Bug #14195: [PATCH] IO#pwrite uses tmp buffer to avoid parallel modification

• Status: Closed
• Assignee: nobu (Nobuyoshi Nakada)
• Target version: -
• Backport: 2.3: UNKNOWN, 2.4: UNKNOWN

[normalperson (Eric Wong)]

Since we release GVL, we must freeze a duplicate the string buffer
to prevent other threads from modifying our buffer while we
are waiting on pwrite(2).

• io.c (rb_io_pwrite): use_rb_str_tmp_frozen_{acquire/release}

Trivial bugfix, will commit before 2.5 final.

I think some ext/socket methods (sendmsg, setsockopt) may need this, too;
and fcntl/ioctl/getsockopt will need locktmp for strings...

[normalperson (Eric Wong)]

• File 0001-io.c-IO-pwrite-uses-tmp-buffer-to-avoid-parallel-mod.patch 0001-io.c-IO-pwrite-uses-tmp-buffer-to-avoid-parallel-mod.patch added

[normalperson (Eric Wong)]

[e-mail] wrote:

I think some ext/socket methods (sendmsg, setsockopt) may need this, too;
and fcntl/ioctl/getsockopt will need locktmp for strings...

N/M, *sockopt do not; but I think others do.
Will work on it later.

• Status changed from Open to Closed

Applied in changeset trunk|r61376.

---

io.c: IO#pwrite uses tmp buffer to avoid parallel modification

Since we release GVL, we must freeze and duplicate the string buffer
to prevent other threads from modifying our buffer while we are
waiting on pwrite(2).

• io.c (rb_io_pwrite): use_rb_str_tmp_frozen_{acquire/release}
  [Bug #14195]