Segmentation fault when window is resized

[anseki]

The process throws "Segmentation fault" if an user resize a window when a script is waiting for user input via TTY, after it accesses to process.stdout.

For example:

var
  fs = require('fs'),
  bufferSize = 1024,
  buffer = new Buffer(bufferSize),
  readSize,
  chunk;

readSize = fs.readSync(fs.openSync('/dev/tty', 'r'), buffer, 0, bufferSize);
chunk = buffer.toString('utf8', 0, readSize);

console.log('INPUT: ' + chunk);

This code above works fine without error.

foo
INPUT: foo

But, if process.stdout is accessed:

var
  fs = require('fs'),
  bufferSize = 1024,
  buffer = new Buffer(bufferSize),
  readSize,
  chunk;

process.stdout; // access to property

readSize = fs.readSync(fs.openSync('/dev/tty', 'r'), buffer, 0, bufferSize);
chunk = buffer.toString('utf8', 0, readSize);

console.log('INPUT: ' + chunk);

If a window is resized when the script is waiting for user input, it throws "Segmentation fault".

I tried this code in some versions, and it seems that this issue occurs in v3.3.0+.
v3.2.0 is OK.
v3.3.0 makes this issue occur.

Is this a problem of libuv v1.7.3 ?

[anseki]

This issue occurs at least in OS X 10 and Ubuntu.
I don't know a case in Windows because Command Window of Windows can't resize window, maybe.

[evanlucas]

hm this is what I'm getting in lldb:

Process 8536 stopped
* thread #1: tid = 0x1057ca, 0x0000000100c1227a node_g`uv__fs_read(req=0x00007fff5fbfe648) + 74 at fs.c:275, queue = 'com.apple.main-thread, stop reason = EXC_BAD_ACCESS (code=1, address=0x0)
    frame #0: 0x0000000100c1227a node_g`uv__fs_read(req=0x00007fff5fbfe648) + 74 at fs.c:275
   272  #endif /* defined(_AIX) */
   273    if (req->off < 0) {
   274      if (req->nbufs == 1)
-> 275        result = read(req->file, req->bufs[0].base, req->bufs[0].len);
   276      else
   277        result = readv(req->file, (struct iovec*) req->bufs, req->nbufs);
   278    } else {

It looks like req->nbufs is 1, but req->bufs is NULL

[indutny]

I believe this should be fixed by libuv update. cc @saghul ;)

[saghul]

Yeah, the next libuv upgrade includes a fix for this.

[MylesBorins]

@saghul @nodejs/lts should we backport the patch to LTS?

[indutny]

I believe we should.

[rvagg]

I'll reserve final judgement until I see the libuv delta, if it's low-impact then that ought to be fine

[saghul]

Agreed with @rvagg. Also, since we keep backwards API compatibility and a stable ABI, all libuv upgrades will end up on LTS, right?

[rvagg]

I think we had this discussion not long ago, didn't we? I'd lean toward not making a firm rule about it but in general ABI and API compat upgrades in libuv would end up in LTS. If there was a particularly big delta then that may be cause for concern.