when the skb
was sent. To make space, we replace the "last_in_flight" field which is
used exclusively for NV congestion control. The stat needed by NV can be
alternatively approximated by existing stats tcp_sock delivered and
mss_cache.
This patch counts the number of packets delivered which have CE marks in
the rate sample, using similar approach of delivery accounting.
Cc: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Luke Hsiao <lukehsiao@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
This commit is a bug fix for the Linux TCP app-limited
(application-limited) logic that is used for collecting rate
(bandwidth) samples.
Previously the app-limited logic only looked for "bubbles" of
silence in between application writes, by checking at the start
of each sendmsg. But "bubbles" of silence can also happen before
retransmits: e.g. bubbles can happen between an application write
and a retransmit, or between two retransmits.
Retransmits are triggered by ACKs or timers. So this commit checks
for bubbles of app-limited silence upon ACKs or timers.
Why does this commit check for app-limited state at the start of
ACKs and timer handling? Because at that point we know whether
inflight was fully using the cwnd. During processing the ACK or
timer event we often change the cwnd; after changing the cwnd we
can't know whether inflight was fully using the old cwnd.
Origin-9xx-SHA1: 3fe9b53291e018407780fb8c356adb5666722cbc
Change-Id: I37221506f5166877c2b110753d39bb0757985e68
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
For understanding the relationship between inflight and ECN signals,
to try to find the highest inflight value that has acceptable levels
ECN marking.
Effort: net-tcp_bbr
Origin-9xx-SHA1: 3eba998f2898541406c2666781182200934965a8
Change-Id: I3a964e04cee83e11649a54507043d2dfe769a3b3
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
For connections experiencing reordering, RACK can mark packets lost
long after we receive the SACKs/ACKs hinting that the packets were
actually lost.
This means that CC modules cannot easily learn the volume of inflight
data at which packet loss happens by looking at the current inflight
or even the packets in flight when the most recently SACKed packet was
sent. To learn this, CC modules need to know how many packets were in
flight at the time lost packets were sent. This new callback, combined
with TCP_SKB_CB(skb)->tx.in_flight, allows them to learn this.
This also provides a consistent callback that is invoked whether
packets are marked lost upon ACK processing, using the RACK reordering
timer, or at RTO time.
Effort: net-tcp_bbr
Origin-9xx-SHA1: afcbebe3374e4632ac6714d39e4dc8a8455956f4
Change-Id: I54826ab53df636be537e5d3c618a46145d12d51a
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
When tcp_shifted_skb() updates state as adjacent SACKed skbs are
coalesced, previously the tx.in_flight was not adjusted, so we could
get contradictory state where the skb's recorded pcount was bigger
than the tx.in_flight (the number of segments that were in_flight
after sending the skb).
Normally have a SACKed skb with contradictory pcount/tx.in_flight
would not matter. However, with SACK reneging, the SACKed bit is
removed, and an skb once again becomes eligible for retransmitting,
fragmenting, SACKing, etc. Packetdrill testing verified the following
sequence is possible in a kernel that does not have this commit:
- skb N is SACKed
- skb N+1 is SACKed and combined with skb N using tcp_shifted_skb()
- tcp_shifted_skb() will increase the pcount of prev,
but leave tx.in_flight as-is
- so prev skb can have pcount > tx.in_flight
- RTO, tcp_timeout_mark_lost(), detect reneg,
remove "SACKed" bit, mark skb N as lost
- find pcount of skb N is greater than its tx.in_flight
I suspect this issue iw what caused the bbr2_inflight_hi_from_lost_skb():
WARN_ON_ONCE(inflight_prev < 0)
to fire in production machines using bbr2.
Effort: net-tcp_bbr
Origin-9xx-SHA1: 1a3e997e613d2dcf32b947992882854ebe873715
Change-Id: I1b0b75c27519953430c7db51c6f358f104c7af55
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
When we fragment an skb that has already been sent, we need to update
the tx.in_flight for the first skb in the resulting pair ("buff").
Because we were not updating the tx.in_flight, the tx.in_flight value
was inconsistent with the pcount of the "buff" skb (tx.in_flight would
be too high). That meant that if the "buff" skb was lost, then
bbr2_inflight_hi_from_lost_skb() would calculate an inflight_hi value
that is too high. This could result in longer queues and higher packet
loss.
Packetdrill testing verified that without this commit, when the second
half of an skb is SACKed and then later the first half of that skb is
marked lost, the calculated inflight_hi was incorrect.
Effort: net-tcp_bbr
Origin-9xx-SHA1: 385f1ddc610798fab2837f9f372857438b25f874
Origin-9xx-SHA1: a0eb099690af net-tcp_bbr: v2: fix tcp_fragment() tx.in_flight recomputation [prod feb 8 2021; use as a fixup]
Origin-9xx-SHA1: 885503228153ff0c9114e net-tcp_bbr: v2: introduce tcp_skb_tx_in_flight_is_suspicious() helper for warnings
Change-Id: I617f8cab4e9be7a0b8e8d30b047bf8645393354d
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
Add a a new ca opts flag TCP_CONG_WANTS_CE_EVENTS that allows a
congestion control module to receive CE events.
Currently congestion control modules have to set the TCP_CONG_NEEDS_ECN
bit in opts flag to receive CE events but this may incur changes in ECN
behavior elsewhere. This patch adds a new bit TCP_CONG_WANTS_CE_EVENTS
that allows congestion control modules to receive CE events
independently of TCP_CONG_NEEDS_ECN.
Effort: net-tcp
Origin-9xx-SHA1: 9f7e14716cde760bc6c67ef8ef7e1ee48501d95b
Change-Id: I2255506985242f376d910c6fd37daabaf4744f24
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
Add logic for an experimental TCP connection behavior, enabled with
tp->fast_ack_mode = 1, which disables checking the receive window
before sending an ack in __tcp_ack_snd_check(). If this behavior is
enabled, the data receiver sends an ACK if the amount of data is >
RCV.MSS.
Change-Id: Iaa0a0fd7108221f883137a79d5bfa724f1b096d4
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
Before this commit, when there is a packet loss that creates a sequence
hole that is filled by a TLP loss probe, then tcp_process_tlp_ack()
only informs the congestion control (CC) module via a back-to-back entry
and exit of CWR. But some congestion control modules (e.g. BBR) do not
respond to CWR events.
This commit adds a new CA event with which the core TCP stack notifies
the CC module when a loss is repaired by a TLP. This will allow CC
modules that do not use the CWR mechanism to have a custom handler for
such TLP recoveries.
Effort: net-tcp_bbr
Change-Id: Ieba72332b401b329bff5a641d2b2043a3fb8f632
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
Introduce is_acking_tlp_retrans_seq into rate_sample. This bool will
export to the CC module the knowledge of whether the current ACK
matched a TLP retransmit.
Note that when this bool is true, we cannot yet tell (in general) whether
this ACK is for the original or the TLP retransmit.
Effort: net-tcp_bbr
Change-Id: I2e6494332167e75efcbdc99bd5c119034e9c39b4
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
