| Age | Commit message (Collapse) | Author |
|---|
|
Eduard Zingerman says:
====================
bpf: simple DFA-based live registers analysis
This patch-set introduces a simple live registers DFA analysis.
Analysis is done as a separate step before main verification pass.
Results are stored in the env->insn_aux_data for each instruction.
The change helps with iterator/callback based loops handling,
as regular register liveness marks are not finalized while
loops are processed. See veristat results in patch #2.
Note: for regular subprogram calls analysis conservatively assumes
that r1-r5 are used, and r0 is used at each 'exit' instruction.
Experiments show that adding logic handling these cases precisely has
no impact on verification performance.
The patch set was tested by disabling the current register parentage
chain liveness computation, using DFA-based liveness for registers
while assuming all stack slots as live. See discussion in [1].
Changes v2 -> v3:
- added support for BPF_LOAD_ACQ, BPF_STORE_REL atomics (Alexei);
- correct use marks for r0 for BPF_CMPXCHG.
Changes v1 -> v2:
- added a refactoring commit extracting utility functions:
jmp_offset(), verbose_insn() (Alexei);
- added a refactoring commit extracting utility function
get_call_summary() in order to share helper/kfunc related code with
mark_fastcall_pattern_for_call() (Alexei);
- comment in the compute_insn_live_regs() extended (Alexei).
Changes RFC -> v1:
- parameter count for helpers and kfuncs is taken into account;
- copy_verifier_state() bugfix had been merged as a separate
patch-set and is no longer a part of this patch set.
RFC: https://lore.kernel.org/bpf/20250122120442.3536298-1-eddyz87@gmail.com/
v1: https://lore.kernel.org/bpf/20250228060032.1425870-1-eddyz87@gmail.com/
v2: https://lore.kernel.org/bpf/20250304074239.2328752-1-eddyz87@gmail.com/
[1] https://lore.kernel.org/bpf/cc29975fbaf163d0c2ed904a9a4d6d9452177542.camel@gmail.com/
====================
Link: https://patch.msgid.link/20250304195024.2478889-1-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Cover instructions from each kind:
- assignment
- arithmetic
- store/load
- endian conversion
- atomics
- branches, conditional branches, may_goto, calls
- LD_ABS/LD_IND
- address_space_cast
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250304195024.2478889-6-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Peilin Ye says:
====================
Introduce load-acquire and store-release BPF instructions
This patchset adds kernel support for BPF load-acquire and store-release
instructions (for background, please see [1]), including core/verifier
and arm64/x86-64 JIT compiler changes, as well as selftests. riscv64 is
also planned to be supported. The corresponding LLVM changes can be
found at:
https://github.com/llvm/llvm-project/pull/108636
The first 3 patches from v4 have already been applied:
- [bpf-next,v4,01/10] bpf/verifier: Factor out atomic_ptr_type_ok()
https://git.kernel.org/bpf/bpf-next/c/b2d9ef71d4c9
- [bpf-next,v4,02/10] bpf/verifier: Factor out check_atomic_rmw()
https://git.kernel.org/bpf/bpf-next/c/d430c46c7580
- [bpf-next,v4,03/10] bpf/verifier: Factor out check_load_mem() and check_store_reg()
https://git.kernel.org/bpf/bpf-next/c/d38ad248fb7a
Please refer to the LLVM PR and individual kernel patches for details.
Thanks!
v5: https://lore.kernel.org/all/cover.1741046028.git.yepeilin@google.com/
v5..v6 change:
o (Alexei) avoid using #ifndef in verifier.c
v4: https://lore.kernel.org/bpf/cover.1740978603.git.yepeilin@google.com/
v4..v5 notable changes:
o (kernel test robot) for 32-bit arches: make the verifier reject
64-bit load-acquires/store-releases, and fix
build error in interpreter changes
* tested ARCH=arc build following instructions from kernel test
robot
o (Alexei) drop Documentation/ patch (v4 10/10) for now
v3: https://lore.kernel.org/bpf/cover.1740009184.git.yepeilin@google.com/
v3..v4 notable changes:
o (Alexei) add x86-64 JIT support (including arena)
o add Acked-by: tags from Xu
v2: https://lore.kernel.org/bpf/cover.1738888641.git.yepeilin@google.com/
v2..v3 notable changes:
o (Alexei) change encoding to BPF_LOAD_ACQ=0x100, BPF_STORE_REL=0x110
o add Acked-by: tags from Ilya and Eduard
o make new selftests depend on:
* __clang_major__ >= 18, and
* ENABLE_ATOMICS_TESTS is defined (currently this means -mcpu=v3 or
v4), and
* JIT supports load_acq/store_rel (currenty only arm64)
o work around llvm-17 CI job failure by conditionally define
__arena_global variables as 64-bit if __clang_major__ < 18, to make
sure .addr_space.1 has no holes
o add Google copyright notice in new files
v1: https://lore.kernel.org/all/cover.1737763916.git.yepeilin@google.com/
v1..v2 notable changes:
o (Eduard) for x86 and s390, make
bpf_jit_supports_insn(..., /*in_arena=*/true) return false
for load_acq/store_rel
o add Eduard's Acked-by: tag
o (Eduard) extract LDX and non-ATOMIC STX handling into helpers, see
PATCH v2 3/9
o allow unpriv programs to store-release pointers to stack
o (Alexei) make it clearer in the interpreter code (PATCH v2 4/9) that
only W and DW are supported for atomic RMW
o test misaligned load_acq/store_rel
o (Eduard) other selftests/ changes:
* test load_acq/store_rel with !atomic_ptr_type_ok() pointers:
- PTR_TO_CTX, for is_ctx_reg()
- PTR_TO_PACKET, for is_pkt_reg()
- PTR_TO_FLOW_KEYS, for is_flow_key_reg()
- PTR_TO_SOCKET, for is_sk_reg()
* drop atomics/ tests
* delete unnecessary 'pid' checks from arena_atomics/ tests
* avoid depending on __BPF_FEATURE_LOAD_ACQ_STORE_REL, use
__imm_insn() and inline asm macros instead
RFC v1: https://lore.kernel.org/all/cover.1734742802.git.yepeilin@google.com
RFC v1..v1 notable changes:
o 1-2/8: minor verifier.c refactoring patches
o 3/8: core/verifier changes
* (Eduard) handle load-acquire properly in backtrack_insn()
* (Eduard) avoid skipping checks (e.g.,
bpf_jit_supports_insn()) for load-acquires
* track the value stored by store-releases, just like how
non-atomic STX instructions are handled
* (Eduard) add missing link in commit message
* (Eduard) always print 'r' for disasm.c changes
o 4/8: arm64/insn: avoid treating load_acq/store_rel as
load_ex/store_ex
o 5/8: arm64/insn: add load_acq/store_rel
* (Xu) include Should-Be-One (SBO) bits in "mask" and "value",
to avoid setting fixed bits during runtime (JIT-compile
time)
o 6/8: arm64 JIT compiler changes
* (Xu) use emit_a64_add_i() for "pointer + offset" to optimize
code emission
o 7/8: selftests
* (Eduard) avoid adding new tests to the 'test_verifier' runner
* add more tests, e.g., checking mark_precise logic
o 8/8: instruction-set.rst changes
[1] https://lore.kernel.org/all/20240729183246.4110549-1-yepeilin@google.com/
Thanks,
====================
Link: https://patch.msgid.link/cover.1741049567.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Liveness analysis DFA computes a set of registers live before each
instruction. Leverage this information to skip comparison of dead
registers in func_states_equal(). This helps with convergance of
iterator processing loops, as bpf_reg_state->live marks can't be used
when loops are processed.
This has certain performance impact for selftests, here is a veristat
listing using `-f "insns_pct>5" -f "!insns<200"`
selftests:
File Program States (A) States (B) States (DIFF)
-------------------- ----------------------------- ---------- ---------- --------------
arena_htab.bpf.o arena_htab_llvm 37 35 -2 (-5.41%)
arena_htab_asm.bpf.o arena_htab_asm 37 33 -4 (-10.81%)
arena_list.bpf.o arena_list_add 37 22 -15 (-40.54%)
dynptr_success.bpf.o test_dynptr_copy 22 16 -6 (-27.27%)
dynptr_success.bpf.o test_dynptr_copy_xdp 68 58 -10 (-14.71%)
iters.bpf.o checkpoint_states_deletion 918 40 -878 (-95.64%)
iters.bpf.o clean_live_states 136 66 -70 (-51.47%)
iters.bpf.o iter_nested_deeply_iters 43 37 -6 (-13.95%)
iters.bpf.o iter_nested_iters 72 62 -10 (-13.89%)
iters.bpf.o iter_pass_iter_ptr_to_subprog 30 26 -4 (-13.33%)
iters.bpf.o iter_subprog_iters 68 59 -9 (-13.24%)
iters.bpf.o loop_state_deps2 35 32 -3 (-8.57%)
iters_css.bpf.o iter_css_for_each 32 29 -3 (-9.38%)
pyperf600_iter.bpf.o on_event 286 192 -94 (-32.87%)
Total progs: 3578
Old success: 2061
New success: 2061
States diff min: -95.64%
States diff max: 0.00%
-100 .. -90 %: 1
-55 .. -45 %: 3
-45 .. -35 %: 2
-35 .. -25 %: 5
-20 .. -10 %: 12
-10 .. 0 %: 6
sched_ext:
File Program States (A) States (B) States (DIFF)
----------------- ---------------------- ---------- ---------- ---------------
bpf.bpf.o lavd_dispatch 8950 7065 -1885 (-21.06%)
bpf.bpf.o lavd_init 516 480 -36 (-6.98%)
bpf.bpf.o layered_dispatch 662 501 -161 (-24.32%)
bpf.bpf.o layered_dump 298 237 -61 (-20.47%)
bpf.bpf.o layered_init 523 423 -100 (-19.12%)
bpf.bpf.o layered_init_task 24 22 -2 (-8.33%)
bpf.bpf.o layered_runnable 151 125 -26 (-17.22%)
bpf.bpf.o p2dq_dispatch 66 53 -13 (-19.70%)
bpf.bpf.o p2dq_init 170 142 -28 (-16.47%)
bpf.bpf.o refresh_layer_cpumasks 120 78 -42 (-35.00%)
bpf.bpf.o rustland_init 37 34 -3 (-8.11%)
bpf.bpf.o rustland_init 37 34 -3 (-8.11%)
bpf.bpf.o rusty_select_cpu 125 108 -17 (-13.60%)
scx_central.bpf.o central_dispatch 59 43 -16 (-27.12%)
scx_central.bpf.o central_init 39 28 -11 (-28.21%)
scx_nest.bpf.o nest_init 58 51 -7 (-12.07%)
scx_pair.bpf.o pair_dispatch 142 111 -31 (-21.83%)
scx_qmap.bpf.o qmap_dispatch 174 141 -33 (-18.97%)
scx_qmap.bpf.o qmap_init 768 654 -114 (-14.84%)
Total progs: 216
Old success: 186
New success: 186
States diff min: -35.00%
States diff max: 0.00%
-35 .. -25 %: 3
-25 .. -20 %: 6
-20 .. -15 %: 6
-15 .. -5 %: 7
-5 .. 0 %: 6
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250304195024.2478889-5-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Add several ./test_progs tests:
- arena_atomics/load_acquire
- arena_atomics/store_release
- verifier_load_acquire/*
- verifier_store_release/*
- verifier_precision/bpf_load_acquire
- verifier_precision/bpf_store_release
The last two tests are added to check if backtrack_insn() handles the
new instructions correctly.
Additionally, the last test also makes sure that the verifier
"remembers" the value (in src_reg) we store-release into e.g. a stack
slot. For example, if we take a look at the test program:
#0: r1 = 8;
/* store_release((u64 *)(r10 - 8), r1); */
#1: .8byte %[store_release];
#2: r1 = *(u64 *)(r10 - 8);
#3: r2 = r10;
#4: r2 += r1;
#5: r0 = 0;
#6: exit;
At #1, if the verifier doesn't remember that we wrote 8 to the stack,
then later at #4 we would be adding an unbounded scalar value to the
stack pointer, which would cause the program to be rejected:
VERIFIER LOG:
=============
...
math between fp pointer and register with unbounded min value is not allowed
For easier CI integration, instead of using built-ins like
__atomic_{load,store}_n() which depend on the new
__BPF_FEATURE_LOAD_ACQ_STORE_REL pre-defined macro, manually craft
load-acquire/store-release instructions using __imm_insn(), as suggested
by Eduard.
All new tests depend on:
(1) Clang major version >= 18, and
(2) ENABLE_ATOMICS_TESTS is defined (currently implies -mcpu=v3 or
v4), and
(3) JIT supports load-acquire/store-release (currently arm64 and
x86-64)
In .../progs/arena_atomics.c:
/* 8-byte-aligned */
__u8 __arena_global load_acquire8_value = 0x12;
/* 1-byte hole */
__u16 __arena_global load_acquire16_value = 0x1234;
That 1-byte hole in the .addr_space.1 ELF section caused clang-17 to
crash:
fatal error: error in backend: unable to write nop sequence of 1 bytes
To work around such llvm-17 CI job failures, conditionally define
__arena_global variables as 64-bit if __clang_major__ < 18, to make sure
.addr_space.1 has no holes. Ideally we should avoid compiling this file
using clang-17 at all (arena tests depend on
__BPF_FEATURE_ADDR_SPACE_CAST, and are skipped for llvm-17 anyway), but
that is a separate topic.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/1b46c6feaf0f1b6984d9ec80e500cc7383e9da1a.1741049567.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Compute may-live registers before each instruction in the program.
The register is live before the instruction I if it is read by I or
some instruction S following I during program execution and is not
overwritten between I and S.
This information would be used in the next patch as a hint in
func_states_equal().
Use a simple algorithm described in [1] to compute this information:
- define the following:
- I.use : a set of all registers read by instruction I;
- I.def : a set of all registers written by instruction I;
- I.in : a set of all registers that may be alive before I execution;
- I.out : a set of all registers that may be alive after I execution;
- I.successors : a set of instructions S that might immediately
follow I for some program execution;
- associate separate empty sets 'I.in' and 'I.out' with each instruction;
- visit each instruction in a postorder and update corresponding
'I.in' and 'I.out' sets as follows:
I.out = U [S.in for S in I.successors]
I.in = (I.out / I.def) U I.use
(where U stands for set union, / stands for set difference)
- repeat the computation while I.{in,out} changes for any instruction.
On implementation side keep things as simple, as possible:
- check_cfg() already marks instructions EXPLORED in post-order,
modify it to save the index of each EXPLORED instruction in a vector;
- represent I.{in,out,use,def} as bitmasks;
- don't split the program into basic blocks and don't maintain the
work queue, instead:
- do fixed-point computation by visiting each instruction;
- maintain a simple 'changed' flag if I.{in,out} for any instruction
change;
Measurements show that even such simplistic implementation does not
add measurable verification time overhead (for selftests, at-least).
Note on check_cfg() ex_insn_beg/ex_done change:
To avoid out of bounds access to env->cfg.insn_postorder array,
it should be guaranteed that instruction transitions to EXPLORED state
only once. Previously this was not the fact for incorrect programs
with direct calls to exception callbacks.
The 'align' selftest needs adjustment to skip computed insn/live
registers printout. Otherwise it matches lines from the live registers
printout.
[1] https://en.wikipedia.org/wiki/Live-variable_analysis
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250304195024.2478889-4-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Recently we introduced BPF load-acquire (BPF_LOAD_ACQ) and store-release
(BPF_STORE_REL) instructions. For x86-64, simply implement them as
regular BPF_LDX/BPF_STX loads and stores. The verifier always rejects
misaligned load-acquires/store-releases (even if BPF_F_ANY_ALIGNMENT is
set), so emitted MOV* instructions are guaranteed to be atomic.
Arena accesses are supported. 8- and 16-bit load-acquires are
zero-extending (i.e., MOVZBQ, MOVZWQ).
Rename emit_atomic{,_index}() to emit_atomic_rmw{,_index}() to make it
clear that they only handle read-modify-write atomics, and extend their
@atomic_op parameter from u8 to u32, since we are starting to use more
than the lowest 8 bits of the 'imm' field.
Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/d22bb3c69f126af1d962b7314f3489eff606a3b7.1741049567.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Refactor mark_fastcall_pattern_for_call() to extract a utility
function get_call_summary(). For a helper or kfunc call this function
fills the following information: {num_params, is_void, fastcall}.
This function would be used in the next patch in order to get number
of parameters of a helper or kfunc call.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250304195024.2478889-3-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Support BPF load-acquire (BPF_LOAD_ACQ) and store-release
(BPF_STORE_REL) instructions in the arm64 JIT compiler. For example
(assuming little-endian):
db 10 00 00 00 01 00 00 r0 = load_acquire((u64 *)(r1 + 0x0))
95 00 00 00 00 00 00 00 exit
opcode (0xdb): BPF_ATOMIC | BPF_DW | BPF_STX
imm (0x00000100): BPF_LOAD_ACQ
The JIT compiler would emit an LDAR instruction for the above, e.g.:
ldar x7, [x0]
Similarly, consider the following 16-bit store-release:
cb 21 00 00 10 01 00 00 store_release((u16 *)(r1 + 0x0), w2)
95 00 00 00 00 00 00 00 exit
opcode (0xcb): BPF_ATOMIC | BPF_H | BPF_STX
imm (0x00000110): BPF_STORE_REL
An STLRH instruction would be emitted, e.g.:
stlrh w1, [x0]
For a complete mapping:
load-acquire 8-bit LDARB
(BPF_LOAD_ACQ) 16-bit LDARH
32-bit LDAR (32-bit)
64-bit LDAR (64-bit)
store-release 8-bit STLRB
(BPF_STORE_REL) 16-bit STLRH
32-bit STLR (32-bit)
64-bit STLR (64-bit)
Arena accesses are supported.
bpf_jit_supports_insn(..., /*in_arena=*/true) always returns true for
BPF_LOAD_ACQ and BPF_STORE_REL instructions, as they don't depend on
ARM64_HAS_LSE_ATOMICS.
Acked-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/51664a1300710238ba2d4d95142b57a52c4f0cae.1741049567.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Extract two utility functions:
- One BPF jump instruction uses .imm field to encode jump offset,
while the rest use .off. Encapsulate this detail as jmp_offset()
function.
- Avoid duplicating instruction printing callback definitions by
defining a verbose_insn() function, which disassembles an
instruction into the verifier log while hiding this detail.
These functions will be used in the next patch.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250304195024.2478889-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Add load-acquire ("load_acq", LDAR{,B,H}) and store-release
("store_rel", STLR{,B,H}) instructions. Breakdown of encoding:
size L (Rs) o0 (Rt2) Rn Rt
mask (0x3fdffc00): 00 111111 1 1 0 11111 1 11111 00000 00000
value, load_acq (0x08dffc00): 00 001000 1 1 0 11111 1 11111 00000 00000
value, store_rel (0x089ffc00): 00 001000 1 0 0 11111 1 11111 00000 00000
As suggested by Xu [1], include all Should-Be-One (SBO) bits ("Rs" and
"Rt2" fields) in the "mask" and "value" numbers.
It is worth noting that we are adding the "no offset" variant of STLR
instead of the "pre-index" variant, which has a different encoding.
Reference: Arm Architecture Reference Manual (ARM DDI 0487K.a,
ID032224),
* C6.2.161 LDAR
* C6.2.353 STLR
[1] https://lore.kernel.org/bpf/4e6641ce-3f1e-4251-8daf-4dd4b77d08c4@huaweicloud.com/
Acked-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/ba92057b7502ce4c9c9b03b7d637abe5e178134e.1741049567.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
We are planning to add load-acquire (LDAR{,B,H}) and store-release
(STLR{,B,H}) instructions to insn.{c,h}; add BIT(23) to mask of load_ex
and store_ex to prevent aarch64_insn_is_{load,store}_ex() from returning
false-positives for load-acquire and store-release instructions.
Reference: Arm Architecture Reference Manual (ARM DDI 0487K.a,
ID032224),
* C6.2.228 LDXR
* C6.2.165 LDAXR
* C6.2.161 LDAR
* C6.2.393 STXR
* C6.2.360 STLXR
* C6.2.353 STLR
Acked-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/5a4d2a52b2cc022bf86d0b572789f0b3bc3d5162.1741049567.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Kumar Kartikeya Dwivedi says:
====================
Timed may_goto
This series replaces the current implementation of cond_break, which
uses the may_goto instruction, and counts 8 million iterations per stack
frame, with an implementation based on sampling time locally on the CPU.
This is done to permit a longer time for a given loop per-program
invocation. The accounting is still done per-stack frame, but the count
is used to instead amortize the cost of the logic to sample and check
the time spent since the start.
This is needed for expressing more complicated algorithms (spin locks,
waiting loops, etc.) in BPF programs without false positive expiration
of the loop. For instance, the plan is to make use of this for
implementing spin locks for BPF arena [0].
For the loop as follows:
for (int i = 0;; i++) {}
Testing on a bare-metal Sapphire Rapids Intel server yields the following
table (taking an average of 25 runs).
+-----------------------------+--------------+--------------+------------------+
| Loop type | Iterations | Time (ms) | Time/iter (ns) |
+-----------------------------|--------------+--------------+------------------+
| may_goto | 8388608 | 3 | 0.36 |
| timed_may_goto (count=65535)| 589674932 | 250 | 0.42 |
| bpf_for | 8388608 | 10 | 1.19 |
+-----------------------------+--------------+--------------+------------------+
Here, count is used to amortize the time sampling and checking logic.
Obviously, this is the limit of an empty loop. Given the complexity of
the loop body, the time spent in the loop can be longer. Cancellations
will address the task of imposing an upper bound on program runtime.
For now, the implementation only supports x86.
[0]: https://lore.kernel.org/bpf/20250118162238.2621311-1-memxor@gmail.com
Changelog:
----------
v1 -> v2
v1: https://lore.kernel.org/bpf/20250302201348.940234-1-memxor@gmail.com
* Address comments from Alexei
* Use kernel comment style for new code.
* Remove p->count == 0 check in bpf_check_timed_may_goto.
* Add comments on AX as argument/retval calling convention.
* Add comments describing how the counting logic works.
* Use BPF_EMIT_CALL instead of open-coding instruction encoding.
* Change if ax != 1 goto pc+X condition to if ax != 0 goto pc+X.
====================
Link: https://patch.msgid.link/20250304003239.2390751-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Introduce BPF instructions with load-acquire and store-release
semantics, as discussed in [1]. Define 2 new flags:
#define BPF_LOAD_ACQ 0x100
#define BPF_STORE_REL 0x110
A "load-acquire" is a BPF_STX | BPF_ATOMIC instruction with the 'imm'
field set to BPF_LOAD_ACQ (0x100).
Similarly, a "store-release" is a BPF_STX | BPF_ATOMIC instruction with
the 'imm' field set to BPF_STORE_REL (0x110).
Unlike existing atomic read-modify-write operations that only support
BPF_W (32-bit) and BPF_DW (64-bit) size modifiers, load-acquires and
store-releases also support BPF_B (8-bit) and BPF_H (16-bit). As an
exception, however, 64-bit load-acquires/store-releases are not
supported on 32-bit architectures (to fix a build error reported by the
kernel test robot).
An 8- or 16-bit load-acquire zero-extends the value before writing it to
a 32-bit register, just like ARM64 instruction LDARH and friends.
Similar to existing atomic read-modify-write operations, misaligned
load-acquires/store-releases are not allowed (even if
BPF_F_ANY_ALIGNMENT is set).
As an example, consider the following 64-bit load-acquire BPF
instruction (assuming little-endian):
db 10 00 00 00 01 00 00 r0 = load_acquire((u64 *)(r1 + 0x0))
opcode (0xdb): BPF_ATOMIC | BPF_DW | BPF_STX
imm (0x00000100): BPF_LOAD_ACQ
Similarly, a 16-bit BPF store-release:
cb 21 00 00 10 01 00 00 store_release((u16 *)(r1 + 0x0), w2)
opcode (0xcb): BPF_ATOMIC | BPF_H | BPF_STX
imm (0x00000110): BPF_STORE_REL
In arch/{arm64,s390,x86}/net/bpf_jit_comp.c, have
bpf_jit_supports_insn(..., /*in_arena=*/true) return false for the new
instructions, until the corresponding JIT compiler supports them in
arena.
[1] https://lore.kernel.org/all/20240729183246.4110549-1-yepeilin@google.com/
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/a217f46f0e445fbd573a1a024be5c6bf1d5fe716.1741049567.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Mykyta Yatsenko says:
====================
Introduce bpf_object__prepare
From: Mykyta Yatsenko <yatsenko@meta.com>
We are introducing a new function in the libbpf API, bpf_object__prepare,
which provides more granular control over the process of loading a
bpf_object. bpf_object__prepare performs ELF processing, relocations,
prepares final state of BPF program instructions (accessible with
bpf_program__insns()), creates and potentially pins maps, and stops short
of loading BPF programs.
There are couple of anticipated usecases for this API:
* Use BPF token for freplace programs that might need to lookup BTF of
other programs (BPF token creation can't be moved to open step, as open
step is "no privilege assumption" step so that tools like bpftool can
generate skeleton, discover the structure of BPF object, etc).
* Stopping at prepare gives users finalized BPF program
instructions (with subprogs appended, everything relocated and
finalized, etc). And that property can be taken advantage of by
veristat (and similar tools) that might want to process one program at
a time, but would like to avoid relatively slow ELF parsing and
processing; and even BPF selftests itself (RUN_TESTS part of it at
least) would benefit from this by eliminating waste of re-processing
ELF many times.
====================
Link: https://patch.msgid.link/20250303135752.158343-1-mykyta.yatsenko5@gmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Implement the arch_bpf_timed_may_goto function using inline assembly to
have control over which registers are spilled, and use our special
protocol of using BPF_REG_AX as an argument into the function, and as
the return value when going back.
Emit call depth accounting for the call made from this stub, and ensure
we don't have naked returns (when rethunk mitigations are enabled) by
falling back to the RET macro (instead of retq). After popping all saved
registers, the return address into the BPF program should be on top of
the stack.
Since the JIT support is now enabled, ensure selftests which are
checking the produced may_goto sequences do not break by adjusting them.
Make sure we still test the old may_goto sequence on other
architectures, while testing the new sequence on x86_64.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250304003239.2390751-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Add selftests, checking that running bpf_object__prepare successfully
creates maps before load step.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250303135752.158343-5-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Implement support in the verifier for replacing may_goto implementation
from a counter-based approach to one which samples time on the local CPU
to have a bigger loop bound.
We implement it by maintaining 16-bytes per-stack frame, and using 8
bytes for maintaining the count for amortizing time sampling, and 8
bytes for the starting timestamp. To minimize overhead, we need to avoid
spilling and filling of registers around this sequence, so we push this
cost into the time sampling function 'arch_bpf_timed_may_goto'. This is
a JIT-specific wrapper around bpf_check_timed_may_goto which returns us
the count to store into the stack through BPF_REG_AX. All caller-saved
registers (r0-r5) are guaranteed to remain untouched.
The loop can be broken by returning count as 0, otherwise we dispatch
into the function when the count drops to 0, and the runtime chooses to
refresh it (by returning count as BPF_MAX_TIMED_LOOPS) or returning 0
and aborting the loop on next iteration.
Since the check for 0 is done right after loading the count from the
stack, all subsequent cond_break sequences should immediately break as
well, of the same loop or subsequent loops in the program.
We pass in the stack_depth of the count (and thus the timestamp, by
adding 8 to it) to the arch_bpf_timed_may_goto call so that it can be
passed in to bpf_check_timed_may_goto as an argument after r1 is saved,
by adding the offset to r10/fp. This adjustment will be arch specific,
and the next patch will introduce support for x86.
Note that depending on loop complexity, time spent in the loop can be
more than the current limit (250 ms), but imposing an upper bound on
program runtime is an orthogonal problem which will be addressed when
program cancellations are supported.
The current time afforded by cond_break may not be enough for cases
where BPF programs want to implement locking algorithms inline, and use
cond_break as a promise to the verifier that they will eventually
terminate.
Below are some benchmarking numbers on the time taken per-iteration for
an empty loop that counts the number of iterations until cond_break
fires. For comparison, we compare it against bpf_for/bpf_repeat which is
another way to achieve the same number of spins (BPF_MAX_LOOPS). The
hardware used for benchmarking was a Sapphire Rapids Intel server with
performance governor enabled, mitigations were enabled.
+-----------------------------+--------------+--------------+------------------+
| Loop type | Iterations | Time (ms) | Time/iter (ns) |
+-----------------------------|--------------+--------------+------------------+
| may_goto | 8388608 | 3 | 0.36 |
| timed_may_goto (count=65535)| 589674932 | 250 | 0.42 |
| bpf_for | 8388608 | 10 | 1.19 |
+-----------------------------+--------------+--------------+------------------+
This gives a good approximation at low overhead while staying close to
the current implementation.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250304003239.2390751-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Introduce bpf_object__prepare API: additional intermediate preparation
step that performs ELF processing, relocations, prepares final state of
BPF program instructions (accessible with bpf_program__insns()), creates
and (potentially) pins maps, and stops short of loading BPF programs.
We anticipate few use cases for this API, such as:
* Use prepare to initialize bpf_token, without loading freplace
programs, unlocking possibility to lookup BTF of other programs.
* Execute prepare to obtain finalized BPF program instructions without
loading programs, enabling tools like veristat to process one program at
a time, without incurring cost of ELF parsing and processing.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250303135752.158343-4-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
We are going to split bpf_object loading into 2 stages: preparation and
loading. This will increase flexibility when working with bpf_object
and unlock some optimizations and use cases.
This patch substitutes a boolean flag (loaded) by more finely-grained
state for bpf_object.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250303135752.158343-3-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Rename the local variable 'off' to 'offset' to avoid shadowing the existing
'off' variable that is declared as an `int` in the outer scope of
bpf_convert_ctx_access().
This fixes a compiler warning:
net/core/filter.c:9679:8: warning: declaration shadows a local variable [-Wshadow]
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://patch.msgid.link/20250228-fix_filter-v1-1-ce13eae66fe9@debian.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Refactoring: use map_is_created helper in map setters that need to check
the state of the map. This helps to reduce the number of the places that
depend explicitly on the loaded flag, simplifying refactoring in the
next patch of this set.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250303135752.158343-2-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Bastien Curutchet says:
====================
selftests/bpf: Migrate test_tunnel.sh to test_progs
Hi all,
This patch series continues the work to migrate the *.sh tests into
prog_tests framework.
The test_tunnel.sh script has already been partly migrated to
test_progs in prog_tests/test_tunnel.c so I add my work to it.
PATCH 1 & 2 create some helpers to avoid code duplication and ease the
migration in the following patches.
PATCH 3 to 9 migrate the tests of gre, ip6gre, erspan, ip6erspan,
geneve, ip6geneve and ip6tnl tunnels.
PATCH 10 removes test_tunnel.sh
====================
Link: https://patch.msgid.link/20250303-tunnels-v2-0-8329f38f0678@bootlin.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
All tests from test_tunnel.sh have been migrated into test test_progs.
The last test remaining in the script is the test_ipip() that is already
covered in the test_prog framework by the NONE case of test_ipip_tunnel().
Remove the test_tunnel.sh script and its Makefile entry
Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250303-tunnels-v2-10-8329f38f0678@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
ip6tnl tunnels are tested in the test_tunnel.sh but not in the test_progs
framework.
Add a new test in test_progs to test ip6tnl tunnels. It uses the same
network topology and the same BPF programs than the script.
Remove test_ipip6() and test_ip6ip6() from the script.
Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250303-tunnels-v2-9-8329f38f0678@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
ip6geneve tunnels are tested in the test_tunnel.sh but not in the
test_progs framework.
Add a new test in test_progs to test ip6geneve tunnels. It uses the same
network topology and the same BPF programs than the script.
Remove test_ip6geneve() from the script.
Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250303-tunnels-v2-8-8329f38f0678@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
geneve tunnels are tested in the test_tunnel.sh but not in the test_progs
framework.
Add a new test in test_progs to test geneve tunnels. It uses the same
network topology and the same BPF programs than the script.
Remove test_geneve() from the script.
Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250303-tunnels-v2-7-8329f38f0678@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
ip6erspan tunnels are tested in the test_tunnel.sh but not in the
test_progs framework.
Add a new test in test_progs to test ip6erspan tunnels. It uses the same
network topology and the same BPF programs than the script.
Remove test_ip6erspan() from the script.
Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250303-tunnels-v2-6-8329f38f0678@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
erspan tunnels are tested in the test_tunnel.sh but not in the test_progs
framework.
Add a new test in test_progs to test erspan tunnels. It uses the same
network topology and the same BPF programs than the script.
Remove test_erspan() from the script.
Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250303-tunnels-v2-5-8329f38f0678@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
ip6gre tunnels are tested in the test_tunnel.sh but not in the test_progs
framework.
Add a new test in test_progs to test ip6gre tunnels. It uses the same
network topology and the same BPF programs than the script. Disable the
IPv6 DAD feature because it can take lot of time and cause some tests to
fail depending on the environment they're run on.
Remove test_ip6gre() and test_ip6gretap() from the script.
Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250303-tunnels-v2-4-8329f38f0678@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
gre tunnels are tested in the test_tunnel.sh but not in the test_progs
framework.
Add a new test in test_progs to test gre tunnels. It uses the same
network topology and the same BPF programs than the script.
Remove test_gre() and test_gre_no_tunnel_key() from the script.
Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250303-tunnels-v2-3-8329f38f0678@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Eduard Zingerman says:
====================
veristat: @files-list.txt notation for object files list
A few small veristat improvements:
- It is possible to hit command line parameters number limit,
e.g. when running veristat for all object files generated for
test_progs. This patch-set adds an option to read objects files list
from a file.
- Correct usage of strerror() function.
- Avoid printing log lines to CSV output.
Changelog:
- v1 -> v2:
- replace strerror(errno) with strerror(-err) in patch #2 (Andrii)
v1: https://lore.kernel.org/bpf/3ee39a16-bc54-4820-984a-0add2b5b5f86@gmail.com/T/
====================
Link: https://patch.msgid.link/20250301000147.1583999-1-eddyz87@gmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
All tests use more or less the same ping commands as final validation.
Also test_ping()'s return value is checked with ASSERT_OK() while this
check is already done by the SYS() macro inside test_ping().
Create helpers around test_ping() and use them in the tests to avoid code
duplication.
Remove the unnecessary ASSERT_OK() from the tests.
Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250303-tunnels-v2-2-8329f38f0678@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Extract BPF_LDX and most non-ATOMIC BPF_STX instruction handling logic
in do_check() into helper functions to be used later. While we are
here, make that comment about "reserved fields" more specific.
Suggested-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/8b39c94eac2bb7389ff12392ca666f939124ec4f.1740978603.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
In order not to pollute CSV output, e.g.:
$ ./veristat -o csv exceptions_ext.bpf.o > test.csv
Using guessed program type 'sched_cls' for exceptions_ext.bpf.o/extension...
Using guessed program type 'sched_cls' for exceptions_ext.bpf.o/throwing_extension...
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>
Link: https://lore.kernel.org/bpf/20250301000147.1583999-4-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
A fair amount of code duplication is present among tests to attach BPF
programs.
Create generic_attach* helpers that attach BPF programs to a given
interface.
Use ASSERT_OK_FD() instead of ASSERT_GE() to check fd's validity.
Use these helpers in all the available tests.
Signed-off-by: Bastien Curutchet (eBPF Foundation) <bastien.curutchet@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250303-tunnels-v2-1-8329f38f0678@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Currently, check_atomic() only handles atomic read-modify-write (RMW)
instructions. Since we are planning to introduce other types of atomic
instructions (i.e., atomic load/store), extract the existing RMW
handling logic into its own function named check_atomic_rmw().
Remove the @insn_idx parameter as it is not really necessary. Use
'env->insn_idx' instead, as in other places in verifier.c.
Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/6323ac8e73a10a1c8ee547c77ed68cf8eb6b90e1.1740978603.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Before:
./veristat -G @foobar iters.bpf.o
Failed to open presets in 'foobar': Unknown error -2
...
After:
./veristat -G @foobar iters.bpf.o
Failed to open presets in 'foobar': No such file or directory
...
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>
Link: https://lore.kernel.org/bpf/20250301000147.1583999-3-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Factor out atomic_ptr_type_ok() as a helper function to be used later.
Signed-off-by: Peilin Ye <yepeilin@google.com>
Link: https://lore.kernel.org/r/e5ef8b3116f3fffce78117a14060ddce05eba52a.1740978603.git.yepeilin@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Allow reading object file list from file.
E.g. the following command:
./veristat @list.txt
Is equivalent to the following invocation:
./veristat line-1 line-2 ... line-N
Where line-i corresponds to lines from list.txt.
Lines starting with '#' are ignored.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>
Link: https://lore.kernel.org/bpf/20250301000147.1583999-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
bpf_sk_storage_clone() is the only caller of bpf_map_inc_not_zero()
and is holding rcu_read_lock().
map_idr_lock does not add any protection, just remove the cost
for passive TCP flows.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Kui-Feng Lee <kuifeng@meta.com>
Cc: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://lore.kernel.org/r/20250301191315.1532629-1-edumazet@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Kumar Kartikeya Dwivedi says:
====================
Global subprogs in RCU/{preempt,irq}-disabled sections
Small change to allow non-sleepable global subprogs in
RCU, preempt-disabled, and irq-disabled sections. For
now, we don't lift the limitation for locks as it requires
more analysis, and will do this one resilient spin locks
land.
This surfaced a bug where sleepable global subprogs were
allowed in RCU read sections, that has been fixed. Tests
have been added to cover various cases.
Changelog:
----------
v2 -> v3
v2: https://lore.kernel.org/bpf/20250301030205.1221223-1-memxor@gmail.com
* Fix broken to_be_replaced argument in the selftest.
* Adjust selftest program type.
v1 -> v2
v1: https://lore.kernel.org/bpf/20250228162858.1073529-1-memxor@gmail.com
* Rename subprog_info[i].sleepable to might_sleep, which more
accurately reflects the nature of the bit. 'sleepable' means whether
a given context is allowed to, while might_sleep captures if it
does.
* Disallow extensions that might sleep to attach to targets that don't
sleep, since they'd be permitted to be called in atomic contexts. (Eduard)
* Add tests for mixing non-sleepable and sleepable global function
calls, and extensions attaching to non-sleepable global functions. (Eduard)
* Rename changes_pkt_data -> summarization
====================
Link: https://patch.msgid.link/20250301151846.1552362-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
test_select_reuseport_kern.c is currently including <stdlib.h>, but it
does not use any definition from there.
Remove stdlib.h inclusion from test_select_reuseport_kern.c
Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore@bootlin.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250227-remove_wrong_header-v1-1-bc94eb4e2f73@bootlin.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Add tests for freplace behavior with the combination of sleepable
and non-sleepable global subprogs. The changes_pkt_data selftest
did all the hardwork, so simply rename it and include new support
for more summarization tests for might_sleep bit.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250301151846.1552362-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Add a few selftests with cgroup prog pre-ordering.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20250224230121.283601-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Add tests for rejecting sleepable and accepting non-sleepable global
function calls in atomic contexts. For spin locks, we still reject
all global function calls. Once resilient spin locks land, we will
carefully lift in cases where we deem it safe.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250301151846.1552362-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Currently for bpf progs in a cgroup hierarchy, the effective prog array
is computed from bottom cgroup to upper cgroups (post-ordering). For
example, the following cgroup hierarchy
root cgroup: p1, p2
subcgroup: p3, p4
have BPF_F_ALLOW_MULTI for both cgroup levels.
The effective cgroup array ordering looks like
p3 p4 p1 p2
and at run time, progs will execute based on that order.
But in some cases, it is desirable to have root prog executes earlier than
children progs (pre-ordering). For example,
- prog p1 intends to collect original pkt dest addresses.
- prog p3 will modify original pkt dest addresses to a proxy address for
security reason.
The end result is that prog p1 gets proxy address which is not what it
wants. Putting p1 to every child cgroup is not desirable either as it
will duplicate itself in many child cgroups. And this is exactly a use case
we are encountering in Meta.
To fix this issue, let us introduce a flag BPF_F_PREORDER. If the flag
is specified at attachment time, the prog has higher priority and the
ordering with that flag will be from top to bottom (pre-ordering).
For example, in the above example,
root cgroup: p1, p2
subcgroup: p3, p4
Let us say p2 and p4 are marked with BPF_F_PREORDER. The final
effective array ordering will be
p2 p4 p3 p1
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20250224230116.283071-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
The verifier currently does not permit global subprog calls when a lock
is held, preemption is disabled, or when IRQs are disabled. This is
because we don't know whether the global subprog calls sleepable
functions or not.
In case of locks, there's an additional reason: functions called by the
global subprog may hold additional locks etc. The verifier won't know
while verifying the global subprog whether it was called in context
where a spin lock is already held by the program.
Perform summarization of the sleepable nature of a global subprog just
like changes_pkt_data and then allow calls to global subprogs for
non-sleepable ones from atomic context.
While making this change, I noticed that RCU read sections had no
protection against sleepable global subprog calls, include it in the
checks and fix this while we're at it.
Care needs to be taken to not allow global subprog calls when regular
bpf_spin_lock is held. When resilient spin locks is held, we want to
potentially have this check relaxed, but not for now.
Also make sure extensions freplacing global functions cannot do so
in case the target is non-sleepable, but the extension is. The other
combination is ok.
Tests are included in the next patch to handle all special conditions.
Fixes: 9bb00b2895cb ("bpf: Add kfunc bpf_rcu_read_lock/unlock()")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250301151846.1552362-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Jiayuan Chen says:
====================
Optimize bpf selftest to increase CI success rate
1. Optimized some static bound port selftests to avoid port occupation
when running test_progs -j.
2. Optimized the retry logic for test_maps.
Some Failed CI:
https://github.com/kernel-patches/bpf/actions/runs/13275542359/job/37064974076
https://github.com/kernel-patches/bpf/actions/runs/13549227497/job/37868926343
https://github.com/kernel-patches/bpf/actions/runs/13548089029/job/37865812030
https://github.com/kernel-patches/bpf/actions/runs/13553536268/job/37883329296
(Perhaps it's due to the large number of pull requests requiring CI runs?)
====================
Link: https://patch.msgid.link/20250227142646.59711-1-jiayuan.chen@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
BPF CI has failed 3 times in the last 24 hours. Add retry for ENOMEM.
It's similar to the optimization plan:
commit 2f553b032cad ("selftsets/bpf: Retry map update for non-preallocated per-cpu map")
Failed CI:
https://github.com/kernel-patches/bpf/actions/runs/13549227497/job/37868926343
https://github.com/kernel-patches/bpf/actions/runs/13548089029/job/37865812030
https://github.com/kernel-patches/bpf/actions/runs/13553536268/job/37883329296
selftests/bpf: Fixes for test_maps test
Fork 100 tasks to 'test_update_delete'
Fork 100 tasks to 'test_update_delete'
Fork 100 tasks to 'test_update_delete'
Fork 100 tasks to 'test_update_delete'
......
test_task_storage_map_stress_lookup:PASS
test_maps: OK, 0 SKIPPED
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://lore.kernel.org/r/20250227142646.59711-4-jiayuan.chen@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
