linux-kernel - INFO: memory leak in gpio device in 6.2-rc6

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Date:   Tue, 31 Jan 2023 10:36:55 +0100
From:   Mirsad Goran Todorovac <mirsad.todorovac@....unizg.hr>
To:     linux-gpio@...r.kernel.org
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        linux-kernel@...r.kernel.org,
        Thorsten Leemhuis <regressions@...mhuis.info>
Subject: INFO: memory leak in gpio device in 6.2-rc6

Hi all,

I came across this memory leak apparently in the GPIO device driver.
It is still present in 6.2-rc6 release candidate kernel (just ran kselftest).

This is a vanilla Torvalds tree kernel with MGLRU and KMEMLEAK (obviously)
enabled.

If you think this bug is significant, I can attempt the bug bisect in the
environment that triggered it (Lenovo LENOVO_MT_10TX_BU_Lenovo_FM_V530S-07ICB)
with BIOS M22KT49A from 11/10/2022 and AlmaLinux 8.7.

Here is the /sys/kernel/debug/kmemleak output:

unreferenced object 0xffff9e67ad71f160 (size 32):
   comm "gpio-sim.sh", pid 208926, jiffies 4372229685 (age 2101.564s)
   hex dump (first 32 bytes):
     67 70 69 6f 2d 73 69 6d 2e 30 2d 6e 6f 64 65 30  gpio-sim.0-node0
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
   backtrace:
     [<0000000098bf3d1b>] slab_post_alloc_hook+0x91/0x320
     [<00000000da3205c5>] __kmem_cache_alloc_node+0x1bf/0x2b0
     [<00000000aa51a58a>] __kmalloc_node_track_caller+0x55/0x140
     [<00000000bd682ecc>] kvasprintf+0x6b/0xd0
     [<00000000a3431d55>] kasprintf+0x4e/0x70
     [<00000000f52d2629>] gpio_sim_device_config_live_store+0x401/0x59d [gpio_sim]
     [<00000000673fc6df>] configfs_write_iter+0xcc/0x130
     [<000000001d5d0829>] vfs_write+0x2b4/0x3d0
     [<00000000d2336251>] ksys_write+0x61/0xe0
     [<00000000f7015bb1>] __x64_sys_write+0x1a/0x20
     [<000000008ac743d2>] do_syscall_64+0x58/0x80
     [<000000004d7b7d50>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[root@...mtodorov marvin]#

Regards,
Mirsad

-- 
Mirsad Todorovac
System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb
Republic of Croatia, the European Union
--
Sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
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