Add elixir bindings by BlazeWasHere · Pull Request #535 · ethereum/c-kzg-4844

BlazeWasHere · 2025-02-14T20:55:22Z

Adds elixir bindings through an Erlang NIF
Was using the python bindings as a reference FFI implementation, not sure if i am missing some things

also not sure if this even cross compiles (i hope :cc_precompiler works)

bindings/elixir/native/src/ckzg_wrap.c

jtraglia · 2025-02-14T21:16:58Z

Hey @BlazeWasHere, this is cool! I would be happy to include this when it's ready. Out of curiosity, what will use these bindings? And another TODO item would be to add CI tests, see: https://github.com/ethereum/c-kzg-4844/tree/main/.github/workflows

BlazeWasHere · 2025-02-14T21:47:44Z

@jtraglia no worries, one main user would be elixir_ethers via ExWeb3/elixir_ethers#178. also saw that lambdaclass used c-kzg-4844 in their elixir consensus client but used bindings from c -> rust -> elixir in kzg_nif (im assuming because there were no elixir bindings at the time)

jtraglia · 2025-02-14T22:16:12Z

Okay nice. So this does have real value. Feel free to ping me if you have any questions.

BlazeWasHere · 2025-02-25T17:16:57Z

ok im struggling to find the reason for the segfault in compute_blob_kzg_proof (TLDR: only segfaults for valid blobs and on -O2 flag)
putting my debug process and brain dump here

DEBUG=1 iex -S mix test test/ckzg_test.exs:84 -b --trace
# run in shell
> System.pid

# another shell
lldb attach-pid <pid>

# run tests
c

then if you step till segfault

(lldb) c
Process 95133 resuming
Process 95133 stopped
* thread #28, name = 'erts_dcpus_12', stop reason = signal SIGSEGV: invalid permissions for mapped object (fault address: 0x747326f93000)
    frame #0: 0x0000747326b9fb12 ckzg_nif.so`sub_mod_256 + 82
ckzg_nif.so`sub_mod_256:
->  0x747326b9fb12 <+82>: movq   %r9, 0x8(%rdi)
    0x747326b9fb16 <+86>: adcq   %rbp, %r11
    0x747326b9fb19 <+89>: movq   %r10, 0x10(%rdi)
    0x747326b9fb1d <+93>: movq   %r11, 0x18(%rdi)
(lldb) bt
* thread #28, name = 'erts_dcpus_12', stop reason = signal SIGSEGV: invalid permissions for mapped object (fault address: 0x747326f93000)
  * frame #0: 0x0000747326b9fb12 ckzg_nif.so`sub_mod_256 + 82
    frame #1: 0x0000747326b76b1f ckzg_nif.so`compute_kzg_proof_impl(proof_out=0x000074731d800790, y_out=0x0000747326fa4b70, polynomial=<unavailable>, z=0x0000747326fa4a80, s=0x000063cdde676c28) at eip4844.c:458:9
    frame #2: 0x0000747326b76fa0 ckzg_nif.so`compute_blob_kzg_proof(out=0x000074731d800790, blob=0x000074732666a370, commitment_bytes=<unavailable>, s=0x000063cdde676c28) at eip4844.c:535:11
    frame #3: 0x0000747326b74037 ckzg_nif.so`compute_blob_kzg_proof_nif(env=0x0000747326fe4ca0, argc=<unavailable>, argv=0x0000747333f70580) at ckzg_wrap.c:271:21
    frame #4: 0x000063cdaaa7cbe6 beam.smp`erts_call_dirty_nif(esdp=0x00007473316f5c80, c_p=0x000063cdde892988, I=0x000063cdde5e09f0, reg=0x0000747333f70580) at erl_nif.c:469:19
    frame #5: 0x000063cdaa8e6ee6 beam.smp`erts_dirty_process_main(esdp=0x00007473316f5c80) at beam_common.c:283:23
    frame #6: 0x000063cdaa80652b beam.smp`sched_dirty_cpu_thread_func(vesdp=0x00007473316f5c80) at erl_process.c:8743:5
    frame #7: 0x000063cdaab58f82 beam.smp`thr_wrapper(vtwd=0x000063cdaa806410) at ethread.c:116:26
    frame #8: 0x0000747374894ac3 libc.so.6`start_thread(arg=<unavailable>) at pthread_create.c:442:8
    frame #9: 0x0000747374926850 libc.so.6`__clone3 at clone3.S:81

and if you check where the location is (in eip4844.c)

(lldb) n
Process 95133 stopped
* thread #28, name = 'erts_dcpus_12', stop reason = step over
    frame #0: 0x0000747326b76b45 ckzg_nif.so`compute_kzg_proof_impl(proof_out=0x000074731d800790, y_out=0x0000747326fa4b70, polynomial=0x0000747326fc4bc8, z=0x0000747326fa4a80, s=0x000063cdde676c28) at eip4844.c:451:26
   448 	    if (ret != C_KZG_OK) goto out;
   449 	
   450 	    for (i = 0; i < FIELD_ELEMENTS_PER_BLOB; i++) {
-> 451 	        if (fr_equal(z, &brp_roots_of_unity[i])) {
   452 	            /* We are asked to compute a KZG proof inside the domain */
   453 	            m = i + 1;
   454 	            inverses_in[i] = FR_ONE;
(lldb)  
Process 95133 stopped
* thread #28, name = 'erts_dcpus_12', stop reason = step over
    frame #0: 0x0000747326b76b00 ckzg_nif.so`compute_kzg_proof_impl(proof_out=0x000074731d800790, y_out=0x0000747326fa4b70, polynomial=0x0000747326fc4bc8, z=0x0000747326fa4a80, s=0x000063cdde676c28) at eip4844.c:458:22
   455 	            continue;
   456 	        }
   457 	        // (p_i - y) / (ω_i - z)
-> 458 	        blst_fr_sub(&q.evals[i], &polynomial->evals[i], y_out);
   459 	        blst_fr_sub(&inverses_in[i], &brp_roots_of_unity[i], z);
   460 	    }
   461

and the variables passed to compute_kzg_proof_impl(out, &y, &polynomial, &evaluation_challenge_fr, s). note that it is compiled with -O2 -g because it only reproduces with -O2 flag.

Details

* thread #28, name = 'erts_dcpus_12', stop reason = breakpoint 4.1
    frame #0: 0x0000747326b76f92 ckzg_nif.so`compute_blob_kzg_proof(out=0x000074731d800790, blob=0x000074732666a370, commitment_bytes=<unavailable>, s=0x000063cdde676c28) at eip4844.c:535:11
   532 	    compute_challenge(&evaluation_challenge_fr, blob, &commitment_g1);
   533 	
   534 	    /* Call helper function to compute proof and y */
-> 535 	    ret = compute_kzg_proof_impl(out, &y, &polynomial, &evaluation_challenge_fr, s);
   536 	    if (ret != C_KZG_OK) goto out;
   537 	
   538 	out:
(lldb) fr variable 
(KZGProof *) out = 0x000074731d800790
(const Blob *) blob = 0x000074732666a370
(const Bytes48 *) commitment_bytes = <could not evaluate DW_OP_entry_value: no matching call site param found>

(const KZGSettings *) s = 0x000063cdde676c28
(Polynomial) polynomial = {
  evals = {
    [0] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [1] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [2] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [3] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [4] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [5] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [6] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [7] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [8] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [9] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [10] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [11] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [12] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [13] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [14] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [15] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [16] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [17] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [18] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [19] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [20] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [21] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [22] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [23] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [24] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [25] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [26] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [27] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [28] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [29] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [30] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [31] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [32] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [33] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [34] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [35] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [36] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [37] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [38] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [39] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [40] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [41] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [42] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [43] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [44] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [45] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [46] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [47] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [48] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [49] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [50] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [51] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [52] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [53] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [54] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [55] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [56] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [57] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [58] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [59] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [60] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [61] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [62] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [63] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [64] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [65] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [66] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [67] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [68] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [69] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [70] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [71] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [72] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [73] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [74] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [75] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [76] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [77] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [78] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [79] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [80] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [81] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [82] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [83] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [84] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [85] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [86] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [87] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [88] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [89] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [90] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [91] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [92] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [93] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [94] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [95] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [96] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [97] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [98] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [99] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [100] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [101] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [102] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [103] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [104] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [105] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [106] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [107] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [108] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [109] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [110] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [111] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [112] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [113] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [114] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [115] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [116] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [117] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [118] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [119] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [120] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [121] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [122] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [123] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [124] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [125] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [126] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [127] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [128] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [129] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [130] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [131] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [132] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [133] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [134] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [135] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [136] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [137] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [138] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [139] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [140] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [141] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [142] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [143] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [144] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [145] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [146] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [147] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [148] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [149] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [150] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [151] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [152] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [153] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [154] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [155] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [156] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [157] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [158] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [159] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [160] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [161] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [162] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [163] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [164] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [165] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [166] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [167] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [168] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [169] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [170] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [171] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [172] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [173] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [174] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [175] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [176] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [177] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [178] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [179] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [180] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [181] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [182] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [183] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [184] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [185] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [186] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [187] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [188] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [189] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [190] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [191] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [192] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [193] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [194] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [195] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [196] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [197] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [198] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [199] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [200] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [201] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [202] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [203] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [204] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [205] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [206] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [207] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [208] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [209] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [210] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [211] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [212] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [213] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [214] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [215] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [216] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [217] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [218] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [219] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [220] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [221] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [222] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [223] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [224] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [225] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [226] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [227] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [228] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [229] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [230] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [231] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [232] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [233] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [234] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [235] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [236] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [237] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [238] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [239] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [240] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [241] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [242] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [243] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [244] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [245] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [246] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [247] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [248] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [249] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [250] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [251] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [252] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [253] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [254] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    [255] = {
      l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0)
    }
    ...
  }
}
(g1_t) commitment_g1 = {
  x = {
    l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0, [4] = 0, [5] = 0)
  }
  y = {
    l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0, [4] = 0, [5] = 0)
  }
  z = {
    l = ([0] = 0, [1] = 0, [2] = 0, [3] = 0, [4] = 0, [5] = 0)
  }
}
(fr_t) evaluation_challenge_fr = {
  l = ([0] = 2654319690706462847, [1] = 17543739849117376762, [2] = 16339604651344585569, [3] = 6982868803808586812)
}
(fr_t) y = {
  l = ([0] = 4996253744963408710, [1] = 6859358674981636434, [2] = 0, [3] = 4503599627370496)
}
(C_KZG_RET) ret = <variable not available>

*** Some of the displayed variables have more members than the debugger will show by default. To show all of them, you can either use the --show-all-children option to frame variable or raise the limit by changing the target.max-children-count setting.

ok so it seems like the method is writing to read only data (writing to const region). but by definition
permalink

C_KZG_RET compute_blob_kzg_proof(
    KZGProof *out, const Blob *blob, const Bytes48 *commitment_bytes, const KZGSettings *s
);

the only mutable data is out and the rest are const.

in ckzg_wrap.c
permalink

    C_KZG_RET ret = compute_blob_kzg_proof(
        (KZGProof *)proof, (Blob *)blob.data, (Bytes48 *)commitment.data, settings
    );

blob.data commitment.data and settings are all read only because of how enif_inspect_* works.
and proof is mutable because of the call made here
permalink

    ERL_NIF_TERM proof_term;
    unsigned char *proof = enif_make_new_binary(env, BYTES_PER_PROOF, &proof_term);
    if (proof == NULL) return make_error(env, ckzg_atoms.out_of_memory);

so im very confused on how the segfault is happening. maybe data misalignment? @jtraglia @alisinabh

jtraglia · 2025-02-25T20:09:13Z

Hey @BlazeWasHere, I did some debugging myself and it appears that the issue is related to allocating the very large polynomials on the stack. I suspect we're surpassing the stack limit. I do not know how to raise this in Elixir though. We ran into several stack size issues when developing the Rust bindings too.

I've pushed a commit which will dynamically allocate this. With this, it no longer crashes for me. If it's possible to fix this in these bindings somehow, that would be preferred. If not, we look into keeping this core implementation change.

Also, I'm working on macOS & when I ran the tests it wanted a .so file instead of .dylib. So I made this change to the Makefile. Feel free to revert this if that's incorrect.

But overall, this is looking really great. Thanks for all of your work!

BlazeWasHere · 2025-02-25T21:24:58Z

@jtraglia thanks so much, i was going crazy thinking it was something on my end!
will try to see if i can increase stack limit for enif programs

Also, I'm working on macOS & when I ran the tests it wanted a .so file instead of .dylib. So I made this change to the Makefile. Feel free to revert this if that's incorrect.

will fix this soon, thanks for reporting

BlazeWasHere · 2025-02-26T00:27:45Z

We ran into several stack size issues when developing the Rust bindings too.

@jtraglia how was this solved? i dont see a stack size increase request

jtraglia · 2025-02-26T14:46:48Z

We ran into several stack size issues when developing the Rust bindings too.

@jtraglia how was this solved? i dont see a stack size increase request

Our solution there was to Box objects. So they were allocated on the heap instead of the stack. For example:

c-kzg-4844/bindings/rust/src/bindings/mod.rs

Lines 447 to 457 in 8f8a2e5

    
           pub fn compute_cells(&self, blob: &Blob) -> Result<Box<[Cell; CELLS_PER_EXT_BLOB]>, Error> { 
        
               let mut cells = [Cell::default(); CELLS_PER_EXT_BLOB]; 
        
               unsafe { 
        
                   let res = compute_cells_and_kzg_proofs(cells.as_mut_ptr(), ptr::null_mut(), blob, self); 
        
                   if let C_KZG_RET::C_KZG_OK = res { 
        
                       Ok(Box::new(cells)) 
        
                   } else { 
        
                       Err(Error::CError(res)) 
        
                   } 
        
               } 
        
           }

BlazeWasHere · 2025-02-27T21:00:14Z

Will revert fea1ea3 pending merge of #539

jtraglia

Seriously great work. I have provided some small comments, but I am happy with the current state of this. If you're willing to make some little changes, I'll wait to merge. Otherwise happy to merge whenever. I see no real problems.

bindings/elixir/lib/kzg.ex

bindings/elixir/native/src/ckzg_wrap.c

bindings/elixir/test/ckzg_test.exs

mix.exs

bindings/elixir/native/src/ckzg_wrap.c

BlazeWasHere · 2025-03-05T01:23:45Z

Seriously great work. I have provided some small comments, but I am happy with the current state of this. If you're willing to make some little changes, I'll wait to merge. Otherwise happy to merge whenever. I see no real problems.

thanks for the review, will address changes in the coming days and will add some speedups and better VM interactions in another PR

BlazeWasHere · 2025-03-05T23:31:04Z

@jtraglia should i add publishing via CI to hex.pm in this PR or another? i also do not mind being a maintainer of the elixir bindings

jtraglia · 2025-03-06T06:26:43Z

@jtraglia should i add publishing via CI to hex.pm in this PR or another? i also do not mind being a maintainer of the elixir bindings

Up to you. But I think a subsequent PR would be better. And thank you! That would help a lot.

BlazeWasHere added 2 commits February 14, 2025 20:44

Add elixir bindings

f3c8df1

Merge branch 'main' of https://github.com/ethereum/c-kzg-4844

d08a7fa

BlazeWasHere commented Feb 14, 2025

View reviewed changes

bindings/elixir/native/src/ckzg_wrap.c Outdated Show resolved Hide resolved

BlazeWasHere added 6 commits February 16, 2025 21:33

use heap alloc if possible

a610f7d

update ci + global makefile

02a9a9b

add elixir project to root

bd47c8f

Merge branch 'main' into main

8b28ca7

add compute_cells/2

89acd0b

fmt

d46e8ed

Dynamically allocate polynomial

fea1ea3

BlazeWasHere added 2 commits February 27, 2025 14:10

fix verify_cell_kzg_proof_batch

913d4f0

load_trusted_setup: accept "normal" strings

b8cec3d

BlazeWasHere marked this pull request as ready for review February 27, 2025 20:59

jtraglia and others added 8 commits February 28, 2025 15:51

Put elixir in alphabetical order

2ac0197

Merge branch 'main' into main

da6548e

Fix two incompatible-pointer-types warnings

ac234b7

Test on different OSes

dce0b54

Remove macOS from list

57a7df9

Try install CL for windows

4be0909

Okay just test on ubuntu

25a1b72

For macOS, remove deprecated compiler option

457c305

BlazeWasHere and others added 4 commits February 28, 2025 22:51

fix int type

a79663a

partial revert "Dynamically allocate polynomial" fea1ea3

948b136

Merge branch 'main' into main

b1c42a2

Use correct makefile when building blst

6ae3cd8

jtraglia approved these changes Mar 4, 2025

View reviewed changes

cleanup code

05cbdf8

jtraglia merged commit d800f8f into ethereum:main Mar 10, 2025
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