From d2e78089cedfac9669d6dea0518d114f296f0287 Mon Sep 17 00:00:00 2001
From: Keno Fischer <keno@juliacomputing.com>
Date: Wed, 1 May 2019 14:16:57 -0400
Subject: [PATCH 1/2] Prevent stack overflow in Profile

As a follow up to #31693, this fixes the other place in Profile
that recurses over Profile data, causing stack overflows. This
should fix a bunch of the recent intermittent CI faults on linux32.
---
 stdlib/Profile/src/Profile.jl | 45 ++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 19 deletions(-)

diff --git a/stdlib/Profile/src/Profile.jl b/stdlib/Profile/src/Profile.jl
index 3c3b6cb65ad00..0fafa94a8cf1f 100644
--- a/stdlib/Profile/src/Profile.jl
+++ b/stdlib/Profile/src/Profile.jl
@@ -560,26 +560,33 @@ function tree!(root::StackFrameTree{T}, all::Vector{UInt64}, lidict::Union{LineI
     return root
 end
 
-# Print a "branch" starting at a particular level. This gets called recursively.
+# Print the stack frame tree starting at a particular root. Uses a worklist to
+# avoid stack overflows.
 function tree(io::IO, bt::StackFrameTree, level::Int, cols::Int, fmt::ProfileFormat, noisefloor::Int)
-    level > fmt.maxdepth && return
-    isempty(bt.down) && return
-    # Order the line information
-    nexts = collect(values(bt.down))
-    lilist = collect(frame.frame for frame in nexts)
-    counts = collect(frame.count for frame in nexts)
-    # Generate the string for each line
-    strs = tree_format(lilist, counts, level, cols)
-    # Recurse to the next level
-    for i in liperm(lilist)
-        down = nexts[i]
-        count = down.count
-        count < fmt.mincount && continue
-        count < noisefloor && continue
-        str = strs[i]
-        println(io, isempty(str) ? "$count unknown stackframe" : str)
-        noisefloor_down = fmt.noisefloor > 0 ? floor(Int, fmt.noisefloor * sqrt(count)) : 0
-        tree(io, down, level + 1, cols, fmt, noisefloor_down)
+    worklist = Tuple{StackFrameTree, Int, Int, Union{String, Nothing}}[
+        (bt, level, noisefloor, nothing)]
+    while !isempty(worklist)
+        (bt, level, noisefloor, str) = popfirst!(worklist)
+        str !== nothing && println(io, str)
+        level > fmt.maxdepth && continue
+        isempty(bt.down) && continue
+        # Order the line information
+        nexts = collect(values(bt.down))
+        lilist = collect(frame.frame for frame in nexts)
+        counts = collect(frame.count for frame in nexts)
+        # Generate the string for each line
+        strs = tree_format(lilist, counts, level, cols)
+        # Recurse to the next level
+        for i in liperm(lilist)
+            down = nexts[i]
+            count = down.count
+            count < fmt.mincount && continue
+            count < noisefloor && continue
+            str = strs[i]
+            isempty(str) && (str = "$count unknown stackframe")
+            noisefloor_down = fmt.noisefloor > 0 ? floor(Int, fmt.noisefloor * sqrt(count)) : 0
+            push!(worklist, (down, level+1, noisefloor_down, str))
+        end
     end
     nothing
 end

From 6639009916abf3178ed79031399c2e19b2249bfb Mon Sep 17 00:00:00 2001
From: Jameson Nash <vtjnash@gmail.com>
Date: Wed, 1 May 2019 15:03:18 -0400
Subject: [PATCH 2/2] fixup! Prevent stack overflow in Profile

---
 stdlib/Profile/src/Profile.jl | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/stdlib/Profile/src/Profile.jl b/stdlib/Profile/src/Profile.jl
index 0fafa94a8cf1f..ffcc6ad10b05a 100644
--- a/stdlib/Profile/src/Profile.jl
+++ b/stdlib/Profile/src/Profile.jl
@@ -562,12 +562,11 @@ end
 
 # Print the stack frame tree starting at a particular root. Uses a worklist to
 # avoid stack overflows.
-function tree(io::IO, bt::StackFrameTree, level::Int, cols::Int, fmt::ProfileFormat, noisefloor::Int)
-    worklist = Tuple{StackFrameTree, Int, Int, Union{String, Nothing}}[
-        (bt, level, noisefloor, nothing)]
+function tree(io::IO, bt::StackFrameTree, cols::Int, fmt::ProfileFormat)
+    worklist = [(bt, 0, 0, "")]
     while !isempty(worklist)
         (bt, level, noisefloor, str) = popfirst!(worklist)
-        str !== nothing && println(io, str)
+        isempty(str) || println(io, str)
         level > fmt.maxdepth && continue
         isempty(bt.down) && continue
         # Order the line information
@@ -577,7 +576,7 @@ function tree(io::IO, bt::StackFrameTree, level::Int, cols::Int, fmt::ProfileFor
         # Generate the string for each line
         strs = tree_format(lilist, counts, level, cols)
         # Recurse to the next level
-        for i in liperm(lilist)
+        for i in reverse(liperm(lilist))
             down = nexts[i]
             count = down.count
             count < fmt.mincount && continue
@@ -585,10 +584,9 @@ function tree(io::IO, bt::StackFrameTree, level::Int, cols::Int, fmt::ProfileFor
             str = strs[i]
             isempty(str) && (str = "$count unknown stackframe")
             noisefloor_down = fmt.noisefloor > 0 ? floor(Int, fmt.noisefloor * sqrt(count)) : 0
-            push!(worklist, (down, level+1, noisefloor_down, str))
+            pushfirst!(worklist, (down, level + 1, noisefloor_down, str))
         end
     end
-    nothing
 end
 
 function tree(io::IO, data::Vector{UInt64}, lidict::Union{LineInfoFlatDict, LineInfoDict}, cols::Int, fmt::ProfileFormat)
@@ -601,8 +599,7 @@ function tree(io::IO, data::Vector{UInt64}, lidict::Union{LineInfoFlatDict, Line
         warning_empty()
         return
     end
-    level = 0
-    tree(io, root, level, cols, fmt, 0)
+    tree(io, root, cols, fmt)
     nothing
 end