When epoch(9) was introduced to network stack, it was basically
dropped in place of existing locking, which was mutexes and
rwlocks. For the sake of performance mutex covered areas were
as small as possible, so became epoch covered areas.
However, epoch doesn't introduce any contention, it just delays
memory reclaim. So, there is no point to minimise epoch covered
areas in sense of performance. Meanwhile entering/exiting epoch
also has non-zero CPU usage, so doing this less often is a win.
Not the least is also code maintainability. In the new paradigm
we can assume that at any stage of processing a packet, we are
inside network epoch. This makes coding both input and output
path way easier.
On output path we already enter epoch quite early - in the
ip_output(), in the ip6_output().
This patch does the same for the input path. All ISR processing,
network related callouts, other ways of packet injection to the
network stack shall be performed in net_epoch. Any leaf function
that walks network configuration now asserts epoch.
Tricky part is configuration code paths - ioctls, sysctls. They
also call into leaf functions, so some need to be changed.
This patch would introduce more epoch recursions (see EPOCH_TRACE)
than we had before. They will be cleaned up separately, as several
of them aren't trivial. Note, that unlike a lock recursion the
epoch recursion is safe and just wastes a bit of resources.
Reviewed by: gallatin, hselasky, cy, adrian, kristof
Differential Revision: https://reviews.freebsd.org/D19111
instead of a linear array.
The multicast memberships for the inpcb structure are protected by a
non-sleepable lock, INP_WLOCK(), which needs to be dropped when
calling the underlying possibly sleeping if_ioctl() method. When using
a linear array to keep track of multicast memberships, the computed
memory location of the multicast filter may suddenly change, due to
concurrent insertion or removal of elements in the linear array. This
in turn leads to various invalid memory access issues and kernel
panics.
To avoid this problem, put all multicast memberships on a STAILQ based
list. Then the memory location of the IPv4 and IPv6 multicast filters
become fixed during their lifetime and use after free and memory leak
issues are easier to track, for example by: vmstat -m | grep multi
All list manipulation has been factored into inline functions
including some macros, to easily allow for a future hash-list
implementation, if needed.
This patch has been tested by pho@ .
Differential Revision: https://reviews.freebsd.org/D20080
Reviewed by: markj @
MFC after: 1 week
Sponsored by: Mellanox Technologies
r333175 converted the global multicast lock to a sleepable sx lock,
so the lock order with respect to the (non-sleepable) inp lock changed.
To handle this, r333175 and r333505 added code to drop the inp lock,
but this opened races that could leave multicast group description
structures in an inconsistent state. This change fixes the problem by
simply acquiring the global lock sooner. Along the way, this fixes
some LORs and bogus error handling introduced in r333175, and commits
some related cleanup.
Reported by: syzbot+ba7c4943547e0604faca@syzkaller.appspotmail.com
Reported by: syzbot+1b803796ab94d11a46f9@syzkaller.appspotmail.com
Reviewed by: ae
MFC after: 3 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20070
Turning on multicast debug made multicast failure worse
because the strings and #define values no longer matched
up. Fix them, and make sure they stay matched-up.
Submitted by: torek
MFC after: 1 week
Sponsored by: iXsystems, Inc.
When leaving a multicast group, a hole may be created in the inpcb's
source filter and group membership arrays. To remove the hole, the
succeeding array elements are copied over by one entry. The multicast
code expects that a newly allocated array element is initialized, but
the code which shifts a tail of the array was leaving stale data
in the final entry. Fix this by explicitly reinitializing the last
entry following such a copy.
Reported by: syzbot+f8c3c564ee21d650475e@syzkaller.appspotmail.com
Reviewed by: ae
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19872
for struct ip_mreq remains in place.
The struct ip_mreqn is Linux extension to classic BSD multicast API. It
has extra field allowing to specify the interface index explicitly. In
Linux it used as argument for IP_MULTICAST_IF and IP_ADD_MEMBERSHIP.
FreeBSD kernel also declares this structure and supports it as argument
to IP_MULTICAST_IF since r170613. So, we have structure declared but
not fully supported, this confused third party application configure
scripts.
Code handling IP_ADD_MEMBERSHIP was mixed together with code for
IP_ADD_SOURCE_MEMBERSHIP. Bringing legacy and new structure support
into the mess would made the "argument switcharoo" intolerable, so
code was separated into its own switch case clause.
MFC after: 3 months
Differential Revision: https://reviews.freebsd.org/D19276
- Remove macros that covertly create epoch_tracker on thread stack. Such
macros a quite unsafe, e.g. will produce a buggy code if same macro is
used in embedded scopes. Explicitly declare epoch_tracker always.
- Unmask interface list IFNET_RLOCK_NOSLEEP(), interface address list
IF_ADDR_RLOCK() and interface AF specific data IF_AFDATA_RLOCK() read
locking macros to what they actually are - the net_epoch.
Keeping them as is is very misleading. They all are named FOO_RLOCK(),
while they no longer have lock semantics. Now they allow recursion and
what's more important they now no longer guarantee protection against
their companion WLOCK macros.
Note: INP_HASH_RLOCK() has same problems, but not touched by this commit.
This is non functional mechanical change. The only functionally changed
functions are ni6_addrs() and ni6_store_addrs(), where we no longer enter
epoch recursively.
Discussed with: jtl, gallatin
This is actually several different bugs:
- The code is not designed to handle inpcb deletion after interface deletion
- add reference for inpcb membership
- The multicast address has to be removed from interface lists when the refcount
goes to zero OR when the interface goes away
- decouple list disconnect from refcount (v6 only for now)
- ifmultiaddr can exist past being on interface lists
- add flag for tracking whether or not it's enqueued
- deferring freeing moptions makes the incpb cleanup code simpler but opens the
door wider still to races
- call inp_gcmoptions synchronously after dropping the the inpcb lock
Fundamentally multicast needs a rewrite - but keep applying band-aids for now.
Tested by: kp
Reported by: novel, kp, lwhsu
On PowerPC (and possibly other architectures), that doesn't use
EARLY_AP_STARTUP, the config task queue may be used initialized.
This was observed while trying to mount the root fs from NFS, as
reported here: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=230168.
This patch has 2 main changes:
1- Perform a basic initialization of qgroup_config, similar to
what is done in taskqgroup_adjust, but simpler.
This makes qgroup_config ready to be used during NFS root mount.
2- When EARLY_AP_STARTUP is not used, call inm_init() and
in6m_init() right before SI_SUB_ROOT_CONF, because bootp needs
to send multicast packages to request an IP.
PR: Bug 230168
Reported by: sbruno
Reviewed by: jhibbits, mmacy, sbruno
Approved by: jhibbits
Differential Revision: D16633
Per vnet(9), CURVNET_SET and CURVNET_RESTORE cannot be used as a single
statement for a conditional and CURVNET_RESTORE must be in the same
block as CURVNET_SET (or a subblock).
Reviewed by: andrew
Sponsored by: The FreeBSD Foundation
Avoid the ugly unlock / lock of the inpcbinfo where we need to
figure out what kind of lock we hold by simply deferring the
operation to another context. (Also a small dependency for
converting the pcbinfo read lock to epoch)
If ifma_protospec is NULL when inm_lookup() is called, there
is a dereference in a NULL struct pointer. This ensures that struct is
not NULL before comparing the address.
Reported by: dumbbell
Reviewed by: sbruno
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D15440
r333175 updated the join_group functions, but not the leave_group ones.
Reviewed by: sbruno
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D15393
to sleep on commands to the NIC when updating multicast filters. More generally this permitted
driver's to use an sx as a softc lock. Unfortunately this change introduced a race whereby a
a multicast update would still be queued for deletion when ifconfig deleted the interface
thus calling down in to _purgemaddrs and synchronously deleting _all_ of the multicast addresses
on the interface.
Synchronously remove all external references to a multicast address before enqueueing for delete.
Reported by: lwhsu
Approved by: sbruno
to avoid a LOR on the multicast list lock in the freemoptions routines.
As it turns out, tcp_usr_detach can acquire the tcbinfo lock readonly.
Trying to wunlock the pcbinfo lock in that context has caused a number
of reported crashes.
This change unclutters in_pcbfree and moves the handling of wunlock vs
runlock of pcbinfo to the freemoptions routine.
Reported by: mjg@, bde@, o.hartmann at walstatt.org
Approved by: sbruno
Multicast incorrectly calls in to drivers with a mutex held causing drivers
to have to go through all manner of contortions to use a non sleepable lock.
Serialize multicast updates instead.
Submitted by: mmacy <mmacy@mattmacy.io>
Reviewed by: shurd, sbruno
Sponsored by: Limelight Networks
Differential Revision: https://reviews.freebsd.org/D14969
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
No functional change intended.
compiled into the kernel
This ensures that .iss_asm (the number of ASM listeners) isn't incorrectly
decremented for MLD-layer source datagrams when inspecting im*s_st[1]
(the second state in the structure).
MFC after: 2 months
PR: 217509 [1]
Reported by: Coverity (Isilon)
Reviewed by: ae ("This patch looks correct to me." [1])
Submitted by: Miles Ohlrich <miles.ohlrich@isilon.com>
Sponsored by: Dell EMC Isilon
inet_ntoa() and inet_ntoa_r() take the address in network
byte-order. When I removed those calls, I should have
replaced them with ntohl() to make the hex addresses slightly
less unreadable. Here they are.
See r315277 regarding classic blunders.
vangyzen: you're deep in "no good deed" territory, it seems
--badger
Reported by: ian
MFC after: 3 days
MFC when: I finally get it right
Sponsored by: Dell EMC
When I made the changes in r313821, I fell victim to one of the
classic blunders, the most famous of which is: never get involved
in a land war in Asia. But only slightly less well known is this:
Keep your brain turned on and engaged when making a tedious, sweeping,
mechanical change. KTR can correctly log the immediate integral values
passed to it, as well as constant strings, but not non-constant strings,
since they might change by the time ktrdump retrieves them.
Reported by: glebius
MFC after: 3 days
Sponsored by: Dell EMC
inet_ntoa() cannot be used safely in a multithreaded environment
because it uses a static local buffer. Instead, use inet_ntoa_r()
with a buffer on the caller's stack.
Suggested by: glebius, emaste
Reviewed by: gnn
MFC after: 2 weeks
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D9625
ip_dooptions(), icmp6_redirect_input(), in6_lltable_rtcheck(),
in6p_lookup_mcast_ifp() and in6_selecthlim() use new routing api.
Eliminate now-unused ip_rtaddr().
Fix lookup key fib6_lookup_nh_basic() which was lost diring merge.
Make fib6_lookup_nh_basic() and fib6_lookup_nh_extended() always
return IPv6 destination address with embedded scope. Currently
rw_gateway has it scope embedded, do the same for non-gatewayed
destinations.
Sponsored by: Yandex LLC
When the M_NOWAIT allocation fails, we recurse the if_addr_lock trying
to clean up. Reorder the cleanup after dropping the if_addr_lock. The
obvious race is already possible between if_addmulti and IF_ADDR_WLOCK
above, so it must be ok.
Submitted by: Ryan Libby <rlibby@gmail.com>
Reviewed by: jhb
Found with: M_NOWAIT failure injection testing
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D4138
Both are used to protect access to IP addresses lists and they can be
acquired for reading several times per packet. To reduce lock contention
it is better to use rmlock here.
Reviewed by: gnn (previous version)
Obtained from: Yandex LLC
Sponsored by: Yandex LLC
Differential Revision: https://reviews.freebsd.org/D3149
These changes prevent sysctl(8) from returning proper output,
such as:
1) no output from sysctl(8)
2) erroneously returning ENOMEM with tools like truss(1)
or uname(1)
truss: can not get etype: Cannot allocate memory
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.
Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.
MFC after: 2 weeks
Sponsored by: Mellanox Technologies
to this event, adding if_var.h to files that do need it. Also, include
all includes that now are included due to implicit pollution via if_var.h
Sponsored by: Netflix
Sponsored by: Nginx, Inc.
