syzbot reported this issue where in the vsock_poll() we find the
socket state at TCP_ESTABLISHED, but 'transport' is null:
  general protection fault, probably for non-canonical address 0xdffffc0000000012: 0000 [#1] PREEMPT SMP KASAN
  KASAN: null-ptr-deref in range [0x0000000000000090-0x0000000000000097]
  CPU: 0 PID: 8227 Comm: syz-executor.2 Not tainted 5.8.0-rc7-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  RIP: 0010:vsock_poll+0x75a/0x8e0 net/vmw_vsock/af_vsock.c:1038
  Call Trace:
   sock_poll+0x159/0x460 net/socket.c:1266
   vfs_poll include/linux/poll.h:90 [inline]
   do_pollfd fs/select.c:869 [inline]
   do_poll fs/select.c:917 [inline]
   do_sys_poll+0x607/0xd40 fs/select.c:1011
   __do_sys_poll fs/select.c:1069 [inline]
   __se_sys_poll fs/select.c:1057 [inline]
   __x64_sys_poll+0x18c/0x440 fs/select.c:1057
   do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

This issue can happen if the TCP_ESTABLISHED state is set after we read
the vsk->transport in the vsock_poll().

We could put barriers to synchronize, but this can only happen during
connection setup, so we can simply check that 'transport' is valid.

Fixes: c0cfa2d8 ("vsock: add multi-transports support")
Reported-and-tested-by: syzbot+a61bac2fcc1a7c6623fe@syzkaller.appspotmail.com
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The handling of the RXQ/TXQ size granularity design-params had two
 problems: it had a 64-bit divide that didn't build on 32-bit platforms,
 and it could divide by zero if the NIC supplied 0 as the value of the
 design-param.  Fix both by checking for 0 and for a granularity bigger
 than our min-size; if the granularity <= EFX_MIN_DMAQ_SIZE then it fits
 in 32 bits, so we can cast it to u32 for the divide.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Edward Cree <ecree@solarflare.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Tim Froidcoeur says:

====================
net: initialize fastreuse on inet_inherit_port

In the case of TPROXY, bind_conflict optimizations for SO_REUSEADDR or
SO_REUSEPORT are broken, possibly resulting in O(n) instead of O(1) bind
behaviour or in the incorrect reuse of a bind.

the kernel keeps track for each bind_bucket if all sockets in the
bind_bucket support SO_REUSEADDR or SO_REUSEPORT in two fastreuse flags.
These flags allow skipping the costly bind_conflict check when possible
(meaning when all sockets have the proper SO_REUSE option).

For every socket added to a bind_bucket, these flags need to be updated.
As soon as a socket that does not support reuse is added, the flag is
set to false and will never go back to true, unless the bind_bucket is
deleted.

Note that there is no mechanism to re-evaluate these flags when a socket
is removed (this might make sense when removing a socket that would not
allow reuse; this leaves room for a future patch).

For this optimization to work, it is mandatory that these flags are
properly initialized and updated.

When a child socket is created from a listen socket in
__inet_inherit_port, the TPROXY case could create a new bind bucket
without properly initializing these flags, thus preventing the
optimization to work. Alternatively, a socket not allowing reuse could
be added to an existing bind bucket without updating the flags, causing
bind_conflict to never be called as it should.

Patch 1/2 refactors the fastreuse update code in inet_csk_get_port into a
small helper function, making the actual fix tiny and easier to understand.

Patch 2/2 calls this new helper when __inet_inherit_port decides to create
a new bind_bucket or use a different bind_bucket than the one of the listen
socket.

v4: - rebase on latest linux/net master branch
v3: - remove company disclaimer from automatic signature
v2: - remove unnecessary cast
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

In the case of TPROXY, bind_conflict optimizations for SO_REUSEADDR or
SO_REUSEPORT are broken, possibly resulting in O(n) instead of O(1) bind
behaviour or in the incorrect reuse of a bind.

the kernel keeps track for each bind_bucket if all sockets in the
bind_bucket support SO_REUSEADDR or SO_REUSEPORT in two fastreuse flags.
These flags allow skipping the costly bind_conflict check when possible
(meaning when all sockets have the proper SO_REUSE option).

For every socket added to a bind_bucket, these flags need to be updated.
As soon as a socket that does not support reuse is added, the flag is
set to false and will never go back to true, unless the bind_bucket is
deleted.

Note that there is no mechanism to re-evaluate these flags when a socket
is removed (this might make sense when removing a socket that would not
allow reuse; this leaves room for a future patch).

For this optimization to work, it is mandatory that these flags are
properly initialized and updated.

When a child socket is created from a listen socket in
__inet_inherit_port, the TPROXY case could create a new bind bucket
without properly initializing these flags, thus preventing the
optimization to work. Alternatively, a socket not allowing reuse could
be added to an existing bind bucket without updating the flags, causing
bind_conflict to never be called as it should.

Call inet_csk_update_fastreuse when __inet_inherit_port decides to create
a new bind_bucket or use a different bind_bucket than the one of the
listen socket.

Fixes: 093d2823 ("tproxy: fix hash locking issue when using port redirection in __inet_inherit_port()")
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Tim Froidcoeur <tim.froidcoeur@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Refactor the fastreuse update code in inet_csk_get_port into a small
helper function that can be called from other places.
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Tim Froidcoeur <tim.froidcoeur@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit c3e302ed ("net: phy: marvell10g: fix temperature sensor on 2110")
added a check for PHY ID via phydev->drv->phy_id in a function which is
called by devres at a time when phydev->drv is already set to null by
phy_remove function.

This null pointer dereference can be triggered via SFP subsystem with a
SFP module containing this Marvell PHY. When the SFP interface is put
down, the SFP subsystem removes the PHY.

Fixes: c3e302ed ("net: phy: marvell10g: fix temperature sensor on 2110")
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Cc: Maxime Chevallier <maxime.chevallier@bootlin.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

If we failed to assign proto idx, we free the twsk_slab_name but forget to
free the twsk_slab. Add a helper function tw_prot_cleanup() to free these
together and also use this helper function in proto_unregister().

Fixes: b45ce321 ("sock: fix potential memory leak in proto_register()")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Fix the missing clk_disable_unprepare() before return
from emac_clks_phase1_init() in the error handling case.

Fixes: b9b17deb ("net: emac: emac gigabit ethernet controller driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Acked-by: Timur Tabi <timur@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

A multiplication for the size determination of a memory allocation
indicated that an array data structure should be processed.
Thus use the corresponding function "devm_kcalloc".
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Acked-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

When creating a raw AF_NFC socket, CAP_NET_RAW needs to be checked first.
Signed-off-by: Qingyu Li <ieatmuttonchuan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

fix the compile warnings of 'strncpy' output truncated before
terminating nul copying N bytes from a string of the same length
Signed-off-by: Luo bin <luobin9@huawei.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1. Added a skb->len check

This driver expects upper layers to include a pseudo header of 1 byte
when passing down a skb for transmission. This driver will read this
1-byte header. This patch added a skb->len check before reading the
header to make sure the header exists.

2. Added needed_headroom

When this driver transmits data,
  first this driver will remove a pseudo header of 1 byte,
  then the lapb module will prepend the LAPB header of 2 or 3 bytes.
So the value of needed_headroom in this driver should be 3 - 1.

Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When MSG_OOB is specified to tls_device_sendpage() the mapped page is
never unmapped.

Hold off mapping the page until after the flags are checked and the page
is actually needed.

Fixes: e8f69799 ("net/tls: Add generic NIC offload infrastructure")
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

When ur_load_imm_any() is inlined into jeq_imm(), it's possible for the
compiler to deduce a case where _val can only have the value of -1 at
compile time. Specifically,

/* struct bpf_insn: _s32 imm */
u64 imm = insn->imm; /* sign extend */
if (imm >> 32) { /* non-zero only if insn->imm is negative */
  /* inlined from ur_load_imm_any */
  u32 __imm = imm >> 32; /* therefore, always 0xffffffff */
  if (__builtin_constant_p(__imm) && __imm > 255)
    compiletime_assert_XXX()

This can result in tripping a BUILD_BUG_ON() in __BF_FIELD_CHECK() that
checks that a given value is representable in one byte (interpreted as
unsigned).

FIELD_FIT() should return true or false at runtime for whether a value
can fit for not. Don't break the build over a value that's too large for
the mask. We'd prefer to keep the inlining and compiler optimizations
though we know this case will always return false.

Cc: stable@vger.kernel.org
Fixes: 1697599e ("bitfield.h: add FIELD_FIT() helper")
Link: https://lore.kernel.org/kernel-hardening/CAK7LNASvb0UDJ0U5wkYYRzTAdnEs64HjXpEUL7d=V0CXiAXcNw@mail.gmail.com/Reported-by: Masahiro Yamada <masahiroy@kernel.org>
Debugged-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

When TFO keys are read back on big endian systems either via the global
sysctl interface or via getsockopt() using TCP_FASTOPEN_KEY, the values
don't match what was written.

For example, on s390x:

# echo "1-2-3-4" > /proc/sys/net/ipv4/tcp_fastopen_key
# cat /proc/sys/net/ipv4/tcp_fastopen_key
02000000-01000000-04000000-03000000

Instead of:

# cat /proc/sys/net/ipv4/tcp_fastopen_key
00000001-00000002-00000003-00000004

Fix this by converting to the correct endianness on read. This was
reported by Colin Ian King when running the 'tcp_fastopen_backup_key' net
selftest on s390x, which depends on the read value matching what was
written. I've confirmed that the test now passes on big and little endian
systems.
Signed-off-by: Jason Baron <jbaron@akamai.com>
Fixes: 438ac880 ("net: fastopen: robustness and endianness fixes for SipHash")
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Eric Dumazet <edumazet@google.com>
Reported-and-tested-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

I'm not doing much work on the NFP driver any more.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Commit dacce2be ("vmxnet3: add geneve and vxlan tunnel offload
support") added support for encapsulation offload. However, while
calculating tcp hdr length, it does not take into account if the
packet is encapsulated or not.

This patch fixes this issue by using correct reference for inner
tcp header.

Fixes: dacce2be ("vmxnet3: add geneve and vxlan tunnel offload support")
Signed-off-by: Ronak Doshi <doshir@vmware.com>
Acked-by: Guolin Yang <gyang@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This reverts commits 6d04fe15 and
a31edb20.

It turns out the idea to share a single pointer for both kernel and user
space address causes various kinds of problems.  So use the slightly less
optimal version that uses an extra bit, but which is guaranteed to be safe
everywhere.

Fixes: 6d04fe15 ("net: optimize the sockptr_t for unified kernel/user address spaces")
Reported-by: Eric Dumazet <edumazet@google.com>
Reported-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Convert the uses of fallthrough comments to fallthrough macro.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use helper function ip_is_fragment() to check ip fragment.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The out_fs jump label has nothing to do but goto out.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

We should fput() file iff FDPUT_FPUT is set. So we should set fput_needed
accordingly.

Fixes: 00e188ef ("sockfd_lookup_light(): switch to fdget^W^Waway from fget_light")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Use helper function fdput() to fput() the file iff FDPUT_FPUT is set.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

A recent commit introduced a late error path in phy_device_create()
which fails to release the device name allocated by dev_set_name().

Fixes: 13d0ab67 ("net: phy: check return code when requesting PHY driver module")
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Trying to use ktls on a system with 32-bit userspace and 64-bit kernel
results in a EOPNOTSUPP message during sendmsg:

  setsockopt(3, SOL_TLS, TLS_TX, …, 40) = 0
  sendmsg(3, …, msg_flags=0}, 0) = -1 EOPNOTSUPP (Operation not supported)

The tls_sw implementation does strict flag checking and does not allow
the MSG_CMSG_COMPAT flag, which is set if the message comes in through
the compat syscall.

This patch adds MSG_CMSG_COMPAT to the flag check to allow the usage of
the TLS SW implementation on systems using the compat syscall path.

Note that the same check is present in the sendmsg path for the TLS
device implementation, however the flag hasn't been added there for lack
of testing hardware.
Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Daniel Borkmann says:

====================
pull-request: bpf 2020-08-08

The following pull-request contains BPF updates for your *net* tree.

We've added 11 non-merge commits during the last 2 day(s) which contain
a total of 24 files changed, 216 insertions(+), 135 deletions(-).

The main changes are:

1) Fix UAPI for BPF map iterator before it gets frozen to allow for more
   extensions/customization in future, from Yonghong Song.

2) Fix selftests build to undo verbose build output, from Andrii Nakryiko.

3) Fix inlining compilation error on bpf_do_trace_printk() due to variable
   argument lists, from Stanislav Fomichev.

4) Fix an uninitialized pointer warning at btf__parse_raw() in libbpf,
   from Daniel T. Lee.

5) Fix several compilation warnings in selftests with regards to ignoring
   return value, from Jianlin Lv.

6) Fix interruptions by switching off timeout for BPF tests, from Jiri Benc.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

With commit b93df08c ("mptcp: explicitly track the fully
established status"), the status of unaccepted mptcp closed in
mptcp_sock_destruct() changes from TCP_SYN_RECV to TCP_ESTABLISHED.

As a result mptcp_sock_destruct() does not perform the proper
cleanup and inet_sock_destruct() will later emit a warn.

Address the issue updating the condition tested in mptcp_sock_destruct().
Also update the related comment.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/66Reported-and-tested-by: Christoph Paasch <cpaasch@apple.com>
Fixes: b93df08c ("mptcp: explicitly track the fully established status")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

During diag self-tests we introduce long wait in the mptcp test
program to give the script enough time to access the sockets
dump.

Such wait is introduced after shutting down one sockets end. Since
commit 43b54c6e ("mptcp: Use full MPTCP-level disconnect state
machine") if both sides shutdown the socket is correctly transitioned
into CLOSED status.

As a side effect some sockets are not dumped via the diag interface,
because the socket state (CLOSED) does not match the default filter, and
this cause self-tests instability.

Address the issue moving the above mentioned wait before shutting
down the socket.

Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/68
Fixes: df62f2ec ("selftests/mptcp: add diag interface tests")
Tested-and-acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Since commit df62f2ec ("selftests/mptcp: add diag interface tests")
the MPTCP selftests relies on the MPTCP diag interface which is
enabled by a specific kconfig knob: be sure to include it.

Fixes: df62f2ec ("selftests/mptcp: add diag interface tests")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Query the USB device's device tree node when looking for a MAC address.
The struct device embedded into the struct net_device does not have a
device tree node attached at all.

The reason why this went unnoticed is because the system where this was
tested was one of the few development units that had its OTP programmed,
as opposed to production systems where the MAC address is stored in a
separate EEPROM and is passed via device tree by the firmware.
Reported-by: EJ Hsu <ejh@nvidia.com>
Fixes: acb6d377 ("r8152: Use MAC address from device tree if available")
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: EJ Hsu <ejh@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Drop repeated words in kernel/bpf/: {has, the}
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200807033141.10437-1-rdunlap@infradead.org

99aacebe ("selftests: do not use .ONESHELL") removed .ONESHELL, which
changes how Makefile "silences" multi-command target recipes. selftests/bpf's
Makefile relied (a somewhat unknowingly) on .ONESHELL behavior of silencing
all commands within the recipe if the first command contains @ symbol.
Removing .ONESHELL exposed this hack.

This patch fixes the issue by explicitly silencing each command with $(Q).

Also explicitly define fallback rule for building *.o from *.c, instead of
relying on non-silent inherited rule. This was causing a non-silent output for
bench.o object file.

Fixes: 92f7440e ("selftests/bpf: More succinct Makefile output")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200807033058.848677-1-andriin@fb.com

The BPF helper bpf_trace_printk() no longer uses trace_printk();
it is now triggers a dedicated trace event.  Hence the described
warning is no longer present, so remove the discussion of it as
it may confuse people.

Fixes: ac5a72ea ("bpf: Use dedicated bpf_trace_printk event instead of trace_printk()")
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/1596801029-32395-1-git-send-email-alan.maguire@oracle.com

1. Added a skb->len check

This driver expects upper layers to include a pseudo header of 1 byte
when passing down a skb for transmission. This driver will read this
1-byte header. This patch added a skb->len check before reading the
header to make sure the header exists.

2. Changed to use needed_headroom instead of hard_header_len to request
necessary headroom to be allocated

In net/packet/af_packet.c, the function packet_snd first reserves a
headroom of length (dev->hard_header_len + dev->needed_headroom).
Then if the socket is a SOCK_DGRAM socket, it calls dev_hard_header,
which calls dev->header_ops->create, to create the link layer header.
If the socket is a SOCK_RAW socket, it "un-reserves" a headroom of
length (dev->hard_header_len), and assumes the user to provide the
appropriate link layer header.

So according to the logic of af_packet.c, dev->hard_header_len should
be the length of the header that would be created by
dev->header_ops->create.

However, this driver doesn't provide dev->header_ops, so logically
dev->hard_header_len should be 0.

So we should use dev->needed_headroom instead of dev->hard_header_len
to request necessary headroom to be allocated.

This change fixes kernel panic when this driver is used with AF_PACKET
SOCK_RAW sockets.

Call stack when panic:

[  168.399197] skbuff: skb_under_panic: text:ffffffff819d95fb len:20
put:14 head:ffff8882704c0a00 data:ffff8882704c09fd tail:0x11 end:0xc0
dev:veth0
...
[  168.399255] Call Trace:
[  168.399259]  skb_push.cold+0x14/0x24
[  168.399262]  eth_header+0x2b/0xc0
[  168.399267]  lapbeth_data_transmit+0x9a/0xb0 [lapbether]
[  168.399275]  lapb_data_transmit+0x22/0x2c [lapb]
[  168.399277]  lapb_transmit_buffer+0x71/0xb0 [lapb]
[  168.399279]  lapb_kick+0xe3/0x1c0 [lapb]
[  168.399281]  lapb_data_request+0x76/0xc0 [lapb]
[  168.399283]  lapbeth_xmit+0x56/0x90 [lapbether]
[  168.399286]  dev_hard_start_xmit+0x91/0x1f0
[  168.399289]  ? irq_init_percpu_irqstack+0xc0/0x100
[  168.399291]  __dev_queue_xmit+0x721/0x8e0
[  168.399295]  ? packet_parse_headers.isra.0+0xd2/0x110
[  168.399297]  dev_queue_xmit+0x10/0x20
[  168.399298]  packet_sendmsg+0xbf0/0x19b0
......

Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Martin Schiller <ms@dev.tdt.de>
Cc: Brian Norris <briannorris@chromium.org>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Clang compiler version: 12.0.0
The following warning appears during the selftests/bpf compilation:

prog_tests/send_signal.c:51:3: warning: ignoring return value of ‘write’,
declared with attribute warn_unused_result [-Wunused-result]
   51 |   write(pipe_c2p[1], buf, 1);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~
prog_tests/send_signal.c:54:3: warning: ignoring return value of ‘read’,
declared with attribute warn_unused_result [-Wunused-result]
   54 |   read(pipe_p2c[0], buf, 1);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~
......

prog_tests/stacktrace_build_id_nmi.c:13:2: warning: ignoring return value
of ‘fscanf’,declared with attribute warn_unused_result [-Wunused-resul]
   13 |  fscanf(f, "%llu", &sample_freq);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

test_tcpnotify_user.c:133:2: warning:ignoring return value of ‘system’,
declared with attribute warn_unused_result [-Wunused-result]
  133 |  system(test_script);
      |  ^~~~~~~~~~~~~~~~~~~
test_tcpnotify_user.c:138:2: warning:ignoring return value of ‘system’,
declared with attribute warn_unused_result [-Wunused-result]
  138 |  system(test_script);
      |  ^~~~~~~~~~~~~~~~~~~
test_tcpnotify_user.c:143:2: warning:ignoring return value of ‘system’,
declared with attribute warn_unused_result [-Wunused-result]
  143 |  system(test_script);
      |  ^~~~~~~~~~~~~~~~~~~

Add code that fix compilation warning about ignoring return value and
handles any errors; Check return value of library`s API make the code
more secure.
Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200806104224.95306-1-Jianlin.Lv@arm.com

Several bpf tests are interrupted by the default timeout of 45 seconds added
by commit 852c8cbf ("selftests/kselftest/runner.sh: Add 45 second
timeout per test"). In my case it was test_progs, test_tunnel.sh,
test_lwt_ip_encap.sh and test_xdping.sh.

There's not much value in having a timeout for bpf tests, switch it off.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/7a9198ed10917f4ecab4a3dd74bcda1200791efd.1596739059.git.jbenc@redhat.com

I get the following error during compilation on my side:
kernel/trace/bpf_trace.c: In function 'bpf_do_trace_printk':
kernel/trace/bpf_trace.c:386:34: error: function 'bpf_do_trace_printk' can never be inlined because it uses variable argument lists
 static inline __printf(1, 0) int bpf_do_trace_printk(const char *fmt, ...)
                                  ^

Fixes: ac5a72ea ("bpf: Use dedicated bpf_trace_printk event instead of trace_printk()")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200806182612.1390883-1-sdf@google.com

int sets_patch(struct object *obj) doesn't have a 'return 0' at the end.

Fixes: fbbb68de ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200806155225.637202-1-sdf@google.com

Recently, from commit 94a1fedd ("libbpf: Add btf__parse_raw() and
generic btf__parse() APIs"), new API has been added to libbpf that
allows to parse BTF from raw data file (btf__parse_raw()).

The commit derives build failure of samples/bpf due to improper access
of uninitialized pointer at btf_parse_raw().

    btf.c: In function btf__parse_raw:
    btf.c:625:28: error: btf may be used uninitialized in this function
      625 |  return err ? ERR_PTR(err) : btf;
          |         ~~~~~~~~~~~~~~~~~~~^~~~~

This commit fixes the build failure of samples/bpf by adding code of
initializing btf pointer as NULL.

Fixes: 94a1fedd ("libbpf: Add btf__parse_raw() and generic btf__parse() APIs")
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200805223359.32109-1-danieltimlee@gmail.com

Yonghong Song says:

====================
Andrii raised a concern that current uapi for bpf iterator map
element is a little restrictive and not suitable for future potential
complex customization. This is a valid suggestion, considering people
may indeed add more complex custimization to the iterator, e.g.,
cgroup_id + user_id, etc. for task or task_file. Another example might
be map_id plus additional control so that the bpf iterator may bail
out a bucket earlier if a bucket has too many elements which may hold
lock too long and impact other parts of systems.

Patch #1 modified uapi with kernel changes. Patch #2
adjusted libbpf api accordingly.

Changelogs:
  v3 -> v4:
    . add a forward declaration of bpf_iter_link_info in
      tools/lib/bpf/bpf.h in case that libbpf is built against
      not-latest uapi bpf.h.
    . target the patch set to "bpf" instead of "bpf-next"
  v2 -> v3:
    . undo "not reject iter_info.map.map_fd == 0" from v1.
      In the future map_fd may become optional, so let us use map_fd == 0
      indicating the map_fd is not set by user space.
    . add link_info_len to bpf_iter_attach_opts to ensure always correct
      link_info_len from user. Otherwise, libbpf may deduce incorrect
      link_info_len if it uses different uapi header than the user app.
  v1 -> v2:
    . ensure link_create target_fd/flags == 0 since they are not used. (Andrii)
    . if either of iter_info ptr == 0 or iter_info_len == 0, but not both,
      return error to user space. (Andrii)
    . do not reject iter_info.map.map_fd == 0, go ahead to use it trying to
      get a map reference since the map_fd is required for map_elem iterator.
    . use bpf_iter_link_info in bpf_iter_attach_opts instead of map_fd.
      this way, user space is responsible to set up bpf_iter_link_info and
      libbpf just passes the data to the kernel, simplifying libbpf design.
      (Andrii)
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>