2 Commits

Author	SHA1	Message	Date
Alexei Starovoitov	e688c3db7c	bpf: Fix register equivalence tracking. ... The 64-bit JEQ/JNE handling in reg_set_min_max() was clearing reg->id in either true or false branch. In the case 'if (reg->id)' check was done on the other branch the counter part register would have reg->id == 0 when called into find_equal_scalars(). In such case the helper would incorrectly identify other registers with id == 0 as equivalent and propagate the state incorrectly. Fix it by preserving ID across reg_set_min_max(). In other words any kind of comparison operator on the scalar register should preserve its ID to recognize: r1 = r2 if (r1 == 20) { #1 here both r1 and r2 == 20 } else if (r2 < 20) { #2 here both r1 and r2 < 20 } The patch is addressing #1 case. The #2 was working correctly already. Fixes: 75748837b7e5 ("bpf: Propagate scalar ranges through register assignments.") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Tested-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20201014175608.1416-1-alexei.starovoitov@gmail.com	2020-10-15 16:05:31 +02:00
Alexei Starovoitov	54fada41e8	selftests/bpf: Asm tests for the verifier regalloc tracking. ... Add asm tests for register allocator tracking logic. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20201009011240.48506-5-alexei.starovoitov@gmail.com	2020-10-09 22:03:06 +02:00