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Pull networking fixes from David Miller:
"Nothing earth shattering here, lots of small fixes (f.e. missing RCU
protection, bad ref counting, missing memset(), etc.) all over the
place:
1) Use get_file_rcu() in task_file iterator, from Yonghong Song.
2) There are two ways to set remote source MAC addresses in macvlan
driver, but only one of which validates things properly. Fix this.
From Alvin Šipraga.
3) Missing of_node_put() in gianfar probing, from Sumera
Priyadarsini.
4) Preserve device wanted feature bits across multiple netlink
ethtool requests, from Maxim Mikityanskiy.
5) Fix rcu_sched stall in task and task_file bpf iterators, from
Yonghong Song.
6) Avoid reset after device destroy in ena driver, from Shay
Agroskin.
7) Missing memset() in netlink policy export reallocation path, from
Johannes Berg.
8) Fix info leak in __smc_diag_dump(), from Peilin Ye.
9) Decapsulate ECN properly for ipv6 in ipv4 tunnels, from Mark
Tomlinson.
10) Fix number of data stream negotiation in SCTP, from David Laight.
11) Fix double free in connection tracker action module, from Alaa
Hleihel.
12) Don't allow empty NHA_GROUP attributes, from Nikolay Aleksandrov"
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (46 commits)
net: nexthop: don't allow empty NHA_GROUP
bpf: Fix two typos in uapi/linux/bpf.h
net: dsa: b53: check for timeout
tipc: call rcu_read_lock() in tipc_aead_encrypt_done()
net/sched: act_ct: Fix skb double-free in tcf_ct_handle_fragments() error flow
net: sctp: Fix negotiation of the number of data streams.
dt-bindings: net: renesas, ether: Improve schema validation
gre6: Fix reception with IP6_TNL_F_RCV_DSCP_COPY
hv_netvsc: Fix the queue_mapping in netvsc_vf_xmit()
hv_netvsc: Remove "unlikely" from netvsc_select_queue
bpf: selftests: global_funcs: Check err_str before strstr
bpf: xdp: Fix XDP mode when no mode flags specified
selftests/bpf: Remove test_align leftovers
tools/resolve_btfids: Fix sections with wrong alignment
net/smc: Prevent kernel-infoleak in __smc_diag_dump()
sfc: fix build warnings on 32-bit
net: phy: mscc: Fix a couple of spelling mistakes "spcified" -> "specified"
libbpf: Fix map index used in error message
net: gemini: Fix missing free_netdev() in error path of gemini_ethernet_port_probe()
net: atlantic: Use readx_poll_timeout() for large timeout
...
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Pull kvm fixes from Paolo Bonzini:
- PAE and PKU bugfixes for x86
- selftests fix for new binutils
- MMU notifier fix for arm64
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: arm64: Only reschedule if MMU_NOTIFIER_RANGE_BLOCKABLE is not set
KVM: Pass MMU notifier range flags to kvm_unmap_hva_range()
kvm: x86: Toggling CR4.PKE does not load PDPTEs in PAE mode
kvm: x86: Toggling CR4.SMAP does not load PDPTEs in PAE mode
KVM: x86: fix access code passed to gva_to_gpa
selftests: kvm: Use a shorter encoding to clear RAX
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Make libbpf logs follow similar pattern and provide more context like section
name or program name, where appropriate. Also, add BPF_INSN_SZ constant and
use it throughout to clean up code a little bit. This commit doesn't have any
functional changes and just removes some code changes out of the way before
bigger refactoring in libbpf internals.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200820231250.1293069-6-andriin@fb.com
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Skip and don't log ELF sections that libbpf knows about and ignores during ELF
processing. This allows to not unnecessarily log details about those ELF
sections and cleans up libbpf debug log. Ignored sections include DWARF data,
string table, empty .text section and few special (e.g., .llvm_addrsig)
useless sections.
With such ELF sections out of the way, log unrecognized ELF sections at
pr_info level to increase visibility.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200820231250.1293069-5-andriin@fb.com
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__noinline is pretty frequently used, especially with BPF subprograms, so add
them along the __always_inline, for user convenience and completeness.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200820231250.1293069-4-andriin@fb.com
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Factor out common ELF operations done throughout the libbpf. This simplifies
usage across multiple places in libbpf, as well as hide error reporting from
higher-level functions and make error logging more consistent.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200820231250.1293069-3-andriin@fb.com
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There is no need to re-build BPF object files if any of the sources of libbpf
change. So record more precise dependency only on libbpf/bpf_*.h headers. This
eliminates unnecessary re-builds.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200820231250.1293069-2-andriin@fb.com
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Add a test which copies a socket from a sockmap into another sockmap
or sockhash. This excercises bpf_map_update_elem support from BPF
context. Compare the socket cookies from source and destination to
ensure that the copy succeeded.
Also check that the verifier rejects map_update from unsafe contexts.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200821102948.21918-7-lmb@cloudflare.com
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Add a set of APIs to perf_buffer manage to allow applications to integrate
perf buffer polling into existing epoll-based infrastructure. One example is
applications using libevent already and wanting to plug perf_buffer polling,
instead of relying on perf_buffer__poll() and waste an extra thread to do it.
But perf_buffer is still extremely useful to set up and consume perf buffer
rings even for such use cases.
So to accomodate such new use cases, add three new APIs:
- perf_buffer__buffer_cnt() returns number of per-CPU buffers maintained by
given instance of perf_buffer manager;
- perf_buffer__buffer_fd() returns FD of perf_event corresponding to
a specified per-CPU buffer; this FD is then polled independently;
- perf_buffer__consume_buffer() consumes data from single per-CPU buffer,
identified by its slot index.
To support a simpler, but less efficient, way to integrate perf_buffer into
external polling logic, also expose underlying epoll FD through
perf_buffer__epoll_fd() API. It will need to be followed by
perf_buffer__poll(), wasting extra syscall, or perf_buffer__consume(), wasting
CPU to iterate buffers with no data. But could be simpler and more convenient
for some cases.
These APIs allow for great flexiblity, but do not sacrifice general usability
of perf_buffer.
Also exercise and check new APIs in perf_buffer selftest.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20200821165927.849538-1-andriin@fb.com
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The link query for bpf iterators is implemented.
Besides being shown to the user what bpf iterator
the link represents, the target_name is also used
to filter out what additional information should be
printed out, e.g., whether map_id should be shown or not.
The following is an example of bpf_iter link dump,
plain output or pretty output.
$ bpftool link show
11: iter prog 59 target_name task
pids test_progs(1749)
34: iter prog 173 target_name bpf_map_elem map_id 127
pids test_progs_1(1753)
$ bpftool -p link show
[{
"id": 11,
"type": "iter",
"prog_id": 59,
"target_name": "task",
"pids": [{
"pid": 1749,
"comm": "test_progs"
}
]
},{
"id": 34,
"type": "iter",
"prog_id": 173,
"target_name": "bpf_map_elem",
"map_id": 127,
"pids": [{
"pid": 1753,
"comm": "test_progs_1"
}
]
}
]
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200821184420.574430-1-yhs@fb.com
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This patch implemented bpf_link callback functions
show_fdinfo and fill_link_info to support link_query
interface.
The general interface for show_fdinfo and fill_link_info
will print/fill the target_name. Each targets can
register show_fdinfo and fill_link_info callbacks
to print/fill more target specific information.
For example, the below is a fdinfo result for a bpf
task iterator.
$ cat /proc/1749/fdinfo/7
pos: 0
flags: 02000000
mnt_id: 14
link_type: iter
link_id: 11
prog_tag: 990e1f8152f7e54f
prog_id: 59
target_name: task
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200821184418.574122-1-yhs@fb.com
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Alexei Starovoitov says:
====================
pull-request: bpf 2020-08-21
The following pull-request contains BPF updates for your *net* tree.
We've added 11 non-merge commits during the last 5 day(s) which contain
a total of 12 files changed, 78 insertions(+), 24 deletions(-).
The main changes are:
1) three fixes in BPF task iterator logic, from Yonghong.
2) fix for compressed dwarf sections in vmlinux, from Jiri.
3) fix xdp attach regression, from Andrii.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Also remove trailing whitespaces in bpf_skb_get_tunnel_key example code.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200821133642.18870-1-tklauser@distanz.ch
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One down side of using TCP rx zerocopy is one extra TLB miss
per page after the mapping operation.
While if the application is using hugepages, the non zerocopy
recvmsg() will not have to pay these TLB costs.
This patch allows server side to use huge pages for
the non zero copy case, to allow fair comparisons when
both solutions use optimal conditions.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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There are significant gains using huge pages when
available, as shown in [1].
This patch adds mmap_large_buffer() and uses it
in client side (tx path of this reference tool)
Following patch will use the feature for server side.
[1] https://patchwork.ozlabs.org/project/netdev/patch/20200820154359.1806305-1-edumazet@google.com/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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When TCP_ZEROCOPY_RECEIVE operation has been added,
I made the mistake of automatically un-mapping prior
content before mapping new pages.
This has the unfortunate effect of adding potentially long
MMU operations (like TLB flushes) while socket lock is held.
Using madvise(MADV_DONTNEED) right after pages has been used
has two benefits :
1) This releases pages sooner, allowing pages to be recycled
if they were part of a page pool in a NIC driver.
2) No more long unmap operations while preventing immediate
processing of incoming packets.
The cost of the added system call is small enough.
Arjun will submit a kernel patch allowing to opt out from
the unmap attempt in tcp_zerocopy_receive()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The error path in libbpf.c:load_program() has calls to pr_warn()
which ends up for global_funcs tests to
test_global_funcs.c:libbpf_debug_print().
For the tests with no struct test_def::err_str initialized with a
string, it causes call of strstr() with NULL as the second argument
and it segfaults.
Fix it by calling strstr() only for non-NULL err_str.
Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200820115843.39454-1-yauheni.kaliuta@redhat.com
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Calling generic selftests "make install" fails as rsync expects all
files from TEST_GEN_PROGS to be present. The binary is not generated
anymore (commit 3b09d27cc93d) so we can safely remove it from there
and also from gitignore.
Fixes: 3b09d27cc93d ("selftests/bpf: Move test_align under test_progs")
Signed-off-by: Veronika Kabatova <vkabatov@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Link: https://lore.kernel.org/bpf/20200819160710.1345956-1-vkabatov@redhat.com
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The data of compressed section should be aligned to 4
(for 32bit) or 8 (for 64 bit) bytes.
The binutils ld sets sh_addralign to 1, which makes libelf
fail with misaligned section error during the update as
reported by Jesper:
FAILED elf_update(WRITE): invalid section alignment
While waiting for ld fix, we can fix compressed sections
sh_addralign value manually.
Adding warning in -vv mode when the fix is triggered:
$ ./tools/bpf/resolve_btfids/resolve_btfids -vv vmlinux
...
section(36) .comment, size 44, link 0, flags 30, type=1
section(37) .debug_aranges, size 45684, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 16, expected 8
section(38) .debug_info, size 129104957, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 1, expected 8
section(39) .debug_abbrev, size 1152583, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 1, expected 8
section(40) .debug_line, size 7374522, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 1, expected 8
section(41) .debug_frame, size 702463, link 0, flags 800, type=1
section(42) .debug_str, size 1017571, link 0, flags 830, type=1
- fixing wrong alignment sh_addralign 1, expected 8
section(43) .debug_loc, size 3019453, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 1, expected 8
section(44) .debug_ranges, size 1744583, link 0, flags 800, type=1
- fixing wrong alignment sh_addralign 16, expected 8
section(45) .symtab, size 2955888, link 46, flags 0, type=2
section(46) .strtab, size 2613072, link 0, flags 0, type=3
...
update ok for vmlinux
Another workaround is to disable compressed debug info data
CONFIG_DEBUG_INFO_COMPRESSED kernel option.
Fixes: fbbb68de80a4 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object")
Reported-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Yonghong Song <yhs@fb.com>
Cc: Mark Wielaard <mjw@redhat.com>
Cc: Nick Clifton <nickc@redhat.com>
Link: https://lore.kernel.org/bpf/20200819092342.259004-1-jolsa@kernel.org
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Record which built-ins are optional and needed for some of recent BPF CO-RE
subtests. Document Clang diff that fixed corner-case issue with
__builtin_btf_type_id().
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200820061411.1755905-4-andriin@fb.com
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GCC 4.9 seems to be more strict in some regards. Fix two minor issue it
reported.
Fixes: 1c1052e0140a ("tools/testing/selftests/bpf: Add self-tests for new helper bpf_get_ns_current_pid_tgid.")
Fixes: 2d7824ffd25c ("selftests: bpf: Add test for sk_assign")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200820061411.1755905-3-andriin@fb.com
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GCC compilers older than version 5 don't support __builtin_mul_overflow yet.
Given GCC 4.9 is the minimal supported compiler for building kernel and the
fact that libbpf is a dependency of resolve_btfids, which is dependency of
CONFIG_DEBUG_INFO_BTF=y, this needs to be handled. This patch fixes the issue
by falling back to slower detection of integer overflow in such cases.
Fixes: 029258d7b228 ("libbpf: Remove any use of reallocarray() in libbpf")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200820061411.1755905-2-andriin@fb.com
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BPF_CALL | BPF_JMP32 is explicitly not allowed by verifier for BPF helper
calls, so don't detect it as a valid call. Also drop the check on func_id
pointer, as it's currently always non-null.
Fixes: 109cea5a594f ("libbpf: Sanitize BPF program code for bpf_probe_read_{kernel, user}[_str]")
Reported-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200820061411.1755905-1-andriin@fb.com
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The error message emitted by bpf_object__init_user_btf_maps() was using the
wrong section ID.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200819110534.9058-1-toke@redhat.com
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Add a test that mounts two bpffs instances and checks progs.debug
and maps.debug for sanity data.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200819042759.51280-5-alexei.starovoitov@gmail.com
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Add kernel module with user mode driver that populates bpffs with
BPF iterators.
$ mount bpffs /my/bpffs/ -t bpf
$ ls -la /my/bpffs/
total 4
drwxrwxrwt 2 root root 0 Jul 2 00:27 .
drwxr-xr-x 19 root root 4096 Jul 2 00:09 ..
-rw------- 1 root root 0 Jul 2 00:27 maps.debug
-rw------- 1 root root 0 Jul 2 00:27 progs.debug
The user mode driver will load BPF Type Formats, create BPF maps, populate BPF
maps, load two BPF programs, attach them to BPF iterators, and finally send two
bpf_link IDs back to the kernel.
The kernel will pin two bpf_links into newly mounted bpffs instance under
names "progs.debug" and "maps.debug". These two files become human readable.
$ cat /my/bpffs/progs.debug
id name attached
11 dump_bpf_map bpf_iter_bpf_map
12 dump_bpf_prog bpf_iter_bpf_prog
27 test_pkt_access
32 test_main test_pkt_access test_pkt_access
33 test_subprog1 test_pkt_access_subprog1 test_pkt_access
34 test_subprog2 test_pkt_access_subprog2 test_pkt_access
35 test_subprog3 test_pkt_access_subprog3 test_pkt_access
36 new_get_skb_len get_skb_len test_pkt_access
37 new_get_skb_ifindex get_skb_ifindex test_pkt_access
38 new_get_constant get_constant test_pkt_access
The BPF program dump_bpf_prog() in iterators.bpf.c is printing this data about
all BPF programs currently loaded in the system. This information is unstable
and will change from kernel to kernel as ".debug" suffix conveys.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200819042759.51280-4-alexei.starovoitov@gmail.com
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Simplify the return expression.
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200819025324.14680-1-vulab@iscas.ac.cn
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Add tests validating existence and value relocations for enum value-based
relocations. If __builtin_preserve_enum_value() built-in is not supported,
skip tests.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200819194519.3375898-6-andriin@fb.com
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Implement two relocations of a new enumerator value-based CO-RE relocation
kind: ENUMVAL_EXISTS and ENUMVAL_VALUE.
First, ENUMVAL_EXISTS, allows to detect the presence of a named enumerator
value in the target (kernel) BTF. This is useful to do BPF helper/map/program
type support detection from BPF program side. bpf_core_enum_value_exists()
macro helper is provided to simplify built-in usage.
Second, ENUMVAL_VALUE, allows to capture enumerator integer value and relocate
it according to the target BTF, if it changes. This is useful to have
a guarantee against intentional or accidental re-ordering/re-numbering of some
of the internal (non-UAPI) enumerations, where kernel developers don't care
about UAPI backwards compatiblity concerns. bpf_core_enum_value() allows to
capture this succinctly and use correct enum values in code.
LLVM uses ldimm64 instruction to capture enumerator value-based relocations,
so add support for ldimm64 instruction patching as well.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200819194519.3375898-5-andriin@fb.com
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Add tests for BTF type ID relocations. To allow testing this, enhance
core_relo.c test runner to allow dynamic initialization of test inputs.
If Clang doesn't have necessary support for new functionality, test is
skipped.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200819194519.3375898-4-andriin@fb.com
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Add selftests for TYPE_EXISTS and TYPE_SIZE relocations, testing correctness
of relocations and handling of type compatiblity/incompatibility.
If __builtin_preserve_type_info() is not supported by compiler, skip tests.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200819194519.3375898-3-andriin@fb.com
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Implement support for TYPE_EXISTS/TYPE_SIZE/TYPE_ID_LOCAL/TYPE_ID_REMOTE
relocations. These are examples of type-based relocations, as opposed to
field-based relocations supported already. The difference is that they are
calculating relocation values based on the type itself, not a field within
a struct/union.
Type-based relos have slightly different semantics when matching local types
to kernel target types, see comments in bpf_core_types_are_compat() for
details. Their behavior on failure to find target type in kernel BTF also
differs. Instead of "poisoning" relocatable instruction and failing load
subsequently in kernel, they return 0 (which is rarely a valid return result,
so user BPF code can use that to detect success/failure of the relocation and
deal with it without extra "guarding" relocations). Also, it's always possible
to check existence of the type in target kernel with TYPE_EXISTS relocation,
similarly to a field-based FIELD_EXISTS.
TYPE_ID_LOCAL relocation is a bit special in that it always succeeds (barring
any libbpf/Clang bugs) and resolved to BTF ID using **local** BTF info of BPF
program itself. Tests in subsequent patches demonstrate the usage and
semantics of new relocations.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200819194519.3375898-2-andriin@fb.com
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It's trivial to handle missing ELF_C_MMAP_READ support in libelf the way that
objtool has solved it in
("774bec3fddcc objtool: Add fallback from ELF_C_READ_MMAP to ELF_C_READ").
So instead of having an entire feature detector for that, just do what objtool
does for perf and libbpf. And keep their Makefiles a bit simpler.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200819013607.3607269-5-andriin@fb.com
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Most of libbpf source files already include libbpf_internal.h, so it's a good
place to centralize identifier poisoning. So move kernel integer type
poisoning there. And also add reallocarray to a poison list to prevent
accidental use of it. libbpf_reallocarray() should be used universally
instead.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200819013607.3607269-4-andriin@fb.com
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Most netlink-related functions were unique to bpftool usage, so I moved them
into net.c. Few functions are still used by both bpftool and libbpf itself
internally, so I've copy-pasted them (libbpf_nl_get_link,
libbpf_netlink_open). It's a bit of duplication of code, but better separation
of libbpf as a library with public API and bpftool, relying on unexposed
functions in libbpf.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200819013607.3607269-3-andriin@fb.com
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Re-implement glibc's reallocarray() for libbpf internal-only use.
reallocarray(), unfortunately, is not available in all versions of glibc, so
requires extra feature detection and using reallocarray() stub from
<tools/libc_compat.h> and COMPAT_NEED_REALLOCARRAY. All this complicates build
of libbpf unnecessarily and is just a maintenance burden. Instead, it's
trivial to implement libbpf-specific internal version and use it throughout
libbpf.
Which is what this patch does, along with converting some realloc() uses that
should really have been reallocarray() in the first place.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200819013607.3607269-2-andriin@fb.com
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Add test simulating ambiguous field size relocation, while fields themselves
are at the exact same offset.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818223921.2911963-5-andriin@fb.com
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Split the instruction patching logic into relocation value calculation and
application of relocation to instruction. Using this, evaluate relocation
against each matching candidate and validate that all candidates agree on
relocated value. If not, report ambiguity and fail load.
This logic is necessary to avoid dangerous (however unlikely) accidental match
against two incompatible candidate types. Without this change, libbpf will
pick a random type as *the* candidate and apply potentially invalid
relocation.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818223921.2911963-4-andriin@fb.com
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Add logging of local/target type kind (struct/union/typedef/etc). Preserve
unresolved root type ID (for cases of typedef). Improve the format of CO-RE
reloc spec output format to contain only relevant and succinct info.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818223921.2911963-3-andriin@fb.com
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Instead of printing out integer value of BTF kind, print out a string
representation of a kind.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818223921.2911963-2-andriin@fb.com
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When the error code is EAGAIN, the kernel signals the user
space should retry the read() operation for bpf iterators.
Let us do it.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200818222312.2181675-1-yhs@fb.com
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Detect whether a kernel supports any BTF at all, and if not, don't even
attempt loading BTF to avoid unnecessary log messages like:
libbpf: Error loading BTF: Invalid argument(22)
libbpf: Error loading .BTF into kernel: -22. BTF is optional, ignoring.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818213356.2629020-8-andriin@fb.com
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Now that libbpf can automatically fallback to bpf_probe_read() on old kernels
not yet supporting bpf_probe_read_kernel(), switch libbpf BPF-side helper
macros to use appropriate BPF helper for reading kernel data.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/bpf/20200818213356.2629020-7-andriin@fb.com
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The test is reading UAPI kernel structure from user-space. So it doesn't need
CO-RE relocations and has to use bpf_probe_read_user().
Fixes: acbd06206bbb ("selftests/bpf: Add vmlinux.h selftest exercising tracing of syscalls")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818213356.2629020-6-andriin@fb.com
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Add BPF program code sanitization pass, replacing calls to BPF
bpf_probe_read_{kernel,user}[_str]() helpers with bpf_probe_read[_str](), if
libbpf detects that kernel doesn't support new variants.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818213356.2629020-5-andriin@fb.com
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Factor out common piece of logic that detects support for a feature based on
successfully created FD. Also take care of closing FD, if it was created.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818213356.2629020-4-andriin@fb.com
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Turn libbpf's kernel feature probing into lazily-performed checks. This allows
to skip performing unnecessary feature checks, if a given BPF application
doesn't rely on a particular kernel feature. As we grow number of feature
probes, libbpf might perform less unnecessary syscalls and scale better with
number of feature probes long-term.
By decoupling feature checks from bpf_object, it's also possible to perform
feature probing from libbpf static helpers and low-level APIs, if necessary.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818213356.2629020-3-andriin@fb.com
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That compilation warning is more annoying, than helpful.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818213356.2629020-2-andriin@fb.com
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Replace a comma between expression statements by a semicolon.
Signed-off-by: Xu Wang <vulab@iscas.ac.cn>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20200818071611.21923-1-vulab@iscas.ac.cn
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