+ mm-use-stack_depot_early_init-for-kmemleak.patch added to mm-unstable branch

From: Andrew Morton <akpm@linux-foundation.org>
To: mm-commits@vger.kernel.org, vbabka@suse.cz, rppt@kernel.org,
	peterz@infradead.org, nathan@kernel.org,
	mirsad.todorovac@alu.unizg.hr, ke.wang@unisoc.com,
	catalin.marinas@arm.com, zhaoyang.huang@unisoc.com,
	akpm@linux-foundation.org
Subject: + mm-use-stack_depot_early_init-for-kmemleak.patch added to mm-unstable branch
Date: Thu, 19 Jan 2023 14:40:21 -0800	[thread overview]
Message-ID: <20230119224022.80752C433F0@smtp.kernel.org> (raw)


The patch titled
     Subject: mm: use stack_depot_early_init for kmemleak
has been added to the -mm mm-unstable branch.  Its filename is
     mm-use-stack_depot_early_init-for-kmemleak.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-use-stack_depot_early_init-for-kmemleak.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Subject: mm: use stack_depot_early_init for kmemleak
Date: Thu, 19 Jan 2023 09:22:25 +0800

Mirsad report the below error which is caused by stack_depot_init()
failure in kvcalloc.  Solve this by having stackdepot use
stack_depot_early_init().

On 1/4/23 17:08, Mirsad Goran Todorovac wrote:
I hate to bring bad news again, but there seems to be a problem with the output of /sys/kernel/debug/kmemleak:

[root@pc-mtodorov ~]# cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff951c118568b0 (size 16):
comm "kworker/u12:2", pid 56, jiffies 4294893952 (age 4356.548s)
hex dump (first 16 bytes):
    6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00 memstick0.......
    backtrace:
[root@pc-mtodorov ~]#

Apparently, backtrace of called functions on the stack is no longer printed with the list of memory leaks.
This appeared on Lenovo desktop 10TX000VCR, with AlmaLinux 8.7 and BIOS version M22KT49A (11/10/2022)
and 6.2-rc1 and 6.2-rc2 builds.
This worked on 6.1 with the same CONFIG_KMEMLEAK=y and MGLRU enabled on a vanilla mainstream kernel
from Mr. Torvalds' tree. I don't know if this is deliberate feature for some reason or a bug.
Please find attached the config, lshw and kmemleak output.

Link: https://lore.kernel.org/all/5272a819-ef74-65ff-be61-4d2d567337de@alu.unizg.hr/
Link: https://lkml.kernel.org/r/1674091345-14799-2-git-send-email-zhaoyang.huang@unisoc.com
Fixes: 56a61617dd22 ("mm: use stack_depot for recording kmemleak's backtrace")
Reported-by: Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: ke.wang <ke.wang@unisoc.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

--- a/mm/Kconfig.debug~mm-use-stack_depot_early_init-for-kmemleak
+++ a/mm/Kconfig.debug
@@ -219,6 +219,7 @@ config DEBUG_KMEMLEAK
 	select KALLSYMS
 	select CRC32
 	select STACKDEPOT
+	select STACKDEPOT_ALWAYS_INIT if !DEBUG_KMEMLEAK_DEFAULT_OFF
 	help
 	  Say Y here if you want to enable the memory leak
 	  detector. The memory allocation/freeing is traced in a way
--- a/mm/kmemleak.c~mm-use-stack_depot_early_init-for-kmemleak
+++ a/mm/kmemleak.c
@@ -2069,8 +2069,10 @@ static int __init kmemleak_boot_config(c
 		return -EINVAL;
 	if (strcmp(str, "off") == 0)
 		kmemleak_disable();
-	else if (strcmp(str, "on") == 0)
+	else if (strcmp(str, "on") == 0) {
 		kmemleak_skip_disable = 1;
+		stack_depot_want_early_init();
+	}
 	else
 		return -EINVAL;
 	return 0;
_

Patches currently in -mm which might be from zhaoyang.huang@unisoc.com are

mm-move-kmemleaks-kconfig-items-from-lib-to-mm.patch
mm-use-stack_depot_early_init-for-kmemleak.patch

