From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4FC2615665C; Wed, 14 Oct 2026 09:53:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.2 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791971602; cv=none; b=CC43tOroXYqCSPmLLq5wa+PewgAFC6X01yO/shOyIrCLWsConJHytDwPGfzbfZ0pIQiJTOJrFY9SVczuCMCWpxPy15MJDmSAHya2/s3wokA5Llf9mFIyU2DVLHq1i5xEpIwS3SAQhT5jGoSt6TtSK4z6R/npbSW4eR1hGllA3hk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791971602; c=relaxed/simple; bh=ulf5xv3gZRkzQ2p4iCZVnIb4iKNqtbR/JTlO3KsKFxU=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=p61BhZzv9CbvgnBY/z6Z3ruz7j09sEqvvTOrC838lK+vxU1h5xFapoSmkeMI+OnJUC45RRO6MNkTMNFQ0HIQz0DyhdfM71ITZgmrHsxAvQ/7ltOKFHYSaXYXaCFH7cRmXfOhzDPMx2WezEV3QdOv0p2uihk2LuC2CkOsQVcQlRk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=P5nRMCTi; arc=none smtp.client-ip=117.135.210.2 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="P5nRMCTi" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=hO qqSU4bOLhFj0Ntu32+7viLCVetkiFnaPi1n9kTbzU=; b=P5nRMCTiZnum/Doead ++0vZl7Y6ejCyKz5hO408VmLoZwO076GqK5QL0N3O8062rn6mfVdw3R/7LTQrBzg kRCB+dixqzp4ULHXH9wlSYLdQiRN982J/49oJ+R37UaWSRG9/Bd+yFNnzX8uf4+Y Lx01p4XhedeqkXEEw4EQ47GbI= Received: from localhost (unknown []) by gzsmtp2 (Coremail) with SMTP id PSgvCgDXX9foUM9qdnafEA--.29710S2; Wed, 14 Oct 2026 17:52:41 +0800 (CST) From: Hui Su To: elver@google.com, dvyukov@google.com Cc: kasan-dev@googlegroups.com, corbet@lwn.net, skhan@linuxfoundation.org, rdunlap@infradead.org, workflows@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH 2/4] kcsan: add debugfs target control Date: Wed, 14 Oct 2026 18:52:36 +0900 Message-ID: <20261014095238.2132580-3-sh_def@163.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:PSgvCgDXX9foUM9qdnafEA--.29710S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxGFyxGF43uF4Utw4rAF1UJrb_yoW5Jw4Up3 45K345Wr4rJrWayr4fCF4kX34rGw1vgr129FWxurZ5C3Z8GryrWayfKFy3tFyYgry8Cr15 WF4q9rWUCFWDAw7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jjv38UUUUU= X-CM-SenderInfo: xvkbvvri6rljoofrz/xtbC6QncPGrPUOnUAwAA3L Expose targeted sampling through the KCSAN debugfs file. Accept address and kallsyms targets, including module:symbol names, and allow sampling to be disabled with target=off. Use KSYM_SYMBOL_LEN for the input buffer so documented module symbols fit, and return -E2BIG for oversized writes. Signed-off-by: Hui Su --- kernel/kcsan/debugfs.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) diff --git a/kernel/kcsan/debugfs.c b/kernel/kcsan/debugfs.c index 2af39ba5b70b..47becde9f1ae 100644 --- a/kernel/kcsan/debugfs.c +++ b/kernel/kcsan/debugfs.c @@ -191,6 +191,7 @@ static ssize_t insert_report_filterlist(const char *func) static int show_info(struct seq_file *file, void *v) { int i; + unsigned long target; unsigned long flags; /* show stats */ @@ -199,6 +200,12 @@ static int show_info(struct seq_file *file, void *v) seq_printf(file, "%s: %ld\n", counter_names[i], atomic_long_read(&kcsan_counters[i])); } + target = kcsan_target_get(); + if (target) + seq_printf(file, "\ntarget: %pK (%pS)\n", (void *)target, + (void *)target); + else + seq_puts(file, "\ntarget: none\n"); /* show filter functions, and filter type */ raw_spin_lock_irqsave(&report_filterlist_lock, flags); @@ -220,10 +227,13 @@ static int debugfs_open(struct inode *inode, struct file *file) static ssize_t debugfs_write(struct file *file, const char __user *buf, size_t count, loff_t *off) { - char kbuf[KSYM_NAME_LEN]; + char kbuf[KSYM_SYMBOL_LEN + sizeof("target=")]; char *arg; const size_t read_len = min(count, sizeof(kbuf) - 1); + if (count > sizeof(kbuf) - 1) + return -E2BIG; + if (copy_from_user(kbuf, buf, read_len)) return -EFAULT; kbuf[read_len] = '\0'; @@ -239,6 +249,22 @@ debugfs_write(struct file *file, const char __user *buf, size_t count, loff_t *o if (kstrtoul(&arg[strlen("microbench=")], 0, &iters)) return -EINVAL; microbenchmark(iters); + } else if (str_has_prefix(arg, "target=")) { + char *target = &arg[strlen("target=")]; + unsigned long addr; + + if (!strcmp(target, "off")) { + kcsan_target_set(0); + } else if (!kstrtoul(target, 0, &addr)) { + if (!addr) + return -EINVAL; + kcsan_target_set(addr); + } else { + addr = kallsyms_lookup_name(target); + if (!addr) + return -ENOENT; + kcsan_target_set(addr); + } } else if (!strcmp(arg, "whitelist")) { set_report_filterlist_whitelist(true); } else if (!strcmp(arg, "blacklist")) { -- 2.55.0