Extending the code in previous commits, introduce referenced kptr
support, which needs to be tagged using 'kptr_ref' tag instead. Unlike
unreferenced kptr, referenced kptr have a lot more restrictions. In
addition to the type matching, only a newly introduced bpf_kptr_xchg
helper is allowed to modify the map value at that offset. This transfers
the referenced pointer being stored into the map, releasing the
references state for the program, and returning the old value and
creating new reference state for the returned pointer.
Similar to unreferenced pointer case, return value for this case will
also be PTR_TO_BTF_ID_OR_NULL. The reference for the returned pointer
must either be eventually released by calling the corresponding release
function, otherwise it must be transferred into another map.
It is also allowed to call bpf_kptr_xchg with a NULL pointer, to clear
the value, and obtain the old value if any.
BPF_LDX, BPF_STX, and BPF_ST cannot access referenced kptr. A future
commit will permit using BPF_LDX for such pointers, but attempt at
making it safe, since the lifetime of object won't be guaranteed.
There are valid reasons to enforce the restriction of permitting only
bpf_kptr_xchg to operate on referenced kptr. The pointer value must be
consistent in face of concurrent modification, and any prior values
contained in the map must also be released before a new one is moved
into the map. To ensure proper transfer of this ownership, bpf_kptr_xchg
returns the old value, which the verifier would require the user to
either free or move into another map, and releases the reference held
for the pointer being moved in.
In the future, direct BPF_XCHG instruction may also be permitted to work
like bpf_kptr_xchg helper.
Note that process_kptr_func doesn't have to call
check_helper_mem_access, since we already disallow rdonly/wronly flags
for map, which is what check_map_access_type checks, and we already
ensure the PTR_TO_MAP_VALUE refers to kptr by obtaining its off_desc,
so check_map_access is also not required.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-4-memxor@gmail.com
Add a new type flag for bpf_arg_type that when set tells verifier that
for a release function, that argument's register will be the one for
which meta.ref_obj_id will be set, and which will then be released
using release_reference. To capture the regno, introduce a new field
release_regno in bpf_call_arg_meta.
This would be required in the next patch, where we may either pass NULL
or a refcounted pointer as an argument to the release function
bpf_kptr_xchg. Just releasing only when meta.ref_obj_id is set is not
enough, as there is a case where the type of argument needed matches,
but the ref_obj_id is set to 0. Hence, we must enforce that whenever
meta.ref_obj_id is zero, the register that is to be released can only
be NULL for a release function.
Since we now indicate whether an argument is to be released in
bpf_func_proto itself, is_release_function helper has lost its utitlity,
hence refactor code to work without it, and just rely on
meta.release_regno to know when to release state for a ref_obj_id.
Still, the restriction of one release argument and only one ref_obj_id
passed to BPF helper or kfunc remains. This may be lifted in the future.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220424214901.2743946-3-memxor@gmail.com
musl nftw implementation does not support FTW_ACTIONRETVAL. There have been
multiple attempts at pushing the feature in musl upstream, but it has been
refused or ignored all the times:
https://www.openwall.com/lists/musl/2021/03/26/1https://www.openwall.com/lists/musl/2022/01/22/1
In this case we only care about /proc/<pid>/fd/<fd>, so it's not too difficult
to reimplement directly instead, and the new implementation makes 'bpftool perf'
slightly faster because it doesn't needlessly stat/readdir unneeded directories
(54ms -> 13ms on my machine).
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220424051022.2619648-4-asmadeus@codewreck.org
The link variable is already of type 'struct bpf_link *', casting it to
'struct bpf_link *' is redundant, drop it.
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220424143420.457082-1-ytcoode@gmail.com
Use bpf_link_create() API in fexit_stress test to attach FEXIT programs.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Kui-Feng Lee <kuifeng@fb.com>
Link: https://lore.kernel.org/bpf/20220421033945.3602803-4-andrii@kernel.org
Teach bpf_link_create() to fallback to bpf_raw_tracepoint_open() on
older kernels for programs that are attachable through
BPF_RAW_TRACEPOINT_OPEN. This makes bpf_link_create() more unified and
convenient interface for creating bpf_link-based attachments.
With this approach end users can just use bpf_link_create() for
tp_btf/fentry/fexit/fmod_ret/lsm program attachments without needing to
care about kernel support, as libbpf will handle this transparently. On
the other hand, as newer features (like BPF cookie) are added to
LINK_CREATE interface, they will be readily usable though the same
bpf_link_create() API without any major refactoring from user's
standpoint.
bpf_program__attach_btf_id() is now using bpf_link_create() internally
as well and will take advantaged of this unified interface when BPF
cookie is added for fentry/fexit.
Doing proactive feature detection of LINK_CREATE support for
fentry/tp_btf/etc is quite involved. It requires parsing vmlinux BTF,
determining some stable and guaranteed to be in all kernels versions
target BTF type (either raw tracepoint or fentry target function),
actually attaching this program and thus potentially affecting the
performance of the host kernel briefly, etc. So instead we are taking
much simpler "lazy" approach of falling back to
bpf_raw_tracepoint_open() call only if initial LINK_CREATE command
fails. For modern kernels this will mean zero added overhead, while
older kernels will incur minimal overhead with a single fast-failing
LINK_CREATE call.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Kui-Feng Lee <kuifeng@fb.com>
Link: https://lore.kernel.org/bpf/20220421033945.3602803-3-andrii@kernel.org
Switching to libbpf 1.0 API broke test_lpm_map and test_lru_map as error
reporting changed. Instead of setting errno and returning -1 bpf calls
now return -Exxx directly.
Drop errno checks and look at return code directly.
Fixes: b858ba8c52 ("selftests/bpf: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK")
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/bpf/20220421094320.1563570-1-asavkov@redhat.com
I am getting the following compilation error for prog_tests/uprobe_autoattach.c:
tools/testing/selftests/bpf/prog_tests/uprobe_autoattach.c: In function ‘test_uprobe_autoattach’:
./test_progs.h:209:26: error: pointer ‘mem’ may be used after ‘free’ [-Werror=use-after-free]
The value of mem is now used in one of the asserts, which is why it may be
confusing compilers. However, it is not dereferenced. Silence this by moving
free(mem) after the assert block.
Fixes: 1717e24801 ("selftests/bpf: Uprobe tests should verify param/return values")
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220421132317.1583867-1-asavkov@redhat.com
Switching to libbpf 1.0 API broke test_sock and test_sysctl as they
check for return of bpf_prog_attach to be exactly -1. Switch the check
to '< 0' instead.
Fixes: b858ba8c52 ("selftests/bpf: Use libbpf 1.0 API mode instead of RLIMIT_MEMLOCK")
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Yafang Shao <laoar.shao@gmail.com>
Link: https://lore.kernel.org/bpf/20220421130104.1582053-1-asavkov@redhat.com
This adds documentation for the following API functions:
- bpf_program__set_expected_attach_type()
- bpf_program__set_type()
- bpf_program__set_attach_target()
- bpf_program__attach()
- bpf_program__pin()
- bpf_program__unpin()
Signed-off-by: Grant Seltzer <grantseltzer@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220420161226.86803-3-grantseltzer@gmail.com
This updates usage of the following API functions within
libbpf so their newly added error return is checked:
- bpf_program__set_expected_attach_type()
- bpf_program__set_type()
Signed-off-by: Grant Seltzer <grantseltzer@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220420161226.86803-2-grantseltzer@gmail.com
This adds an error return to the following API functions:
- bpf_program__set_expected_attach_type()
- bpf_program__set_type()
In both cases, the error occurs when the BPF object has
already been loaded when the function is called. In this
case -EBUSY is returned.
Signed-off-by: Grant Seltzer <grantseltzer@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220420161226.86803-1-grantseltzer@gmail.com
Use bpf_prog_test_run_opts to test the skb_load_bytes function. Tests
the behavior when offset is greater than INT_MAX or a normal value.
Signed-off-by: Liu Jian <liujian56@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220416105801.88708-4-liujian56@huawei.com
Add riscv-specific USDT argument specification parsing logic.
riscv USDT argument format is shown below:
- Memory dereference case:
"size@off(reg)", e.g. "-8@-88(s0)"
- Constant value case:
"size@val", e.g. "4@5"
- Register read case:
"size@reg", e.g. "-8@a1"
s8 will be marked as poison while it's a reg of riscv, we need
to alias it in advance. Both RV32 and RV64 have been tested.
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220419145238.482134-3-pulehui@huawei.com
The usdt_cookie is defined as __u64, which should not be
used as a long type because it will be cast to 32 bits
in 32-bit platforms.
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220419145238.482134-2-pulehui@huawei.com
Add a few test cases that ensure we catch cases of badly ordered type
tags in modifier chains.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220419164608.1990559-3-memxor@gmail.com
Take advantage of new libbpf feature for declarative non-autoloaded BPF
program SEC() definitions in few test that test single program at a time
out of many available programs within the single BPF object.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220419002452.632125-2-andrii@kernel.org
Establish SEC("?abc") naming convention (i.e., adding question mark in
front of otherwise normal section name) that allows to set corresponding
program's autoload property to false. This is effectively just
a declarative way to do bpf_program__set_autoload(prog, false).
Having a way to do this declaratively in BPF code itself is useful and
convenient for various scenarios. E.g., for testing, when BPF object
consists of multiple independent BPF programs that each needs to be
tested separately. Opting out all of them by default and then setting
autoload to true for just one of them at a time simplifies testing code
(see next patch for few conversions in BPF selftests taking advantage of
this new feature).
Another real-world use case is in libbpf-tools for cases when different
BPF programs have to be picked depending on particulars of the host
kernel due to various incompatible changes (like kernel function renames
or signature change, or to pick kprobe vs fentry depending on
corresponding kernel support for the latter). Marking all the different
BPF program candidates as non-autoloaded declaratively makes this more
obvious in BPF source code and allows simpler code in user-space code.
When BPF program marked as SEC("?abc") it is otherwise treated just like
SEC("abc") and bpf_program__section_name() reported will be "abc".
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220419002452.632125-1-andrii@kernel.org
The llvm patch [1] enabled opaque pointer which caused selftest
'exhandler' failure.
...
; work = task->task_works;
7: (79) r1 = *(u64 *)(r6 +2120) ; R1_w=ptr_callback_head(off=0,imm=0) R6_w=ptr_task_struct(off=0,imm=0)
; func = work->func;
8: (79) r2 = *(u64 *)(r1 +8) ; R1_w=ptr_callback_head(off=0,imm=0) R2_w=scalar()
; if (!work && !func)
9: (4f) r1 |= r2
math between ptr_ pointer and register with unbounded min value is not allowed
below is insn 10 and 11
10: (55) if r1 != 0 goto +5
11: (18) r1 = 0 ll
...
In llvm, the code generation of 'r1 |= r2' happened in codegen
selectiondag phase due to difference of opaque pointer vs. non-opaque pointer.
Without [1], the related code looks like:
r2 = *(u64 *)(r6 + 2120)
r1 = *(u64 *)(r2 + 8)
if r2 != 0 goto +6 <LBB0_4>
if r1 != 0 goto +5 <LBB0_4>
r1 = 0 ll
...
I haven't found a good way in llvm to fix this issue. So let us workaround the
problem first so bpf CI won't be blocked.
[1] https://reviews.llvm.org/D123300
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220419050900.3136024-1-yhs@fb.com
This is a pre-req to add separate logging for each subtest in
test_progs.
Move all the mutable test data to the test_result struct.
Move per-test init/de-init into the run_one_test function.
Consolidate data aggregation and final log output in
calculate_and_print_summary function.
As a side effect, this patch fixes double counting of errors
for subtests and possible duplicate output of subtest log
on failures.
Also, add prog_tests_framework.c test to verify some of the
counting logic.
As part of verification, confirmed that number of reported
tests is the same before and after the change for both parallel
and sequential test execution.
Signed-off-by: Mykola Lysenko <mykolal@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220418222507.1726259-1-mykolal@fb.com
Parsing of USDT arguments is architecture-specific. On aarch64 it is
relatively easy since registers used are x[0-31] and sp. Format is
slightly different compared to x86_64. Possible forms are:
- "size@[reg[,offset]]" for dereferences, e.g. "-8@[sp,76]" and "-4@[sp]";
- "size@reg" for register values, e.g. "-4@x0";
- "size@value" for raw values, e.g. "-8@1".
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1649690496-1902-2-git-send-email-alan.maguire@oracle.com
We have switched to memcg-based memory accouting and thus the rlimit is
not needed any more. LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK was introduced in
libbpf for backward compatibility, so we can use it instead now.
libbpf_set_strict_mode always return 0, so we don't need to check whether
the return value is 0 or not.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220409125958.92629-4-laoar.shao@gmail.com
We have switched to memcg-based memory accouting and thus the rlimit is
not needed any more. LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK was introduced in
libbpf for backward compatibility, so we can use it instead now. After
this change, the header tools/testing/selftests/bpf/bpf_rlimit.h can be
removed.
This patch also removes the useless header sys/resource.h from many files
in tools/testing/selftests/bpf/.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220409125958.92629-3-laoar.shao@gmail.com
Background:
Libbpf automatically replaces calls to BPF bpf_probe_read_{kernel,user}
[_str]() helpers with bpf_probe_read[_str](), if libbpf detects that
kernel doesn't support new APIs. Specifically, libbpf invokes the
probe_kern_probe_read_kernel function to load a small eBPF program into
the kernel in which bpf_probe_read_kernel API is invoked and lets the
kernel checks whether the new API is valid. If the loading fails, libbpf
considers the new API invalid and replaces it with the old API.
static int probe_kern_probe_read_kernel(void)
{
struct bpf_insn insns[] = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10), /* r1 = r10 (fp) */
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8), /* r1 += -8 */
BPF_MOV64_IMM(BPF_REG_2, 8), /* r2 = 8 */
BPF_MOV64_IMM(BPF_REG_3, 0), /* r3 = 0 */
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_probe_read_kernel),
BPF_EXIT_INSN(),
};
int fd, insn_cnt = ARRAY_SIZE(insns);
fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL,
"GPL", insns, insn_cnt, NULL);
return probe_fd(fd);
}
Bug:
On older kernel versions [0], the kernel checks whether the version
number provided in the bpf syscall, matches the LINUX_VERSION_CODE.
If not matched, the bpf syscall fails. eBPF However, the
probe_kern_probe_read_kernel code does not set the kernel version
number provided to the bpf syscall, which causes the loading process
alwasys fails for old versions. It means that libbpf will replace the
new API with the old one even the kernel supports the new one.
Solution:
After a discussion in [1], the solution is using BPF_PROG_TYPE_TRACEPOINT
program type instead of BPF_PROG_TYPE_KPROBE because kernel does not
enfoce version check for tracepoint programs. I test the patch in old
kernels (4.18 and 4.19) and it works well.
[0] https://elixir.bootlin.com/linux/v4.19/source/kernel/bpf/syscall.c#L1360
[1] Closes: https://github.com/libbpf/libbpf/issues/473
Signed-off-by: Runqing Yang <rainkin1993@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220409144928.27499-1-rainkin1993@gmail.com
Improve subtest selection logic when using -t/-a/-d parameters.
In particular, more than one subtest can be specified or a
combination of tests / subtests.
-a send_signal -d send_signal/send_signal_nmi* - runs send_signal
test without nmi tests
-a send_signal/send_signal_nmi*,find_vma - runs two send_signal
subtests and find_vma test
-a 'send_signal*' -a find_vma -d send_signal/send_signal_nmi* -
runs 2 send_signal test and find_vma test. Disables two send_signal
nmi subtests
-t send_signal -t find_vma - runs two *send_signal* tests and one
*find_vma* test
This will allow us to have granular control over which subtests
to disable in the CI system instead of disabling whole tests.
Also, add new selftest to avoid possible regression when
changing prog_test test name selection logic.
Signed-off-by: Mykola Lysenko <mykolal@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220409001750.529930-1-mykolal@fb.com
Daniel Borkmann says:
====================
pull-request: bpf-next 2022-04-09
We've added 63 non-merge commits during the last 9 day(s) which contain
a total of 68 files changed, 4852 insertions(+), 619 deletions(-).
The main changes are:
1) Add libbpf support for USDT (User Statically-Defined Tracing) probes.
USDTs are an abstraction built on top of uprobes, critical for tracing
and BPF, and widely used in production applications, from Andrii Nakryiko.
2) While Andrii was adding support for x86{-64}-specific logic of parsing
USDT argument specification, Ilya followed-up with USDT support for s390
architecture, from Ilya Leoshkevich.
3) Support name-based attaching for uprobe BPF programs in libbpf. The format
supported is `u[ret]probe/binary_path:[raw_offset|function[+offset]]`, e.g.
attaching to libc malloc can be done in BPF via SEC("uprobe/libc.so.6:malloc")
now, from Alan Maguire.
4) Various load/store optimizations for the arm64 JIT to shrink the image
size by using arm64 str/ldr immediate instructions. Also enable pointer
authentication to verify return address for JITed code, from Xu Kuohai.
5) BPF verifier fixes for write access checks to helper functions, e.g.
rd-only memory from bpf_*_cpu_ptr() must not be passed to helpers that
write into passed buffers, from Kumar Kartikeya Dwivedi.
6) Fix overly excessive stack map allocation for its base map structure and
buckets which slipped-in from cleanups during the rlimit accounting removal
back then, from Yuntao Wang.
7) Extend the unstable CT lookup helpers for XDP and tc/BPF to report netfilter
connection tracking tuple direction, from Lorenzo Bianconi.
8) Improve bpftool dump to show BPF program/link type names, Milan Landaverde.
9) Minor cleanups all over the place from various others.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (63 commits)
bpf: Fix excessive memory allocation in stack_map_alloc()
selftests/bpf: Fix return value checks in perf_event_stackmap test
selftests/bpf: Add CO-RE relos into linked_funcs selftests
libbpf: Use weak hidden modifier for USDT BPF-side API functions
libbpf: Don't error out on CO-RE relos for overriden weak subprogs
samples, bpf: Move routes monitor in xdp_router_ipv4 in a dedicated thread
libbpf: Allow WEAK and GLOBAL bindings during BTF fixup
libbpf: Use strlcpy() in path resolution fallback logic
libbpf: Add s390-specific USDT arg spec parsing logic
libbpf: Make BPF-side of USDT support work on big-endian machines
libbpf: Minor style improvements in USDT code
libbpf: Fix use #ifdef instead of #if to avoid compiler warning
libbpf: Potential NULL dereference in usdt_manager_attach_usdt()
selftests/bpf: Uprobe tests should verify param/return values
libbpf: Improve string parsing for uprobe auto-attach
libbpf: Improve library identification for uprobe binary path resolution
selftests/bpf: Test for writes to map key from BPF helpers
selftests/bpf: Test passing rdonly mem to global func
bpf: Reject writes for PTR_TO_MAP_KEY in check_helper_mem_access
bpf: Check PTR_TO_MEM | MEM_RDONLY in check_helper_mem_access
...
====================
Link: https://lore.kernel.org/r/20220408231741.19116-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The bpf_get_stackid() function may also return 0 on success as per UAPI BPF
helper documentation. Therefore, correct checks from 'val > 0' to 'val >= 0'
to ensure that they cover all possible success return values.
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220408041452.933944-1-ytcoode@gmail.com
Add CO-RE relocations into __weak subprogs for multi-file linked_funcs
selftest to make sure libbpf handles such combination well.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220408181425.2287230-4-andrii@kernel.org
Use __weak __hidden for bpf_usdt_xxx() APIs instead of much more
confusing `static inline __noinline`. This was previously impossible due
to libbpf erroring out on CO-RE relocations pointing to eliminated weak
subprogs. Now that previous patch fixed this issue, switch back to
__weak __hidden as it's a more direct way of specifying the desired
behavior.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220408181425.2287230-3-andrii@kernel.org
During BPF static linking, all the ELF relocations and .BTF.ext
information (including CO-RE relocations) are preserved for __weak
subprograms that were logically overriden by either previous weak
subprogram instance or by corresponding "strong" (non-weak) subprogram.
This is just how native user-space linkers work, nothing new.
But libbpf is over-zealous when processing CO-RE relocation to error out
when CO-RE relocation belonging to such eliminated weak subprogram is
encountered. Instead of erroring out on this expected situation, log
debug-level message and skip the relocation.
Fixes: db2b8b0642 ("libbpf: Support CO-RE relocations for multi-prog sections")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220408181425.2287230-2-andrii@kernel.org
During BTF fix up for global variables, global variable can be global
weak and will have STB_WEAK binding in ELF. Support such global
variables in addition to non-weak ones.
This is not the problem when using BPF static linking, as BPF static
linker "fixes up" BTF during generation so that libbpf doesn't have to
do it anymore during bpf_object__open(), which led to this not being
noticed for a while, along with a pretty rare (currently) use of __weak
variables and maps.
Reported-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220407230446.3980075-2-andrii@kernel.org
Coverity static analyzer complains that strcpy() can cause buffer
overflow. Use libbpf_strlcpy() instead to be 100% sure this doesn't
happen.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220407230446.3980075-1-andrii@kernel.org
The logic is superficially similar to that of x86, but the small
differences (no need for register table and dynamic allocation of
register names, no $ sign before constants) make maintaining a common
implementation too burdensome. Therefore simply add a s390x-specific
version of parse_usdt_arg().
Note that while bcc supports index registers, this patch does not. This
should not be a problem in most cases, since s390 uses a default value
"nor" for STAP_SDT_ARG_CONSTRAINT.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220407214411.257260-4-iii@linux.ibm.com
BPF_USDT_ARG_REG_DEREF handling always reads 8 bytes, regardless of
the actual argument size. On little-endian the relevant argument bits
end up in the lower bits of val, and later on the code that handles
all the argument types expects them to be there.
On big-endian they end up in the upper bits of val, breaking that
expectation. Fix by right-shifting val on big-endian.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220407214411.257260-3-iii@linux.ibm.com
Fix several typos and references to non-existing headers.
Also use __BYTE_ORDER__ instead of __BYTE_ORDER for consistency with
the rest of the bpf code - see commit 45f2bebc80 ("libbpf: Fix
endianness detection in BPF_CORE_READ_BITFIELD_PROBED()") for
rationale).
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220407214411.257260-2-iii@linux.ibm.com
As reported by Naresh:
perf build errors on i386 [1] on Linux next-20220407 [2]
usdt.c:1181:5: error: "__x86_64__" is not defined, evaluates to 0
[-Werror=undef]
1181 | #if __x86_64__
| ^~~~~~~~~~
usdt.c:1196:5: error: "__x86_64__" is not defined, evaluates to 0
[-Werror=undef]
1196 | #if __x86_64__
| ^~~~~~~~~~
cc1: all warnings being treated as errors
Use #ifdef instead of #if to avoid this.
Fixes: 4c59e584d1 ("libbpf: Add x86-specific USDT arg spec parsing logic")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220407203842.3019904-1-andrii@kernel.org
uprobe/uretprobe tests don't do any validation of arguments/return values,
and without this we can't be sure we are attached to the right function,
or that we are indeed attached to a uprobe or uretprobe. To fix this
record argument and return value for auto-attached functions and ensure
these match expectations. Also need to filter by pid to ensure we do
not pick up stray malloc()s since auto-attach traces libc system-wide.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1649245431-29956-4-git-send-email-alan.maguire@oracle.com
For uprobe auto-attach, the parsing can be simplified for the SEC()
name to a single sscanf(); the return value of the sscanf can then
be used to distinguish between sections that simply specify
"u[ret]probe" (and thus cannot auto-attach), those that specify
"u[ret]probe/binary_path:function+offset" etc.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1649245431-29956-3-git-send-email-alan.maguire@oracle.com
In the process of doing path resolution for uprobe attach, libraries are
identified by matching a ".so" substring in the binary_path.
This matches a lot of patterns that do not conform to library.so[.version]
format, so instead match a ".so" _suffix_, and if that fails match a
".so." substring for the versioned library case.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/1649245431-29956-2-git-send-email-alan.maguire@oracle.com
Alexei Starovoitov says:
====================
pull-request: bpf 2022-04-06
We've added 8 non-merge commits during the last 8 day(s) which contain
a total of 9 files changed, 139 insertions(+), 36 deletions(-).
The main changes are:
1) rethook related fixes, from Jiri and Masami.
2) Fix the case when tracing bpf prog is attached to struct_ops, from Martin.
3) Support dual-stack sockets in bpf_tcp_check_syncookie, from Maxim.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf: Adjust bpf_tcp_check_syncookie selftest to test dual-stack sockets
bpf: Support dual-stack sockets in bpf_tcp_check_syncookie
bpf: selftests: Test fentry tracing a struct_ops program
bpf: Resolve to prog->aux->dst_prog->type only for BPF_PROG_TYPE_EXT
rethook: Fix to use WRITE_ONCE() for rethook:: Handler
selftests/bpf: Fix warning comparing pointer to 0
bpf: Fix sparse warnings in kprobe_multi_resolve_syms
bpftool: Explicit errno handling in skeletons
====================
Link: https://lore.kernel.org/r/20220407031245.73026-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When invoking bpf_for_each_map_elem callback, we are passed a
PTR_TO_MAP_KEY, previously writes to this through helper may be allowed,
but the fix in previous patches is meant to prevent that case. The test
case tries to pass it as writable memory to helper, and fails test if it
succeeds to pass the verifier.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220319080827.73251-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add two test cases, one pass read only map value pointer to global
func, which should be rejected. The same code checks it for kfunc, so
that is covered as well. Second one tries to use the missing check for
PTR_TO_MEM's MEM_RDONLY flag and tries to write to a read only memory
pointer. Without prior patches, both of these tests fail.
Reviewed-by: Hao Luo <haoluo@google.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220319080827.73251-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
