bug#11536: [Emacs-diffs] /srv/bzr/emacs/trunk r110781: Fix a race condition in wait_reading_process_output (tiny change).

[Chong Yidong]

"Herbert J. Skuhra" <hskuhra@eumx.net> writes:

> the changes in r110781 (and r110782) make Emacs hang on both Arch
> GNU/Linux (i686) and FreeBSD 9.1-PRERELEASE (i386), e.g: 
> when Wanderlust is checking IMAP4 mailboxes.
>
> Strace on GNU/Linux is showing a loop of:
>
> poll([{fd=5, events=POLLIN}, {fd=6, events=POLLIN}, {fd=7,
> events=POLLIN}, {fd=3, events=POLLIN}], 4, 0) = 0 (Timeout)
> pselect6(13, [12], [], NULL, {0, 0}, {NULL, 8}) = 0 (Timeout)
> clock_gettime(CLOCK_REALTIME, {1352071692, 886361097}) = 0
> clock_gettime(CLOCK_REALTIME, {1352071692, 886549522}) = 0
> recv(6, 0x887ea58, 4096, 0) = -1 EAGAIN (Resource temporarily
> unavailable)
>
> Ktrace on FreeBSD is showing a loop of:
>
> 11723 emacs-24.3.50 RET   poll 0
> 11723 emacs-24.3.50 CALL  pselect(0x13,0xbfbf98bc,0xbfbf983c,0,0xbfbf99f8,0)
> 11723 emacs-24.3.50 RET   pselect 0
> 11723 emacs-24.3.50 CALL  read(0x3,0x849a018,0x1000)
> 11723 emacs-24.3.50 RET   read -1 errno 35 Resource temporarily unavailable

OK.  I'm reverting the change and reopening Bug#11536.