The stack allocator introduced in #948 fails to build

[anh0516]

INFO: autodetecting backend as ninja
INFO: calculating backend command to run: /usr/bin/ninja -C /home/avraham/Documents/scx/build
ninja: Entering directory `/home/avraham/Documents/scx/build'
[1/40] Generating libbpf with a custom command

[5/40] Generating bpftool_target with a custom command

[16/40] Generating 'scheds/c/scx_sdt.p/scx_sdt.bpf.o'
FAILED: scheds/c/scx_sdt.p/scx_sdt.bpf.o 
/usr/lib/llvm/19/bin/clang -g -O2 -Wall -Wno-compare-distinct-pointer-types -D__TARGET_ARCH_x86 -mcpu=v3 -mlittle-endian '-idirafter /usr/lib/llvm/19/bin/../../../../lib/clang/19/include' '-idirafter /usr/include' -target bpf -I /home/avraham/Documents/scx/scheds/include -I /home/avraham/Documents/scx/scheds/include/arch/x86 -I /home/avraham/Documents/scx/scheds/include/bpf-compat -c ../scheds/c/scx_sdt.bpf.c -o scheds/c/scx_sdt.p/scx_sdt.bpf.o
In file included from ../scheds/c/scx_sdt.bpf.c:3:
In file included from /home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:9:
/home/avraham/Documents/scx/scheds/include/scx/sdt_task.h:51:19: error: field may not be qualified with an address space
   51 |         __u64                           __arena payload[];
      |                                                 ^
In file included from ../scheds/c/scx_sdt.bpf.c:3:
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:236:35: error: passing 'struct sdt_task_pool *' to parameter of type '__arena struct sdt_task_pool *' changes address space of pointer
  236 |         chunk = sdt_task_alloc_from_pool(&sdt_task_chunk_pool, stack);
      |                                          ^~~~~~~~~~~~~~~~~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:204:70: note: passing argument to parameter 'pool' here
  204 | void __arena *sdt_task_alloc_from_pool(struct sdt_task_pool __arena *pool,
      |                                                                      ^
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:237:34: error: passing 'struct sdt_task_pool *' to parameter of type '__arena struct sdt_task_pool *' changes address space of pointer
  237 |         desc = sdt_task_alloc_from_pool(&sdt_task_desc_pool, stack);
      |                                         ^~~~~~~~~~~~~~~~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:204:70: note: passing argument to parameter 'pool' here
  204 | void __arena *sdt_task_alloc_from_pool(struct sdt_task_pool __arena *pool,
      |                                                                      ^
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:279:26: error: passing 'struct sdt_task_pool *' to parameter of type '__arena struct sdt_task_pool *' changes address space of pointer
  279 |         ret = sdt_pool_set_size(&sdt_task_chunk_pool, sizeof(struct sdt_task_chunk));
      |                                 ^~~~~~~~~~~~~~~~~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:251:78: note: passing argument to parameter 'pool' here
  251 | static SDT_TASK_FN_ATTRS int sdt_pool_set_size(struct sdt_task_pool __arena *pool, __u64 data_size)
      |                                                                              ^
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:283:26: error: passing 'struct sdt_task_pool *' to parameter of type '__arena struct sdt_task_pool *' changes address space of pointer
  283 |         ret = sdt_pool_set_size(&sdt_task_desc_pool, sizeof(struct sdt_task_desc));
      |                                 ^~~~~~~~~~~~~~~~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:251:78: note: passing argument to parameter 'pool' here
  251 | static SDT_TASK_FN_ATTRS int sdt_pool_set_size(struct sdt_task_pool __arena *pool, __u64 data_size)
      |                                                                              ^
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:291:26: error: passing 'struct sdt_task_pool *' to parameter of type '__arena struct sdt_task_pool *' changes address space of pointer
  291 |         ret = sdt_pool_set_size(&sdt_task_data_pool, data_size);
      |                                 ^~~~~~~~~~~~~~~~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:251:78: note: passing argument to parameter 'pool' here
  251 | static SDT_TASK_FN_ATTRS int sdt_pool_set_size(struct sdt_task_pool __arena *pool, __u64 data_size)
      |                                                                              ^
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:375:8: error: assigning '__arena struct sdt_task_desc *' (aka 'struct sdt_task_desc *__attribute__((address_space(1)))') to '__arena struct sdt_task_desc *' (aka '__attribute__((address_space(1))) struct sdt_task_desc *') changes address space of pointer
  375 |                 desc = desc_children[pos];
      |                      ^ ~~~~~~~~~~~~~~~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:514:8: error: assigning '__arena struct sdt_task_desc *' (aka 'struct sdt_task_desc *__attribute__((address_space(1)))') to '__arena struct sdt_task_desc *' (aka '__attribute__((address_space(1))) struct sdt_task_desc *') changes address space of pointer
  514 |                 desc = desc_children[pos];
      |                      ^ ~~~~~~~~~~~~~~~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:516:27: error: passing 'struct sdt_alloc_stack *' to parameter of type '__arena struct sdt_alloc_stack *' changes address space of pointer
  516 |                         desc = sdt_alloc_chunk(stack);
      |                                                ^~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:230:79: note: passing argument to parameter 'stack' here
  230 | struct sdt_task_desc __arena *sdt_alloc_chunk(struct sdt_alloc_stack __arena *stack)
      |                                                                               ^
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:517:23: error: assigning '__arena struct sdt_task_desc *' (aka '__attribute__((address_space(1))) struct sdt_task_desc *') to '__arena struct sdt_task_desc *' (aka 'struct sdt_task_desc *__attribute__((address_space(1)))') changes address space of pointer
  517 |                         desc_children[pos] = desc;
      |                                            ^ ~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:536:9: error: assigning '__arena struct sdt_task_desc *' (aka '__attribute__((address_space(1))) struct sdt_task_desc *') to '__arena struct sdt_task_desc *' (aka 'struct sdt_task_desc *__attribute__((address_space(1)))') changes address space of pointer
  536 |         *descp = desc;
      |                ^ ~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:564:48: error: passing '__arena struct sdt_alloc_stack *' to parameter of type 'struct sdt_alloc_stack *' changes address space of pointer
  564 |         ret = sdt_task_find_empty(sdt_task_desc_root, stack, &desc, &idx);
      |                                                       ^~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:471:26: note: passing argument to parameter 'stack' here
  471 |         struct sdt_alloc_stack *stack,
      |                                 ^
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:579:35: error: passing 'struct sdt_task_pool *' to parameter of type '__arena struct sdt_task_pool *' changes address space of pointer
  579 |                 data = sdt_task_alloc_from_pool(&sdt_task_data_pool, stack);
      |                                                 ^~~~~~~~~~~~~~~~~~~
/home/avraham/Documents/scx/scheds/include/scx/sdt_task_impl.bpf.h:204:70: note: passing argument to parameter 'pool' here
  204 | void __arena *sdt_task_alloc_from_pool(struct sdt_task_pool __arena *pool,
      |                                                                      ^
13 errors generated.
[24/40] Generating rust_all with a custom command (wrapped by meson to set env)
ninja: build stopped: subcommand failed.

I'm running Linux 6.12.2 and LLVM/Clang 19.1.5 on Gentoo; this is with up-to-date main branch.

[etsal]

@anh0516 Thank you for opening the issue. These errors happen because LLVM 19 is stricter in its use of the __arena primitive than LLVM 18. I will be uploading a fix today or tomorrow, do you mind applying and testing to make sure it works?

[anh0516]

Of course, thanks.

[etsal]

Could you try and see if #1061 works for you?

[anh0516]

It works. Thanks.