diff --git a/.buildkite/misc/doctest.yml b/.buildkite/misc/doctest.yml
new file mode 100644
index 00000000000000..bff10aa69ff203
--- /dev/null
+++ b/.buildkite/misc/doctest.yml
@@ -0,0 +1,39 @@
+# These steps should only run on `sandbox.jl` machines, not `docker`-isolated ones
+# since we need nestable sandboxing.  The rootfs images being used here are built from
+# the `.buildkite/rootfs_images/llvm-passes.jl` file.
+agents:
+  queue: "julia"
+  # Only run on `sandbox.jl` machines (not `docker`-isolated ones) since we need nestable sandboxing
+  sandbox.jl: "true"
+  os: "linux"
+
+steps:
+  - label: "doctest"
+    key: doctest
+    plugins:
+      - JuliaCI/julia#v1:
+          version: 1.6
+      - staticfloat/sandbox#v1:
+          rootfs_url: https://github.com/JuliaCI/rootfs-images/releases/download/v1.1/llvm-passes.tar.gz
+          rootfs_treehash: "e2ac426534f821efc0194a0cc8d79340c2c5ae23"
+          uid: 1000
+          gid: 1000
+          workspaces:
+            # Include `/cache/repos` so that our `git` version introspection works.
+            - "/cache/repos:/cache/repos"
+    commands: |
+      echo "--- Build Julia from source"
+      make -j 6
+
+      echo "--- Print Julia version info"
+      ./julia -e 'using InteractiveUtils; InteractiveUtils.versioninfo()'
+
+      echo "--- Build Julia docs"
+      make docs
+
+      echo "--- Run Julia doctests"
+      JULIA_NUM_THREADS=1 make -C doc doctest=true
+    timeout_in_minutes: 120
+    notify:
+      - github_commit_status:
+          context: "doctest"
diff --git a/.buildkite/embedding.yml b/.buildkite/misc/embedding.yml
similarity index 100%
rename from .buildkite/embedding.yml
rename to .buildkite/misc/embedding.yml
diff --git a/.buildkite/llvm_passes.yml b/.buildkite/misc/llvmpasses.yml
similarity index 100%
rename from .buildkite/llvm_passes.yml
rename to .buildkite/misc/llvmpasses.yml
diff --git a/.buildkite/whitespace.yml b/.buildkite/misc/whitespace.yml
similarity index 100%
rename from .buildkite/whitespace.yml
rename to .buildkite/misc/whitespace.yml
diff --git a/.buildkite/pipeline.yml b/.buildkite/pipeline.yml
index 097b8976eea702..e3755ecd5131c9 100644
--- a/.buildkite/pipeline.yml
+++ b/.buildkite/pipeline.yml
@@ -14,10 +14,16 @@
 steps:
   - label: ":buildkite: Launch unsigned pipelines"
     commands: |
-      # We launch whitespace first, because we want that pipeline to finish as quickly as possible.
-      # The remaining unsigned pipelines are launched in alphabetical order.
+      # First, we launch whitespace, because we want that pipeline to finish as quickly as possible.
       buildkite-agent pipeline upload .buildkite/whitespace.yml
-      buildkite-agent pipeline upload .buildkite/embedding.yml
-      buildkite-agent pipeline upload .buildkite/llvm_passes.yml
+
+      # Next, we launch the miscellaneous pipelines in alphabetical order.
+      buildkite-agent pipeline upload .buildkite/misc/doctest.yml
+      buildkite-agent pipeline upload .buildkite/misc/embedding.yml
+      buildkite-agent pipeline upload .buildkite/misc/llvm_passes.yml
+      buildkite-agent pipeline upload .buildkite/misc/sanitizers.yml
+
+      # Finally, we launch the platform pipelines in alphabetical order.
+      buildkite-agent pipeline upload .buildkite/platforms/linux64.yml
     agents:
       queue: julia
diff --git a/.buildkite/platforms/linux64.yml b/.buildkite/platforms/linux64.yml
new file mode 100644
index 00000000000000..ac7f21592c7470
--- /dev/null
+++ b/.buildkite/platforms/linux64.yml
@@ -0,0 +1,106 @@
+# These steps should only run on `sandbox.jl` machines, not `docker`-isolated ones
+# since we need nestable sandboxing.  The rootfs images being used here are built from
+# the `.buildkite/rootfs_images/llvm-passes.jl` file.
+agents:
+  queue: "julia"
+  # Only run on `sandbox.jl` machines (not `docker`-isolated ones) since we need nestable sandboxing
+  sandbox.jl: "true"
+  os: "linux"
+
+steps:
+  - label: "package_linux64"
+    key: package_linux64
+    plugins:
+      - JuliaCI/julia#v1:
+          version: 1.6
+      - staticfloat/sandbox#v1:
+          rootfs_url: https://github.com/JuliaCI/rootfs-images/releases/download/v1/package_linux64.tar.gz
+          rootfs_treehash: "6b521782a12c789148465f5270788d9883a06894"
+          uid: 1000
+          gid: 1000
+          workspaces:
+            # Include `/cache/repos` so that our `git` version introspection works.
+            - "/cache/repos:/cache/repos"
+    commands: |
+      echo "--- Build Julia from source"
+      make -j 6
+      make release
+      make install
+
+      echo "--- Print Julia version info"
+      ./julia -e 'using InteractiveUtils; InteractiveUtils.versioninfo()'
+
+      echo "--- Compress build artifacts"
+      mv julia-* julia-artifact
+      rm -rf julia-linux64.tar.gz
+      tar czf julia-linux64.tar.gz julia-artifact/
+
+      echo "--- Upload build artifacts"
+      buildkite-agent artifact upload julia-linux64.tar.gz
+    timeout_in_minutes: 60
+    notify:
+      - github_commit_status:
+          context: "package_linux64"
+
+  - label: "tester_linux64"
+    key: tester_linux64
+    depends_on: package_linux64
+    plugins:
+      - JuliaCI/julia#v1:
+          version: 1.6
+      - staticfloat/sandbox#v1:
+          rootfs_url: https://github.com/JuliaCI/rootfs-images/releases/download/v1/package_linux64.tar.gz
+          rootfs_treehash: "6b521782a12c789148465f5270788d9883a06894"
+          uid: 1000
+          gid: 1000
+          workspaces:
+            # Include `/cache/repos` so that our `git` version introspection works.
+            - "/cache/repos:/cache/repos"
+    env:
+      JULIA_SHELL: "/bin/bash"
+    commands: |
+      echo "--- Debugging: echo USER"
+      echo $$USER
+
+      echo "--- Debugging: echo HOME"
+      echo $$HOME
+
+      echo "--- Debugging: id"
+      id
+
+      echo "--- Debugging: which bash"
+      which bash
+
+      echo "--- Debugging: which -a bash"
+      which -a bash
+
+      echo "--- Debugging: SHELL"
+      echo $$SHELL
+
+      echo "--- Debugging: JULIA_SHELL"
+      echo $$JULIA_SHELL
+
+      echo "--- Debugging: echo HOME"
+      echo $$HOME
+
+      echo "--- Debugging: ls -ld HOME"
+      ls -ld $$HOME
+
+      echo "--- Download build artifacts"
+      rm -rf julia-linux64.tar.gz
+      buildkite-agent artifact download julia-linux64.tar.gz .
+
+      echo "--- Extract build artifacts"
+      rm -rf julia-artifact/
+      tar xzf julia-linux64.tar.gz julia-artifact/
+
+      echo "--- Print Julia version info"
+      julia-artifact/bin/julia -e 'using InteractiveUtils; InteractiveUtils.versioninfo()'
+      julia-artifact/bin/julia -e '@info "" Sys.CPU_THREADS homedir() withenv(homedir, "HOME" => nothing) ENV["USER"]'
+
+      echo "--- Run the Julia test suite"
+      julia-artifact/bin/julia .buildkite/rr_capture.jl julia-artifact/bin/julia -e 'Base.runtests(["all"]; ncores = Sys.CPU_THREADS)'
+    timeout_in_minutes: 120
+    notify:
+      - github_commit_status:
+          context: "tester_linux64"
diff --git a/.buildkite/rr_capture.jl b/.buildkite/rr_capture.jl
new file mode 100644
index 00000000000000..07d57f31ff29cf
--- /dev/null
+++ b/.buildkite/rr_capture.jl
@@ -0,0 +1,134 @@
+using Dates
+using Pkg
+using Tar
+
+if Base.VERSION < v"1.6"
+    throw(ErrorException("The `rr_capture.jl` script requires Julia 1.6 or greater"))
+end
+
+if length(ARGS) < 1
+    throw(ErrorException("Usage: rr_capture.jl [command...]"))
+end
+
+const TIMEOUT = 2 * 60 * 60 # timeout in seconds
+
+# We only use `rr` on the `tester_linux64` builder
+const use_rr_if_builder_is = "tester_linux64"
+
+const run_id = get(ENV, "BUILDKITE_JOB_ID", "unknown")
+const shortcommit = get(ENV, "BUILDKITE_COMMIT", "unknown")
+const builder = get(ENV, "BUILDKITE_STEP_KEY", use_rr_if_builder_is)
+const use_rr = builder == use_rr_if_builder_is
+
+@info "" run_id shortcommit builder use_rr
+@info "" ARGS
+
+# if !use_rr # TODO: uncomment this line
+if true # TODO: delete this line
+    @info "We will not run the tests under rr"
+    p = run(`$ARGS`)
+    exit(p.exitcode)
+end
+
+@info "We will run the tests under rr"
+
+const num_cores = min(Sys.CPU_THREADS, 8, parse(Int, get(ENV, "JULIA_TEST_NUM_CORES", "8")) + 1)
+@info "" num_cores
+
+proc = nothing
+
+new_env = copy(ENV)
+mktempdir() do dir
+    Pkg.activate(dir)
+    Pkg.add("rr_jll")
+    Pkg.add("Zstd_jll")
+
+    rr_jll = Base.require(Base.PkgId(Base.UUID((0xe86bdf43_55f7_5ea2_9fd0_e7daa2c0f2b4)), "rr_jll"))
+    zstd_jll = Base.require(Base.PkgId(Base.UUID((0x3161d3a3_bdf6_5164_811a_617609db77b4)), "Zstd_jll"))
+    rr(func) = Base.invokelatest(rr_jll.rr, func; adjust_LIBPATH=false)
+    rr() do rr_path
+        capture_script_path = joinpath(dir, "capture_output.sh")
+        loader = Sys.WORD_SIZE == 64 ? "/lib64/ld-linux-x86-64.so.2" : "/lib/ld-linux.so.2"
+        open(capture_script_path, "w") do io
+            write(io, """
+            #!/bin/bash
+
+            $(rr_path) record --nested=detach "\$@" > >(tee -a $(dir)/stdout.log) 2> >(tee -a $(dir)/stderr.log >&2)
+            """)
+        end
+        chmod(capture_script_path, 0o755)
+
+        new_env = copy(ENV)
+        new_env["_RR_TRACE_DIR"] = joinpath(dir, "rr_traces")
+        new_env["RR_LOG"]="all:debug"
+        new_env["RR_LOG_BUFFER"]="100000"
+        new_env["JULIA_RR"] = capture_script_path
+        t_start = time()
+        global proc = run(setenv(`$(rr_path) record --num-cores=$(num_cores) $ARGS`, new_env), (stdin, stdout, stderr); wait=false)
+
+        # Start asynchronous timer that will kill `rr`
+        @async begin
+            sleep(TIMEOUT)
+
+            # If we've exceeded the timeout and `rr` is still running, kill it.
+            if isopen(proc)
+                println(stderr, "\n\nProcess timed out. Signalling `rr` for force-cleanup!")
+                kill(proc, Base.SIGTERM)
+
+                # Give `rr` a chance to cleanup
+                sleep(60)
+
+                if isopen(proc)
+                    println(stderr, "\n\n`rr` failed to cleanup within one minute, killing and exiting immediately!")
+                    kill(proc, Base.SIGKILL)
+                    exit(1)
+                end
+            end
+        end
+
+        # Wait for `rr` to finish, either through naturally finishing its run, or `SIGTERM`.
+        # If we have to `SIGKILL`
+        wait(proc)
+
+        # On a non-zero exit code, upload the `rr` trace
+        if !success(proc)
+            println(stderr, "`rr` returned $(proc.exitcode), packing and uploading traces...")
+
+            if !isdir(joinpath(dir, "rr_traces"))
+                println(stderr, "No `rr_traces` directory!  Did `rr` itself fail?")
+                exit(1)
+            end
+
+            # Clean up non-traces
+            rm(joinpath(dir, "rr_traces", "latest-trace"))
+            rm(joinpath(dir, "rr_traces", "cpu_lock"))
+
+            # Create a directory for the pack files to go
+            pack_dir = joinpath(dir, "pack")
+            mkdir(pack_dir)
+
+            # Pack all traces
+            trace_dirs = [joinpath(dir, "rr_traces", f) for f in readdir(joinpath(dir, "rr_traces"))]
+            filter!(isdir, trace_dirs)
+            run(ignorestatus(`$(rr_path) pack --pack-dir=$pack_dir $(trace_dirs)`))
+
+            # Tar it up
+            mkpath("dumps")
+            datestr = Dates.format(now(), dateformat"yyyy-mm-dd_HH_MM_SS")
+            dst_path = "dumps/rr-run_$(run_id)-gitsha_$(shortcommit)-$(datestr).tar.zst"
+            zstd_jll.zstdmt() do zstdp
+                tarproc = open(`$zstdp -o $dst_path`, "w")
+                Tar.create(dir, tarproc)
+                close(tarproc.in)
+            end
+        end
+    end
+end
+
+# Pass the exit code back up to Buildkite
+if proc.termsignal != 0
+    ccall(:raise, Cvoid, (Cint,), proc.termsignal)
+    exit(1) # Just in case the signal did not cause an exit
+else
+    exit(proc.exitcode)
+end