From: Yuan Fu <casouri@gmail.com>
To: Juri Linkov <juri@linkov.net>
Cc: 71681@debbugs.gnu.org
Subject: bug#71681: 29.3.50; tree-sitter crash
Date: Sat, 29 Jun 2024 16:54:39 -0700 [thread overview]
Message-ID: <25A37A53-DD48-4E34-ABD7-1BACECCD8CEC@gmail.com> (raw)
In-Reply-To: <E28313FF-A353-4BB5-BC06-FFD4E5F19385@gmail.com>
> On Jun 25, 2024, at 11:04 PM, Yuan Fu <casouri@gmail.com> wrote:
>
>
>
>> On Jun 24, 2024, at 12:46 AM, Yuan Fu <casouri@gmail.com> wrote:
>>
>>
>>
>>> On Jun 23, 2024, at 10:38 AM, Juri Linkov <juri@linkov.net> wrote:
>>>
>>>>> Evaluating this expression causes a crash:
>>>>>
>>>>> (progn
>>>>> (find-file (expand-file-name "src/treesit.c" installation-directory))
>>>>> (c-ts-mode)
>>>>> (font-lock-ensure 63209 63387))
>>>>>
>>>>> in latest master, but not in latest emacs-29 (only in 5-months old emacs-29).
>>>>>
>>>>> If this is not reproducible, I could provide more details.
>>>>>
>>>>> libtree-sitter is at the latest version.
>>>>
>>>> Hmm, I can’t reproduce with latest master and libtree-sitter. Maybe you can send me the exact commits that you used?
>>>>
>>>> Here’s mine:
>>>>
>>>> Emacs: 72f2b01e318
>>>> Tree-sitter: 6ec478c1
>>>
>>> Probably reproducibility depends on the content of the src/treesit.c file.
>>> Then the most reliable way to reproduce it is this:
>>>
>>> 0. emacs -Q
>>> 1. eval: (add-to-list 'major-mode-remap-alist '(c-mode . c-ts-mode))
>>> 2. C-x v L
>>> 3. in the *vc-change-log* buffer move point to the commit 20af58d3a13
>>> 4. type D
>>> 5. crash caused by diff-font-lock-syntax fontification that uses treesit
>>>
>>> The numbers in (font-lock-ensure 63209 63387) above were extracted
>>> from diff hunk boundaries that might be different when the file was edited.
>>
>> I reproduce it once with the first set of commits you provided, but for some reason couldn’t reproduce it again. I’m sure it’s something wrong that I did. I’ll report back when I make progress. TBH it seems like something wrong with tree-sitter itself, but I’ll make sure to figure out what’s the problem exactly.
>>
>> Yuan
>
> Ok, I can reproduce it now. Looking into it…
Finally figured out why. It’s not tree-sitter’s problem, but ours. I reduced the crash to a signal and pushed the fix to emacs-30. Next I’ll make sure the signal is properly handled. Below quoting the commit message:
The immediate cause of the crash is that tree-sitter accessed a node's
tree, but the tree is already deleted.
What happended, I think, is this:
1. Buffer modified, parser->need_reparse set to true,
parser->timestamp incremented.
2. A node is created from the parser, this node has the old tree but
the _new_ timestamp (bad!).
3. Parser re-parses (treesit_ensure_parsed), new tree created, old
tree deleted.
4. Ftreesit_query_capture accessed the old node, and the old tree,
crash.
We shouldn't bump the parser timestamp when we set
parser->need_reparse to true; instead, we should bump the timestamp
when we actually reparsed and created a new tree.
Yuan
next prev parent reply other threads:[~2024-06-29 23:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-20 16:33 bug#71681: 29.3.50; tree-sitter crash Juri Linkov
2024-06-22 23:55 ` Yuan Fu
2024-06-23 5:32 ` Eli Zaretskii
2024-06-23 6:46 ` Juri Linkov
2024-06-23 17:38 ` Juri Linkov
2024-06-24 7:46 ` Yuan Fu
2024-06-26 6:04 ` Yuan Fu
2024-06-29 23:54 ` Yuan Fu [this message]
2024-06-30 14:28 ` Vincenzo Pupillo
2024-06-30 16:15 ` Juri Linkov
2024-06-30 19:22 ` Vincenzo Pupillo
2024-07-01 5:37 ` Yuan Fu
2024-07-01 10:20 ` Vincenzo Pupillo
2024-07-01 6:49 ` Juri Linkov
2024-07-01 7:01 ` Yuan Fu
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