Segmentation fault

[themihai]

Watching and shuffling through a video file produces a segmentation fault.

Initial command btfs -d torrents/av.torrent mnt2

handle_piece_finished_alert: 1398
handle_piece_finished_alert: 1403
handle_piece_finished_alert: 1401
handle_piece_finished_alert: 1404
handle_piece_finished_alert: 1389
unique: 8, opcode: READ (15), nodeid: 4, insize: 80, pid: 5015
read[0] 65536 bytes from 338395136 flags: 0x0
handle_read_piece_alert: piece 1290 size 0
Segmentation fault: 11

---

OSX Sierra

btfs --version
btfs version: 2.15
libtorrent version: 1.1.4.0
OSXFUSE 3.6.3
FUSE library version: 2.9.7
fuse: no mount point

[johang]

Piece size is 0. Maybe the read request failed.

I can't reproduce this. Can you try with this patch?

diff --git a/src/btfs.cc b/src/btfs.cc
index 2a74bac..f4b3f2c 100644
--- a/src/btfs.cc
+++ b/src/btfs.cc
@@ -140,6 +140,13 @@ Read::Read(char *buf, int index, off_t offset, size_t size) {
 	}
 }
 
+void Read::fail(int piece) {
+	for (parts_iter i = parts.begin(); i != parts.end(); ++i) {
+		if (i->part.piece == piece && !i->filled)
+			failed = true;
+	}
+}
+
 void Read::copy(int piece, char *buffer, int size) {
 	for (parts_iter i = parts.begin(); i != parts.end(); ++i) {
 		if (i->part.piece == piece && !i->filled)
@@ -184,11 +191,14 @@ int Read::read() {
 	// Move sliding window to first piece to serve this request
 	jump(parts.front().part.piece, size());
 
-	while (!finished())
+	while (!finished() && !failed)
 		// Wait for any piece to downloaded
 		pthread_cond_wait(&signal_cond, &lock);
 
-	return size();
+	if (failed)
+		return -EIO;
+	else
+		return size();
 }
 
 static void
@@ -240,12 +250,19 @@ setup() {
 
 static void
 handle_read_piece_alert(libtorrent::read_piece_alert *a, Log *log) {
-	printf("%s: piece %d size %d\n", __func__, a->piece, a->size);
+	printf("%s: piece %d size %d buf %p\n", __func__, a->piece, a->size,
+		a->buffer.get());
 
 	pthread_mutex_lock(&lock);
 
-	for (reads_iter i = reads.begin(); i != reads.end(); ++i) {
-		(*i)->copy(a->piece, a->buffer.get(), a->size);
+	if (a->ec) {
+		for (reads_iter i = reads.begin(); i != reads.end(); ++i) {
+			(*i)->fail(a->piece);
+		}
+	} else {
+		for (reads_iter i = reads.begin(); i != reads.end(); ++i) {
+			(*i)->copy(a->piece, a->buffer.get(), a->size);
+		}
 	}
 
 	pthread_mutex_unlock(&lock);
@@ -511,6 +528,9 @@ btfs_read(const char *path, char *buf, size_t size, off_t offset,
 	// Wait for read to finish
 	int s = r->read();
 
+	if (s < 0)
+		printf("btfs_read about to return -1");
+
 	reads.remove(r);
 
 	delete r;
diff --git a/src/btfs.h b/src/btfs.h
index 020881b..c1cd290 100644
--- a/src/btfs.h
+++ b/src/btfs.h
@@ -60,6 +60,8 @@ class Read
 public:
 	Read(char *buf, int index, off_t offset, size_t size);
 
+	void fail(int piece);
+
 	void copy(int piece, char *buffer, int size);
 
 	void trigger();
@@ -71,6 +73,8 @@ public:
 	int read();
 
 private:
+	bool failed = false;
+
 	std::vector<Part> parts;
 };

[themihai]

Thanks for the patch! I will update when/if I reproduce it. It happened to me twice(before I reported it) stressing the Chrome player (-> File -> Open File) .

[johang]

Did you reproduce it?