Blame SOURCES/bcc-0.25.0-Fix-bpf_pseudo_fd-type-conversion-error.patch

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From c17a12ac030c5d9c812e611f8132570af0e795af Mon Sep 17 00:00:00 2001
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From: Yonghong Song <yhs@fb.com>
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Date: Sat, 13 Aug 2022 17:50:07 -0700
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Subject: [PATCH 1/2] Fix bpf_pseudo_fd() type conversion error
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With llvm15 and llvm16, the following command line
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  sudo ./trace.py 'smp_call_function_single "%K", arg1'
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will cause error:
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  /virtual/main.c:60:36: error: incompatible integer to pointer conversion passing 'u64'
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    (aka 'unsigned long long') to parameter of type 'void *' [-Wint-conversion]
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        bpf_perf_event_output(ctx, bpf_pseudo_fd(1, -1), CUR_CPU_IDENTIFIER, &__data, sizeof(__data));
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                                   ^~~~~~~~~~~~~~~~~~~~
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  1 error generated.
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  Failed to compile BPF module <text>
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In helpers.h, we have
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  u64 bpf_pseudo_fd(u64, u64) asm("llvm.bpf.pseudo");
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Apparently, <= llvm14 can tolerate u64 -> 'void *' conversion, but
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llvm15 by default will cause an error.
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Let us explicitly convert bpf_pseudo_fd to 'void *' to avoid
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such errors.
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Signed-off-by: Yonghong Song <yhs@fb.com>
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---
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 src/cc/frontends/clang/b_frontend_action.cc | 10 +++++-----
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 1 file changed, 5 insertions(+), 5 deletions(-)
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diff --git a/src/cc/frontends/clang/b_frontend_action.cc b/src/cc/frontends/clang/b_frontend_action.cc
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index a4e05b16..dbeba3e4 100644
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--- a/src/cc/frontends/clang/b_frontend_action.cc
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+++ b/src/cc/frontends/clang/b_frontend_action.cc
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@@ -957,7 +957,7 @@ bool BTypeVisitor::VisitCallExpr(CallExpr *Call) {
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           string arg0 = rewriter_.getRewrittenText(expansionRange(Call->getArg(0)->getSourceRange()));
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           string args_other = rewriter_.getRewrittenText(expansionRange(SourceRange(GET_BEGINLOC(Call->getArg(1)),
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                                                            GET_ENDLOC(Call->getArg(2)))));
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-          txt = "bpf_perf_event_output(" + arg0 + ", bpf_pseudo_fd(1, " + fd + ")";
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+          txt = "bpf_perf_event_output(" + arg0 + ", (void *)bpf_pseudo_fd(1, " + fd + ")";
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           txt += ", CUR_CPU_IDENTIFIER, " + args_other + ")";
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           // e.g.
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@@ -986,7 +986,7 @@ bool BTypeVisitor::VisitCallExpr(CallExpr *Call) {
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           string meta_len = rewriter_.getRewrittenText(expansionRange(Call->getArg(3)->getSourceRange()));
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           txt = "bpf_perf_event_output(" +
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             skb + ", " +
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-            "bpf_pseudo_fd(1, " + fd + "), " +
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+            "(void *)bpf_pseudo_fd(1, " + fd + "), " +
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             "((__u64)" + skb_len + " << 32) | BPF_F_CURRENT_CPU, " +
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             meta + ", " +
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             meta_len + ");";
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@@ -1006,12 +1006,12 @@ bool BTypeVisitor::VisitCallExpr(CallExpr *Call) {
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           string keyp = rewriter_.getRewrittenText(expansionRange(Call->getArg(1)->getSourceRange()));
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           string flag = rewriter_.getRewrittenText(expansionRange(Call->getArg(2)->getSourceRange()));
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           txt = "bpf_" + string(memb_name) + "(" + ctx + ", " +
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-            "bpf_pseudo_fd(1, " + fd + "), " + keyp + ", " + flag + ");";
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+            "(void *)bpf_pseudo_fd(1, " + fd + "), " + keyp + ", " + flag + ");";
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         } else if (memb_name == "ringbuf_output") {
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           string name = string(Ref->getDecl()->getName());
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           string args = rewriter_.getRewrittenText(expansionRange(SourceRange(GET_BEGINLOC(Call->getArg(0)),
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                                                            GET_ENDLOC(Call->getArg(2)))));
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-          txt = "bpf_ringbuf_output(bpf_pseudo_fd(1, " + fd + ")";
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+          txt = "bpf_ringbuf_output((void *)bpf_pseudo_fd(1, " + fd + ")";
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           txt += ", " + args + ")";
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           // e.g.
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@@ -1033,7 +1033,7 @@ bool BTypeVisitor::VisitCallExpr(CallExpr *Call) {
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         } else if (memb_name == "ringbuf_reserve") {
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           string name = string(Ref->getDecl()->getName());
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           string arg0 = rewriter_.getRewrittenText(expansionRange(Call->getArg(0)->getSourceRange()));
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-          txt = "bpf_ringbuf_reserve(bpf_pseudo_fd(1, " + fd + ")";
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+          txt = "bpf_ringbuf_reserve((void *)bpf_pseudo_fd(1, " + fd + ")";
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           txt += ", " + arg0 + ", 0)"; // Flags in reserve are meaningless
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         } else if (memb_name == "ringbuf_discard") {
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           string name = string(Ref->getDecl()->getName());
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-- 
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2.38.1
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