When attach_prog_fd field was removed in libbpf 1.0 and replaced with
`long: 0` placeholder, it actually shifted all the subsequent fields by
8 byte. This is due to `long: 0` promising to adjust next field's offset
to long-aligned offset. But in this case we were already long-aligned
as pin_root_path is a pointer. So `long: 0` had no effect, and thus
didn't feel the gap created by removed attach_prog_fd.
Non-zero bitfield should have been used instead. I validated using
pahole. Originally kconfig field was at offset 40. With `long: 0` it's
at offset 32, which is wrong. With this change it's back at offset 40.
While technically libbpf 1.0 is allowed to break backwards
compatibility and applications should have been recompiled against
libbpf 1.0 headers, but given how trivial it is to preserve memory
layout, let's fix this.
Reported-by: Grant Seltzer Richman <grantseltzer@gmail.com>
Fixes: 146bf811f5ac ("libbpf: remove most other deprecated high-level APIs")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20220923230559.666608-1-andrii@kernel.org
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Currently, the default vmlinux files at '/boot/vmlinux-*',
'/lib/modules/*/vmlinux-*' etc. are parsed with 'btf__parse_elf()' to
extract BTF. It is possible that these files are actually raw BTF files
similar to /sys/kernel/btf/vmlinux. So parse these files with
'btf__parse' which tries both raw format and ELF format.
This might be useful in some scenarios where users put their custom BTF
into known locations and don't want to specify btf_custom_path option.
Signed-off-by: Tao Chen <chentao.kernel@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/3f59fb5a345d2e4f10e16fe9e35fbc4c03ecaa3e.1662999860.git.chentao.kernel@linux.alibaba.com
Commit 34586d29f8df ("libbpf: Add new BPF_PROG2 macro") added BPF_PROG2
macro for trampoline based programs with struct arguments. Andrii
made a few suggestions to improve code quality and description.
This patch implemented these suggestions including better internal
macro name, consistent usage pattern for __builtin_choose_expr(),
simpler macro definition for always-inline func arguments and
better macro description.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20220910025214.1536510-1-yhs@fb.com
Now that all of the logic is in place in the kernel to support user-space
produced ring buffers, we can add the user-space logic to libbpf. This
patch therefore adds the following public symbols to libbpf:
struct user_ring_buffer *
user_ring_buffer__new(int map_fd,
const struct user_ring_buffer_opts *opts);
void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size);
void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb,
__u32 size, int timeout_ms);
void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample);
void user_ring_buffer__discard(struct user_ring_buffer *rb,
void user_ring_buffer__free(struct user_ring_buffer *rb);
A user-space producer must first create a struct user_ring_buffer * object
with user_ring_buffer__new(), and can then reserve samples in the
ring buffer using one of the following two symbols:
void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size);
void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb,
__u32 size, int timeout_ms);
With user_ring_buffer__reserve(), a pointer to a 'size' region of the ring
buffer will be returned if sufficient space is available in the buffer.
user_ring_buffer__reserve_blocking() provides similar semantics, but will
block for up to 'timeout_ms' in epoll_wait if there is insufficient space
in the buffer. This function has the guarantee from the kernel that it will
receive at least one event-notification per invocation to
bpf_ringbuf_drain(), provided that at least one sample is drained, and the
BPF program did not pass the BPF_RB_NO_WAKEUP flag to bpf_ringbuf_drain().
Once a sample is reserved, it must either be committed to the ring buffer
with user_ring_buffer__submit(), or discarded with
user_ring_buffer__discard().
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-4-void@manifault.com
In a prior change, we added a new BPF_MAP_TYPE_USER_RINGBUF map type which
will allow user-space applications to publish messages to a ring buffer
that is consumed by a BPF program in kernel-space. In order for this
map-type to be useful, it will require a BPF helper function that BPF
programs can invoke to drain samples from the ring buffer, and invoke
callbacks on those samples. This change adds that capability via a new BPF
helper function:
bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void *ctx,
u64 flags)
BPF programs may invoke this function to run callback_fn() on a series of
samples in the ring buffer. callback_fn() has the following signature:
long callback_fn(struct bpf_dynptr *dynptr, void *context);
Samples are provided to the callback in the form of struct bpf_dynptr *'s,
which the program can read using BPF helper functions for querying
struct bpf_dynptr's.
In order to support bpf_ringbuf_drain(), a new PTR_TO_DYNPTR register
type is added to the verifier to reflect a dynptr that was allocated by
a helper function and passed to a BPF program. Unlike PTR_TO_STACK
dynptrs which are allocated on the stack by a BPF program, PTR_TO_DYNPTR
dynptrs need not use reference tracking, as the BPF helper is trusted to
properly free the dynptr before returning. The verifier currently only
supports PTR_TO_DYNPTR registers that are also DYNPTR_TYPE_LOCAL.
Note that while the corresponding user-space libbpf logic will be added
in a subsequent patch, this patch does contain an implementation of the
.map_poll() callback for BPF_MAP_TYPE_USER_RINGBUF maps. This
.map_poll() callback guarantees that an epoll-waiting user-space
producer will receive at least one event notification whenever at least
one sample is drained in an invocation of bpf_user_ringbuf_drain(),
provided that the function is not invoked with the BPF_RB_NO_WAKEUP
flag. If the BPF_RB_FORCE_WAKEUP flag is provided, a wakeup
notification is sent even if no sample was drained.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-3-void@manifault.com
We want to support a ringbuf map type where samples are published from
user-space, to be consumed by BPF programs. BPF currently supports a
kernel -> user-space circular ring buffer via the BPF_MAP_TYPE_RINGBUF
map type. We'll need to define a new map type for user-space -> kernel,
as none of the helpers exported for BPF_MAP_TYPE_RINGBUF will apply
to a user-space producer ring buffer, and we'll want to add one or
more helper functions that would not apply for a kernel-producer
ring buffer.
This patch therefore adds a new BPF_MAP_TYPE_USER_RINGBUF map type
definition. The map type is useless in its current form, as there is no
way to access or use it for anything until we one or more BPF helpers. A
follow-on patch will therefore add a new helper function that allows BPF
programs to run callbacks on samples that are published to the ring
buffer.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220920000100.477320-2-void@manifault.com
We found that function btf_dump__dump_type_data can be called by the
user as an API, but in this function, the `opts` parameter may be used
as a null pointer.This causes `opts->indent_str` to trigger a NULL
pointer exception.
Fixes: 2ce8450ef5a3 ("libbpf: add bpf_object__open_{file, mem} w/ extensible opts")
Signed-off-by: Xin Liu <liuxin350@huawei.com>
Signed-off-by: Weibin Kong <kongweibin2@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220917084809.30770-1-liuxin350@huawei.com
Fix SIGSEGV caused by libbpf trying to find attach type in vmlinux BTF
for freplace programs. It's wrong to search in vmlinux BTF and libbpf
doesn't even mark vmlinux BTF as required for freplace programs. So
trying to search anything in obj->vmlinux_btf might cause NULL
dereference if nothing else in BPF object requires vmlinux BTF.
Instead, error out if freplace (EXT) program doesn't specify
attach_prog_fd during at the load time.
Fixes: 91abb4a6d79d ("libbpf: Support attachment of BPF tracing programs to kernel modules")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220909193053.577111-3-andrii@kernel.org
This reverts commit 14e5ce79943a ("libbpf: Add GCC support for
bpf_tail_call_static"). Reason is that gcc invented their own BPF asm
which is not conform with LLVM one, and going forward this would be
more painful to maintain here and in other areas of the library. Thus
remove it; ask to gcc folks is to align with LLVM one to use exact
same syntax.
Fixes: 14e5ce79943a ("libbpf: Add GCC support for bpf_tail_call_static")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: James Hilliard <james.hilliard1@gmail.com>
Cc: Jose E. Marchesi <jose.marchesi@oracle.com>
To support struct arguments in trampoline based programs,
existing BPF_PROG doesn't work any more since
the type size is needed to find whether a parameter
takes one or two registers. So this patch added a new
BPF_PROG2 macro to support such trampoline programs.
The idea is suggested by Andrii. For example, if the
to-be-traced function has signature like
typedef struct {
void *x;
int t;
} sockptr;
int blah(sockptr x, char y);
In the new BPF_PROG2 macro, the argument can be
represented as
__bpf_prog_call(
({ union {
struct { __u64 x, y; } ___z;
sockptr x;
} ___tmp = { .___z = { ctx[0], ctx[1] }};
___tmp.x;
}),
({ union {
struct { __u8 x; } ___z;
char y;
} ___tmp = { .___z = { ctx[2] }};
___tmp.y;
}));
In the above, the values stored on the stack are properly
assigned to the actual argument type value by using 'union'
magic. Note that the macro also works even if no arguments
are with struct types.
Note that new BPF_PROG2 works for both llvm16 and pre-llvm16
compilers where llvm16 supports bpf target passing value
with struct up to 16 byte size and pre-llvm16 will pass
by reference by storing values on the stack. With static functions
with struct argument as always inline, the compiler is able
to optimize and remove additional stack saving of struct values.
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220831152707.2079473-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now instead of the number of arguments, the number of registers
holding argument values are stored in trampoline. Update
the description of bpf_get_func_arg[_cnt]() helpers. Previous
programs without struct arguments should continue to work
as usual.
Signed-off-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20220831152657.2078805-1-yhs@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Existing 'bpf_skb_get_tunnel_key' extracts various tunnel parameters
(id, ttl, tos, local and remote) but does not expose ip_tunnel_info's
tun_flags to the BPF program.
It makes sense to expose tun_flags to the BPF program.
Assume for example multiple GRE tunnels maintained on a single GRE
interface in collect_md mode. The program expects origins to initiate
over GRE, however different origins use different GRE characteristics
(e.g. some prefer to use GRE checksum, some do not; some pass a GRE key,
some do not, etc..).
A BPF program getting tun_flags can therefore remember the relevant
flags (e.g. TUNNEL_CSUM, TUNNEL_SEQ...) for each initiating remote. In
the reply path, the program can use 'bpf_skb_set_tunnel_key' in order
to correctly reply to the remote, using similar characteristics, based
on the stored tunnel flags.
Introduce BPF_F_TUNINFO_FLAGS flag for bpf_skb_get_tunnel_key. If
specified, 'bpf_tunnel_key->tunnel_flags' is set with the tun_flags.
Decided to use the existing unused 'tunnel_ext' as the storage for the
'tunnel_flags' in order to avoid changing bpf_tunnel_key's layout.
Also, the following has been considered during the design:
1. Convert the "interesting" internal TUNNEL_xxx flags back to BPF_F_yyy
and place into the new 'tunnel_flags' field. This has 2 drawbacks:
- The BPF_F_yyy flags are from *set_tunnel_key* enumeration space,
e.g. BPF_F_ZERO_CSUM_TX. It is awkward that it is "returned" into
tunnel_flags from a *get_tunnel_key* call.
- Not all "interesting" TUNNEL_xxx flags can be mapped to existing
BPF_F_yyy flags, and it doesn't make sense to create new BPF_F_yyy
flags just for purposes of the returned tunnel_flags.
2. Place key.tun_flags into 'tunnel_flags' but mask them, keeping only
"interesting" flags. That's ok, but the drawback is that what's
"interesting" for my usecase might be limiting for other usecases.
Therefore I decided to expose what's in key.tun_flags *as is*, which seems
most flexible. The BPF user can just choose to ignore bits he's not
interested in. The TUNNEL_xxx are also UAPI, so no harm exposing them
back in the get_tunnel_key call.
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220831144010.174110-1-shmulik.ladkani@gmail.com
The bpf_tail_call_static function is currently not defined unless
using clang >= 8.
To support bpf_tail_call_static on GCC we can check if __clang__ is
not defined to enable bpf_tail_call_static.
We need to use GCC assembly syntax when the compiler does not define
__clang__ as LLVM inline assembly is not fully compatible with GCC.
Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220829210546.755377-1-james.hilliard1@gmail.com
bpf_cgroup_iter_order is globally visible but the entries do not have
CGROUP prefix. As requested by Andrii, put a CGROUP in the names
in bpf_cgroup_iter_order.
This patch fixes two previous commits: one introduced the API and
the other uses the API in bpf selftest (that is, the selftest
cgroup_hierarchical_stats).
I tested this patch via the following command:
test_progs -t cgroup,iter,btf_dump
Fixes: d4ccaf58a847 ("bpf: Introduce cgroup iter")
Fixes: 88886309d2e8 ("selftests/bpf: add a selftest for cgroup hierarchical stats collection")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20220825223936.1865810-1-haoluo@google.com
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Cgroup_iter is a type of bpf_iter. It walks over cgroups in four modes:
- walking a cgroup's descendants in pre-order.
- walking a cgroup's descendants in post-order.
- walking a cgroup's ancestors.
- process only the given cgroup.
When attaching cgroup_iter, one can set a cgroup to the iter_link
created from attaching. This cgroup is passed as a file descriptor
or cgroup id and serves as the starting point of the walk. If no
cgroup is specified, the starting point will be the root cgroup v2.
For walking descendants, one can specify the order: either pre-order or
post-order. For walking ancestors, the walk starts at the specified
cgroup and ends at the root.
One can also terminate the walk early by returning 1 from the iter
program.
Note that because walking cgroup hierarchy holds cgroup_mutex, the iter
program is called with cgroup_mutex held.
Currently only one session is supported, which means, depending on the
volume of data bpf program intends to send to user space, the number
of cgroups that can be walked is limited. For example, given the current
buffer size is 8 * PAGE_SIZE, if the program sends 64B data for each
cgroup, assuming PAGE_SIZE is 4kb, the total number of cgroups that can
be walked is 512. This is a limitation of cgroup_iter. If the output
data is larger than the kernel buffer size, after all data in the
kernel buffer is consumed by user space, the subsequent read() syscall
will signal EOPNOTSUPP. In order to work around, the user may have to
update their program to reduce the volume of data sent to output. For
example, skip some uninteresting cgroups. In future, we may extend
bpf_iter flags to allow customizing buffer size.
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20220824233117.1312810-2-haoluo@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
* replace 'syscall' with 'upper layers', still mention that it's being
exported via syscall errno
* describe what happens in set_retval(-EPERM) + return 1
* describe what happens with bind's 'return 3'
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20220823222555.523590-5-sdf@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, attaching BPF_PROG_TYPE_FLOW_DISSECTOR programs completely
replaces the flow-dissector logic with custom dissection logic. This
forces implementors to write programs that handle dissection for any
flows expected in the namespace.
It makes sense for flow-dissector BPF programs to just augment the
dissector with custom logic (e.g. dissecting certain flows or custom
protocols), while enjoying the broad capabilities of the standard
dissector for any other traffic.
Introduce BPF_FLOW_DISSECTOR_CONTINUE retcode. Flow-dissector BPF
programs may return this to indicate no dissection was made, and
fallback to the standard dissector is requested.
Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220821113519.116765-3-shmulik.ladkani@gmail.com
Now that we are including the upstream allow/deny lists we can remove
any duplicates from our local lists. While at it, we also add some usdt
tests to the denylist, which are currently failing. This is the same
step we took in the vmtest repository [0].
[0] https://github.com/kernel-patches/vmtest/pull/133
Signed-off-by: Daniel Müller <deso@posteo.net>
Commit 693de729d0 ("Rename blacklists and whitelists") renamed the
black and white lists but missed the adjustment of a comment,
referencing a file name. Update it accordingly.
Signed-off-by: Daniel Müller <deso@posteo.net>
With an upcoming change we would like to invoke bpftool checks from the
run-qemu action (https://github.com/libbpf/ci/pull/37). This action
requires two environment variables, KERNEL and REPO_ROOT, set in order
to function.
Make sure to set them now. Long term we should probably make them
explicit input arguments instead of implicit global state, but there are
many more such instances that we need to clean up.
Signed-off-by: Daniel Müller <deso@posteo.net>
With https://github.com/libbpf/ci/pull/36 merged the run-qemu action now
accepts an additional argument, `kernel-root`.
Provide it to the action with the value appropriate for this repository.
Signed-off-by: Daniel Müller <deso@posteo.net>
Let's make the "kernel-root" explicit when using the prepare-rootfs
action, instead of relying on the default, .kernel.
Signed-off-by: Daniel Müller <deso@posteo.net>
Currently, the runner name is taken from the docker container's
hostname.
This changes across restarts, causing the runner name to change across
restarts too.
This uses the host name to keep a consistent name.
The path to the helpers.sh script to source was put one level too deep
by cfbd763ef8 ("Use foldable helpers where applicable") and the
GITHUB_ACTION_PATH variable is not actually defined in a workflow.
Fix up both issues.
Signed-off-by: Daniel Müller <deso@posteo.net>
Add auto-selectable libbpf logo for light and dark themes.
Suggested-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Add three layouts of libbpf logos (sparse, compact, sideways) with three
color variants (light bg, dark bg, monochrome).
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
As discussed at some earlier point in time, some of the actions/workflow
logic does not use our foldable helpers despite being able to. Switch
them over.
Signed-off-by: Daniel Müller <deso@posteo.net>
Add libbpf logo to the header and restructure and rewrite a bit
intro part about libbpf, it's bpf-next origins, etc.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
This change adjusts the run_selftests.sh script to accept an optional
list of arguments specifying the tests to run. We will make use of it
once we run selftests in parallel.
Signed-off-by: Daniel Müller <deso@posteo.net>
Make sure we don't fail on lru_bug selftests as it relies of BPF
trampoline, not supported by s390x.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Make sure that entire libbpf code base is initializing bpf_attr and
perf_event_attr with memset(0). Also for bpf_attr make sure we
clear and pass to kernel only relevant parts of bpf_attr. bpf_attr is
a huge union of independent sub-command attributes, so there is no need
to clear and pass entire union bpf_attr, which over time grows quite
a lot and for most commands this growth is completely irrelevant.
Few cases where we were relying on compiler initialization of BPF UAPI
structs (like bpf_prog_info, bpf_map_info, etc) with `= {};` were
switched to memset(0) pattern for future-proofing.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/bpf/20220816001929.369487-3-andrii@kernel.org
Similar with commit 10b62d6a38f7 ("libbpf: Add names for auxiliary maps"),
let's make bpf_prog_load() also ignore name if kernel doesn't support
program name.
To achieve this, we need to call sys_bpf_prog_load() directly in
probe_kern_prog_name() to avoid circular dependency. sys_bpf_prog_load()
also need to be exported in the libbpf_internal.h file.
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220813000936.6464-1-liuhangbin@gmail.com
Adding or removing room space _below_ layers 2 or 3, as the description
mentions, is ambiguous. This was written with a mental image of the
packet with layer 2 at the top, layer 3 under it, and so on. But it has
led users to believe that it was on lower layers (before the beginning
of the L2 and L3 headers respectively).
Let's make it more explicit, and specify between which layers the room
space is adjusted.
Reported-by: Rumen Telbizov <rumen.telbizov@menlosecurity.com>
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220812153727.224500-3-quentin@isovalent.com
The bpftool self-created maps can appear in final map show output due to
deferred removal in kernel. These maps don't have a name, which would make
users confused about where it comes from.
With a libbpf_ prefix name, users could know who created these maps.
It also could make some tests (like test_offload.py, which skip base maps
without names as a workaround) filter them out.
Kernel adds bpf prog/map name support in the same merge
commit fadad670a8ab ("Merge branch 'bpf-extend-info'"). So we can also use
kernel_supports(NULL, FEAT_PROG_NAME) to check if kernel supports map name.
As discussed [1], Let's make bpf_map_create accept non-null
name string, and silently ignore the name if kernel doesn't support.
[1] https://lore.kernel.org/bpf/CAEf4BzYL1TQwo1231s83pjTdFPk9XWWhfZC5=KzkU-VO0k=0Ug@mail.gmail.com/
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220811034020.529685-1-liuhangbin@gmail.com
The path to the file system image used by our invocation of Qemu is
currently hard coded to /tmp/root.img somewhere in a different
repository. With
da44c0b6ee
landed we have the option of specifying it explicitly from here. Let's
do just that, so that we can remove the default value from libbpf/ci
altogether.
Signed-off-by: Daniel Müller <deso@posteo.net>
