After @blk_fill_in_prog_lock is acquired there is an early out vnet
situation that can occur. In that case, the rwlock needs to be
released.
Also, since @blk_fill_in_prog_lock is only acquired when @tp_version
is exactly TPACKET_V3, only release it on that exact condition as
well.
And finally, add sparse annotation so that it is clearer that
prb_fill_curr_block() and prb_clear_blk_fill_status() are acquiring
and releasing @blk_fill_in_prog_lock, respectively. sparse is still
unable to understand the balance, but the warnings are now on a
higher level that make more sense.
Fixes: 632ca50f2c ("af_packet: TPACKET_V3: replace busy-wait loop")
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rework the remaining setsockopt code to pass a sockptr_t instead of a
plain user pointer. This removes the last remaining set_fs(KERNEL_DS)
outside of architecture specific code.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> [ieee802154]
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass a sockptr_t to prepare for set_fs-less handling of the kernel
pointer from bpf-cgroup.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Just check for a NULL method instead of wiring up
sock_no_{get,set}sockopt.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a helper that copies either a native or compat bpf_fprog from
userspace after verifying the length, and remove the compat setsockopt
handlers that now aren't required.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
A busy-wait loop is used to implement waiting for bits to be copied
from the skb to the kernel buffer before retiring a block. This is
a problem on PREEMPT_RT because the copying task could be preempted
by the busy-waiting task and thus live lock in the busy-wait loop.
Replace the busy-wait logic with an rwlock_t. This provides lockdep
coverage and makes the code RT ready.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The variable err is being initialized with a value that is never read
and it is being updated later with a new value. The initialization is
redundant and can be removed.
Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since commit 84af7a6194 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.
This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.
There are a variety of indentation styles found.
a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'
In order to convert all of them to 1 tab + 'help', I ran the
following commend:
$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
PACKET_RX_RING can cause multiple writers to access the same slot if a
fast writer wraps the ring while a slow writer is still copying. This
is particularly likely with few, large, slots (e.g., GSO packets).
Synchronize kernel thread ownership of rx ring slots with a bitmap.
Writers acquire a slot race-free by testing tp_status TP_STATUS_KERNEL
while holding the sk receive queue lock. They release this lock before
copying and set tp_status to TP_STATUS_USER to release to userspace
when done. During copying, another writer may take the lock, also see
TP_STATUS_KERNEL, and start writing to the same slot.
Introduce a new rx_owner_map bitmap with a bit per slot. To acquire a
slot, test and set with the lock held. To release race-free, update
tp_status and owner bit as a transaction, so take the lock again.
This is the one of a variety of discussed options (see Link below):
* instead of a shadow ring, embed the data in the slot itself, such as
in tp_padding. But any test for this field may match a value left by
userspace, causing deadlock.
* avoid the lock on release. This leaves a small race if releasing the
shadow slot before setting TP_STATUS_USER. The below reproducer showed
that this race is not academic. If releasing the slot after tp_status,
the race is more subtle. See the first link for details.
* add a new tp_status TP_KERNEL_OWNED to avoid the transactional store
of two fields. But, legacy applications may interpret all non-zero
tp_status as owned by the user. As libpcap does. So this is possible
only opt-in by newer processes. It can be added as an optional mode.
* embed the struct at the tail of pg_vec to avoid extra allocation.
The implementation proved no less complex than a separate field.
The additional locking cost on release adds contention, no different
than scaling on multicore or multiqueue h/w. In practice, below
reproducer nor small packet tcpdump showed a noticeable change in
perf report in cycles spent in spinlock. Where contention is
problematic, packet sockets support mitigation through PACKET_FANOUT.
And we can consider adding opt-in state TP_KERNEL_OWNED.
Easy to reproduce by running multiple netperf or similar TCP_STREAM
flows concurrently with `tcpdump -B 129 -n greater 60000`.
Based on an earlier patchset by Jon Rosen. See links below.
I believe this issue goes back to the introduction of tpacket_rcv,
which predates git history.
Link: https://www.mail-archive.com/netdev@vger.kernel.org/msg237222.html
Suggested-by: Jon Rosen <jrosen@cisco.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jon Rosen <jrosen@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In one error case, tpacket_rcv drops packets after incrementing the
ring producer index.
If this happens, it does not update tp_status to TP_STATUS_USER and
thus the reader is stalled for an iteration of the ring, causing out
of order arrival.
The only such error path is when virtio_net_hdr_from_skb fails due
to encountering an unknown GSO type.
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull y2038 updates from Arnd Bergmann:
"Core, driver and file system changes
These are updates to device drivers and file systems that for some
reason or another were not included in the kernel in the previous
y2038 series.
I've gone through all users of time_t again to make sure the kernel is
in a long-term maintainable state, replacing all remaining references
to time_t with safe alternatives.
Some related parts of the series were picked up into the nfsd, xfs,
alsa and v4l2 trees. A final set of patches in linux-mm removes the
now unused time_t/timeval/timespec types and helper functions after
all five branches are merged for linux-5.6, ensuring that no new users
get merged.
As a result, linux-5.6, or my backport of the patches to 5.4 [1],
should be the first release that can serve as a base for a 32-bit
system designed to run beyond year 2038, with a few remaining caveats:
- All user space must be compiled with a 64-bit time_t, which will be
supported in the coming musl-1.2 and glibc-2.32 releases, along
with installed kernel headers from linux-5.6 or higher.
- Applications that use the system call interfaces directly need to
be ported to use the time64 syscalls added in linux-5.1 in place of
the existing system calls. This impacts most users of futex() and
seccomp() as well as programming languages that have their own
runtime environment not based on libc.
- Applications that use a private copy of kernel uapi header files or
their contents may need to update to the linux-5.6 version, in
particular for sound/asound.h, xfs/xfs_fs.h, linux/input.h,
linux/elfcore.h, linux/sockios.h, linux/timex.h and
linux/can/bcm.h.
- A few remaining interfaces cannot be changed to pass a 64-bit
time_t in a compatible way, so they must be configured to use
CLOCK_MONOTONIC times or (with a y2106 problem) unsigned 32-bit
timestamps. Most importantly this impacts all users of 'struct
input_event'.
- All y2038 problems that are present on 64-bit machines also apply
to 32-bit machines. In particular this affects file systems with
on-disk timestamps using signed 32-bit seconds: ext4 with
ext3-style small inodes, ext2, xfs (to be fixed soon) and ufs"
[1] https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git/log/?h=y2038-endgame
* tag 'y2038-drivers-for-v5.6-signed' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (21 commits)
Revert "drm/etnaviv: reject timeouts with tv_nsec >= NSEC_PER_SEC"
y2038: sh: remove timeval/timespec usage from headers
y2038: sparc: remove use of struct timex
y2038: rename itimerval to __kernel_old_itimerval
y2038: remove obsolete jiffies conversion functions
nfs: fscache: use timespec64 in inode auxdata
nfs: fix timstamp debug prints
nfs: use time64_t internally
sunrpc: convert to time64_t for expiry
drm/etnaviv: avoid deprecated timespec
drm/etnaviv: reject timeouts with tv_nsec >= NSEC_PER_SEC
drm/msm: avoid using 'timespec'
hfs/hfsplus: use 64-bit inode timestamps
hostfs: pass 64-bit timestamps to/from user space
packet: clarify timestamp overflow
tsacct: add 64-bit btime field
acct: stop using get_seconds()
um: ubd: use 64-bit time_t where possible
xtensa: ISS: avoid struct timeval
dlm: use SO_SNDTIMEO_NEW instead of SO_SNDTIMEO_OLD
...
If __ethtool_get_link_ksettings() is failed and with
non-zero value, prb_calc_retire_blk_tmo() should return
DEFAULT_PRB_RETIRE_TOV firstly.
This patch is to refactory code and make it more readable.
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The memory mapped packet socket data structure in version 1 through 3
all contain 32-bit second values for the packet time stamps, which makes
them suffer from the overflow of time_t in y2038 or y2106 (depending
on whether user space interprets the value as signed or unsigned).
The implementation uses the deprecated getnstimeofday() function.
In order to get rid of that, this changes the code to use
ktime_get_real_ts64() as a replacement, documenting the nature of the
overflow. As long as the user applications treat the timestamps as
unsigned, or only use the difference between timestamps, they are
fine, and changing the timestamps to 64-bit wouldn't require a more
invasive user space API change.
Note: a lot of other APIs suffer from incompatible structures when
time_t gets redefined to 64-bit in 32-bit user space, but this one
does not.
Acked-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/lkml/CAF=yD-Jomr-gWSR-EBNKnSpFL46UeG564FLfqTCMNEm-prEaXA@mail.gmail.com/T/#u
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
There is softlockup when using TPACKET_V3:
...
NMI watchdog: BUG: soft lockup - CPU#2 stuck for 60010ms!
(__irq_svc) from [<c0558a0c>] (_raw_spin_unlock_irqrestore+0x44/0x54)
(_raw_spin_unlock_irqrestore) from [<c027b7e8>] (mod_timer+0x210/0x25c)
(mod_timer) from [<c0549c30>]
(prb_retire_rx_blk_timer_expired+0x68/0x11c)
(prb_retire_rx_blk_timer_expired) from [<c027a7ac>]
(call_timer_fn+0x90/0x17c)
(call_timer_fn) from [<c027ab6c>] (run_timer_softirq+0x2d4/0x2fc)
(run_timer_softirq) from [<c021eaf4>] (__do_softirq+0x218/0x318)
(__do_softirq) from [<c021eea0>] (irq_exit+0x88/0xac)
(irq_exit) from [<c0240130>] (msa_irq_exit+0x11c/0x1d4)
(msa_irq_exit) from [<c0209cf0>] (handle_IPI+0x650/0x7f4)
(handle_IPI) from [<c02015bc>] (gic_handle_irq+0x108/0x118)
(gic_handle_irq) from [<c0558ee4>] (__irq_usr+0x44/0x5c)
...
If __ethtool_get_link_ksettings() is failed in
prb_calc_retire_blk_tmo(), msec and tmo will be zero, so tov_in_jiffies
is zero and the timer expire for retire_blk_timer is turn to
mod_timer(&pkc->retire_blk_timer, jiffies + 0),
which will trigger cpu usage of softirq is 100%.
Fixes: f6fb8f100b ("af-packet: TPACKET_V3 flexible buffer implementation.")
Tested-by: Xiao Jiangfeng <xiaojiangfeng@huawei.com>
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit 174e23810c
("sk_buff: drop all skb extensions on free and skb scrubbing") made napi
recycle always drop skb extensions. The additional skb_ext_del() that is
performed via nf_reset on napi skb recycle is not needed anymore.
Most nf_reset() calls in the stack are there so queued skb won't block
'rmmod nf_conntrack' indefinitely.
This removes the skb_ext_del from nf_reset, and renames it to a more
fitting nf_reset_ct().
In a few selected places, add a call to skb_ext_reset to make sure that
no active extensions remain.
I am submitting this for "net", because we're still early in the release
cycle. The patch applies to net-next too, but I think the rename causes
needless divergence between those trees.
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
The new route handling in ip_mc_finish_output() from 'net' overlapped
with the new support for returning congestion notifications from BPF
programs.
In order to handle this I had to take the dev_loopback_xmit() calls
out of the switch statement.
The aquantia driver conflicts were simple overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
When an application is run that:
a) Sets its scheduler to be SCHED_FIFO
and
b) Opens a memory mapped AF_PACKET socket, and sends frames with the
MSG_DONTWAIT flag cleared, its possible for the application to hang
forever in the kernel. This occurs because when waiting, the code in
tpacket_snd calls schedule, which under normal circumstances allows
other tasks to run, including ksoftirqd, which in some cases is
responsible for freeing the transmitted skb (which in AF_PACKET calls a
destructor that flips the status bit of the transmitted frame back to
available, allowing the transmitting task to complete).
However, when the calling application is SCHED_FIFO, its priority is
such that the schedule call immediately places the task back on the cpu,
preventing ksoftirqd from freeing the skb, which in turn prevents the
transmitting task from detecting that the transmission is complete.
We can fix this by converting the schedule call to a completion
mechanism. By using a completion queue, we force the calling task, when
it detects there are no more frames to send, to schedule itself off the
cpu until such time as the last transmitted skb is freed, allowing
forward progress to be made.
Tested by myself and the reporter, with good results
Change Notes:
V1->V2:
Enhance the sleep logic to support being interruptible and
allowing for honoring to SK_SNDTIMEO (Willem de Bruijn)
V2->V3:
Rearrage the point at which we wait for the completion queue, to
avoid needing to check for ph/skb being null at the end of the loop.
Also move the complete call to the skb destructor to avoid needing to
modify __packet_set_status. Also gate calling complete on
packet_read_pending returning zero to avoid multiple calls to complete.
(Willem de Bruijn)
Move timeo computation within loop, to re-fetch the socket
timeout since we also use the timeo variable to record the return code
from the wait_for_complete call (Neil Horman)
V3->V4:
Willem has requested that the control flow be restored to the
previous state. Doing so lets us eliminate the need for the
po->wait_on_complete flag variable, and lets us get rid of the
packet_next_frame function, but introduces another complexity.
Specifically, but using the packet pending count, we can, if an
applications calls sendmsg multiple times with MSG_DONTWAIT set, each
set of transmitted frames, when complete, will cause
tpacket_destruct_skb to issue a complete call, for which there will
never be a wait_on_completion call. This imbalance will lead to any
future call to wait_for_completion here to return early, when the frames
they sent may not have completed. To correct this, we need to re-init
the completion queue on every call to tpacket_snd before we enter the
loop so as to ensure we wait properly for the frames we send in this
iteration.
Change the timeout and interrupted gotos to out_put rather than
out_status so that we don't try to free a non-existant skb
Clean up some extra newlines (Willem de Bruijn)
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are two places where we want to clear the pressure
if possible, add a helper to make it more obvious.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Willem de Bruijn <willemb@google.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
__packet_rcv_has_room() can now be run without lock being held.
po->pressure is only a non persistent hint, we can mark
all read/write accesses with READ_ONCE()/WRITE_ONCE()
to document the fact that the field could be written
without any synchronization.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
tpacket_rcv() can be hit under DDOS quite hard, since
it will always grab a socket spinlock, to eventually find
there is no room for an additional packet.
Using tcpdump [1] on a busy host can lead to catastrophic consequences,
because of all cpus spinning on a contended spinlock.
This replicates a similar strategy used in packet_rcv()
[1] Also some applications mistakenly use af_packet socket
bound to ETH_P_ALL only to send packets.
Receive queue is never drained and immediately full.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Under DDOS, we want to be able to increment tp_drops without
touching the spinlock. This will help readers to drain
the receive queue slightly faster :/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
