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caf62492f4
Remove invalid assumption in libbpf that .bss map doesn't have to be updated
in kernel. With addition of skeleton and memory-mapped initialization image,
.bss doesn't have to be all zeroes when BPF map is created, because user-code
might have initialized those variables from user-space.
Fixes: eba9c5f498 ("libbpf: Refactor global data map initialization")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200612194504.557844-1-andriin@fb.com
================== BPF Selftest Notes ================== General instructions on running selftests can be found in `Documentation/bpf/bpf_devel_QA.rst`_. Additional information about selftest failures are documented here. bpf_iter test failures with clang/llvm 10.0.0 ============================================= With clang/llvm 10.0.0, the following two bpf_iter tests failed: * ``bpf_iter/ipv6_route`` * ``bpf_iter/netlink`` The symptom for ``bpf_iter/ipv6_route`` looks like .. code-block:: c 2: (79) r8 = *(u64 *)(r1 +8) ... 14: (bf) r2 = r8 15: (0f) r2 += r1 ; BPF_SEQ_PRINTF(seq, "%pi6 %02x ", &rt->fib6_dst.addr, rt->fib6_dst.plen); 16: (7b) *(u64 *)(r8 +64) = r2 only read is supported The symptom for ``bpf_iter/netlink`` looks like .. code-block:: c ; struct netlink_sock *nlk = ctx->sk; 2: (79) r7 = *(u64 *)(r1 +8) ... 15: (bf) r2 = r7 16: (0f) r2 += r1 ; BPF_SEQ_PRINTF(seq, "%pK %-3d ", s, s->sk_protocol); 17: (7b) *(u64 *)(r7 +0) = r2 only read is supported This is due to a llvm BPF backend bug. The fix https://reviews.llvm.org/D78466 has been pushed to llvm 10.x release branch and will be available in 10.0.1. The fix is available in llvm 11.0.0 trunk.