public inbox for git@vger.kernel.org 
 help / color / mirror / Atom feed
From: Patrick Steinhardt <ps@pks•im>
To: Lidong Yan via GitGitGadget <gitgitgadget@gmail•com>
Cc: git@vger•kernel.org, Lidong Yan <502024330056@smail•nju.edu.cn>
Subject: Re: [PATCH v2] reftable/writer: fix memory leak if write fails
Date: Mon, 12 May 2025 10:25:37 +0200	[thread overview]
Message-ID: <aCGwgbJ_dbO4vKq3@pks.im> (raw)
In-Reply-To: <pull.1958.v2.git.git.1746980165245.gitgitgadget@gmail.com>

On Sun, May 11, 2025 at 04:16:04PM +0000, Lidong Yan via GitGitGadget wrote:
> From: Lidong Yan <502024330056@smail•nju.edu.cn>
> 
> In reftable/writer.c:padded_write(), if w->writer failed, zeroed
> allocated in `reftable_calloc` will leak. w->writer could be
> `reftable_write_data` in reftable/stack.c, and could fail due to
> some write error. Simply add reftable_free(zeroed) will solve this
> problem.
> 
> In reftable/writer.c:writer_index_hash(), if `reftable_buf_add` failed,
> key allocated by `reftable_malloc` will not be insert into `obj_index_tree`
> thus leaks. Simple add reftable_free(key) will solve this problem.

Nit: I think it would be sensible to split these up into two commits, as
they touch different areas of the code.

> diff --git a/reftable/writer.c b/reftable/writer.c
> index cb16f71be49..3b4ebdd6dce 100644
> --- a/reftable/writer.c
> +++ b/reftable/writer.c
> @@ -57,8 +57,10 @@ static int padded_write(struct reftable_writer *w, uint8_t *data, size_t len,
>  			return -1;
>  
>  		n = w->write(w->write_arg, zeroed, w->pending_padding);
> -		if (n < 0)
> +		if (n < 0) {
> +			reftable_free(zeroed);
>  			return n;
> +		}
>  
>  		w->pending_padding = 0;
>  		reftable_free(zeroed);

Makes sense.

> @@ -256,8 +258,10 @@ static int writer_index_hash(struct reftable_writer *w, struct reftable_buf *has
>  
>  		reftable_buf_reset(&key->hash);
>  		err = reftable_buf_add(&key->hash, hash->buf, hash->len);
> -		if (err < 0)
> +		if (err < 0) {
> +			reftable_free(key);
>  			return err;
> +		}
>  		tree_insert(&w->obj_index_tree, key,
>  			    &obj_index_tree_node_compare);
>  	} else {

Makes sense, as well. We want to add the node to the object index tree,
but if a step before fails then we naturally want to free the node.

Patrick

  reply	other threads:[~2025-05-12  8:25 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-10  3:50 [PATCH] reftable/writer: fix memory leak when `padded_write()` fails Lidong Yan via GitGitGadget
2025-05-11 16:16 ` [PATCH v2] reftable/writer: fix memory leak if write fails Lidong Yan via GitGitGadget
2025-05-12  8:25   ` Patrick Steinhardt [this message]
2025-05-12 10:54     ` lidongyan
2025-05-12 12:49   ` [PATCH v3 0/2] reftable/writer: fix memory leak when " Lidong Yan via GitGitGadget
2025-05-12 12:49     ` [PATCH v3 1/2] reftable/writer: fix memory leak when `padded_write()` fails Lidong Yan via GitGitGadget
2025-05-12 12:49     ` [PATCH v3 2/2] reftable/writer: fix memory leak when `writer_index_hash()` fails Lidong Yan via GitGitGadget
2025-05-12 14:34     ` [PATCH v3 0/2] reftable/writer: fix memory leak when write fails Patrick Steinhardt

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=aCGwgbJ_dbO4vKq3@pks.im \
    --to=ps@pks$(echo .)im \
    --cc=502024330056@smail$(echo .)nju.edu.cn \
    --cc=git@vger$(echo .)kernel.org \
    --cc=gitgitgadget@gmail$(echo .)com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox