andreacavalli/rocksdb
0
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Fix Iterator::Prev memory pinning bug

Browse Source 
Summary: We should not use IterKey::SetKey with copy = false except if we are pinning the iterator thru it's life time, otherwise we may release the temporarily pinned blocks and in this case the IterKey will be pointing to freed memory

Test Plan: added a new test

Reviewers: sdong, andrewkr

Reviewed By: andrewkr

Subscribers: andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D57561
This commit is contained in:
Islam AbdelRahman 2016-05-03 16:50:01 -07:00 committed by Yi Wu
parent a9f71f1b6e
commit 2137377f0e
2 changed files with 67 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
db/db_iter.cc
View File

@ -369,21 +369,24 @@ void DBIter::FindNextUserEntryInternal(bool skipping, bool prefix_check) {
case kTypeSingleDeletion:
// Arrange to skip all upcoming entries for this key since
// they are hidden by this deletion.
saved_key_.SetKey(ikey.user_key,
!iter_->IsKeyPinned() /* copy */);
saved_key_.SetKey(
ikey.user_key,
!iter_->IsKeyPinned() || !pin_thru_lifetime_ /* copy */);
skipping = true;
num_skipped = 0;
PERF_COUNTER_ADD(internal_delete_skipped_count, 1);
break;
case kTypeValue:
valid_ = true;
saved_key_.SetKey(ikey.user_key,
!iter_->IsKeyPinned() /* copy */);
saved_key_.SetKey(
ikey.user_key,
!iter_->IsKeyPinned() || !pin_thru_lifetime_ /* copy */);
return;
case kTypeMerge:
// By now, we are sure the current ikey is going to yield a value
saved_key_.SetKey(ikey.user_key,
!iter_->IsKeyPinned() /* copy */);
saved_key_.SetKey(
ikey.user_key,
!iter_->IsKeyPinned() || !pin_thru_lifetime_ /* copy */);
current_entry_is_merged_ = true;
valid_ = true;
MergeValuesNewToOld(); // Go to a different state machine
@ -547,7 +550,7 @@ void DBIter::PrevInternal() {
while (iter_->Valid()) {
saved_key_.SetKey(ExtractUserKey(iter_->key()),
!iter_->IsKeyPinned() /* copy */);
!iter_->IsKeyPinned() || !pin_thru_lifetime_ /* copy */);
if (FindValueForCurrentKey()) {
valid_ = true;
if (!iter_->Valid()) {

57
db/db_iterator_test.cc
View File

@ -1384,6 +1384,63 @@ TEST_F(DBIteratorTest, IterPrevKeyCrossingBlocksRandomized) {
delete iter;
}
{
ReadOptions ro;
ro.fill_cache = false;
Iterator* iter = db_->NewIterator(ro);
auto data_iter = true_data.rbegin();
int entries_right = 0;
std::string seek_key;
for (iter->SeekToLast(); iter->Valid(); iter->Prev()) {
// Verify key/value of current position
ASSERT_EQ(iter->key().ToString(), data_iter->first);
ASSERT_EQ(iter->value().ToString(), data_iter->second);
bool restore_position_with_seek = rnd.Uniform(2);
if (restore_position_with_seek) {
seek_key = iter->key().ToString();
}
// Do some Next() operations the restore the iterator to orignal position
int next_count =
entries_right > 0 ? rnd.Uniform(std::min(entries_right, 10)) : 0;
for (int i = 0; i < next_count; i++) {
iter->Next();
data_iter--;
ASSERT_EQ(iter->key().ToString(), data_iter->first);
ASSERT_EQ(iter->value().ToString(), data_iter->second);
}
if (restore_position_with_seek) {
// Restore orignal position using Seek()
iter->Seek(seek_key);
for (int i = 0; i < next_count; i++) {
data_iter++;
}
ASSERT_EQ(iter->key().ToString(), data_iter->first);
ASSERT_EQ(iter->value().ToString(), data_iter->second);
} else {
// Restore original position using Prev()
for (int i = 0; i < next_count; i++) {
iter->Prev();
data_iter++;
ASSERT_EQ(iter->key().ToString(), data_iter->first);
ASSERT_EQ(iter->value().ToString(), data_iter->second);
}
}
entries_right++;
data_iter++;
}
ASSERT_EQ(data_iter, true_data.rend());
delete iter;
}
}
TEST_F(DBIteratorTest, IteratorWithLocalStatistics) {