From 2d005827b874f27535cda72c80b6558d9d4cd30c Mon Sep 17 00:00:00 2001 From: Andrew Kelley Date: Mon, 9 Sep 2024 21:16:06 -0700 Subject: [PATCH] make lowest stack an internal libfuzzer detail This value is useful to help determine run uniqueness in the face of recursion, however it is not valuable to expose to the fuzzing UI. --- lib/fuzzer.zig | 6 +++--- lib/fuzzer/web/index.html | 1 - lib/fuzzer/web/main.js | 2 -- lib/fuzzer/web/main.zig | 7 ------- lib/std/Build/Fuzz/WebServer.zig | 2 -- lib/std/Build/Fuzz/abi.zig | 2 -- 6 files changed, 3 insertions(+), 17 deletions(-) diff --git a/lib/fuzzer.zig b/lib/fuzzer.zig index 6cc8f9cc2879ebff3cee22811bd7f055231ba542..3f8a99114876a97fc37e13c73bfff486f3f64b2e 100644 --- a/lib/fuzzer.zig +++ b/lib/fuzzer.zig @@ -28,7 +28,8 @@ fn logOverride( f.writer().print(prefix1 ++ prefix2 ++ format ++ "\n", args) catch @panic("failed to write to fuzzer log"); } -export threadlocal var __sancov_lowest_stack: usize = std.math.maxInt(usize); +/// Helps determine run uniqueness in the face of recursion. +export threadlocal var __sancov_lowest_stack: usize = 0; export fn __sanitizer_cov_trace_const_cmp1(arg1: u8, arg2: u8) void { handleCmp(@returnAddress(), arg1, arg2); @@ -220,7 +221,6 @@ const Fuzzer = struct { .n_runs = 0, .unique_runs = 0, .pcs_len = pcs.len, - .lowest_stack = std.math.maxInt(usize), }; f.seen_pcs.appendSliceAssumeCapacity(std.mem.asBytes(&header)); f.seen_pcs.appendNTimesAssumeCapacity(0, n_bitset_elems * @sizeOf(usize)); @@ -261,8 +261,8 @@ const Fuzzer = struct { f.input.appendSliceAssumeCapacity(run.input); try f.mutate(); - _ = @atomicRmw(usize, &header.lowest_stack, .Min, __sancov_lowest_stack, .monotonic); @memset(f.pc_counters, 0); + __sancov_lowest_stack = std.math.maxInt(usize); f.coverage.reset(); fuzzer_one(f.input.items.ptr, f.input.items.len); diff --git a/lib/fuzzer/web/index.html b/lib/fuzzer/web/index.html index 16fa8799137715ab9f3ea1830e4b5005185697d1..0addd9f88288fdcf1adca2769f24012004c388ed 100644 --- a/lib/fuzzer/web/index.html +++ b/lib/fuzzer/web/index.html @@ -147,7 +147,6 @@
  • Total Runs:
  • Unique Runs:
  • Coverage:
    • -
  • Lowest Stack:
  • Entry Points:
    • diff --git a/lib/fuzzer/web/main.js b/lib/fuzzer/web/main.js index ce02276f981936b5863bff76bd694abd1b50478a..9ee6b445e287401877c232ce1915048be7158bf7 100644 --- a/lib/fuzzer/web/main.js +++ b/lib/fuzzer/web/main.js @@ -6,7 +6,6 @@ const domStatTotalRuns = document.getElementById("statTotalRuns"); const domStatUniqueRuns = document.getElementById("statUniqueRuns"); const domStatCoverage = document.getElementById("statCoverage"); - const domStatLowestStack = document.getElementById("statLowestStack"); const domEntryPointsList = document.getElementById("entryPointsList"); let wasm_promise = fetch("main.wasm"); @@ -158,7 +157,6 @@ domStatTotalRuns.innerText = totalRuns; domStatUniqueRuns.innerText = uniqueRuns + " (" + percent(uniqueRuns, totalRuns) + "%)"; domStatCoverage.innerText = coveredSourceLocations + " / " + totalSourceLocations + " (" + percent(coveredSourceLocations, totalSourceLocations) + "%)"; - domStatLowestStack.innerText = unwrapString(wasm_exports.lowestStack()); const entryPoints = unwrapInt32Array(wasm_exports.entryPoints()); resizeDomList(domEntryPointsList, entryPoints.length, "
  • "); diff --git a/lib/fuzzer/web/main.zig b/lib/fuzzer/web/main.zig index 342adc3b56083f42f6ebf2aee10172b8943f3556..94ea8cc92f2a8569abd55d6fe9974b35e0cc7e48 100644 --- a/lib/fuzzer/web/main.zig +++ b/lib/fuzzer/web/main.zig @@ -106,13 +106,6 @@ export fn decl_source_html(decl_index: Decl.Index) String { return String.init(string_result.items); } -export fn lowestStack() String { - const header: *abi.CoverageUpdateHeader = @ptrCast(recent_coverage_update.items[0..@sizeOf(abi.CoverageUpdateHeader)]); - string_result.clearRetainingCapacity(); - string_result.writer(gpa).print("0x{d}", .{header.lowest_stack}) catch @panic("OOM"); - return String.init(string_result.items); -} - export fn totalSourceLocations() usize { return coverage_source_locations.items.len; } diff --git a/lib/std/Build/Fuzz/WebServer.zig b/lib/std/Build/Fuzz/WebServer.zig index b5ad86af15fd5a9f45c9e934818f830228e7b09c..391f67e8231c6281b4fd23c23d16c165f79552e8 100644 --- a/lib/std/Build/Fuzz/WebServer.zig +++ b/lib/std/Build/Fuzz/WebServer.zig @@ -406,7 +406,6 @@ fn sendCoverageContext( const seen_pcs = cov_header.seenBits(); const n_runs = @atomicLoad(usize, &cov_header.n_runs, .monotonic); const unique_runs = @atomicLoad(usize, &cov_header.unique_runs, .monotonic); - const lowest_stack = @atomicLoad(usize, &cov_header.lowest_stack, .monotonic); if (prev_unique_runs.* != unique_runs) { // There has been an update. if (prev_unique_runs.* == 0) { @@ -431,7 +430,6 @@ fn sendCoverageContext( const header: abi.CoverageUpdateHeader = .{ .n_runs = n_runs, .unique_runs = unique_runs, - .lowest_stack = lowest_stack, }; const iovecs: [2]std.posix.iovec_const = .{ makeIov(std.mem.asBytes(&header)), diff --git a/lib/std/Build/Fuzz/abi.zig b/lib/std/Build/Fuzz/abi.zig index 0e16f0d5fa3f123ba9e5b4973055aeb64e72a8cd..c3f32d309b6971173d19587a952f5a0b4a5c939e 100644 --- a/lib/std/Build/Fuzz/abi.zig +++ b/lib/std/Build/Fuzz/abi.zig @@ -13,7 +13,6 @@ pub const SeenPcsHeader = extern struct { n_runs: usize, unique_runs: usize, pcs_len: usize, - lowest_stack: usize, /// Used for comptime assertions. Provides a mechanism for strategically /// causing compile errors. @@ -79,7 +78,6 @@ pub const CoverageUpdateHeader = extern struct { flags: Flags = .{}, n_runs: u64, unique_runs: u64, - lowest_stack: u64, pub const Flags = packed struct(u64) { tag: ToClientTag = .coverage_update, -- 2.54.0