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[73.78.62.130]) by smtp.googlemail.com with ESMTPSA id g12-20020a92520c000000b0035913c8423esm84399ilb.73.2023.11.16.14.43.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Nov 2023 14:43:38 -0800 (PST) From: Jim Cromie To: linux-kernel@vger.kernel.org Cc: catalin.marinas@arm.com, akpm@linux-foundation.org, Jim Cromie Subject: [PATCH 1/2] kmemleak: drop (age ) from leak record Date: Thu, 16 Nov 2023 15:43:17 -0700 Message-ID: <20231116224318.124209-2-jim.cromie@gmail.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231116224318.124209-1-jim.cromie@gmail.com> References: <20231116224318.124209-1-jim.cromie@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-0.6 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on fry.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (fry.vger.email [0.0.0.0]); Thu, 16 Nov 2023 14:44:15 -0800 (PST) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1782762343464768335 X-GMAIL-MSGID: 1782762343464768335 Displaying age is pretty, but counter-productive; it changes with current-time, so it surrenders idempotency of the output, which breaks simple hash-based cataloging of the records by the user. The trouble: sequential reads, wo new leaks, get new results: :#> sum /sys/kernel/debug/kmemleak 53439 74 /sys/kernel/debug/kmemleak :#> sum /sys/kernel/debug/kmemleak 59066 74 /sys/kernel/debug/kmemleak and age is why (nothing else changes): :#> grep -v age /sys/kernel/debug/kmemleak | sum 58894 67 :#> grep -v age /sys/kernel/debug/kmemleak | sum 58894 67 Since jiffies is already printed in the "comm" line, age adds nothing. Notably, syzkaller reads kmemleak only for "unreferenced object", and won't care about this reform of age-ism. A few moribund github repos mention it, but don't compile. Signed-off-by: Jim Cromie Reviewed-by: Catalin Marinas --- mm/kmemleak.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 1eacca03bedd..10c9b611c395 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -355,14 +355,12 @@ static void print_unreferenced(struct seq_file *seq, int i; unsigned long *entries; unsigned int nr_entries; - unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies); nr_entries = stack_depot_fetch(object->trace_handle, &entries); warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n", object->pointer, object->size); - warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n", - object->comm, object->pid, object->jiffies, - msecs_age / 1000, msecs_age % 1000); + warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n", + object->comm, object->pid, object->jiffies); hex_dump_object(seq, object); warn_or_seq_printf(seq, " backtrace:\n"); From patchwork Thu Nov 16 22:43:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jim Cromie X-Patchwork-Id: 165956 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:9910:0:b0:403:3b70:6f57 with SMTP id i16csp161973vqn; Thu, 16 Nov 2023 14:43:59 -0800 (PST) X-Google-Smtp-Source: AGHT+IFZR6c2DQ6X5s3BRZhLVliKT9iE6RmouOTwhyLEqaxQQEzxbN2ckEgPAUyqvDpfDU+MwTdE X-Received: by 2002:aa7:8750:0:b0:6b1:e876:168b with SMTP id g16-20020aa78750000000b006b1e876168bmr17009485pfo.11.1700174639236; Thu, 16 Nov 2023 14:43:59 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1700174639; cv=none; d=google.com; s=arc-20160816; b=hTU0wWX9pT5vnu1kHVmzFbZaFVgvNhLuhmdFveQuYWNn0WTxfBR0dSq8fJRVYVagMB QKlv7OrIRHHN4iye7cDORjckkJFYlek3bIMT/SZnPYT78HcqxKziGtmU2EC3hNumTYY4 Zo98E1eYVASGusQxHfiwLGiBjvJcUG1jXIdkgXreGq8opdn+APT59yxmZoDqacLNP3+5 qOJfqtxxLxP9wdP2pvSyBZ7JcHMO5w7M+pv5+Pg/AkTweIDgQTdXWKyfMygrFXbisbzd Igc38Zzu4HzU9oEozKO9+Zwg6uyGNxgrRhq639/9K24K0dJwIRKq6pgvkfT3cTjp5Kn5 33Fw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=+2UNwLHsfjJtEfaIA7r+LiQYjr8iboIsfl4RMvTTOCM=; fh=EgVkNH+Cb9K8YOTSQBPxNV2o+rDWdzEBRqk7dHoL+c0=; b=MGxUNrCvBm4FXTnP9ZKzXFJuv5z0txkNR7IqTpnLWNfScfbAaZiJycqd5StJa2Ux2I T8xkHontrIhBqt95WDm2joV1RY54AVPmcO01PA9n8FzfTjiySzz+cXYruWsLjfqvUUbj 69gPs86f3VcctJQO9QgL+HdjoIIilMXSdRjq+YbA8e2p46WWtZ/vs6/a0jcpUIMlQn+f jdQELIfyK+/HGSASZpLOWbDurvZ4S4vMRHg0+iWdFNSBqn2FP/YjcSjg49SSIgrSsOB9 kr0SSFpNz2oYWCCgvcRzcM3sZpq6/+IAwtT77xy8r3/PZcNULgem9Grygb7rZoFgmYDE M1XQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=Az5QZQD6; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.37 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from snail.vger.email (snail.vger.email. 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[73.78.62.130]) by smtp.googlemail.com with ESMTPSA id g12-20020a92520c000000b0035913c8423esm84399ilb.73.2023.11.16.14.43.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Nov 2023 14:43:39 -0800 (PST) From: Jim Cromie To: linux-kernel@vger.kernel.org Cc: catalin.marinas@arm.com, akpm@linux-foundation.org, Jim Cromie Subject: [PATCH 2/2] kmemleak: add checksum to backtrace report Date: Thu, 16 Nov 2023 15:43:18 -0700 Message-ID: <20231116224318.124209-3-jim.cromie@gmail.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20231116224318.124209-1-jim.cromie@gmail.com> References: <20231116224318.124209-1-jim.cromie@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (snail.vger.email [0.0.0.0]); Thu, 16 Nov 2023 14:43:58 -0800 (PST) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1782762322439081104 X-GMAIL-MSGID: 1782762322439081104 Change /sys/kernel/debug/kmemleak report format slightly, adding "(extra info)" to the backtrace header: from: " backtrace:" to: " backtrace (crc ):" The allows a user to see recurring backtraces without detailed/careful reading of multiline stacks. So after cycling kmemleak-test a few times, I know some leaks are repeating. bash-5.2# grep backtrace /sys/kernel/debug/kmemleak | wc 62 186 1792 bash-5.2# grep backtrace /sys/kernel/debug/kmemleak | sort -u | wc 37 111 1067 syzkaller parses kmemleak for "unreferenced object" only, so is unaffected by this change. Other github repos are moribund. Signed-off-by: Jim Cromie Reviewed-by: Catalin Marinas --- mm/kmemleak.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 10c9b611c395..4c22a2d7cab4 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -362,7 +362,7 @@ static void print_unreferenced(struct seq_file *seq, warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n", object->comm, object->pid, object->jiffies); hex_dump_object(seq, object); - warn_or_seq_printf(seq, " backtrace:\n"); + warn_or_seq_printf(seq, " backtrace (crc %x):\n", object->checksum); for (i = 0; i < nr_entries; i++) { void *ptr = (void *)entries[i];