[ Cc MIPS folks ] Hassan, James, Paul, others, please take a look. Thanks! -------- Forwarded Message -------- Subject: [Bug 205459] New: mips: bpf: test_bpf failures, eBPF JIT on mips32 outputs invalid 64-bit insns Date: Thu, 07 Nov 2019 06:41:21 +0000 From: bugzilla-daemon@xxxxxxxxxxxxxxxxxxx To: daniel@xxxxxxxxxxxxx https://bugzilla.kernel.org/show_bug.cgi?id=205459 Bug ID: 205459 Summary: mips: bpf: test_bpf failures, eBPF JIT on mips32 outputs invalid 64-bit insns Product: Networking Version: 2.5 Kernel Version: 5.2.17 Hardware: Mips32 OS: Linux Tree: Mainline Status: NEW Severity: high Priority: P1 Component: Other Assignee: stephen@xxxxxxxxxxxxxxxxxx Reporter: itugrok@xxxxxxxxx Regression: No Created attachment 285809 --> https://bugzilla.kernel.org/attachment.cgi?id=285809&action=edit EXCEPTION/failures: kernel 5.2.17/mips32 (Debian 10.1) Summary: ======== Linux 5.2.x added an eBPF JIT for MIPS32 (yay!). Based on discussion of the original submission (https://www.spinics.net/lists/mips/msg77008.html) I expected that: (1) all tests from module test_bpf.ko would pass, and (2) any previously JITed tests (i.e. cBPF) would still be JITed. However, I can't reproduce the above based on my testing as per the attached log. Point (2) doesn't stand since the first ~30 tests are not JITed, but were previously cBPF JITed for the most part. As for point (1), the full test set doesn't complete, but errors out early on with a "Reserved instruction in kernel code[#1]" error. Manually hopping through some of the tests yields the same error for many: #68 ALU_MOV_K: 0x0000ffffffff0000 = 0x00000000ffffffff jited:1 #73 ALU_ADD_X: 1 + 2 = 3 jited:1 #74 ALU_ADD_X: 1 + 4294967294 = 4294967295 jited:1 #75 ALU_ADD_X: 2 + 4294967294 = 0 jited:1 #79 ALU_ADD_K: 1 + 2 = 3 jited:1 (.. and so on ...) Disassembling the JITed code for test #68 shows incorrect MIPS64 instructions: 24 03 00 20 li v1,32 34 05 ff ff li a1,0xffff 00 05 2c 38 dsll a1,a1,0x10 <=== MIPS64 insn 34 a5 ff ff ori a1,a1,0xffff 00 05 2c 38 dsll a1,a1,0x10 <=== MIPS64 insn 34 06 ff ff li a2,0xffff 00 06 34 38 dsll a2,a2,0x10 <=== MIPS64 insn 34 c6 ff ff ori a2,a2,0xffff Since this was tested in the past, I'm really hoping there's a simple solution to these problems, or else a case of "operator error". A review by someone more knowledgeable with the MIPS32 eBPF JIT would be appreciated. Steps to Reproduce: =================== # sysctl net.core.bpf_jit_enable=1 # modprobe test_bpf <Kernel log with "Reserved instruction" exception> Affected Systems Tested: ======================== Debian 10.1 on QEMU/malta(mips32_be) [distro kernel 5.2.17-1~bpo10+1 (2019-09-30)] Kernel Logs: ============ Boot log with test results up to first failure is attached. -- You are receiving this mail because: You are watching the assignee of the bug.
