From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Fri, 20 Sep 2019 12:48:10 +0000 (+0300)
Subject: lib-index: Fix potential assert-crash when rotating log file
X-Git-Tag: 2.3.10~115
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=663a98bfc7f0b12b47a6f30fa4279a52e5f68bc1;p=thirdparty%2Fdovecot%2Fcore.git

lib-index: Fix potential assert-crash when rotating log file

Unlock the old head file before attempting to clean it. Fixes:

Panic: file mail-transaction-log.c: line 229 (mail_transaction_logs_clean): assertion failed: (!file->locked || file->refcount > 0)

This seems to only have happened during new obox index merging.
---

diff --git a/src/lib-index/mail-transaction-log.c b/src/lib-index/mail-transaction-log.c
index 044153f9cd..5a9cee1623 100644
--- a/src/lib-index/mail-transaction-log.c
+++ b/src/lib-index/mail-transaction-log.c
@@ -260,7 +260,7 @@ bool mail_transaction_log_want_rotate(struct mail_transaction_log *log)
 
 int mail_transaction_log_rotate(struct mail_transaction_log *log, bool reset)
 {
-	struct mail_transaction_log_file *file;
+	struct mail_transaction_log_file *file, *old_head;
 	const char *path = log->head->filepath;
 	struct stat st;
 	int ret;
@@ -304,15 +304,15 @@ int mail_transaction_log_rotate(struct mail_transaction_log *log, bool reset)
 		i_assert(file->locked);
 	}
 
-	if (--log->head->refcount == 0)
-		mail_transaction_logs_clean(log);
-	else {
-		/* the newly created log file is already locked */
-		mail_transaction_log_file_unlock(log->head,
-			!log->index->log_sync_locked ? "rotating" :
-			"rotating while syncing");
-	}
+	old_head = log->head;
 	mail_transaction_log_set_head(log, file);
+
+	/* the newly created log file is already locked */
+	mail_transaction_log_file_unlock(old_head,
+		!log->index->log_sync_locked ? "rotating" :
+		"rotating while syncing");
+	if (--old_head->refcount == 0)
+		mail_transaction_logs_clean(log);
 	return 0;
 }