From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4FF8C4FC8FC for ; Thu, 3 Sep 2026 17:48:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788457716; cv=none; b=VdHkhQsfxAMZRlRXo5lu2QGBN3PsTwJ8yV8b+wLN13THgsbBmoEJGsWg9nI/91h7OXOfjuwRRH+2gV0MFBdS0SmuoixGvbcs1llMzt20k+ls7HOvvpvc0M0MIz9WFztf41Jdf8CrCHuDIojwGUJAbXMyNmzTObGtS6NZI9bj5+A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788457716; c=relaxed/simple; bh=LLM7j1D1k7zj5nY+sZ/O93n0eysLxRCtI80EBnGA2dQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FOL4y679NoJnQ71pwwfN/kyVz/vg6oM235cy1YIVhaXfUfMZjJ0luNf85h3SdfdrMI+lduxxRqvzhCbzcfL+KQBev2tgu3r1k+yAVDSbL3B4hkqLRXyn2YWZ++qfwR76dgU0xWoTfuF05RuTUroRil/kQdynrD+XZXdgNERKR5E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CE8N0EHO; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="CE8N0EHO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFA151F000E9; Thu, 3 Sep 2026 17:48:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788457714; bh=SYrqsleLgvHItJhh4JOTWTWJ79EdLVRelMtAxg1HQUs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CE8N0EHOM8+Wbc1S9F9SCKsGVKjuxe29cpM6neZM6kGyjXbYJg6Kjd7MrrhZoqgVs nWORdTCMQYo4DiA41XUcOW8Ym46VAd6ZC8tJ26tAzLL4IslpdIKQ0n+CGUxXIai1eP sGdaHU9/0rMMH6lfk/sf0FprUS8Dl91IWpm0jnQ5ELUlIEaJSwJ7JL7Jm+6zGHK5w9 SIcAbw9Y74U66+pgUbjCOt41JZ4g4XR4qUD2rjPPNGw1pwvuen9J6DEZXo4NUCc1We Bki3hrV+Cz1Olh+VuXwcfq9C4MINhFzF8H6txD/A9rwf5wThxD2XEMqeI58Xcn6M1H olb3NhsmTvMCQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Zhaoyang Huang , Catalin Marinas , "ke.wang" , "Matthew Wilcox (Oracle)" , Vlastimil Babka , Zhaoyang Huang , Andrew Morton , Sasha Levin Subject: [PATCH 6.1.y 1/4] mm: use stack_depot for recording kmemleak's backtrace Date: Thu, 3 Sep 2026 13:48:29 -0400 Message-ID: <20260903174832.1263842-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026090332-elliptic-contort-6cb3@gregkh> References: <2026090332-elliptic-contort-6cb3@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Zhaoyang Huang [ Upstream commit 56a61617dd2276cbc56a6c868599716386d70041 ] Using stack_depot to record kmemleak's backtrace which has been implemented on slub for reducing redundant information. [akpm@linux-foundation.org: fix build - remove now-unused __save_stack_trace()] [zhaoyang.huang@unisoc.com: v3] Link: https://lkml.kernel.org/r/1667101354-4669-1-git-send-email-zhaoyang.huang@unisoc.com [akpm@linux-foundation.org: fix v3 layout oddities] [akpm@linux-foundation.org: coding-style cleanups] Link: https://lkml.kernel.org/r/1666864224-27541-1-git-send-email-zhaoyang.huang@unisoc.com Signed-off-by: Zhaoyang Huang Acked-by: Catalin Marinas Cc: ke.wang Cc: Matthew Wilcox (Oracle) Cc: Vlastimil Babka Cc: Zhaoyang Huang Signed-off-by: Andrew Morton Stable-dep-of: 5d10d4e19e6d ("mm/kmemleak: avoid soft lockup when scanning task stacks") Signed-off-by: Sasha Levin --- lib/Kconfig.debug | 1 + mm/kmemleak.c | 46 ++++++++++++++++++++++++++++------------------ 2 files changed, 29 insertions(+), 18 deletions(-) diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index d00c695bf4921..cfff3f1e4713d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -737,6 +737,7 @@ config DEBUG_KMEMLEAK select STACKTRACE if STACKTRACE_SUPPORT select KALLSYMS select CRC32 + select STACKDEPOT help Say Y here if you want to enable the memory leak detector. The memory allocation/freeing is traced in a way diff --git a/mm/kmemleak.c b/mm/kmemleak.c index d3c9a63d7a9d5..eaa89f20cd35d 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -79,6 +79,7 @@ #include #include #include +#include #include #include #include @@ -159,8 +160,7 @@ struct kmemleak_object { u32 checksum; /* memory ranges to be scanned inside an object (empty for all) */ struct hlist_head area_list; - unsigned long trace[MAX_TRACE]; - unsigned int trace_len; + depot_stack_handle_t trace_handle; unsigned long jiffies; /* creation timestamp */ pid_t pid; /* pid of the current task */ char comm[TASK_COMM_LEN]; /* executable name */ @@ -346,18 +346,21 @@ static void print_unreferenced(struct seq_file *seq, struct kmemleak_object *object) { 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); + 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); + object->comm, object->pid, object->jiffies, + msecs_age / 1000, msecs_age % 1000); hex_dump_object(seq, object); warn_or_seq_printf(seq, " backtrace:\n"); - for (i = 0; i < object->trace_len; i++) { - void *ptr = (void *)object->trace[i]; + for (i = 0; i < nr_entries; i++) { + void *ptr = (void *)entries[i]; warn_or_seq_printf(seq, " [<%p>] %pS\n", ptr, ptr); } } @@ -370,15 +373,16 @@ static void print_unreferenced(struct seq_file *seq, static void dump_object_info(struct kmemleak_object *object) { pr_notice("Object 0x%08lx (size %zu):\n", - object->pointer, object->size); + object->pointer, object->size); pr_notice(" comm \"%s\", pid %d, jiffies %lu\n", - object->comm, object->pid, object->jiffies); + object->comm, object->pid, object->jiffies); pr_notice(" min_count = %d\n", object->min_count); pr_notice(" count = %d\n", object->count); pr_notice(" flags = 0x%x\n", object->flags); pr_notice(" checksum = %u\n", object->checksum); pr_notice(" backtrace:\n"); - stack_trace_print(object->trace, object->trace_len, 4); + if (object->trace_handle) + stack_depot_print(object->trace_handle); } /* @@ -594,12 +598,18 @@ static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int ali return object; } -/* - * Save stack trace to the given array of MAX_TRACE size. - */ -static int __save_stack_trace(unsigned long *trace) +static noinline depot_stack_handle_t set_track_prepare(void) { - return stack_trace_save(trace, MAX_TRACE, 2); + depot_stack_handle_t trace_handle; + unsigned long entries[MAX_TRACE]; + unsigned int nr_entries; + + if (!kmemleak_initialized) + return 0; + nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3); + trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT); + + return trace_handle; } /* @@ -656,7 +666,7 @@ static void __create_object(unsigned long ptr, size_t size, } /* kernel backtrace */ - object->trace_len = __save_stack_trace(object->trace); + object->trace_handle = set_track_prepare(); raw_spin_lock_irqsave(&kmemleak_lock, flags); @@ -695,7 +705,6 @@ static void __create_object(unsigned long ptr, size_t size, rb_link_node(&object->rb_node, rb_parent, link); rb_insert_color(&object->rb_node, is_phys ? &object_phys_tree_root : &object_tree_root); - list_add_tail_rcu(&object->object_list, &object_list); out: raw_spin_unlock_irqrestore(&kmemleak_lock, flags); @@ -1094,7 +1103,7 @@ void __ref kmemleak_update_trace(const void *ptr) } raw_spin_lock_irqsave(&object->lock, flags); - object->trace_len = __save_stack_trace(object->trace); + object->trace_handle = set_track_prepare(); raw_spin_unlock_irqrestore(&object->lock, flags); put_object(object); @@ -2092,6 +2101,7 @@ void __init kmemleak_init(void) if (kmemleak_error) return; + stack_depot_init(); jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE); jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000); -- 2.53.0