[ilyas-mallah]

liburing-ffi.so doesn't export io_uring_buf_ring_head(), so a C program that links it gets an undefined reference and a binding gets NULL from dlsym(). Commit 9304009 named it in its title but only added io_uring_buf_ring_available to liburing-ffi.map.

I put it in LIBURING_2.16, the current development node. Listing it under LIBURING_2.6 would claim that released versions of liburing-ffi.so had it. liburing.so is unchanged and keeps it at LIBURING_2.6.

I linked a small program that calls it on a fresh ring against liburing-ffi.so.2.15, before and after the change:

before: undefined reference to `io_uring_buf_ring_head'
        dlsym(handle, "io_uring_buf_ring_head") -> (nil)
after:  nm -D: T io_uring_buf_ring_head@@LIBURING_2.16
        dlsym(handle, "io_uring_buf_ring_head") -> 0x7f6105028370
        io_uring_buf_ring_head() -> -22 (from the kernel, 5.15 has no IORING_REGISTER_PBUF_STATUS)

It was the only name in liburing.map missing from liburing-ffi.map, and this prints nothing after the change:

comm -23 <(grep -oP '^\s+\K\w+(?=;)' src/liburing.map | sort -u) <(grep -oP '^\s+\K\w+(?=;)' src/liburing-ffi.map | sort -u)

The tree builds with make -j4. I added no test, since nothing in test/ links against liburing-ffi.

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git request-pull output:

The following changes since commit f4fdfd910ad15e5477c68f2eec208581e3f2239e:

  test/waitid: test a non-blocking pidfd (2026-10-19 15:03:12 -0600)

are available in the Git repository at:

  https://github.com/ilyas-mallah/liburing ffi-map-buf-ring-head

for you to fetch changes up to acbe866a91a76737d343bae63de782e73234a537:

  src/liburing-ffi.map: add io_uring_buf_ring_head (2026-10-20 03:33:01 +0200)

----------------------------------------------------------------
Ilyas Mallah (1):
      src/liburing-ffi.map: add io_uring_buf_ring_head

 src/liburing-ffi.map | 1 +
 1 file changed, 1 insertion(+)

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Fixes: https://github.com/axboe/liburing/issues/402
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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