On 09/14/2021 05:18 PM, Johan Almbladh wrote:
This patch fixes an error in the tail call limit test that caused the test to fail on for x86-64 JIT. Previously, the register R0 was used to report the total number of tail calls made. However, after a tail call fall-through, the value of the R0 register is undefined. Now, all tail call error path tests instead use context state to store the count. Fixes: 874be05f525e ("bpf, tests: Add tail call test suite") Reported-by: Paul Chaignon <paul@xxxxxxxxx> Reported-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx> Signed-off-by: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx> --- lib/test_bpf.c | 37 +++++++++++++++++++++++++++---------- 1 file changed, 27 insertions(+), 10 deletions(-) diff --git a/lib/test_bpf.c b/lib/test_bpf.c index 7475abfd2186..ddb9a8089d2e 100644 --- a/lib/test_bpf.c +++ b/lib/test_bpf.c @@ -12179,10 +12179,15 @@ static __init int test_bpf(void) struct tail_call_test { const char *descr; struct bpf_insn insns[MAX_INSNS]; + int flags; int result; int stack_depth; };+/* Flags that can be passed to tail call test cases */+#define FLAG_NEED_STATE BIT(0) +#define FLAG_RESULT_IN_STATE BIT(1) + /* * Magic marker used in test snippets for tail calls below. * BPF_LD/MOV to R2 and R2 with this immediate value is replaced @@ -12252,32 +12257,38 @@ static struct tail_call_test tail_call_tests[] = { { "Tail call error path, max count reached", .insns = { - BPF_ALU64_IMM(BPF_ADD, R1, 1), - BPF_ALU64_REG(BPF_MOV, R0, R1), + BPF_LDX_MEM(BPF_W, R2, R1, 0), + BPF_ALU64_IMM(BPF_ADD, R2, 1), + BPF_STX_MEM(BPF_W, R1, R2, 0), TAIL_CALL(0), BPF_EXIT_INSN(), }, - .result = MAX_TAIL_CALL_CNT + 1, + .flags = FLAG_NEED_STATE | FLAG_RESULT_IN_STATE, + .result = (MAX_TAIL_CALL_CNT + 1 + 1) * MAX_TESTRUNS,
Hi Johan, I have tested this patch, It should be "MAX_TAIL_CALL_CNT + 1" instead of "MAX_TAIL_CALL_CNT + 1 + 1"? [...] Thanks, Tiezhu
