GNU bug report logs - #28233
CC Mode 5.33 (C/*l); Emacs may get stuck with 100% CPU

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Package: cc-mode;

Reported by: Mohammed Sadiq <sadiq <at> sadiqpk.org>

Date: Fri, 25 Aug 2017 15:32:01 UTC

Severity: normal

Done: Alan Mackenzie <acm <at> muc.de>

Bug is archived. No further changes may be made.

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Alan Mackenzie <acm <at> muc.de>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#28233: closed (CC Mode 5.33 (C/*l); Emacs may get stuck with
 100% CPU)
Date: Sun, 27 Aug 2017 10:50:02 +0000
[Message part 1 (text/plain, inline)]
Your message dated Sun, 27 Aug 2017 10:47:16 +0000
with message-id <20170827104716.GB3520 <at> ACM>
and subject line Re: bug#28233: CC Mode 5.33 (C/*l); Emacs may get stuck with 100% CPU
has caused the debbugs.gnu.org bug report #28233,
regarding CC Mode 5.33 (C/*l); Emacs may get stuck with 100% CPU
to be marked as done.

(If you believe you have received this mail in error, please contact
help-debbugs <at> gnu.org.)


-- 
28233: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=28233
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems
[Message part 2 (message/rfc822, inline)]
From: Mohammed Sadiq <sadiq <at> sadiqpk.org>
To: submit <at> debbugs.gnu.org
Subject: CC Mode 5.33 (C/*l); Emacs may get stuck with 100% CPU
Date: Fri, 25 Aug 2017 21:00:52 +0530

Emacs always get stuck when writing some code (given below), using 100 % CPU for
(probably) limitless time:

How to reproduce:

1. Open a new empty file: emacs -Q test.c
2. Write the following (| is where the point is)
   #include<|
3. Delete the content: C-a C-k
4. Try to write the same again:
   #include<|

Result:
  At the 4th step, after typing #,GNU Emacs begins to use full CPU and
  does nothing. Though this can be cancelled using C-g.


Emacs  : GNU Emacs 26.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
 of 2017-08-25
Package: CC Mode 5.33 (C/*l)
Buffer Style: gnu
c-emacs-features: (pps-extended-state col-0-paren posix-char-classes gen-string-delim gen-comment-delim syntax-properties 1-bit)

current state:
==============
(setq
 c-basic-offset 2
 c-comment-only-line-offset '(0 . 0)
 c-indent-comment-alist '((anchored-comment column . 0) (end-block space . 1)
			  (cpp-end-block space . 2))
 c-indent-comments-syntactically-p nil
 c-block-comment-prefix ""
 c-comment-prefix-regexp '((pike-mode . "//+!?\\|\\**") (awk-mode . "#+")
			   (other . "//+\\|\\**"))
 c-doc-comment-style '((java-mode . javadoc) (pike-mode . autodoc)
		       (c-mode . gtkdoc))
 c-cleanup-list '(scope-operator)
 c-hanging-braces-alist '((substatement-open before after)
			  (arglist-cont-nonempty))
 c-hanging-colons-alist nil
 c-hanging-semi&comma-criteria '(c-semi&comma-inside-parenlist)
 c-backslash-column 48
 c-backslash-max-column 72
 c-special-indent-hook '(c-gnu-impose-minimum)
 c-label-minimum-indentation 1
 c-offsets-alist '((inexpr-class . +)
		   (inexpr-statement . +)
		   (lambda-intro-cont . +)
		   (inlambda . c-lineup-inexpr-block)
		   (template-args-cont c-lineup-template-args +)
		   (incomposition . +)
		   (inmodule . +)
		   (innamespace . +)
		   (inextern-lang . +)
		   (composition-close . 0)
		   (module-close . 0)
		   (namespace-close . 0)
		   (extern-lang-close . 0)
		   (composition-open . 0)
		   (module-open . 0)
		   (namespace-open . 0)
		   (extern-lang-open . 0)
		   (objc-method-call-cont
		    c-lineup-ObjC-method-call-colons
		    c-lineup-ObjC-method-call
		    +
		    )
		   (objc-method-args-cont . c-lineup-ObjC-method-args)
		   (objc-method-intro . [0])
		   (friend . 0)
		   (cpp-define-intro c-lineup-cpp-define +)
		   (cpp-macro-cont . +)
		   (cpp-macro . [0])
		   (inclass . +)
		   (stream-op . c-lineup-streamop)
		   (arglist-cont-nonempty
		    c-lineup-gcc-asm-reg
		    c-lineup-arglist
		    )
		   (arglist-cont c-lineup-gcc-asm-reg 0)
		   (comment-intro c-lineup-knr-region-comment c-lineup-comment)
		   (catch-clause . 0)
		   (else-clause . 0)
		   (do-while-closure . 0)
		   (access-label . -)
		   (case-label . 0)
		   (substatement . +)
		   (statement-case-intro . +)
		   (statement . 0)
		   (brace-entry-open . 0)
		   (brace-list-entry . c-lineup-under-anchor)
		   (brace-list-close . 0)
		   (block-close . 0)
		   (block-open . 0)
		   (inher-cont . c-lineup-multi-inher)
		   (inher-intro . +)
		   (member-init-cont . c-lineup-multi-inher)
		   (member-init-intro . +)
		   (annotation-var-cont . +)
		   (annotation-top-cont . 0)
		   (topmost-intro . 0)
		   (knr-argdecl . 0)
		   (func-decl-cont . +)
		   (inline-close . 0)
		   (class-close . 0)
		   (class-open . 0)
		   (defun-block-intro . +)
		   (defun-close . 0)
		   (defun-open . 0)
		   (c . c-lineup-C-comments)
		   (string . c-lineup-dont-change)
		   (topmost-intro-cont
		    first
		    c-lineup-topmost-intro-cont
		    c-lineup-gnu-DEFUN-intro-cont
		    )
		   (brace-list-intro . c-lineup-arglist-intro-after-paren)
		   (brace-list-open . +)
		   (inline-open . 0)
		   (arglist-close . c-lineup-arglist)
		   (arglist-intro . c-lineup-arglist-intro-after-paren)
		   (statement-cont . +)
		   (statement-case-open . +)
		   (label . 0)
		   (substatement-label . 0)
		   (substatement-open . +)
		   (knr-argdecl-intro . 5)
		   (statement-block-intro . +)
		   )
 c-buffer-is-cc-mode 'c-mode
 c-tab-always-indent t
 c-syntactic-indentation t
 c-syntactic-indentation-in-macros t
 c-ignore-auto-fill '(string cpp code)
 c-auto-align-backslashes t
 c-backspace-function 'backward-delete-char-untabify
 c-delete-function 'delete-char
 c-electric-pound-behavior nil
 c-default-style '((java-mode . "java") (awk-mode . "awk") (other . "gnu"))
 c-enable-xemacs-performance-kludge-p nil
 c-old-style-variable-behavior nil
 defun-prompt-regexp nil
 tab-width 8
 comment-column 32
 parse-sexp-ignore-comments t
 parse-sexp-lookup-properties t
 auto-fill-function nil
 comment-multi-line t
 comment-start-skip "\\(//+\\|/\\*+\\)\\s *"
 fill-prefix nil
 fill-column 70
 paragraph-start "[ 	]*\\(//+\\|\\**\\)[ 	]*$\\|^\f"
 adaptive-fill-mode t
 adaptive-fill-regexp "[ 	]*\\(//+\\|\\**\\)[ 	]*\\([ 	]*\\([-–!|#%;>*·•‣⁃◦]+[ 	]*\\)*\\)"
 )


[Message part 3 (message/rfc822, inline)]
From: Alan Mackenzie <acm <at> muc.de>
To: Mohammed Sadiq <sadiq <at> sadiqpk.org>
Cc: 28233-done <at> debbugs.gnu.org
Subject: Re: bug#28233: CC Mode 5.33 (C/*l); Emacs may get stuck with 100% CPU
Date: Sun, 27 Aug 2017 10:47:16 +0000
Hello, Mohammed.

On Sun, Aug 27, 2017 at 06:54:11 +0530, Mohammed Sadiq wrote:

> > On August 26, 2017 at 10:59 PM Alan Mackenzie <acm <at> muc.de> wrote:


> > Hello, Mohammed.

> Hi


> > Yes.  There is a bug in some cache handling code for macros, which
> > results in that cache thinking there's still a macro after it's been
> > deleted.

> > Thanks indeed for the bug report!

> > Would you please apply the following patch, then confirm to me that it's
> > fixed the problem, or else tell me what's still not working.  Thanks!

>  <snipped>

> The patch surely fixed the issue. Thanks

I actually committed a rather simpler patch.  The problem was "merely" an
off-by-1 bug, but in the same function.

[ .... ]

-- 
Alan Mackenzie (Nuremberg, Germany).


This bug report was last modified 7 years and 348 days ago.

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