From: "Paul Tarjan via GitGitGadget" <gitgitgadget@gmail•com>
To: git@vger•kernel.org
Cc: "René Scharfe" <l.s.r@web•de>,
"Paul Tarjan" <github@paulisageek•com>,
"Paul Tarjan" <github@paulisageek•com>
Subject: [PATCH v2] fsmonitor: fix khash memory leak in do_handle_client
Date: Wed, 31 Dec 2025 14:39:03 +0000 [thread overview]
Message-ID: <pull.2148.v2.git.git.1767191943962.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.2148.git.git.1767098576384.gitgitgadget@gmail.com>
From: Paul Tarjan <github@paulisageek•com>
The do_handle_client() function allocates a khash table to de-duplicate
pathnames when responding to client requests. However, kh_release_str()
was used instead of kh_destroy_str(). The release function only frees
internal arrays (flags, keys, vals) but not the struct itself, which is
allocated by kh_init_str() via xcalloc. This caused a 40-byte leak per
client request.
Fix by using kh_destroy_str() which properly frees both internal arrays
and the struct itself. Also move the cleanup to the cleanup section and
initialize shown to NULL so that kh_destroy_str() is safe to call on all
exit paths.
Signed-off-by: Paul Tarjan <github@paulisageek•com>
---
fsmonitor: fix khash memory leak in do_handle_client
The do_handle_client() function allocates a khash table to de-duplicate
pathnames when responding to client requests. However, kh_release_str()
was used instead of kh_destroy_str(). The release function only frees
internal arrays (flags, keys, vals) but not the struct itself, which is
allocated by kh_init_str() via xcalloc. This caused a 40-byte leak per
client request.
Fix by using kh_destroy_str() which properly frees both internal arrays
and the struct itself. Also move the cleanup to the cleanup section and
initialize shown to NULL so that kh_destroy_str() is safe to call on all
exit paths.
Changes since v1:
* Removed incorrect claim about interrupted threads reaching cleanup
* Simplified commit message to focus on the real bug (kh_release vs
kh_destroy)
Signed-off-by: Paul Tarjan github@paulisageek•com
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-2148%2Fptarjan%2Fclaude%2Ffix-fsmonitor-hashmap-leak-gfDCU-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-2148/ptarjan/claude/fix-fsmonitor-hashmap-leak-gfDCU-v2
Pull-Request: https://github.com/git/git/pull/2148
Range-diff vs v1:
1: 18670d3230 ! 1: 0a754c7f09 fsmonitor: fix khash memory leak in do_handle_client
@@ Commit message
fsmonitor: fix khash memory leak in do_handle_client
The do_handle_client() function allocates a khash table to de-duplicate
- pathnames when responding to client requests. Two issues existed:
+ pathnames when responding to client requests. However, kh_release_str()
+ was used instead of kh_destroy_str(). The release function only frees
+ internal arrays (flags, keys, vals) but not the struct itself, which is
+ allocated by kh_init_str() via xcalloc. This caused a 40-byte leak per
+ client request.
- 1. kh_release_str() was used instead of kh_destroy_str(). The release
- function only frees internal arrays (flags, keys, vals) but not the
- struct itself (allocated by kh_init_str via xcalloc). This caused a
- 40-byte leak per request.
+ Fix by using kh_destroy_str() which properly frees both internal arrays
+ and the struct itself. Also move the cleanup to the cleanup section and
+ initialize shown to NULL so that kh_destroy_str() is safe to call on all
+ exit paths.
- 2. The khash was freed mid-function rather than in the cleanup section,
- so if the worker thread was interrupted before reaching that point
- during daemon shutdown, the memory would leak.
-
- Fix both issues by:
- - Initializing shown = NULL at declaration
- - Using kh_destroy_str() which handles NULL and frees both internal
- arrays and the struct itself
- - Moving the cleanup to the cleanup section so it runs on all exit paths
-
- Signed-off-by: Claude <claude@anthropic•com>
+ Signed-off-by: Paul Tarjan <github@paulisageek•com>
## builtin/fsmonitor--daemon.c ##
@@ builtin/fsmonitor--daemon.c: static int do_handle_client(struct fsmonitor_daemon_state *state,
builtin/fsmonitor--daemon.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/builtin/fsmonitor--daemon.c b/builtin/fsmonitor--daemon.c
index 242c594646..bc4571938c 100644
--- a/builtin/fsmonitor--daemon.c
+++ b/builtin/fsmonitor--daemon.c
@@ -671,7 +671,7 @@ static int do_handle_client(struct fsmonitor_daemon_state *state,
const struct fsmonitor_batch *batch;
struct fsmonitor_batch *remainder = NULL;
intmax_t count = 0, duplicates = 0;
- kh_str_t *shown;
+ kh_str_t *shown = NULL;
int hash_ret;
int do_trivial = 0;
int do_flush = 0;
@@ -909,8 +909,6 @@ static int do_handle_client(struct fsmonitor_daemon_state *state,
total_response_len += payload.len;
}
- kh_release_str(shown);
-
pthread_mutex_lock(&state->main_lock);
if (token_data->client_ref_count > 0)
@@ -954,6 +952,7 @@ static int do_handle_client(struct fsmonitor_daemon_state *state,
trace2_data_intmax("fsmonitor", the_repository, "response/count/duplicates", duplicates);
cleanup:
+ kh_destroy_str(shown);
strbuf_release(&response_token);
strbuf_release(&requested_token_id);
strbuf_release(&payload);
base-commit: 7c7698a654a7a0031f65b0ab0c1c4e438e95df60
--
gitgitgadget
next prev parent reply other threads:[~2025-12-31 14:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-30 12:42 [PATCH] fsmonitor: fix khash memory leak in do_handle_client Paul Tarjan via GitGitGadget
2025-12-31 8:37 ` René Scharfe
2025-12-31 14:39 ` Paul Tarjan via GitGitGadget [this message]
2026-01-01 23:14 ` [PATCH v2] " Junio C Hamano
2026-01-02 1:24 ` Paul Tarjan
2026-01-04 2:19 ` Junio C Hamano
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