Created attachment 3537 [details]
a one-line CSS with import -- Emacs loops on TAB

emacs22-X11-gtk-22.2-alt5
emacs-apel-10.6-alt1.20050606
emacs22-common-22.2-alt5
emacs-cedet-speedbar-1.0.1-alt0.10.pre4
emacs22-leim-22.2-alt5
emacs22-nox-22.2-alt5
emacs-cedet-1.0-alt0.10.pre4
emacs-git-1.5.5.5-alt1
emacs22-elisp-manual-22.2-alt5
emacs22-el-22.2-alt5
emacs-mode-psgml-1.2.5-alt1
emacs-ecb-2.32-alt4
emacs-base-0.0.7-alt1
emacs-mode-auctex-11.85-alt1
emacs-elscreen-1.3.2-alt0.2
emacs22-tramp-2.0.57-alt5
emacs-elib-1.0-alt7
emacs22-X11-22.2-alt5

How to reproduce: 

emacs a.css (reproduceable with emacs22-nox and emacs22-gtk)

go to the 2nd line

press TAB

Result: it loops, only C-g helps.

Expected: no effect.

strace tells us at this time:

$ strace -p 22615
Process 22615 attached - interrupt to quit
select(7, [3 4 6], NULL, NULL, {0, 224000}) = 0 (Timeout)
gettimeofday({1242513491, 582980}, NULL) = 0
gettimeofday({1242513491, 583088}, NULL) = 0
read(4, 0x85c82d4, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
read(4, 0x85c82d4, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
gettimeofday({1242513491, 583373}, NULL) = 0
select(7, [3 4 6], NULL, NULL, {0, 495679}) = 0 (Timeout)
gettimeofday({1242513492, 78966}, NULL) = 0
gettimeofday({1242513492, 79041}, NULL) = 0
select(7, [3 4 6], NULL, NULL, {0, 11}) = 0 (Timeout)
gettimeofday({1242513492, 82920}, NULL) = 0
gettimeofday({1242513492, 83019}, NULL) = 0
read(4, 0x85c82d4, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
read(4, 0x85c82d4, 4096)                = -1 EAGAIN (Resource temporarily unavailable)
gettimeofday({1242513492, 83270}, NULL) = 0
select(7, [3 4 6], NULL, NULL, {0, 495782}) = 0 (Timeout)
...