[RFC PATCH 4/5] pack-objects: avoid reading uninitalized data
- From
Jeff King <peff@peff.net>
- Date
- Oct 22, 2008, 20:31 UTC
- Message-ID
- <20081022203103.GD4547@coredump.intra.peff.net>
- In-Reply-To
- <20081022202810.GA4439@coredump.intra.peff.net>
In the main loop of find_deltas, we do:
struct object_entry *entry = *list++; ... if (!*list_size) ... break
Because we look at and increment *list _before_ the check of list_size, in the very last iteration of the loop we will look at uninitialized data, and increment the pointer beyond one past the end of the allocated space. Since we don't actually do anything with the data until after the check, this is not a problem in practice.
But since it technically violates the C standard, and because it provokes a spurious valgrind warning, let's just move the initialization of entry to a safe place.
This fixes valgrind errors in t5300, t5301, t5302, t303, and t9400.
Signed-off-by: Jeff King <peff@peff.net> --- builtin-pack-objects.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c index 59c30d1..15b80db 100644 --- a/builtin-pack-objects.c +++ b/builtin-pack-objects.c @@ -1375,7 +1375,7 @@ static void find_deltas(struct object_entry **list, unsigned *list_size, array = xcalloc(window, sizeof(struct unpacked)); for (;;) { - struct object_entry *entry = *list++; + struct object_entry *entry; struct unpacked *n = array + idx; int j, max_depth, best_base = -1; @@ -1384,6 +1384,7 @@ static void find_deltas(struct object_entry **list, unsigned *list_size, progress_unlock(); break; } + entry = *list++; (*list_size)--; if (!entry->preferred_base) { (*processed)++;
-- 1.6.0.2.825.g6d19d