Commit graph

983599 commits

Author SHA1 Message Date
Song Liu
e8168840e1 selftests/bpf: Add test for bpf_iter_task_vma
The test dumps information similar to /proc/pid/maps. The first line of
the output is compared against the /proc file to make sure they match.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210212183107.50963-4-songliubraving@fb.com
2021-02-12 12:56:54 -08:00
Song Liu
3d06f34aa8 bpf: Allow bpf_d_path in bpf_iter program
task_file and task_vma iter programs have access to file->f_path. Enable
bpf_d_path to print paths of these file.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210212183107.50963-3-songliubraving@fb.com
2021-02-12 12:56:53 -08:00
Song Liu
3a7b35b899 bpf: Introduce task_vma bpf_iter
Introduce task_vma bpf_iter to print memory information of a process. It
can be used to print customized information similar to /proc/<pid>/maps.

Current /proc/<pid>/maps and /proc/<pid>/smaps provide information of
vma's of a process. However, these information are not flexible enough to
cover all use cases. For example, if a vma cover mixed 2MB pages and 4kB
pages (x86_64), there is no easy way to tell which address ranges are
backed by 2MB pages. task_vma solves the problem by enabling the user to
generate customize information based on the vma (and vma->vm_mm,
vma->vm_file, etc.).

To access the vma safely in the BPF program, task_vma iterator holds
target mmap_lock while calling the BPF program. If the mmap_lock is
contended, task_vma unlocks mmap_lock between iterations to unblock the
writer(s). This lock contention avoidance mechanism is similar to the one
used in show_smaps_rollup().

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210212183107.50963-2-songliubraving@fb.com
2021-02-12 12:56:53 -08:00
Martin KaFai Lau
a79e88dd2c bpf: selftests: Add non function pointer test to struct_ops
This patch adds a "void *owner" member.  The existing
bpf_tcp_ca test will ensure the bpf_cubic.o and bpf_dctcp.o
can be loaded.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210212021037.267278-1-kafai@fb.com
2021-02-12 11:49:36 -08:00
Martin KaFai Lau
d2836dddc9 libbpf: Ignore non function pointer member in struct_ops
When libbpf initializes the kernel's struct_ops in
"bpf_map__init_kern_struct_ops()", it enforces all
pointer types must be a function pointer and rejects
others.  It turns out to be too strict.  For example,
when directly using "struct tcp_congestion_ops" from vmlinux.h,
it has a "struct module *owner" member and it is set to NULL
in a bpf_tcp_cc.o.

Instead, it only needs to ensure the member is a function
pointer if it has been set (relocated) to a bpf-prog.
This patch moves the "btf_is_func_proto(kern_mtype)" check
after the existing "if (!prog) { continue; }".  The original debug
message in "if (!prog) { continue; }" is also removed since it is
no longer valid.  Beside, there is a later debug message to tell
which function pointer is set.

The "btf_is_func_proto(mtype)" has already been guaranteed
in "bpf_object__collect_st_ops_relos()" which has been run
before "bpf_map__init_kern_struct_ops()".  Thus, this check
is removed.

v2:
- Remove outdated debug message (Andrii)
  Remove because there is a later debug message to tell
  which function pointer is set.
- Following mtype->type is no longer needed. Remove:
  "skip_mods_and_typedefs(btf, mtype->type, &mtype_id)"
- Do "if (!prog)" test before skip_mods_and_typedefs.

Fixes: 590a008882 ("bpf: libbpf: Add STRUCT_OPS support")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210212021030.266932-1-kafai@fb.com
2021-02-12 11:49:36 -08:00
Stanislav Fomichev
1e0aa3fb05 libbpf: Use AF_LOCAL instead of AF_INET in xsk.c
We have the environments where usage of AF_INET is prohibited
(cgroup/sock_create returns EPERM for AF_INET). Let's use
AF_LOCAL instead of AF_INET, it should perfectly work with SIOCETHTOOL.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Björn Töpel <bjorn.topel@intel.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/20210209221826.922940-1-sdf@google.com
2021-02-12 11:36:48 -08:00
Ilya Leoshkevich
b2e37a7114 bpf: Fix subreg optimization for BPF_FETCH
All 32-bit variants of BPF_FETCH (add, and, or, xor, xchg, cmpxchg)
define a 32-bit subreg and thus have zext_dst set. Their encoding,
however, uses dst_reg field as a base register, which causes
opt_subreg_zext_lo32_rnd_hi32() to zero-extend said base register
instead of the one the insn really defines (r0 or src_reg).

Fix by properly choosing a register being defined, similar to how
check_atomic() already does that.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210210204502.83429-1-iii@linux.ibm.com
2021-02-11 22:03:19 -08:00
Ilya Leoshkevich
6a5df969ff docs: bpf: Clarify BPF_CMPXCHG wording
Based on [1], BPF_CMPXCHG should always load the old value into R0. The
phrasing in bpf.rst is somewhat ambiguous in this regard, improve it to
make this aspect crystal clear.

  [1] https://lore.kernel.org/bpf/CAADnVQJFcFwxEz=wnV=hkie-EDwa8s5JGbBQeFt1TGux1OihJw@mail.gmail.com/

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210210142853.82203-1-iii@linux.ibm.com
2021-02-11 22:01:13 -08:00
Alexei Starovoitov
1336c66247 bpf: Clear per_cpu pointers during bpf_prog_realloc
bpf_prog_realloc copies contents of struct bpf_prog.
The pointers have to be cleared before freeing old struct.

Reported-by: Ilya Leoshkevich <iii@linux.ibm.com>
Fixes: 700d4796ef ("bpf: Optimize program stats")
Fixes: ca06f55b90 ("bpf: Add per-program recursion prevention mechanism")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2021-02-11 19:35:00 -08:00
Florent Revest
6fdd671baa selftests/bpf: Add a selftest for the tracing bpf_get_socket_cookie
This builds up on the existing socket cookie test which checks whether
the bpf_get_socket_cookie helpers provide the same value in
cgroup/connect6 and sockops programs for a socket created by the
userspace part of the test.

Instead of having an update_cookie sockops program tag a socket local
storage with 0xFF, this uses both an update_cookie_sockops program and
an update_cookie_tracing program which succesively tag the socket with
0x0F and then 0xF0.

Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210210111406.785541-5-revest@chromium.org
2021-02-11 17:44:41 -08:00
Florent Revest
6cd4dcc3fb selftests/bpf: Use vmlinux.h in socket_cookie_prog.c
When migrating from the bpf.h's to the vmlinux.h's definition of struct
bps_sock, an interesting LLVM behavior happened. LLVM started producing
two fetches of ctx->sk in the sockops program this means that the
verifier could not keep track of the NULL-check on ctx->sk. Therefore,
we need to extract ctx->sk in a variable before checking and
dereferencing it.

Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210210111406.785541-4-revest@chromium.org
2021-02-11 17:44:41 -08:00
Florent Revest
61f8c9c8f3 selftests/bpf: Integrate the socket_cookie test to test_progs
Currently, the selftest for the BPF socket_cookie helpers is built and
run independently from test_progs. It's easy to forget and hard to
maintain.

This patch moves the socket cookies test into prog_tests/ and vastly
simplifies its logic by:
- rewriting the loading code with BPF skeletons
- rewriting the server/client code with network helpers
- rewriting the cgroup code with test__join_cgroup
- rewriting the error handling code with CHECKs

Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210210111406.785541-3-revest@chromium.org
2021-02-11 17:44:41 -08:00
Florent Revest
c5dbb89fc2 bpf: Expose bpf_get_socket_cookie to tracing programs
This needs a new helper that:
- can work in a sleepable context (using sock_gen_cookie)
- takes a struct sock pointer and checks that it's not NULL

Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210210111406.785541-2-revest@chromium.org
2021-02-11 17:44:41 -08:00
Florent Revest
07881ccbf4 bpf: Be less specific about socket cookies guarantees
Since "92acdc58ab11 bpf, net: Rework cookie generator as per-cpu one"
socket cookies are not guaranteed to be non-decreasing. The
bpf_get_socket_cookie helper descriptions are currently specifying that
cookies are non-decreasing but we don't want users to rely on that.

Reported-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Florent Revest <revest@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210210111406.785541-1-revest@chromium.org
2021-02-11 17:44:40 -08:00
Jiri Olsa
0e1aa629f1 kbuild: Do not clean resolve_btfids if the output does not exist
Nathan reported issue with cleaning empty build directory:

  $ make -s O=build distclean
  ../../scripts/Makefile.include:4: *** \
  O=/ho...build/tools/bpf/resolve_btfids does not exist.  Stop.

The problem that tools scripts require existing output
directory, otherwise it fails.

Adding check around the resolve_btfids clean target to
ensure the output directory is in place.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/bpf/20210211124004.1144344-1-jolsa@kernel.org
2021-02-11 11:27:58 -08:00
Alexei Starovoitov
750e5d7649 selftests/bpf: Add a test for map-in-map and per-cpu maps in sleepable progs
Add a basic test for map-in-map and per-cpu maps in sleepable programs.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210210033634.62081-10-alexei.starovoitov@gmail.com
2021-02-11 16:19:28 +01:00
Alexei Starovoitov
638e4b825d bpf: Allows per-cpu maps and map-in-map in sleepable programs
Since sleepable programs are now executing under migrate_disable
the per-cpu maps are safe to use.
The map-in-map were ok to use in sleepable from the time sleepable
progs were introduced.

Note that non-preallocated maps are still not safe, since there is
no rcu_read_lock yet in sleepable programs and dynamically allocated
map elements are relying on rcu protection. The sleepable programs
have rcu_read_lock_trace instead. That limitation will be addresses
in the future.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210210033634.62081-9-alexei.starovoitov@gmail.com
2021-02-11 16:19:26 +01:00
Alexei Starovoitov
dcf33b6f4d selftests/bpf: Improve recursion selftest
Since recursion_misses counter is available in bpf_prog_info
improve the selftest to make sure it's counting correctly.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210210033634.62081-8-alexei.starovoitov@gmail.com
2021-02-11 16:19:24 +01:00
Alexei Starovoitov
9ed9e9ba23 bpf: Count the number of times recursion was prevented
Add per-program counter for number of times recursion prevention mechanism
was triggered and expose it via show_fdinfo and bpf_prog_info.
Teach bpftool to print it.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210210033634.62081-7-alexei.starovoitov@gmail.com
2021-02-11 16:19:20 +01:00
Alexei Starovoitov
406c557edc selftest/bpf: Add a recursion test
Add recursive non-sleepable fentry program as a test.
All attach points where sleepable progs can execute are non recursive so far.
The recursion protection mechanism for sleepable cannot be activated yet.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210210033634.62081-6-alexei.starovoitov@gmail.com
2021-02-11 16:19:16 +01:00
Alexei Starovoitov
ca06f55b90 bpf: Add per-program recursion prevention mechanism
Since both sleepable and non-sleepable programs execute under migrate_disable
add recursion prevention mechanism to both types of programs when they're
executed via bpf trampoline.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210210033634.62081-5-alexei.starovoitov@gmail.com
2021-02-11 16:19:13 +01:00
Alexei Starovoitov
f2dd3b3946 bpf: Compute program stats for sleepable programs
Since sleepable programs don't migrate from the cpu the excution stats can be
computed for them as well. Reuse the same infrastructure for both sleepable and
non-sleepable programs.

run_cnt     -> the number of times the program was executed.
run_time_ns -> the program execution time in nanoseconds including the
               off-cpu time when the program was sleeping.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210210033634.62081-4-alexei.starovoitov@gmail.com
2021-02-11 16:19:06 +01:00
Alexei Starovoitov
031d6e02dd bpf: Run sleepable programs with migration disabled
In older non-RT kernels migrate_disable() was the same as preempt_disable().
Since commit 74d862b682 ("sched: Make migrate_disable/enable() independent of RT")
migrate_disable() is real and doesn't prevent sleeping.

Running sleepable programs with migration disabled allows to add support for
program stats and per-cpu maps later.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20210210033634.62081-3-alexei.starovoitov@gmail.com
2021-02-11 16:18:55 +01:00
Alexei Starovoitov
700d4796ef bpf: Optimize program stats
Move bpf_prog_stats from prog->aux into prog to avoid one extra load
in critical path of program execution.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210210033634.62081-2-alexei.starovoitov@gmail.com
2021-02-11 16:17:50 +01:00
Marco Elver
6df8fb8330 bpf_lru_list: Read double-checked variable once without lock
For double-checked locking in bpf_common_lru_push_free(), node->type is
read outside the critical section and then re-checked under the lock.
However, concurrent writes to node->type result in data races.

For example, the following concurrent access was observed by KCSAN:

  write to 0xffff88801521bc22 of 1 bytes by task 10038 on cpu 1:
   __bpf_lru_node_move_in        kernel/bpf/bpf_lru_list.c:91
   __local_list_flush            kernel/bpf/bpf_lru_list.c:298
   ...
  read to 0xffff88801521bc22 of 1 bytes by task 10043 on cpu 0:
   bpf_common_lru_push_free      kernel/bpf/bpf_lru_list.c:507
   bpf_lru_push_free             kernel/bpf/bpf_lru_list.c:555
   ...

Fix the data races where node->type is read outside the critical section
(for double-checked locking) by marking the access with READ_ONCE() as
well as ensuring the variable is only accessed once.

Fixes: 3a08c2fd76 ("bpf: LRU List")
Reported-by: syzbot+3536db46dfa58c573458@syzkaller.appspotmail.com
Reported-by: syzbot+516acdb03d3e27d91bcd@syzkaller.appspotmail.com
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210209112701.3341724-1-elver@google.com
2021-02-10 15:54:26 -08:00
Jiapeng Chong
bd2d4e6c6e selftests/bpf: Simplify the calculation of variables
Fix the following coccicheck warnings:

./tools/testing/selftests/bpf/xdpxceiver.c:954:28-30: WARNING !A || A &&
B is equivalent to !A || B.

./tools/testing/selftests/bpf/xdpxceiver.c:932:28-30: WARNING !A || A &&
B is equivalent to !A || B.

./tools/testing/selftests/bpf/xdpxceiver.c:909:28-30: WARNING !A || A &&
B is equivalent to !A || B.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1612860398-102839-1-git-send-email-jiapeng.chong@linux.alibaba.com
2021-02-10 12:14:27 -08:00
Ilya Leoshkevich
45df305268 selftests/bpf: Fix endianness issues in atomic tests
Atomic tests store a DW, but then load it back as a W from the same
address. This doesn't work on big-endian systems, and since the point
of those tests is not testing narrow loads, fix simply by loading a
DW.

Fixes: 98d666d05a ("bpf: Add tests for new BPF atomic operations")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210210020713.77911-1-iii@linux.ibm.com
2021-02-10 11:55:22 -08:00
Alexei Starovoitov
cf2d0a5e78 Merge branch 'allow variable-offset stack acces'
Andrei Matei says:

====================

Before this patch, variable offset access to the stack was dissalowed
for regular instructions, but was allowed for "indirect" accesses (i.e.
helpers). This patch removes the restriction, allowing reading and
writing to the stack through stack pointers with variable offsets. This
makes stack-allocated buffers more usable in programs, and brings stack
pointers closer to other types of pointers.

The motivation is being able to use stack-allocated buffers for data
manipulation. When the stack size limit is sufficient, allocating
buffers on the stack is simpler than per-cpu arrays, or other
alternatives.

V2 -> V3

- var-offset writes mark all the stack slots in range as initialized, so
  that future reads are not rejected.
- rewrote the C test to not use uprobes, as per Andrii's suggestion.
- addressed other review comments from Alexei.

V1 -> V2

- add support for var-offset stack writes, in addition to reads
- add a C test
- made variable offset direct reads no longer destroy spilled registers
  in the access range
- address review nits
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2021-02-10 11:10:45 -08:00
Andrei Matei
0fd7562af1 selftest/bpf: Add test for var-offset stack access
Add a higher-level test (C BPF program) for the new functionality -
variable access stack reads and writes.

Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210207011027.676572-5-andreimatei1@gmail.com
2021-02-10 11:05:34 -08:00
Andrei Matei
7a22930c41 selftest/bpf: Verifier tests for var-off access
Add tests for the new functionality - reading and writing to the stack
through a variable-offset pointer.

Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210207011027.676572-4-andreimatei1@gmail.com
2021-02-10 10:44:19 -08:00
Andrei Matei
a680cb3d8e selftest/bpf: Adjust expected verifier errors
The verifier errors around stack accesses have changed slightly in the
previous commit (generally for the better).

Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210207011027.676572-3-andreimatei1@gmail.com
2021-02-10 10:44:19 -08:00
Andrei Matei
01f810ace9 bpf: Allow variable-offset stack access
Before this patch, variable offset access to the stack was dissalowed
for regular instructions, but was allowed for "indirect" accesses (i.e.
helpers). This patch removes the restriction, allowing reading and
writing to the stack through stack pointers with variable offsets. This
makes stack-allocated buffers more usable in programs, and brings stack
pointers closer to other types of pointers.

The motivation is being able to use stack-allocated buffers for data
manipulation. When the stack size limit is sufficient, allocating
buffers on the stack is simpler than per-cpu arrays, or other
alternatives.

In unpriviledged programs, variable-offset reads and writes are
disallowed (they were already disallowed for the indirect access case)
because the speculative execution checking code doesn't support them.
Additionally, when writing through a variable-offset stack pointer, if
any pointers are in the accessible range, there's possilibities of later
leaking pointers because the write cannot be tracked precisely.

Writes with variable offset mark the whole range as initialized, even
though we don't know which stack slots are actually written. This is in
order to not reject future reads to these slots. Note that this doesn't
affect writes done through helpers; like before, helpers need the whole
stack range to be initialized to begin with.
All the stack slots are in range are considered scalars after the write;
variable-offset register spills are not tracked.

For reads, all the stack slots in the variable range needs to be
initialized (but see above about what writes do), otherwise the read is
rejected. All register spilled in stack slots that might be read are
marked as having been read, however reads through such pointers don't do
register filling; the target register will always be either a scalar or
a constant zero.

Signed-off-by: Andrei Matei <andreimatei1@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210207011027.676572-2-andreimatei1@gmail.com
2021-02-10 10:44:19 -08:00
Andrii Nakryiko
ee5cc0363e Merge branch 'kbuild/resolve_btfids: Invoke resolve_btfids'
Jiri Olsa says:

====================

hi,
resolve_btfids tool is used during the kernel build,
so we should clean it on kernel's make clean.

v2 changes:
  - add Song's acks on patches 1 and 4 (others changed) [Song]
  - add missing / [Andrii]
  - change srctree variable initialization [Andrii]
  - shifted ifdef for clean target [Andrii]

thanks,
jirka
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2021-02-08 21:21:39 -08:00
Jiri Olsa
50d3a3f816 kbuild: Add resolve_btfids clean to root clean target
The resolve_btfids tool is used during the kernel build,
so we should clean it on kernel's make clean.

Invoking the the resolve_btfids clean as part of root
'make clean'.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20210205124020.683286-5-jolsa@kernel.org
2021-02-08 21:21:39 -08:00
Jiri Olsa
7962cb9b64 tools/resolve_btfids: Set srctree variable unconditionally
We want this clean to be called from tree's root Makefile,
which defines same srctree variable and that will screw
the make setup.

We actually do not use srctree being passed from outside,
so we can solve this by setting current srctree value
directly.

Also changing the way how srctree is initialized as suggested
by Andrri.

Also root Makefile does not define the implicit RM variable,
so adding RM initialization.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210205124020.683286-4-jolsa@kernel.org
2021-02-08 21:21:39 -08:00
Jiri Olsa
f23130979c tools/resolve_btfids: Check objects before removing
We want this clean to be called from tree's root clean
and that one is silent if there's nothing to clean.

Adding check for all object to clean and display CLEAN
messages only if there are objects to remove.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210205124020.683286-3-jolsa@kernel.org
2021-02-08 21:21:39 -08:00
Jiri Olsa
fc6b48f692 tools/resolve_btfids: Build libbpf and libsubcmd in separate directories
Setting up separate build directories for libbpf and libpsubcmd,
so it's separated from other objects and we don't get them mixed
in the future.

It also simplifies cleaning, which is now simple rm -rf.

Also there's no need for FEATURE-DUMP.libbpf and bpf_helper_defs.h
files in .gitignore anymore.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210205124020.683286-2-jolsa@kernel.org
2021-02-08 21:21:39 -08:00
Jiapeng Chong
0a1b0fd929 bpf: Simplify bool comparison
Fix the following coccicheck warning:

./tools/bpf/bpf_dbg.c:893:32-36: WARNING: Comparison to bool.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1612777416-34339-1-git-send-email-jiapeng.chong@linux.alibaba.com
2021-02-08 17:55:38 -08:00
Brendan Jackman
1589a1fa4e selftests/bpf: Add missing cleanup in atomic_bounds test
Add missing skeleton destroy call.

Fixes: 37086bfdc7 ("bpf: Propagate stack bounds to registers in atomics w/ BPF_FETCH")
Reported-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210208123737.963172-1-jackmanb@google.com
2021-02-08 17:55:01 -08:00
Yang Li
11da9f0c6d selftests/bpf: Remove unneeded semicolon
Eliminate the following coccicheck warning:
./tools/testing/selftests/bpf/test_flow_dissector.c:506:2-3: Unneeded
semicolon

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1612780213-84583-1-git-send-email-yang.lee@linux.alibaba.com
2021-02-08 17:54:24 -08:00
Yang Li
215cb7d382 bpf/benchs/bench_ringbufs: Remove unneeded semicolon
Eliminate the following coccicheck warning:
./tools/testing/selftests/bpf/benchs/bench_ringbufs.c:322:2-3: Unneeded
semicolon

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1612684360-115910-1-git-send-email-yang.lee@linux.alibaba.com
2021-02-08 13:41:24 -08:00
Yonghong Song
23a2d70c7a bpf: Refactor BPF_PSEUDO_CALL checking as a helper function
There is no functionality change. This refactoring intends
to facilitate next patch change with BPF_PSEUDO_FUNC.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210204234827.1628953-1-yhs@fb.com
2021-02-04 21:51:47 -08:00
Andrii Nakryiko
ecda49c522 Merge branch 'BPF ring buffer + sleepable programs'
KP Singh says:

====================

- Use ring_buffer__consume without BPF_RB_FORCE_WAKEUP as suggested by
  Andrii
- Use ASSERT_OK_PTR macro

Sleepable programs currently do not have access to any ringbuffer and
since the perf ring buffer is a per-cpu map, it would not be trivial to
enable for sleepable programs. Our specific use-case is to use the
bpf_ima_inode_hash helper and write the hash to a ring buffer from a
sleepable LSM hook.

This series allows the BPF ringbuffer to be used in sleepable programs
(tracing and lsm). Since the helper prototypes were already exposed
the only change required was have the verifier allow
BPF_MAP_TYPE_RINGBUF for sleepable programs. The ima test is also
modified to use the ringbuffer instead of global variables.

Based on dicussions we had over the BPF office hours and enabling all
the possible debug options, I could not find any issues or warnings when
using the ring buffer from sleepable programs.
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2021-02-04 16:35:05 -08:00
KP Singh
f446b570ac bpf/selftests: Update the IMA test to use BPF ring buffer
Instead of using shared global variables between userspace and BPF, use
the ring buffer to send the IMA hash on the BPF ring buffer. This helps
in validating both IMA and the usage of the ringbuffer in sleepable
programs.

Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210204193622.3367275-3-kpsingh@kernel.org
2021-02-04 16:35:05 -08:00
KP Singh
ba90c2cc02 bpf: Allow usage of BPF ringbuffer in sleepable programs
The BPF ringbuffer map is pre-allocated and the implementation logic
does not rely on disabling preemption or per-cpu data structures. Using
the BPF ringbuffer sleepable LSM and tracing programs does not trigger
any warnings with DEBUG_ATOMIC_SLEEP, DEBUG_PREEMPT,
PROVE_RCU and PROVE_LOCKING and LOCKDEP enabled.

This allows helpers like bpf_copy_from_user and bpf_ima_inode_hash to
write to the BPF ring buffer from sleepable BPF programs.

Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210204193622.3367275-2-kpsingh@kernel.org
2021-02-04 16:35:00 -08:00
Andrii Nakryiko
ec45c5faa2 Merge branch 'BPF selftest helper script'
KP Singh says:

====================

# v4 -> v5

- Use %Y (modification time) instead of %W (creation time) of the local
  copy of the kernel config to check for newer upstream config.
- Rename the script to vmtest.sh

# v3 -> v4

- Fix logic for updating kernel config to not download the file
  if there are no upstream modifications and avoid extraneous
  kernel compilation as suggested by Andrii.
- This also removes the need for the -k flag.

# v2 -> v3

- Fixes to silence verbose commands
- Fixed output buffering without being teed out
- Fixed the clobbered error code of the script
- Other fixes suggested by Andrii

# v1 -> v2

- The script now compiles the kernel by default, and the -k option
  implies "keep the kernel"
- Pointer to the script in the docs.
- Some minor simplifications.

Allow developers and contributors to understand if their changes would
end up breaking the BPF CI and avoid the back and forth required for
fixing the test cases in the CI environment. The se
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2021-02-04 16:03:17 -08:00
KP Singh
881949f770 bpf/selftests: Add a short note about vmtest.sh in README.rst
Add a short note to make contributors aware of the existence of the
script. The documentation does not intentionally document all the
options of the script to avoid mentioning it in two places (it's
available in the usage / help message of the script).

Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210204194544.3383814-3-kpsingh@kernel.org
2021-02-04 16:03:16 -08:00
KP Singh
c9709f5238 bpf: Helper script for running BPF presubmit tests
The script runs the BPF selftests locally on the same kernel image
as they would run post submit in the BPF continuous integration
framework.

The goal of the script is to allow contributors to run selftests locally
in the same environment to check if their changes would end up breaking
the BPF CI and reduce the back-and-forth between the maintainers and the
developers.

Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/bpf/20210204194544.3383814-2-kpsingh@kernel.org
2021-02-04 16:03:16 -08:00
Alexei Starovoitov
4c5de12759 bpf: Emit explicit NULL pointer checks for PROBE_LDX instructions.
PTR_TO_BTF_ID registers contain either kernel pointer or NULL.
Emit the NULL check explicitly by JIT instead of going into
do_user_addr_fault() on NULL deference.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20210202053837.95909-1-alexei.starovoitov@gmail.com
2021-02-04 16:46:44 +01:00
Andrii Nakryiko
5f10c1aac8 libbpf: Stop using feature-detection Makefiles
Libbpf's Makefile relies on Linux tools infrastructure's feature detection
framework, but libbpf's needs are very modest: it detects the presence of
libelf and libz, both of which are mandatory. So it doesn't benefit much from
the framework, but pays significant costs in terms of maintainability and
debugging experience, when something goes wrong. The other feature detector,
testing for the presernce of minimal BPF API in system headers is long
obsolete as well, providing no value.

So stop using feature detection and just assume the presence of libelf and
libz during build time. Worst case, user will get a clear and actionable
linker error, e.g.:

  /usr/bin/ld: cannot find -lelf

On the other hand, we completely bypass recurring issues various users
reported over time with false negatives of feature detection (libelf or libz
not being detected, while they are actually present in the system).

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/bpf/20210203203445.3356114-1-andrii@kernel.org
2021-02-04 01:22:00 +01:00