16 Oct, 2020
1 commit
-
Pull networking updates from Jakub Kicinski:
- Add redirect_neigh() BPF packet redirect helper, allowing to limit
stack traversal in common container configs and improving TCP
back-pressure.Daniel reports ~10Gbps => ~15Gbps single stream TCP performance gain.
- Expand netlink policy support and improve policy export to user
space. (Ge)netlink core performs request validation according to
declared policies. Expand the expressiveness of those policies
(min/max length and bitmasks). Allow dumping policies for particular
commands. This is used for feature discovery by user space (instead
of kernel version parsing or trial and error).- Support IGMPv3/MLDv2 multicast listener discovery protocols in
bridge.- Allow more than 255 IPv4 multicast interfaces.
- Add support for Type of Service (ToS) reflection in SYN/SYN-ACK
packets of TCPv6.- In Multi-patch TCP (MPTCP) support concurrent transmission of data on
multiple subflows in a load balancing scenario. Enhance advertising
addresses via the RM_ADDR/ADD_ADDR options.- Support SMC-Dv2 version of SMC, which enables multi-subnet
deployments.- Allow more calls to same peer in RxRPC.
- Support two new Controller Area Network (CAN) protocols - CAN-FD and
ISO 15765-2:2016.- Add xfrm/IPsec compat layer, solving the 32bit user space on 64bit
kernel problem.- Add TC actions for implementing MPLS L2 VPNs.
- Improve nexthop code - e.g. handle various corner cases when nexthop
objects are removed from groups better, skip unnecessary
notifications and make it easier to offload nexthops into HW by
converting to a blocking notifier.- Support adding and consuming TCP header options by BPF programs,
opening the doors for easy experimental and deployment-specific TCP
option use.- Reorganize TCP congestion control (CC) initialization to simplify
life of TCP CC implemented in BPF.- Add support for shipping BPF programs with the kernel and loading
them early on boot via the User Mode Driver mechanism, hence reusing
all the user space infra we have.- Support sleepable BPF programs, initially targeting LSM and tracing.
- Add bpf_d_path() helper for returning full path for given 'struct
path'.- Make bpf_tail_call compatible with bpf-to-bpf calls.
- Allow BPF programs to call map_update_elem on sockmaps.
- Add BPF Type Format (BTF) support for type and enum discovery, as
well as support for using BTF within the kernel itself (current use
is for pretty printing structures).- Support listing and getting information about bpf_links via the bpf
syscall.- Enhance kernel interfaces around NIC firmware update. Allow
specifying overwrite mask to control if settings etc. are reset
during update; report expected max time operation may take to users;
support firmware activation without machine reboot incl. limits of
how much impact reset may have (e.g. dropping link or not).- Extend ethtool configuration interface to report IEEE-standard
counters, to limit the need for per-vendor logic in user space.- Adopt or extend devlink use for debug, monitoring, fw update in many
drivers (dsa loop, ice, ionic, sja1105, qed, mlxsw, mv88e6xxx,
dpaa2-eth).- In mlxsw expose critical and emergency SFP module temperature alarms.
Refactor port buffer handling to make the defaults more suitable and
support setting these values explicitly via the DCBNL interface.- Add XDP support for Intel's igb driver.
- Support offloading TC flower classification and filtering rules to
mscc_ocelot switches.- Add PTP support for Marvell Octeontx2 and PP2.2 hardware, as well as
fixed interval period pulse generator and one-step timestamping in
dpaa-eth.- Add support for various auth offloads in WiFi APs, e.g. SAE (WPA3)
offload.- Add Lynx PHY/PCS MDIO module, and convert various drivers which have
this HW to use it. Convert mvpp2 to split PCS.- Support Marvell Prestera 98DX3255 24-port switch ASICs, as well as
7-port Mediatek MT7531 IP.- Add initial support for QCA6390 and IPQ6018 in ath11k WiFi driver,
and wcn3680 support in wcn36xx.- Improve performance for packets which don't require much offloads on
recent Mellanox NICs by 20% by making multiple packets share a
descriptor entry.- Move chelsio inline crypto drivers (for TLS and IPsec) from the
crypto subtree to drivers/net. Move MDIO drivers out of the phy
directory.- Clean up a lot of W=1 warnings, reportedly the actively developed
subsections of networking drivers should now build W=1 warning free.- Make sure drivers don't use in_interrupt() to dynamically adapt their
code. Convert tasklets to use new tasklet_setup API (sadly this
conversion is not yet complete).* tag 'net-next-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2583 commits)
Revert "bpfilter: Fix build error with CONFIG_BPFILTER_UMH"
net, sockmap: Don't call bpf_prog_put() on NULL pointer
bpf, selftest: Fix flaky tcp_hdr_options test when adding addr to lo
bpf, sockmap: Add locking annotations to iterator
netfilter: nftables: allow re-computing sctp CRC-32C in 'payload' statements
net: fix pos incrementment in ipv6_route_seq_next
net/smc: fix invalid return code in smcd_new_buf_create()
net/smc: fix valid DMBE buffer sizes
net/smc: fix use-after-free of delayed events
bpfilter: Fix build error with CONFIG_BPFILTER_UMH
cxgb4/ch_ipsec: Replace the module name to ch_ipsec from chcr
net: sched: Fix suspicious RCU usage while accessing tcf_tunnel_info
bpf: Fix register equivalence tracking.
rxrpc: Fix loss of final ack on shutdown
rxrpc: Fix bundle counting for exclusive connections
netfilter: restore NF_INET_NUMHOOKS
ibmveth: Identify ingress large send packets.
ibmveth: Switch order of ibmveth_helper calls.
cxgb4: handle 4-tuple PEDIT to NAT mode translation
selftests: Add VRF route leaking tests
...
13 Oct, 2020
1 commit
-
Pull dlm updates from David Teigland:
"This set continues the ongoing rework of the low level communication
layer in the dlm.The focus here is on improvements to connection handling, and
reworking the receiving of messages"* tag 'dlm-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
fs: dlm: fix race in nodeid2con
fs: dlm: rework receive handling
fs: dlm: disallow buffer size below default
fs: dlm: handle range check as callback
fs: dlm: fix mark per nodeid setting
fs: dlm: remove lock dependency warning
fs: dlm: use free_con to free connection
fs: dlm: handle possible othercon writequeues
fs: dlm: move free writequeue into con free
fs: dlm: fix configfs memory leak
fs: dlm: fix dlm_local_addr memory leak
fs: dlm: make connection hash lockless
fs: dlm: synchronize dlm before shutdown
03 Oct, 2020
1 commit
-
Bulk of the genetlink users can use smaller ops, move them.
Signed-off-by: Jakub Kicinski
Reviewed-by: Johannes Berg
Signed-off-by: David S. Miller
01 Oct, 2020
1 commit
-
This patch fixes a race in nodeid2con in cases that we parallel running
a lookup and both will create a connection structure for the same nodeid.
It's a rare case to create a new connection structure to keep reader
lockless we just do a lookup inside the protection area again and drop
previous work if this race happens.Fixes: a47666eb763cc ("fs: dlm: make connection hash lockless")
Signed-off-by: Alexander Aring
Signed-off-by: David Teigland
30 Sep, 2020
5 commits
-
This patch reworks the current receive handling of dlm. As I tried to
change the send handling to fix reorder issues I took a look into the
receive handling and simplified it, it works as the following:Each connection has a preallocated receive buffer with a minimum length of
4096. On receive, the upper layer protocol will process all dlm message
until there is not enough data anymore. If there exists "leftover" data at
the end of the receive buffer because the dlm message wasn't fully received
it will be copied to the begin of the preallocated receive buffer. Next
receive more data will be appended to the previous "leftover" data and
processing will begin again.This will remove a lot of code of the current mechanism. Inside the
processing functionality we will ensure with a memmove() that the dlm
message should be memory aligned. To have a dlm message always started
at the beginning of the buffer will reduce some amount of memmove()
calls because src and dest pointers are the same.The cluster attribute "buffer_size" becomes a new meaning, it's now the
size of application layer receive buffer size. If this is changed during
runtime the receive buffer will be reallocated. It's important that the
receive buffer size has at minimum the size of the maximum possible dlm
message size otherwise the received message cannot be placed inside
the receive buffer size.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
I observed that the upper layer will not send messages above this value.
As conclusion the application receive buffer should not below that
value, otherwise we are not capable to deliver the dlm message to the
upper layer. This patch forbids to set the receive buffer below the
maximum possible dlm message size.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
This patch adds a callback to CLUSTER_ATTR macro to allow individual
callbacks for attributes which might have a more complex attribute range
checking just than non zero.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
This patch fixes to set per nodeid mark configuration for accepted
sockets as well. Before this patch only the listen socket mark value was
used for all accepted connections. This patch will ensure that the
cluster mark attribute value will be always used for all sockets, if a
per nodeid mark value is specified dlm will use this value for the
specific node.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
During my experiments to make dlm robust against tcpkill application I
was able to run sometimes in a circular lock dependency warning between
clusters_root.subsys.su_mutex and con->sock_mutex. We don't need to
held the sock_mutex when getting the mark value which held the
clusters_root.subsys.su_mutex. This patch moves the specific handling
just before the sock_mutex will be held.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland
28 Aug, 2020
7 commits
-
This patch use free_con() functionality to free the listen connection if
listen fails. It also fixes an issue that a freed resource is still part
of the connection_hash as hlist_del() is not called in this case. The
only difference is that free_con() handles othercon as well, but this is
never been set for the listen connection.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
This patch adds free of possible other writequeue entries in othercon
member of struct connection.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
This patch just move the free of struct connection member writequeue
into the functionality when struct connection will be freed instead of
doing two iterations.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
This patch fixes the following memory detected by kmemleak and umount
gfs2 filesystem which removed the last lockspace:unreferenced object 0xffff9264f482f600 (size 192):
comm "dlm_controld", pid 325, jiffies 4294690276 (age 48.136s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 6e 6f 64 65 73 00 00 00 ........nodes...
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[] make_space+0x41/0x130
[] configfs_mkdir+0x1a2/0x5f0
[] vfs_mkdir+0x155/0x210
[] do_mkdirat+0x6d/0x110
[] do_syscall_64+0x33/0x40
[] entry_SYSCALL_64_after_hwframe+0x44/0xa9The patch just remembers the "nodes" entry pointer in space as I think
it's created as subdirectory when parent "spaces" is created. In
function drop_space() we will lost the pointer reference to nds because
configfs_remove_default_groups(). However as this subdirectory is always
available when "spaces" exists it will just be freed when "spaces" will be
freed.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
This patch fixes the following memory detected by kmemleak and umount
gfs2 filesystem which removed the last lockspace:unreferenced object 0xffff9264f4f48f00 (size 128):
comm "mount", pid 425, jiffies 4294690253 (age 48.159s)
hex dump (first 32 bytes):
02 00 52 48 c0 a8 7a fb 00 00 00 00 00 00 00 00 ..RH..z.........
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[] kmemdup+0x18/0x40
[] init_local+0x4c/0xa0
[] dlm_lowcomms_start+0x28/0x160
[] dlm_new_lockspace+0x7e/0xb80
[] gdlm_mount+0x1cc/0x5de
[] gfs2_lm_mount.constprop.0+0x1a3/0x1d3
[] gfs2_fill_super+0x717/0xba9
[] get_tree_bdev+0x17f/0x280
[] gfs2_get_tree+0x21/0x90
[] vfs_get_tree+0x28/0xc0
[] path_mount+0x434/0xc00
[] __x64_sys_mount+0xe3/0x120
[] do_syscall_64+0x33/0x40
[] entry_SYSCALL_64_after_hwframe+0x44/0xa9Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
There are some problems with the connections_lock. During my
experiements I saw sometimes circular dependencies with sock_lock.
The reason here might be code parts which runs nodeid2con() before
or after sock_lock is acquired.Another issue are missing locks in for_conn() iteration. Maybe this
works fine because for_conn() is running in a context where
connection_hash cannot be manipulated by others anymore.However this patch changes the connection_hash to be protected by
sleepable rcu. The hotpath function __find_con() is implemented
lockless as it is only a reader of connection_hash and this hopefully
fixes the circular locking dependencies. The iteration for_conn() will
still call some sleepable functionality, that's why we use sleepable rcu
in this case.This patch removes the kmemcache functionality as I think I need to
make some free() functionality via call_rcu(). However allocation time
isn't here an issue. The dlm_allow_con will not be protected by a lock
anymore as I think it's enough to just set and flush workqueues
afterwards.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
This patch moves the dlm workqueue dlm synchronization before shutdown
handling. The patch just flushes all pending work before starting to
shutdown the connection. At least for the send_workqeue we should flush
the workqueue to make sure there is no new connection handling going on
as dlm_allow_conn switch is turned to false before.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland
24 Aug, 2020
1 commit
-
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through
Signed-off-by: Gustavo A. R. Silva
07 Aug, 2020
1 commit
-
Pull dlm updates from David Teigland:
"This set includes a some improvements to the dlm networking layer:
improving the ability to trace dlm messages for debugging, and
improved handling of bad messages or disrupted connections"* tag 'dlm-5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
fs: dlm: implement tcp graceful shutdown
fs: dlm: change handling of reconnects
fs: dlm: don't close socket on invalid message
fs: dlm: set skb mark per peer socket
fs: dlm: set skb mark for listen socket
net: sock: add sock_set_mark
dlm: Fix kobject memleak
06 Aug, 2020
6 commits
-
During my code inspection I saw there is no implementation of a graceful
shutdown for tcp. This patch will introduce a graceful shutdown for tcp
connections. The shutdown is implemented synchronized as
dlm_lowcomms_stop() is called to end all dlm communication. After shutdown
is done, a lot of flush and closing functionality will be called. However
I don't see a problem with that.The waitqueue for synchronize the shutdown has a timeout of 10 seconds, if
timeout a force close will be exectued.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
This patch changes the handling of reconnects. At first we only close
the connection related to the communication failure. If we get a new
connection for an already existing connection we close the existing
connection and take the new one.This patch improves significantly the stability of tcp connections while
running "tcpkill -9 -i $IFACE port 21064" while generating a lot of dlm
messages e.g. on a gfs2 mount with many files. My test setup shows that a
deadlock is "more" unlikely. Before this patch I wasn't able to get
not a deadlock after 5 seconds. After this patch my observation is
that it's more likely to survive after 5 seconds and more, but still a
deadlock occurs after certain time. My guess is that there are still
"segments" inside the tcp writequeue or retransmit queue which get dropped
when receiving a tcp reset [1]. Hard to reproduce because the right message
need to be inside these queues, which might even be in the 5 first seconds
with this patch.[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/net/ipv4/tcp_input.c?h=v5.8-rc6#n4122
Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
This patch doesn't close sockets when there is an invalid dlm message
received. The connection will probably reconnect anyway so. To not
close the connection will reduce the number of possible failtures.
As we don't have a different strategy to react on such scenario
just keep going the connection and ignore the message.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
This patch adds support to set the skb mark value for the DLM tcp and
sctp socket per peer. The mark value will be offered as per comm value
of configfs. At creation time of the peer socket it will be set as
socket option.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
This patch adds support to set the skb mark value for the DLM listen
tcp and sctp sockets. The mark value will be offered as cluster
configuration. At creation time of the listen socket it will be set as
socket option.Signed-off-by: Alexander Aring
Signed-off-by: David Teigland -
Currently the error return path from kobject_init_and_add() is not
followed by a call to kobject_put() - which means we are leaking
the kobject.Set do_unreg = 1 before kobject_init_and_add() to ensure that
kobject_put() can be called in its error patch.Fixes: 901195ed7f4b ("Kobject: change GFS2 to use kobject_init_and_add")
Reported-by: Hulk Robot
Signed-off-by: Wang Hai
Signed-off-by: David Teigland
17 Jul, 2020
1 commit
-
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
xargs perl -pi -e \
's/\buninitialized_var\(([^\)]+)\)/\1/g;
s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/Reviewed-by: Leon Romanovsky # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe # IB
Acked-by: Kalle Valo # wireless drivers
Reviewed-by: Chao Yu # erofs
Signed-off-by: Kees Cook
06 Jun, 2020
1 commit
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Pull dlm updates from David Teigland:
"This set includes a couple minor cleanups, and dropping the
interruptible from a wait_event that waits for an event from the
userspace cluster management"* tag 'dlm-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
dlm: remove BUG() before panic()
dlm: Switch to using wait_event()
fs:dlm:remove unneeded semicolon in rcom.c
dlm: user: Replace zero-length array with flexible-array member
dlm: dlm_internal: Replace zero-length array with flexible-array member
30 May, 2020
2 commits
-
The SCTP protocol allows to bind multiple address to a socket. That
feature is currently only exposed as a socket option. Add a bind_add
method struct proto that allows to bind additional addresses, and
switch the dlm code to use the method instead of going through the
socket option from kernel space.Signed-off-by: Christoph Hellwig
Acked-by: Marcelo Ricardo Leitner
Signed-off-by: David S. Miller -
Add a helper to directly set the SCTP_NODELAY sockopt from kernel space
without going through a fake uaccess.Signed-off-by: Christoph Hellwig
Acked-by: Marcelo Ricardo Leitner
Signed-off-by: David S. Miller
29 May, 2020
5 commits
-
Add a helper to directly set the TCP_NODELAY sockopt from kernel space
without going through a fake uaccess. Cleanup the callers to avoid
pointless wrappers now that this is a simple function call.Signed-off-by: Christoph Hellwig
Acked-by: Sagi Grimberg
Acked-by: Jason Gunthorpe
Signed-off-by: David S. Miller -
Add a helper to directly set the SO_RCVBUFFORCE sockopt from kernel space
without going through a fake uaccess.Signed-off-by: Christoph Hellwig
Signed-off-by: David S. Miller -
Add a helper to directly set the SO_KEEPALIVE sockopt from kernel space
without going through a fake uaccess.Signed-off-by: Christoph Hellwig
Signed-off-by: David S. Miller -
Add a helper to directly set the SO_SNDTIMEO_NEW sockopt from kernel
space without going through a fake uaccess. The interface is
simplified to only pass the seconds value, as that is the only
thing needed at the moment.Signed-off-by: Christoph Hellwig
Signed-off-by: David S. Miller -
Add a helper to directly set the SO_REUSEADDR sockopt from kernel space
without going through a fake uaccess.For this the iscsi target now has to formally depend on inet to avoid
a mostly theoretical compile failure. For actual operation it already
did depend on having ipv4 or ipv6 support.Signed-off-by: Christoph Hellwig
Acked-by: Sagi Grimberg
Signed-off-by: David S. Miller
28 May, 2020
1 commit
-
The only difference between a few missing fixes applied to the SCTP
one is that TCP uses ->getpeername to get the remote address, while
SCTP uses kernel_getsockopt(.. SCTP_PRIMARY_ADDR). But given that
getpeername is defined to return the primary address for sctp, there
doesn't seem to be any reason for the different way of quering the
peername, or all the code duplication.Signed-off-by: Christoph Hellwig
Signed-off-by: David S. Miller
13 May, 2020
5 commits
-
Building a kernel with clang sometimes fails with an objtool error in dlm:
fs/dlm/lock.o: warning: objtool: revert_lock_pc()+0xbd: can't find jump dest instruction at .text+0xd7fc
The problem is that BUG() never returns and the compiler knows
that anything after it is unreachable, however the panic still
emits some code that does not get fully eliminated.Having both BUG() and panic() is really pointless as the BUG()
kills the current process and the subsequent panic() never hits.
In most cases, we probably don't really want either and should
replace the DLM_ASSERT() statements with WARN_ON(), as has
been done for some of them.Remove the BUG() here so the user at least sees the panic message
and we can reliably build randconfig kernels.Fixes: e7fd41792fc0 ("[DLM] The core of the DLM for GFS2/CLVM")
Cc: Josh Poimboeuf
Cc: clang-built-linux@googlegroups.com
Signed-off-by: Arnd Bergmann
Signed-off-by: David Teigland -
We saw an issue in a production server on a customer deployment where
DLM 4.0.7 gets "stuck" and unable to join new lockspaces.There is no useful response for the dlm in do_event() if
wait_event_interruptible() is interrupted, so switch to
wait_event().Signed-off-by: Ross Lagerwall
Signed-off-by: David Teigland -
Fix the following coccicheck warning:
fs/dlm/rcom.c:566:2-3: Unneeded semicolonSigned-off-by: Wu Bo
Signed-off-by: David Teigland -
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:struct foo {
int stuff;
struct boo array[];
};By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.Also, notice that, dynamic memory allocations won't be affected by
this change:"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")Signed-off-by: Gustavo A. R. Silva
Signed-off-by: David Teigland -
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:struct foo {
int stuff;
struct boo array[];
};By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.Also, notice that, dynamic memory allocations won't be affected by
this change:"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")Signed-off-by: Gustavo A. R. Silva
Signed-off-by: David Teigland
19 Dec, 2019
1 commit
-
Eliminate one more use of 'struct timeval' from the kernel so
we can eventually remove the definition as well.The kernel supports the new format with a 64-bit time_t version
of timeval here, so use that instead of the old timeval.Acked-by: Deepa Dinamani
Signed-off-by: Arnd Bergmann