Re: [PATCH v2 2/2] name-hash: fix buffer overrun

[Junio C Hamano <gitster@pobox.com>]

git@jeffhostetler.com writes:

> From: Kevin Willford <kewillf@microsoft.com>
>
> Add check for the end of the entries for the thread partition.
> Add test for lazy init name hash with specific directory structure
>
> The lazy init hash name was causing a buffer overflow when the last
> entry in the index was multiple folder deep with parent folders that
> did not have any files in them.
>
> This adds a test for the boundary condition of the thread partitions
> with the folder structure that was triggering the buffer overflow.
> The test is skipped on single-cpu machines because the original code
> path is used in name-hash.c
>
> The fix was to check if it is the last entry for the thread partition
> in the handle_range_dir and not try to use the next entry in the cache.

As I merged the older one already to 'next', I'll queue 1/2 of v2 on
top of them and then the following (which is incremental between v1
and this v2 2/2) on top.

-- >8 --
From: Kevin Willford <kewillf@microsoft.com>
Date: Mon, 3 Apr 2017 15:16:42 +0000
Subject: [PATCH] t3008: skip lazy-init test on a single-core box

The lazy-init codepath will not be exercised uniless threaded.  Skip
the entire test on a single-core box.  Also replace a hard-coded
constant of 2000 (number of cache entries to manifacture for tests)
with a variable with a human readable name.

Signed-off-by: Kevin Willford <kewillf@microsoft.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 t/t3008-ls-files-lazy-init-name-hash.sh | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/t/t3008-ls-files-lazy-init-name-hash.sh b/t/t3008-ls-files-lazy-init-name-hash.sh
index 971975bff4..bdf5198b7e 100755
--- a/t/t3008-ls-files-lazy-init-name-hash.sh
+++ b/t/t3008-ls-files-lazy-init-name-hash.sh
@@ -4,14 +4,22 @@ test_description='Test the lazy init name hash with various folder structures'
 
 . ./test-lib.sh
 
+if test 1 -eq $($GIT_BUILD_DIR/t/helper/test-online-cpus)
+then
+	skip_all='skipping lazy-init tests, single cpu'
+	test_done
+fi
+
+LAZY_THREAD_COST=2000
+
 test_expect_success 'no buffer overflow in lazy_init_name_hash' '
 	(
-	    test_seq 2000 | sed "s/^/a_/"
+	    test_seq $LAZY_THREAD_COST | sed "s/^/a_/"
 	    echo b/b/b
-	    test_seq 2000 | sed "s/^/c_/"
+	    test_seq $LAZY_THREAD_COST | sed "s/^/c_/"
 	    test_seq 50 | sed "s/^/d_/" | tr "\n" "/"; echo d
 	) |
-	sed -e "s/^/100644 $EMPTY_BLOB	/" |
+	sed "s/^/100644 $EMPTY_BLOB	/" |
 	git update-index --index-info &&
 	test-lazy-init-name-hash -m
 '
-- 
2.12.2-776-gded3dc243c