The bpf-tc prog has already been able to access the
skb_hwtstamps(skb)->hwtstamp. This patch extends the same hwtstamp
access to the sockops prog.
In sockops, the skb is also available to the bpf prog during
the BPF_SOCK_OPS_PARSE_HDR_OPT_CB event. There is a use case
that the hwtstamp will be useful to the sockops prog to better
measure the one-way-delay when the sender has put the tx
timestamp in the tcp header option.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221107230420.4192307-2-martin.lau@linux.dev
xdp_synproxy fails to be compiled in the 32-bit arch, log is as follows:
xdp_synproxy.c: In function 'parse_options':
xdp_synproxy.c:175:36: error: left shift count >= width of type [-Werror=shift-count-overflow]
175 | *tcpipopts = (mss6 << 32) | (ttl << 24) | (wscale << 16) | mss4;
| ^~
xdp_synproxy.c: In function 'syncookie_open_bpf_maps':
xdp_synproxy.c:289:28: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
289 | .map_ids = (__u64)map_ids,
| ^
Fix it.
Fixes: fb5cd0ce70 ("selftests/bpf: Add selftests for raw syncookie helpers")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221111030836.37632-1-yangjihong1@huawei.com
Add documentation for the BPF_MAP_TYPE_ARRAY including kernel version
introduced, usage and examples. Also document BPF_MAP_TYPE_PERCPU_ARRAY
which is similar.
Co-developed-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: Dave Tucker <dave@dtucker.co.uk>
Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Maryam Tahhan <mtahhan@redhat.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/bpf/20221109174604.31673-2-donald.hunter@gmail.com
Add documentation for BPF_MAP_TYPE_QUEUE and BPF_MAP_TYPE_STACK,
including usage and examples.
Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221108093314.44851-1-donald.hunter@gmail.com
Add documentation for the ARRAY_OF_MAPS and HASH_OF_MAPS map types,
including usage and examples.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221108102215.47297-1-donald.hunter@gmail.com
Add documentation for BPF_MAP_TYPE_CPUMAP including
kernel version introduced, usage and examples.
Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Maryam Tahhan <mtahhan@redhat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221107165207.2682075-2-mtahhan@redhat.com
A fix for the LLVM compilation error while building bpftool.
Replaces the expression:
_Static_assert((p) == NULL || ...)
by expression:
_Static_assert((__builtin_constant_p((p)) ? (p) == NULL : 0) || ...)
When "p" is not a constant the former is not considered to be a
constant expression by LLVM 14.
The error was introduced in the following patch-set: [1].
The error was reported here: [2].
[1] https://lore.kernel.org/bpf/20221109142611.879983-1-eddyz87@gmail.com/
[2] https://lore.kernel.org/all/202211110355.BcGcbZxP-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Fixes: c302378bc1 ("libbpf: Hashmap interface update to allow both long and void* keys/values")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20221110223240.1350810-1-eddyz87@gmail.com
John Fastabend says:
====================
Not sure if folks want to take this through BPF tree or networking tree.
I took a quick look and didn't see any pending fixes so seems no one
has noticed the panic yet. It reproducible and easy to repro.
I put bpf in the title thinking it woudl be great to run through the
BPF selftests given its XDP triggering the panic.
Sorry maintainers resent with CC'ing actual lists. Had a scripting
issue. Also dropped henqqi has they are bouncing.
Thanks!
====================
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
The following panic is observed when bringing up (veth_open) a veth device
that has an XDP program attached.
[ 61.519185] kernel BUG at net/core/dev.c:6442!
[ 61.519456] invalid opcode: 0000 [#1] PREEMPT SMP PTI
[ 61.519752] CPU: 0 PID: 408 Comm: ip Tainted: G W 6.1.0-rc2-185930-gd9095f92950b-dirty #26
[ 61.520288] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
[ 61.520806] RIP: 0010:napi_enable+0x3d/0x40
[ 61.521077] Code: f6 f6 80 61 08 00 00 02 74 0d 48 83 bf 88 01 00 00 00 74 03 80 cd 01 48 89 d0 f0 48 0f b1 4f 10 48 39 c2 75 c8 c3 cc cc cc cc <0f> 0b 90 48 8b 87 b0 00 00 00 48 81 c7 b0 00 00 00 45 31 c0 48 39
[ 61.522226] RSP: 0018:ffffbc9800cc36f8 EFLAGS: 00010246
[ 61.522557] RAX: 0000000000000001 RBX: 0000000000000300 RCX: 0000000000000001
[ 61.523004] RDX: 0000000000000010 RSI: ffffffff8b0de852 RDI: ffff9f03848e5000
[ 61.523452] RBP: 0000000000000000 R08: 0000000000000800 R09: 0000000000000000
[ 61.523899] R10: ffff9f0384a96800 R11: ffffffffffa48061 R12: ffff9f03849c3000
[ 61.524345] R13: 0000000000000300 R14: ffff9f03848e5000 R15: 0000001000000100
[ 61.524792] FS: 00007f58cb64d2c0(0000) GS:ffff9f03bbc00000(0000) knlGS:0000000000000000
[ 61.525301] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 61.525673] CR2: 00007f6cc629b498 CR3: 000000010498c000 CR4: 00000000000006f0
[ 61.526121] Call Trace:
[ 61.526284] <TASK>
[ 61.526425] __veth_napi_enable_range+0xd6/0x230
[ 61.526723] veth_enable_xdp+0xd0/0x160
[ 61.526969] veth_open+0x2e/0xc0
[ 61.527180] __dev_open+0xe2/0x1b0
[ 61.527405] __dev_change_flags+0x1a1/0x210
[ 61.527673] dev_change_flags+0x1c/0x60
This happens because we are calling veth_napi_enable() on already enabled
queues. The root cause is in commit 2e0de6366a changed the control logic
dropping this case,
if (priv->_xdp_prog) {
err = veth_enable_xdp(dev);
if (err)
return err;
- } else if (veth_gro_requested(dev)) {
+ /* refer to the logic in veth_xdp_set() */
+ if (!rtnl_dereference(peer_rq->napi)) {
+ err = veth_napi_enable(peer);
+ if (err)
+ return err;
+ }
so that now veth_napi_enable is called if the peer has not yet
initialiazed its peer_rq->napi. The issue is this will happen
even if the NIC is not up. Then in veth_enable_xdp just above
we have similar path,
veth_enable_xdp
napi_already_on = (dev->flags & IFF_UP) && rcu_access_pointer(rq->napi)
err = veth_enable_xdp_range(dev, 0, dev->real_num_rx_queues, napi_already_on);
The trouble is an xdp prog is assigned before bringing the device up each
of the veth_open path will enable the peers xdp napi structs. But then when
we bring the peer up it will similar try to enable again because from
veth_open the IFF_UP flag is not set until after the op in __dev_open so
we believe napi_alread_on = false.
To fix this just drop the IFF_UP test and rely on checking if the napi
struct is enabled. This also matches the peer check in veth_xdp for
disabling.
To reproduce run ./test_xdp_meta.sh I found adding Cilium/Tetragon tests
for XDP.
Fixes: 2e0de6366a ("veth: Avoid drop packets when xdp_redirect performs")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20221108221650.808950-2-john.fastabend@gmail.com
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
When showing the result of a test group, if one
of the subtests was skipped, while still having
passing subtests, the group result was marked as
SKIP. E.g.:
223/1 usdt/basic:SKIP
223/2 usdt/multispec:OK
223/3 usdt/urand_auto_attach:OK
223/4 usdt/urand_pid_attach:OK
223 usdt:SKIP
The test result of usdt in the example above
should be OK instead of SKIP, because the test
group did have passing tests and it would be
considered in "normal" state.
With this change, only if all of the subtests
were skipped, the group test is marked as SKIP.
When only some of the subtests are skipped, a
more detailed result is given, stating how
many of the subtests were skipped. E.g:
223/1 usdt/basic:SKIP
223/2 usdt/multispec:OK
223/3 usdt/urand_auto_attach:OK
223/4 usdt/urand_pid_attach:OK
223 usdt:OK (SKIP: 1/4)
Signed-off-by: Domenico Cerasuolo <dceras@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221109184039.3514033-1-cerasuolodomenico@gmail.com
Eduard Zingerman says:
====================
The patch-set is consists of the following parts:
- An update for libbpf's hashmap interface from void* -> void* to a
polymorphic one, allowing to use both long and void* keys and values
w/o additional casts. Interface functions are hidden behind
auxiliary macro that add casts as necessary.
This simplifies many use cases in libbpf as hashmaps there are
mostly integer to integer and required awkward looking incantations
like `(void *)(long)off` previously. Also includes updates for perf
as it copies map implementation from libbpf.
- A change to `lib/bpf/btf.c:btf__dedup` that adds a new pass named
"Resolve unambiguous forward declaration". This pass builds a
hashmap `name_off -> uniquely named struct or union` and uses it to
replace FWD types by structs or unions. This is necessary for corner
cases when FWD is not used as a part of some struct or union
definition de-duplicated by `btf_dedup_struct_types`.
The goal of the patch-set is to resolve forward declarations that
don't take part in type graphs comparisons if declaration name is
unambiguous.
Example:
CU #1:
struct foo; // standalone forward declaration
struct foo *some_global;
CU #2:
struct foo { int x; };
struct foo *another_global;
Currently the de-duplicated BTF for this example looks as follows:
[1] STRUCT 'foo' size=4 vlen=1 ...
[2] INT 'int' size=4 ...
[3] PTR '(anon)' type_id=1
[4] FWD 'foo' fwd_kind=struct
[5] PTR '(anon)' type_id=4
The goal of this patch-set is to simplify it as follows:
[1] STRUCT 'foo' size=4 vlen=1
'x' type_id=2 bits_offset=0
[2] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
[3] PTR '(anon)' type_id=1
For defconfig kernel with BTF enabled this removes 63 forward
declarations.
For allmodconfig kernel with BTF enabled this removes ~5K out of ~21K
forward declarations in ko objects. This unlocks some additional
de-duplication in ko objects, but impact is tiny: ~13K less BTF ids
out of ~2M.
Changelog:
v3 -> v4
Changes suggested by Andrii:
- hashmap interface rework to allow use of integer and pointer keys
an values w/o casts as suggested in [1].
v2 -> v3
Changes suggested by Andrii:
- perf's util/hashtable.{c,h} are synchronized with libbpf
implementation, perf's source code updated accordingly;
- changes to libbpf, bpf selftests and perf are combined in a single
patch to simplify bisecting;
- hashtable interface updated to be long -> long instead of
uintptr_t -> uintptr_t;
- btf_dedup_resolve_fwds updated to correctly use IS_ERR / PTR_ERR
macro;
- test cases for btf_dedup_resolve_fwds are updated for better
clarity.
v1 -> v2
- Style fixes in btf_dedup_resolve_fwd and btf_dedup_resolve_fwds as
suggested by Alan.
[v1] https://lore.kernel.org/bpf/20221102110905.2433622-1-eddyz87@gmail.com/
[v2] https://lore.kernel.org/bpf/20221103033430.2611623-1-eddyz87@gmail.com/
[v3] https://lore.kernel.org/bpf/20221106202910.4193104-1-eddyz87@gmail.com/
[1] https://lore.kernel.org/bpf/CAEf4BzZ8KFneEJxFAaNCCFPGqp20hSpS2aCj76uRk3-qZUH5xg@mail.gmail.com/
====================
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tests to verify the following behavior of `btf_dedup_resolve_fwds`:
- remapping for struct forward declarations;
- remapping for union forward declarations;
- no remapping if forward declaration kind does not match similarly
named struct or union declaration;
- no remapping if forward declaration name is ambiguous;
- base ids are considered for fwd resolution in split btf scenario.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/20221109142611.879983-4-eddyz87@gmail.com
Resolve forward declarations that don't take part in type graphs
comparisons if declaration name is unambiguous. Example:
CU #1:
struct foo; // standalone forward declaration
struct foo *some_global;
CU #2:
struct foo { int x; };
struct foo *another_global;
The `struct foo` from CU #1 is not a part of any definition that is
compared against another definition while `btf_dedup_struct_types`
processes structural types. The the BTF after `btf_dedup_struct_types`
the BTF looks as follows:
[1] STRUCT 'foo' size=4 vlen=1 ...
[2] INT 'int' size=4 ...
[3] PTR '(anon)' type_id=1
[4] FWD 'foo' fwd_kind=struct
[5] PTR '(anon)' type_id=4
This commit adds a new pass `btf_dedup_resolve_fwds`, that maps such
forward declarations to structs or unions with identical name in case
if the name is not ambiguous.
The pass is positioned before `btf_dedup_ref_types` so that types
[3] and [5] could be merged as a same type after [1] and [4] are merged.
The final result for the example above looks as follows:
[1] STRUCT 'foo' size=4 vlen=1
'x' type_id=2 bits_offset=0
[2] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED
[3] PTR '(anon)' type_id=1
For defconfig kernel with BTF enabled this removes 63 forward
declarations. Examples of removed declarations: `pt_regs`, `in6_addr`.
The running time of `btf__dedup` function is increased by about 3%.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221109142611.879983-3-eddyz87@gmail.com
An update for libbpf's hashmap interface from void* -> void* to a
polymorphic one, allowing both long and void* keys and values.
This simplifies many use cases in libbpf as hashmaps there are mostly
integer to integer.
Perf copies hashmap implementation from libbpf and has to be
updated as well.
Changes to libbpf, selftests/bpf and perf are packed as a single
commit to avoid compilation issues with any future bisect.
Polymorphic interface is acheived by hiding hashmap interface
functions behind auxiliary macros that take care of necessary
type casts, for example:
#define hashmap_cast_ptr(p) \
({ \
_Static_assert((p) == NULL || sizeof(*(p)) == sizeof(long),\
#p " pointee should be a long-sized integer or a pointer"); \
(long *)(p); \
})
bool hashmap_find(const struct hashmap *map, long key, long *value);
#define hashmap__find(map, key, value) \
hashmap_find((map), (long)(key), hashmap_cast_ptr(value))
- hashmap__find macro casts key and value parameters to long
and long* respectively
- hashmap_cast_ptr ensures that value pointer points to a memory
of appropriate size.
This hack was suggested by Andrii Nakryiko in [1].
This is a follow up for [2].
[1] https://lore.kernel.org/bpf/CAEf4BzZ8KFneEJxFAaNCCFPGqp20hSpS2aCj76uRk3-qZUH5xg@mail.gmail.com/
[2] https://lore.kernel.org/bpf/af1facf9-7bc8-8a3d-0db4-7b3f333589a2@meta.com/T/#m65b28f1d6d969fcd318b556db6a3ad499a42607d
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221109142611.879983-2-eddyz87@gmail.com
since commit 450b167fb9be("libbpf: clean up SEC() handling"),
sec_def_matches() does not recognize "socket/xxx" as "socket", therefore,
the BPF program type is not recognized.
Instead of sockex3_user.c parsing section names to get the BPF program fd.
We use the program array map to assign a static index to each BPF program
(get inspired by selftests/bpf progs/test_prog_array_init.c).
Therefore, use SEC("socket") as section name instead of SEC("socket/xxx"),
so that the BPF program is parsed to SOCKET_FILTER type. The "missing BPF
prog type" problem is solved.
How to reproduce this error:
$ cd samples/bpf
$ sudo ./sockex3
libbpf: prog 'bpf_func_PARSE_IP': missing BPF prog type, check ELF section name 'socket/3'
libbpf: prog 'bpf_func_PARSE_IP': failed to load: -22
libbpf: failed to load object './sockex3_kern.o'
ERROR: loading BPF object file failed
Signed-off-by: Rong Tao <rongtao@cestc.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/tencent_EBA3C18864069E42175946973C2ACBAF5408@qq.com
Variable ret is compared with less than zero even though it was set as u32.
So u32 to int conversion is needed.
Signed-off-by: Kang Minchul <tegongkang@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20221105183656.86077-1-tegongkang@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Sphinx reported unknown target warning:
Documentation/bpf/bpf_design_QA.rst:329: WARNING: Unknown target name: "bpf".
The warning is caused by BPF type name prefix ("bpf_") which is written
without escaping the trailing underscore.
Escape the underscore to fix the warning. While at it, wrap the
containing paragraph in less than 80 characters.
Fixes: 9805af8d8a ("bpf: Document UAPI details for special BPF types")
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20221104123913.50610-1-bagasdotme@gmail.com
lld produces "fast" style build-ids by default, which is inconsistent
with ld's "sha1" style. Explicitly specify build-id style to be "sha1"
when linking liburandom_read.so the same way it is already done for
urandom_read.
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/bpf/20221104094016.102049-1-asavkov@redhat.com
Copy libbpf_strlcpy() from libbpf_internal.h to bpf_util.h, and rename it
to bpf_strlcpy(), then replace selftests strncpy()/libbpf_strlcpy() with
bpf_strlcpy(), fix compile warning.
The libbpf_internal.h header cannot be used directly here, because
references to cgroup_helpers.c in samples/bpf will generate compilation
errors. We also can't add libbpf_strlcpy() directly to bpf_util.h,
because the definition of libbpf_strlcpy() in libbpf_internal.h is
duplicated. In order not to modify the libbpf code, add a new function
bpf_strlcpy() to selftests bpf_util.h.
How to reproduce this compilation warning:
$ make -C samples/bpf
cgroup_helpers.c: In function ‘__enable_controllers’:
cgroup_helpers.c:80:17: warning: ‘strncpy’ specified bound 4097 equals destination size [-Wstringop-truncation]
80 | strncpy(enable, controllers, sizeof(enable));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: Rong Tao <rongtao@cestc.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/tencent_469D8AF32BD56816A29981BED06E96D22506@qq.com
since commit c504e5c2f964("net: skb: introduce kfree_skb_reason()")
kfree_skb() is replaced by kfree_skb_reason() and kfree_skb() is set to
the inline function. So, we replace kprobe/kfree_skb with
kprobe/kfree_skb_reason to solve the tracex2 error.
$ cd samples/bpf
$ sudo ./tracex2
libbpf: prog 'bpf_prog2': failed to create kprobe 'kfree_skb+0x0' perf event: No such file or directory
ERROR: bpf_program__attach failed
Signed-off-by: Rong Tao <rongtao@cestc.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/tencent_0F0DAE84C0B3C42E0B550E5E9F47A9114D09@qq.com
A set of test cases to verify enum fwd resolution logic:
- verify that enum fwd can be resolved as full enum64;
- verify that enum64 fwd can be resolved as full enum;
- verify that enum size is considered when enums are compared for
equivalence.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221101235413.1824260-2-eddyz87@gmail.com
Changes de-duplication logic for enums in the following way:
- update btf_hash_enum to ignore size and kind fields to get
ENUM and ENUM64 types in a same hash bucket;
- update btf_compat_enum to consider enum fwd to be compatible with
full enum64 (and vice versa);
This allows BTF de-duplication in the following case:
// CU #1
enum foo;
struct s {
enum foo *a;
} *x;
// CU #2
enum foo {
x = 0xfffffffff // big enough to force enum64
};
struct s {
enum foo *a;
} *y;
De-duplicated BTF prior to this commit:
[1] ENUM64 'foo' encoding=UNSIGNED size=8 vlen=1
'x' val=68719476735ULL
[2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64
encoding=(none)
[3] STRUCT 's' size=8 vlen=1
'a' type_id=4 bits_offset=0
[4] PTR '(anon)' type_id=1
[5] PTR '(anon)' type_id=3
[6] STRUCT 's' size=8 vlen=1
'a' type_id=8 bits_offset=0
[7] ENUM 'foo' encoding=UNSIGNED size=4 vlen=0
[8] PTR '(anon)' type_id=7
[9] PTR '(anon)' type_id=6
De-duplicated BTF after this commit:
[1] ENUM64 'foo' encoding=UNSIGNED size=8 vlen=1
'x' val=68719476735ULL
[2] INT 'long unsigned int' size=8 bits_offset=0 nr_bits=64
encoding=(none)
[3] STRUCT 's' size=8 vlen=1
'a' type_id=4 bits_offset=0
[4] PTR '(anon)' type_id=1
[5] PTR '(anon)' type_id=3
Enum forward declarations in C do not provide information about
enumeration values range. Thus the `btf_type->size` field is
meaningless for forward enum declarations. In fact, GCC does not
encode size in DWARF for forward enum declarations
(but dwarves sets enumeration size to a default value of `sizeof(int) * 8`
when size is not specified see dwarf_loader.c:die__create_new_enumeration).
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20221101235413.1824260-1-eddyz87@gmail.com
Andrii Nakryiko says:
====================
This patch set fixes and improves BPF verifier's precision tracking logic for
SCALAR registers.
Patches #1 and #2 are bug fixes discovered while working on these changes.
Patch #3 enables precision tracking for BPF programs that contain subprograms.
This was disabled before and prevent any modern BPF programs that use
subprograms from enjoying the benefits of SCALAR (im)precise logic.
Patch #4 is few lines of code changes and many lines of explaining why those
changes are correct. We establish why ignoring precise markings in current
state is OK.
Patch #5 build on explanation in patch #4 and pushes it to the limit by
forcefully forgetting inherited precise markins. Patch #4 by itself doesn't
prevent current state from having precise=true SCALARs, so patch #5 is
necessary to prevent such stray precise=true registers from creeping in.
Patch #6 adjusts test_align selftests to work around BPF verifier log's
limitations when it comes to interactions between state output and precision
backtracking output.
Overall, the goal of this patch set is to make BPF verifier's state tracking
a bit more efficient by trying to preserve as much generality in checkpointed
states as possible.
v1->v2:
- adjusted patch #1 commit message to make it clear we are fixing forward
step, not precision backtracking (Alexei);
- moved last_idx/first_idx verbose logging up to make it clear when global
func reaches the first empty state (Alexei).
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
test_align selftest relies on BPF verifier log emitting register states
for specific instructions in expected format. Unfortunately, BPF
verifier precision backtracking log interferes with such expectations.
And instruction on which precision propagation happens sometimes don't
output full expected register states. This does indeed look like
something to be improved in BPF verifier, but is beyond the scope of
this patch set.
So to make test_align a bit more robust, inject few dummy R4 = R5
instructions which capture desired state of R5 and won't have precision
tracking logs on them. This fixes tests until we can improve BPF
verifier output in the presence of precision tracking.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221104163649.121784-7-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Exploit the property of about-to-be-checkpointed state to be able to
forget all precise markings up to that point even more aggressively. We
now clear all potentially inherited precise markings right before
checkpointing and branching off into child state. If any of children
states require precise knowledge of any SCALAR register, those will be
propagated backwards later on before this state is finalized, preserving
correctness.
There is a single selftests BPF program change, but tremendous one: 25x
reduction in number of verified instructions and states in
trace_virtqueue_add_sgs.
Cilium results are more modest, but happen across wider range of programs.
SELFTESTS RESULTS
=================
$ ./veristat -C -e file,prog,insns,states ~/imprecise-early-results.csv ~/imprecise-aggressive-results.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
------------------- ----------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
loop6.bpf.linked1.o trace_virtqueue_add_sgs 398057 15114 -382943 (-96.20%) 8717 336 -8381 (-96.15%)
------------------- ----------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
CILIUM RESULTS
==============
$ ./veristat -C -e file,prog,insns,states ~/imprecise-early-results-cilium.csv ~/imprecise-aggressive-results-cilium.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
------------- -------------------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
bpf_host.o tail_handle_nat_fwd_ipv4 23426 23221 -205 (-0.88%) 1537 1515 -22 (-1.43%)
bpf_host.o tail_handle_nat_fwd_ipv6 13009 12904 -105 (-0.81%) 719 708 -11 (-1.53%)
bpf_host.o tail_nodeport_nat_ingress_ipv6 5261 5196 -65 (-1.24%) 247 243 -4 (-1.62%)
bpf_host.o tail_nodeport_nat_ipv6_egress 3446 3406 -40 (-1.16%) 203 198 -5 (-2.46%)
bpf_lxc.o tail_handle_nat_fwd_ipv4 23426 23221 -205 (-0.88%) 1537 1515 -22 (-1.43%)
bpf_lxc.o tail_handle_nat_fwd_ipv6 13009 12904 -105 (-0.81%) 719 708 -11 (-1.53%)
bpf_lxc.o tail_ipv4_ct_egress 5074 4897 -177 (-3.49%) 255 248 -7 (-2.75%)
bpf_lxc.o tail_ipv4_ct_ingress 5100 4923 -177 (-3.47%) 255 248 -7 (-2.75%)
bpf_lxc.o tail_ipv4_ct_ingress_policy_only 5100 4923 -177 (-3.47%) 255 248 -7 (-2.75%)
bpf_lxc.o tail_ipv6_ct_egress 4558 4536 -22 (-0.48%) 188 187 -1 (-0.53%)
bpf_lxc.o tail_ipv6_ct_ingress 4578 4556 -22 (-0.48%) 188 187 -1 (-0.53%)
bpf_lxc.o tail_ipv6_ct_ingress_policy_only 4578 4556 -22 (-0.48%) 188 187 -1 (-0.53%)
bpf_lxc.o tail_nodeport_nat_ingress_ipv6 5261 5196 -65 (-1.24%) 247 243 -4 (-1.62%)
bpf_overlay.o tail_nodeport_nat_ingress_ipv6 5261 5196 -65 (-1.24%) 247 243 -4 (-1.62%)
bpf_overlay.o tail_nodeport_nat_ipv6_egress 3482 3442 -40 (-1.15%) 204 201 -3 (-1.47%)
bpf_xdp.o tail_nodeport_nat_egress_ipv4 17200 15619 -1581 (-9.19%) 1111 1010 -101 (-9.09%)
------------- -------------------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221104163649.121784-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Setting reg->precise to true in current state is not necessary from
correctness standpoint, but it does pessimise the whole precision (or
rather "imprecision", because that's what we want to keep as much as
possible) tracking. Why is somewhat subtle and my best attempt to
explain this is recorded in an extensive comment for __mark_chain_precise()
function. Some more careful thinking and code reading is probably required
still to grok this completely, unfortunately. Whiteboarding and a bunch
of extra handwaiving in person would be even more helpful, but is deemed
impractical in Git commit.
Next patch pushes this imprecision property even further, building on top of
the insights described in this patch.
End results are pretty nice, we get reduction in number of total instructions
and states verified due to a better states reuse, as some of the states are now
more generic and permissive due to less unnecessary precise=true requirements.
SELFTESTS RESULTS
=================
$ ./veristat -C -e file,prog,insns,states ~/subprog-precise-results.csv ~/imprecise-early-results.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
--------------------------------------- ---------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
bpf_iter_ksym.bpf.linked1.o dump_ksym 347 285 -62 (-17.87%) 20 19 -1 (-5.00%)
pyperf600_bpf_loop.bpf.linked1.o on_event 3678 3736 +58 (+1.58%) 276 285 +9 (+3.26%)
setget_sockopt.bpf.linked1.o skops_sockopt 4038 3947 -91 (-2.25%) 347 343 -4 (-1.15%)
test_l4lb.bpf.linked1.o balancer_ingress 4559 2611 -1948 (-42.73%) 118 105 -13 (-11.02%)
test_l4lb_noinline.bpf.linked1.o balancer_ingress 6279 6268 -11 (-0.18%) 237 236 -1 (-0.42%)
test_misc_tcp_hdr_options.bpf.linked1.o misc_estab 1307 1303 -4 (-0.31%) 100 99 -1 (-1.00%)
test_sk_lookup.bpf.linked1.o ctx_narrow_access 456 447 -9 (-1.97%) 39 38 -1 (-2.56%)
test_sysctl_loop1.bpf.linked1.o sysctl_tcp_mem 1389 1384 -5 (-0.36%) 26 25 -1 (-3.85%)
test_tc_dtime.bpf.linked1.o egress_fwdns_prio101 518 485 -33 (-6.37%) 51 46 -5 (-9.80%)
test_tc_dtime.bpf.linked1.o egress_host 519 468 -51 (-9.83%) 50 44 -6 (-12.00%)
test_tc_dtime.bpf.linked1.o ingress_fwdns_prio101 842 1000 +158 (+18.76%) 73 88 +15 (+20.55%)
xdp_synproxy_kern.bpf.linked1.o syncookie_tc 405757 373173 -32584 (-8.03%) 25735 22882 -2853 (-11.09%)
xdp_synproxy_kern.bpf.linked1.o syncookie_xdp 479055 371590 -107465 (-22.43%) 29145 22207 -6938 (-23.81%)
--------------------------------------- ---------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
Slight regression in test_tc_dtime.bpf.linked1.o/ingress_fwdns_prio101
is left for a follow up, there might be some more precision-related bugs
in existing BPF verifier logic.
CILIUM RESULTS
==============
$ ./veristat -C -e file,prog,insns,states ~/subprog-precise-results-cilium.csv ~/imprecise-early-results-cilium.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
------------- ------------------------------ --------------- --------------- ------------------ ---------------- ---------------- -------------------
bpf_host.o cil_from_host 762 556 -206 (-27.03%) 43 37 -6 (-13.95%)
bpf_host.o tail_handle_nat_fwd_ipv4 23541 23426 -115 (-0.49%) 1538 1537 -1 (-0.07%)
bpf_host.o tail_nodeport_nat_egress_ipv4 33592 33566 -26 (-0.08%) 2163 2161 -2 (-0.09%)
bpf_lxc.o tail_handle_nat_fwd_ipv4 23541 23426 -115 (-0.49%) 1538 1537 -1 (-0.07%)
bpf_overlay.o tail_nodeport_nat_egress_ipv4 33581 33543 -38 (-0.11%) 2160 2157 -3 (-0.14%)
bpf_xdp.o tail_handle_nat_fwd_ipv4 21659 20920 -739 (-3.41%) 1440 1376 -64 (-4.44%)
bpf_xdp.o tail_handle_nat_fwd_ipv6 17084 17039 -45 (-0.26%) 907 905 -2 (-0.22%)
bpf_xdp.o tail_lb_ipv4 73442 73430 -12 (-0.02%) 4370 4369 -1 (-0.02%)
bpf_xdp.o tail_lb_ipv6 152114 151895 -219 (-0.14%) 6493 6479 -14 (-0.22%)
bpf_xdp.o tail_nodeport_nat_egress_ipv4 17377 17200 -177 (-1.02%) 1125 1111 -14 (-1.24%)
bpf_xdp.o tail_nodeport_nat_ingress_ipv6 6405 6397 -8 (-0.12%) 309 308 -1 (-0.32%)
bpf_xdp.o tail_rev_nodeport_lb4 7126 6934 -192 (-2.69%) 414 402 -12 (-2.90%)
bpf_xdp.o tail_rev_nodeport_lb6 18059 17905 -154 (-0.85%) 1105 1096 -9 (-0.81%)
------------- ------------------------------ --------------- --------------- ------------------ ---------------- ---------------- -------------------
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221104163649.121784-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stop forcing precise=true for SCALAR registers when BPF program has any
subprograms. Current restriction means that any BPF program, as soon as
it uses subprograms, will end up not getting any of the precision
tracking benefits in reduction of number of verified states.
This patch keeps the fallback mark_all_scalars_precise() behavior if
precise marking has to cross function frames. E.g., if subprogram
requires R1 (first input arg) to be marked precise, ideally we'd need to
backtrack to the parent function and keep marking R1 and its
dependencies as precise. But right now we give up and force all the
SCALARs in any of the current and parent states to be forced to
precise=true. We can lift that restriction in the future.
But this patch fixes two issues identified when trying to enable
precision tracking for subprogs.
First, prevent "escaping" from top-most state in a global subprog. While
with entry-level BPF program we never end up requesting precision for
R1-R5 registers, because R2-R5 are not initialized (and so not readable
in correct BPF program), and R1 is PTR_TO_CTX, not SCALAR, and so is
implicitly precise. With global subprogs, though, it's different, as
global subprog a) can have up to 5 SCALAR input arguments, which might
get marked as precise=true and b) it is validated in isolation from its
main entry BPF program. b) means that we can end up exhausting parent
state chain and still not mark all registers in reg_mask as precise,
which would lead to verifier bug warning.
To handle that, we need to consider two cases. First, if the very first
state is not immediately "checkpointed" (i.e., stored in state lookup
hashtable), it will get correct first_insn_idx and last_insn_idx
instruction set during state checkpointing. As such, this case is
already handled and __mark_chain_precision() already handles that by
just doing nothing when we reach to the very first parent state.
st->parent will be NULL and we'll just stop. Perhaps some extra check
for reg_mask and stack_mask is due here, but this patch doesn't address
that issue.
More problematic second case is when global function's initial state is
immediately checkpointed before we manage to process the very first
instruction. This is happening because when there is a call to global
subprog from the main program the very first subprog's instruction is
marked as pruning point, so before we manage to process first
instruction we have to check and checkpoint state. This patch adds
a special handling for such "empty" state, which is identified by having
st->last_insn_idx set to -1. In such case, we check that we are indeed
validating global subprog, and with some sanity checking we mark input
args as precise if requested.
Note that we also initialize state->first_insn_idx with correct start
insn_idx offset. For main program zero is correct value, but for any
subprog it's quite confusing to not have first_insn_idx set. This
doesn't have any functional impact, but helps with debugging and state
printing. We also explicitly initialize state->last_insns_idx instead of
relying on is_state_visited() to do this with env->prev_insns_idx, which
will be -1 on the very first instruction. This concludes necessary
changes to handle specifically global subprog's precision tracking.
Second identified problem was missed handling of BPF helper functions
that call into subprogs (e.g., bpf_loop and few others). From precision
tracking and backtracking logic's standpoint those are effectively calls
into subprogs and should be called as BPF_PSEUDO_CALL calls.
This patch takes the least intrusive way and just checks against a short
list of current BPF helpers that do call subprogs, encapsulated in
is_callback_calling_function() function. But to prevent accidentally
forgetting to add new BPF helpers to this "list", we also do a sanity
check in __check_func_call, which has to be called for each such special
BPF helper, to validate that BPF helper is indeed recognized as
callback-calling one. This should catch any missed checks in the future.
Adding some special flags to be added in function proto definitions
seemed like an overkill in this case.
With the above changes, it's possible to remove forceful setting of
reg->precise to true in __mark_reg_unknown, which turns on precision
tracking both inside subprogs and entry progs that have subprogs. No
warnings or errors were detected across all the selftests, but also when
validating with veristat against internal Meta BPF objects and Cilium
objects. Further, in some BPF programs there are noticeable reduction in
number of states and instructions validated due to more effective
precision tracking, especially benefiting syncookie test.
$ ./veristat -C -e file,prog,insns,states ~/baseline-results.csv ~/subprog-precise-results.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
---------------------------------------- -------------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
pyperf600_bpf_loop.bpf.linked1.o on_event 3966 3678 -288 (-7.26%) 306 276 -30 (-9.80%)
pyperf_global.bpf.linked1.o on_event 7563 7530 -33 (-0.44%) 520 517 -3 (-0.58%)
pyperf_subprogs.bpf.linked1.o on_event 36358 36934 +576 (+1.58%) 2499 2531 +32 (+1.28%)
setget_sockopt.bpf.linked1.o skops_sockopt 3965 4038 +73 (+1.84%) 343 347 +4 (+1.17%)
test_cls_redirect_subprogs.bpf.linked1.o cls_redirect 64965 64901 -64 (-0.10%) 4619 4612 -7 (-0.15%)
test_misc_tcp_hdr_options.bpf.linked1.o misc_estab 1491 1307 -184 (-12.34%) 110 100 -10 (-9.09%)
test_pkt_access.bpf.linked1.o test_pkt_access 354 349 -5 (-1.41%) 25 24 -1 (-4.00%)
test_sock_fields.bpf.linked1.o egress_read_sock_fields 435 375 -60 (-13.79%) 22 20 -2 (-9.09%)
test_sysctl_loop2.bpf.linked1.o sysctl_tcp_mem 1508 1501 -7 (-0.46%) 29 28 -1 (-3.45%)
test_tc_dtime.bpf.linked1.o egress_fwdns_prio100 468 435 -33 (-7.05%) 45 41 -4 (-8.89%)
test_tc_dtime.bpf.linked1.o ingress_fwdns_prio100 398 408 +10 (+2.51%) 42 39 -3 (-7.14%)
test_tc_dtime.bpf.linked1.o ingress_fwdns_prio101 1096 842 -254 (-23.18%) 97 73 -24 (-24.74%)
test_tcp_hdr_options.bpf.linked1.o estab 2758 2408 -350 (-12.69%) 208 181 -27 (-12.98%)
test_urandom_usdt.bpf.linked1.o urand_read_with_sema 466 448 -18 (-3.86%) 31 28 -3 (-9.68%)
test_urandom_usdt.bpf.linked1.o urand_read_without_sema 466 448 -18 (-3.86%) 31 28 -3 (-9.68%)
test_urandom_usdt.bpf.linked1.o urandlib_read_with_sema 466 448 -18 (-3.86%) 31 28 -3 (-9.68%)
test_urandom_usdt.bpf.linked1.o urandlib_read_without_sema 466 448 -18 (-3.86%) 31 28 -3 (-9.68%)
test_xdp_noinline.bpf.linked1.o balancer_ingress_v6 4302 4294 -8 (-0.19%) 257 256 -1 (-0.39%)
xdp_synproxy_kern.bpf.linked1.o syncookie_tc 583722 405757 -177965 (-30.49%) 35846 25735 -10111 (-28.21%)
xdp_synproxy_kern.bpf.linked1.o syncookie_xdp 609123 479055 -130068 (-21.35%) 35452 29145 -6307 (-17.79%)
---------------------------------------- -------------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221104163649.121784-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When equivalent completed state is found and it has additional precision
restrictions, BPF verifier propagates precision to
currently-being-verified state chain (i.e., including parent states) so
that if some of the states in the chain are not yet completed, necessary
precision restrictions are enforced.
Unfortunately, right now this happens only for the last frame (deepest
active subprogram's frame), not all the frames. This can lead to
incorrect matching of states due to missing precision marker. Currently
this doesn't seem possible as BPF verifier forces everything to precise
when validated BPF program has any subprograms. But with the next patch
lifting this restriction, this becomes problematic.
In fact, without this fix, we'll start getting failure in one of the
existing test_verifier test cases:
#906/p precise: cross frame pruning FAIL
Unexpected success to load!
verification time 48 usec
stack depth 0+0
processed 26 insns (limit 1000000) max_states_per_insn 3 total_states 17 peak_states 17 mark_read 8
This patch adds precision propagation across all frames.
Fixes: a3ce685dd0 ("bpf: fix precision tracking")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221104163649.121784-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When processing ALU/ALU64 operations (apart from BPF_MOV, which is
handled correctly already; and BPF_NEG and BPF_END are special and don't
have source register), if destination register is already marked
precise, this causes problem with potentially missing precision tracking
for the source register. E.g., when we have r1 >>= r5 and r1 is marked
precise, but r5 isn't, this will lead to r5 staying as imprecise. This
is due to the precision backtracking logic stopping early when it sees
r1 is already marked precise. If r1 wasn't precise, we'd keep
backtracking and would add r5 to the set of registers that need to be
marked precise. So there is a discrepancy here which can lead to invalid
and incompatible states matched due to lack of precision marking on r5.
If r1 wasn't precise, precision backtracking would correctly mark both
r1 and r5 as precise.
This is simple to fix, though. During the forward instruction simulation
pass, for arithmetic operations of `scalar <op>= scalar` form (where
<op> is ALU or ALU64 operations), if destination register is already
precise, mark source register as precise. This applies only when both
involved registers are SCALARs. `ptr += scalar` and `scalar += ptr`
cases are already handled correctly.
This does have (negative) effect on some selftest programs and few
Cilium programs. ~/baseline-tmp-results.csv are veristat results with
this patch, while ~/baseline-results.csv is without it. See post
scriptum for instructions on how to make Cilium programs testable with
veristat. Correctness has a price.
$ ./veristat -C -e file,prog,insns,states ~/baseline-results.csv ~/baseline-tmp-results.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
----------------------- -------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
bpf_cubic.bpf.linked1.o bpf_cubic_cong_avoid 997 1700 +703 (+70.51%) 62 90 +28 (+45.16%)
test_l4lb.bpf.linked1.o balancer_ingress 4559 5469 +910 (+19.96%) 118 126 +8 (+6.78%)
----------------------- -------------------- --------------- --------------- ------------------ ---------------- ---------------- -------------------
$ ./veristat -C -e file,prog,verdict,insns,states ~/baseline-results-cilium.csv ~/baseline-tmp-results-cilium.csv | grep -v '+0'
File Program Total insns (A) Total insns (B) Total insns (DIFF) Total states (A) Total states (B) Total states (DIFF)
------------- ------------------------------ --------------- --------------- ------------------ ---------------- ---------------- -------------------
bpf_host.o tail_nodeport_nat_ingress_ipv6 4448 5261 +813 (+18.28%) 234 247 +13 (+5.56%)
bpf_host.o tail_nodeport_nat_ipv6_egress 3396 3446 +50 (+1.47%) 201 203 +2 (+1.00%)
bpf_lxc.o tail_nodeport_nat_ingress_ipv6 4448 5261 +813 (+18.28%) 234 247 +13 (+5.56%)
bpf_overlay.o tail_nodeport_nat_ingress_ipv6 4448 5261 +813 (+18.28%) 234 247 +13 (+5.56%)
bpf_xdp.o tail_lb_ipv4 71736 73442 +1706 (+2.38%) 4295 4370 +75 (+1.75%)
------------- ------------------------------ --------------- --------------- ------------------ ---------------- ---------------- -------------------
P.S. To make Cilium ([0]) programs libbpf-compatible and thus
veristat-loadable, apply changes from topmost commit in [1], which does
minimal changes to Cilium source code, mostly around SEC() annotations
and BPF map definitions.
[0] https://github.com/cilium/cilium/
[1] https://github.com/anakryiko/cilium/commits/libbpf-friendliness
Fixes: b5dc0163d8 ("bpf: precise scalar_value tracking")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221104163649.121784-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Refactor map->off_arr handling into generic functions that can work on
their own without hardcoding map specific code. The btf_fields_offs
structure is now returned from btf_parse_field_offs, which can be reused
later for types in program BTF.
All functions like copy_map_value, zero_map_value call generic
underlying functions so that they can also be reused later for copying
to values allocated in programs which encode specific fields.
Later, some helper functions will also require access to this
btf_field_offs structure to be able to skip over special fields at
runtime.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-9-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Now that kptr_off_tab has been refactored into btf_record, and can hold
more than one specific field type, accomodate bpf_spin_lock and
bpf_timer as well.
While they don't require any more metadata than offset, having all
special fields in one place allows us to share the same code for
allocated user defined types and handle both map values and these
allocated objects in a similar fashion.
As an optimization, we still keep spin_lock_off and timer_off offsets in
the btf_record structure, just to avoid having to find the btf_field
struct each time their offset is needed. This is mostly needed to
manipulate such objects in a map value at runtime. It's ok to hardcode
just one offset as more than one field is disallowed.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-8-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Andrii Nakryiko says:
====================
This patch set adds a bunch of new featurs and improvements that were sorely
missing during recent active use of veristat to develop BPF verifier precision
changes. Individual patches provide justification, explanation and often
examples showing how new capabilities can be used.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Finally add support for filtering stats values, similar to
non-comparison mode filtering. For comparison mode 4 variants of stats
are important for filtering, as they allow to filter either A or B side,
but even more importantly they allow to filter based on value
difference, and for verdict stat value difference is MATCH/MISMATCH
classification. So with these changes it's finally possible to easily
check if there were any mismatches between failure/success outcomes on
two separate data sets. Like in an example below:
$ ./veristat -e file,prog,verdict,insns -C ~/baseline-results.csv ~/shortest-results.csv -f verdict_diff=mismatch
File Program Verdict (A) Verdict (B) Verdict (DIFF) Insns (A) Insns (B) Insns (DIFF)
------------------------------------- --------------------- ----------- ----------- -------------- --------- --------- -------------------
dynptr_success.bpf.linked1.o test_data_slice success failure MISMATCH 85 0 -85 (-100.00%)
dynptr_success.bpf.linked1.o test_read_write success failure MISMATCH 1992 0 -1992 (-100.00%)
dynptr_success.bpf.linked1.o test_ringbuf success failure MISMATCH 74 0 -74 (-100.00%)
kprobe_multi.bpf.linked1.o test_kprobe failure success MISMATCH 0 246 +246 (+100.00%)
kprobe_multi.bpf.linked1.o test_kprobe_manual failure success MISMATCH 0 246 +246 (+100.00%)
kprobe_multi.bpf.linked1.o test_kretprobe failure success MISMATCH 0 248 +248 (+100.00%)
kprobe_multi.bpf.linked1.o test_kretprobe_manual failure success MISMATCH 0 248 +248 (+100.00%)
kprobe_multi.bpf.linked1.o trigger failure success MISMATCH 0 2 +2 (+100.00%)
netcnt_prog.bpf.linked1.o bpf_nextcnt failure success MISMATCH 0 56 +56 (+100.00%)
pyperf600_nounroll.bpf.linked1.o on_event success failure MISMATCH 568128 1000001 +431873 (+76.02%)
ringbuf_bench.bpf.linked1.o bench_ringbuf success failure MISMATCH 8 0 -8 (-100.00%)
strobemeta.bpf.linked1.o on_event success failure MISMATCH 557149 1000001 +442852 (+79.49%)
strobemeta_nounroll1.bpf.linked1.o on_event success failure MISMATCH 57240 1000001 +942761 (+1647.03%)
strobemeta_nounroll2.bpf.linked1.o on_event success failure MISMATCH 501725 1000001 +498276 (+99.31%)
strobemeta_subprogs.bpf.linked1.o on_event success failure MISMATCH 65420 1000001 +934581 (+1428.59%)
test_map_in_map_invalid.bpf.linked1.o xdp_noop0 success failure MISMATCH 2 0 -2 (-100.00%)
test_mmap.bpf.linked1.o test_mmap success failure MISMATCH 46 0 -46 (-100.00%)
test_verif_scale3.bpf.linked1.o balancer_ingress success failure MISMATCH 845499 1000001 +154502 (+18.27%)
------------------------------------- --------------------- ----------- ----------- -------------- --------- --------- -------------------
Note that by filtering on verdict_diff=mismatch, it's now extremely easy and
fast to see any changes in verdict. Example above showcases both failure ->
success transitions (which are generally surprising) and success -> failure
transitions (which are expected if bugs are present).
Given veristat allows to query relative percent difference values, internal
logic for comparison mode is based on floating point numbers, so requires a bit
of epsilon precision logic, deviating from typical integer simple handling
rules.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-11-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Introduce the concept of "stat variant", by which it's possible to
specify whether to use the value from A (baseline) side, B (comparison
or control) side, the absolute difference value or relative (percentage)
difference value.
To support specifying this, veristat recognizes `_a`, `_b`, `_diff`,
`_pct` suffixes, which can be appended to stat name(s). In
non-comparison mode variants are ignored (there is only `_a` variant
effectively), if no variant suffix is provided, `_b` is assumed, as
control group is of primary interest in comparison mode.
These stat variants can be flexibly combined with asc/desc orders.
Here's an example of ordering results first by verdict match/mismatch (or n/a
if one of the sides is missing; n/a is always considered to be the lowest
value), and within each match/mismatch/n/a group further sort by number of
instructions in B side. In this case we don't have MISMATCH cases, but N/A are
split from MATCH, demonstrating this custom ordering.
$ ./veristat -e file,prog,verdict,insns -s verdict_diff,insns_b_ -C ~/base.csv ~/comp.csv
File Program Verdict (A) Verdict (B) Verdict (DIFF) Insns (A) Insns (B) Insns (DIFF)
------------------ ------------------------------ ----------- ----------- -------------- --------- --------- --------------
bpf_xdp.o tail_lb_ipv6 N/A success N/A N/A 151895 N/A
bpf_xdp.o tail_nodeport_nat_egress_ipv4 N/A success N/A N/A 15619 N/A
bpf_xdp.o tail_nodeport_ipv6_dsr N/A success N/A N/A 1206 N/A
bpf_xdp.o tail_nodeport_ipv4_dsr N/A success N/A N/A 1162 N/A
bpf_alignchecker.o tail_icmp6_send_echo_reply N/A failure N/A N/A 74 N/A
bpf_alignchecker.o __send_drop_notify success N/A N/A 53 N/A N/A
bpf_host.o __send_drop_notify success N/A N/A 53 N/A N/A
bpf_host.o cil_from_host success N/A N/A 762 N/A N/A
bpf_xdp.o tail_lb_ipv4 success success MATCH 71736 73430 +1694 (+2.36%)
bpf_xdp.o tail_handle_nat_fwd_ipv4 success success MATCH 21547 20920 -627 (-2.91%)
bpf_xdp.o tail_rev_nodeport_lb6 success success MATCH 17954 17905 -49 (-0.27%)
bpf_xdp.o tail_handle_nat_fwd_ipv6 success success MATCH 16974 17039 +65 (+0.38%)
bpf_xdp.o tail_nodeport_nat_ingress_ipv4 success success MATCH 7658 7713 +55 (+0.72%)
bpf_xdp.o tail_rev_nodeport_lb4 success success MATCH 7126 6934 -192 (-2.69%)
bpf_xdp.o tail_nodeport_nat_ingress_ipv6 success success MATCH 6405 6397 -8 (-0.12%)
bpf_xdp.o tail_nodeport_nat_ipv6_egress failure failure MATCH 752 752 +0 (+0.00%)
bpf_xdp.o cil_xdp_entry success success MATCH 423 423 +0 (+0.00%)
bpf_xdp.o __send_drop_notify success success MATCH 151 151 +0 (+0.00%)
bpf_alignchecker.o tail_icmp6_handle_ns failure failure MATCH 33 33 +0 (+0.00%)
------------------ ------------------------------ ----------- ----------- -------------- --------- --------- --------------
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-10-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When comparing two datasets, if either side is missing corresponding
record with the same file and prog name, currently veristat emits
misleading zeros/failures, and even tried to calculate a difference,
even though there is no data to compare against.
This patch improves internal logic of handling such situations. Now
we'll emit "N/A" in places where data is missing and comparison is
non-sensical.
As an example, in an artificially truncated and mismatched Cilium
results, the output looks like below:
$ ./veristat -e file,prog,verdict,insns -C ~/base.csv ~/comp.csv
File Program Verdict (A) Verdict (B) Verdict (DIFF) Insns (A) Insns (B) Insns (DIFF)
------------------ ------------------------------ ----------- ----------- -------------- --------- --------- --------------
bpf_alignchecker.o __send_drop_notify success N/A N/A 53 N/A N/A
bpf_alignchecker.o tail_icmp6_handle_ns failure failure MATCH 33 33 +0 (+0.00%)
bpf_alignchecker.o tail_icmp6_send_echo_reply N/A failure N/A N/A 74 N/A
bpf_host.o __send_drop_notify success N/A N/A 53 N/A N/A
bpf_host.o cil_from_host success N/A N/A 762 N/A N/A
bpf_xdp.o __send_drop_notify success success MATCH 151 151 +0 (+0.00%)
bpf_xdp.o cil_xdp_entry success success MATCH 423 423 +0 (+0.00%)
bpf_xdp.o tail_handle_nat_fwd_ipv4 success success MATCH 21547 20920 -627 (-2.91%)
bpf_xdp.o tail_handle_nat_fwd_ipv6 success success MATCH 16974 17039 +65 (+0.38%)
bpf_xdp.o tail_lb_ipv4 success success MATCH 71736 73430 +1694 (+2.36%)
bpf_xdp.o tail_lb_ipv6 N/A success N/A N/A 151895 N/A
bpf_xdp.o tail_nodeport_ipv4_dsr N/A success N/A N/A 1162 N/A
bpf_xdp.o tail_nodeport_ipv6_dsr N/A success N/A N/A 1206 N/A
bpf_xdp.o tail_nodeport_nat_egress_ipv4 N/A success N/A N/A 15619 N/A
bpf_xdp.o tail_nodeport_nat_ingress_ipv4 success success MATCH 7658 7713 +55 (+0.72%)
bpf_xdp.o tail_nodeport_nat_ingress_ipv6 success success MATCH 6405 6397 -8 (-0.12%)
bpf_xdp.o tail_nodeport_nat_ipv6_egress failure failure MATCH 752 752 +0 (+0.00%)
bpf_xdp.o tail_rev_nodeport_lb4 success success MATCH 7126 6934 -192 (-2.69%)
bpf_xdp.o tail_rev_nodeport_lb6 success success MATCH 17954 17905 -49 (-0.27%)
------------------ ------------------------------ ----------- ----------- -------------- --------- --------- --------------
Internally veristat now separates joining two datasets and remembering the
join, and actually emitting a comparison view. This will come handy when we add
support for filtering and custom ordering in comparison mode.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-9-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Make veristat distinguish between table and CSV output formats and use
different default set of stats (columns) that are emitted. While for
human-readable table output it doesn't make sense to output all known
stats, it is very useful for CSV mode to record all possible data, so
that it can later be queried and filtered in replay or comparison mode.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-8-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Define simple expressions to filter not just by file and program name,
but also by resulting values of collected stats. Support usual
equality and inequality operators. Verdict, which is a boolean-like
field can be also filtered either as 0/1, failure/success (with f/s,
fail/succ, and failure/success aliases) symbols, or as false/true (f/t).
Aliases are case insensitive.
Currently this filtering is honored only in verification and replay
modes. Comparison mode support will be added in next patch.
Here's an example of verifying a bunch of BPF object files and emitting
only results for successfully validated programs that have more than 100
total instructions processed by BPF verifier, sorted by number of
instructions in ascending order:
$ sudo ./veristat *.bpf.o -s insns^ -f 'insns>100'
There can be many filters (both allow and deny flavors), all of them are
combined.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-7-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allow to specify '^' at the end of stat name to designate that it should
be sorted in ascending order. Similarly, allow any of 'v', 'V', '.',
'!', or '_' suffix "symbols" to designate descending order. It's such
a zoo for descending order because there is no single intuitive symbol
that could be used (using 'v' looks pretty weird in practice), so few
symbols that are "downwards leaning or pointing" were chosen. Either
way, it shouldn't cause any troubles in practice.
This new feature allows to customize sortering order to match user's
needs.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-6-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Always fall back to unique file/prog comparison if user's custom order
specs are ambiguous. This ensures stable output no matter what.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Slightly change rules of specifying file/prog glob filters. In practice
it's quite often inconvenient to do `*/<prog-glob>` if that program glob
is unique enough and won't accidentally match any file names.
This patch changes the rules so that `-f <glob>` will apply specified
glob to both file and program names. User still has all the control by
doing '*/<prog-only-glob>' or '<file-only-glob/*'. We also now allow
'/<prog-glob>' and '<file-glob/' (all matching wildcard is assumed if
missing).
Also, internally unify file-only and file+prog checks
(should_process_file and should_process_prog are now
should_process_file_prog that can handle prog name as optional). This
makes maintaining and extending this code easier.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-4-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
In comparison mode the "Total " part is pretty useless, but takes
a considerable amount of horizontal space. Drop the "Total " parts.
Also make sure that table headers for numerical columns are aligned in
the same fashion as integer values in those columns. This looks better
and is now more obvious with shorter "Insns" and "States" column
headers.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Replay mode allow to parse previously stored CSV file with verification
results and present it in desired output (presumable human-readable
table, but CSV to CSV convertion is supported as well). While doing
that, it's possible to use veristat's sorting rules, specify subset of
columns, and filter by file and program name.
In subsequent patches veristat's filtering capabilities will just grow
making replay mode even more useful in practice for post-processing
results.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20221103055304.2904589-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
To prepare the BPF verifier to handle special fields in both map values
and program allocated types coming from program BTF, we need to refactor
the kptr_off_tab handling code into something more generic and reusable
across both cases to avoid code duplication.
Later patches also require passing this data to helpers at runtime, so
that they can work on user defined types, initialize them, destruct
them, etc.
The main observation is that both map values and such allocated types
point to a type in program BTF, hence they can be handled similarly. We
can prepare a field metadata table for both cases and store them in
struct bpf_map or struct btf depending on the use case.
Hence, refactor the code into generic btf_record and btf_field member
structs. The btf_record represents the fields of a specific btf_type in
user BTF. The cnt indicates the number of special fields we successfully
recognized, and field_mask is a bitmask of fields that were found, to
enable quick determination of availability of a certain field.
Subsequently, refactor the rest of the code to work with these generic
types, remove assumptions about kptr and kptr_off_tab, rename variables
to more meaningful names, etc.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
It is not scalable to maintain a list of types that can have non-zero
ref_obj_id. It is never set for scalars anyway, so just remove the
conditional on register types and print it whenever it is non-zero.
Acked-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For the case where allow_ptr_leaks is false, code is checking whether
slot type is STACK_INVALID and STACK_SPILL and rejecting other cases.
This is a consequence of incorrectly checking for register type instead
of the slot type (NOT_INIT and SCALAR_VALUE respectively). Fix the
check.
Fixes: 01f810ace9 ("bpf: Allow variable-offset stack access")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When support was added for spilled PTR_TO_BTF_ID to be accessed by
helper memory access, the stack slot was not overwritten to STACK_MISC
(and that too is only safe when env->allow_ptr_leaks is true).
This means that helpers who take ARG_PTR_TO_MEM and write to it may
essentially overwrite the value while the verifier continues to track
the slot for spilled register.
This can cause issues when PTR_TO_BTF_ID is spilled to stack, and then
overwritten by helper write access, which can then be passed to BPF
helpers or kfuncs.
Handle this by falling back to the case introduced in a later commit,
which will also handle PTR_TO_BTF_ID along with other pointer types,
i.e. cd17d38f8b ("bpf: Permits pointers on stack for helper calls").
Finally, include a comment on why REG_LIVE_WRITTEN is not being set when
clobber is set to true. In short, the reason is that while when clobber
is unset, we know that we won't be writing, when it is true, we *may*
write to any of the stack slots in that range. It may be a partial or
complete write, to just one or many stack slots.
We cannot be sure, hence to be conservative, we leave things as is and
never set REG_LIVE_WRITTEN for any stack slot. However, clobber still
needs to reset them to STACK_MISC assuming writes happened. However read
marks still need to be propagated upwards from liveness point of view,
as parent stack slot's contents may still continue to matter to child
states.
Cc: Yonghong Song <yhs@meta.com>
Fixes: 1d68f22b3d ("bpf: Handle spilled PTR_TO_BTF_ID properly when checking stack_boundary")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This is useful in particular to mark the pointer as volatile, so that
compiler treats each load and store to the field as a volatile access.
The alternative is having to define and use READ_ONCE and WRITE_ONCE in
the BPF program.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The kernel recognizes some special BPF types in map values or local
kptrs. Document that only bpf_spin_lock and bpf_timer will preserve
backwards compatibility, and kptr will preserve backwards compatibility
for the operations on the pointer, not the types supported for such
kptrs.
For local kptrs, document that there are no stability guarantees at all.
Finally, document that 'bpf_' namespace is reserved for adding future
special fields, hence BPF programs must not declare types with such
names in their programs and still expect backwards compatibility.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20221103191013.1236066-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
syzkaller managed to trigger another case where skb->len == 0
when we enter __dev_queue_xmit:
WARNING: CPU: 0 PID: 2470 at include/linux/skbuff.h:2576 skb_assert_len include/linux/skbuff.h:2576 [inline]
WARNING: CPU: 0 PID: 2470 at include/linux/skbuff.h:2576 __dev_queue_xmit+0x2069/0x35e0 net/core/dev.c:4295
Call Trace:
dev_queue_xmit+0x17/0x20 net/core/dev.c:4406
__bpf_tx_skb net/core/filter.c:2115 [inline]
__bpf_redirect_no_mac net/core/filter.c:2140 [inline]
__bpf_redirect+0x5fb/0xda0 net/core/filter.c:2163
____bpf_clone_redirect net/core/filter.c:2447 [inline]
bpf_clone_redirect+0x247/0x390 net/core/filter.c:2419
bpf_prog_48159a89cb4a9a16+0x59/0x5e
bpf_dispatcher_nop_func include/linux/bpf.h:897 [inline]
__bpf_prog_run include/linux/filter.h:596 [inline]
bpf_prog_run include/linux/filter.h:603 [inline]
bpf_test_run+0x46c/0x890 net/bpf/test_run.c:402
bpf_prog_test_run_skb+0xbdc/0x14c0 net/bpf/test_run.c:1170
bpf_prog_test_run+0x345/0x3c0 kernel/bpf/syscall.c:3648
__sys_bpf+0x43a/0x6c0 kernel/bpf/syscall.c:5005
__do_sys_bpf kernel/bpf/syscall.c:5091 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5089 [inline]
__x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5089
do_syscall_64+0x54/0x70 arch/x86/entry/common.c:48
entry_SYSCALL_64_after_hwframe+0x61/0xc6
The reproducer doesn't really reproduce outside of syzkaller
environment, so I'm taking a guess here. It looks like we
do generate correct ETH_HLEN-sized packet, but we redirect
the packet to the tunneling device. Before we do so, we
__skb_pull l2 header and arrive again at skb->len == 0.
Doesn't seem like we can do anything better than having
an explicit check after __skb_pull?
Cc: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot+f635e86ec3fa0a37e019@syzkaller.appspotmail.com
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20221027225537.353077-1-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
