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Date:   Tue, 8 Mar 2022 10:58:02 +0300
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Subject: Re: Fw:Re: [PATCH] fs: nilfs2: fix memory leak in nilfs sysfs create
 device group
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To:     Dongliang Mu <mudongliangabcd@gmail.com>,
        Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        linux-nilfs <linux-nilfs@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Nanyong Sun <sunnanyong@huawei.com>,
        =?UTF-8?B?5oWV5Yas5Lqu?= <dzm91@hust.edu.cn>
References: <3192BC90-D082-472B-B310-6E09A14A77C6@hust.edu.cn>
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From:   Pavel Skripkin <paskripkin@gmail.com>
In-Reply-To: <CAD-N9QU8-Od3G+-=RHM5K7vR2-4Af+4t=XutJJVdmkKhH7OarA@mail.gmail.com>
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Hi Dongliang,

On 3/8/22 05:22, Dongliang Mu wrote:
> Hi Ryusuke,
> 
> My local syzkaller instance always complains about the following crash
> report no matter how many times I clean up the generated crash
> reports.
> 
> BUG: memory leak
> unreferenced object 0xffff88812e902be0 (size 32):
>    comm "syz-executor.2", pid 25972, jiffies 4295025942 (age 12.490s)
>    hex dump (first 32 bytes):
>      6c 6f 6f 70 32 00 00 00 00 00 00 00 00 00 00 00  loop2...........
>      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>    backtrace:
>      [<ffffffff8148a466>] kstrdup+0x36/0x70 mm/util.c:60
>      [<ffffffff8148a4f3>] kstrdup_const+0x53/0x80 mm/util.c:83
>      [<ffffffff8228dcd2>] kvasprintf_const+0xc2/0x110 lib/kasprintf.c:48
>      [<ffffffff8238ca5b>] kobject_set_name_vargs+0x3b/0xe0 lib/kobject.c:289
>      [<ffffffff8238d3bd>] kobject_add_varg lib/kobject.c:384 [inline]
>      [<ffffffff8238d3bd>] kobject_init_and_add+0x6d/0xc0 lib/kobject.c:473
>      [<ffffffff81d39d3a>] nilfs_sysfs_create_device_group+0x9a/0x3d0
> fs/nilfs2/sysfs.c:991
>      [<ffffffff81d22ee0>] init_nilfs+0x420/0x580 fs/nilfs2/the_nilfs.c:637
>      [<ffffffff81d108e2>] nilfs_fill_super fs/nilfs2/super.c:1046 [inline]
>      [<ffffffff81d108e2>] nilfs_mount+0x532/0x8c0 fs/nilfs2/super.c:1316
>      [<ffffffff815de0db>] legacy_get_tree+0x2b/0x90 fs/fs_context.c:610
>      [<ffffffff81579ba8>] vfs_get_tree+0x28/0x100 fs/super.c:1497
>      [<ffffffff815bb582>] do_new_mount fs/namespace.c:3024 [inline]
>      [<ffffffff815bb582>] path_mount+0xb92/0xfe0 fs/namespace.c:3354
>      [<ffffffff815bba71>] do_mount+0xa1/0xc0 fs/namespace.c:3367
>      [<ffffffff815bc084>] __do_sys_mount fs/namespace.c:3575 [inline]
>      [<ffffffff815bc084>] __se_sys_mount fs/namespace.c:3552 [inline]
>      [<ffffffff815bc084>] __x64_sys_mount+0xf4/0x160 fs/namespace.c:3552
>      [<ffffffff843dd8e5>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>      [<ffffffff843dd8e5>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>      [<ffffffff84400068>] entry_SYSCALL_64_after_hwframe+0x44/0xae
> 
> Unfortunately, there is no reproducer attached to the crash report.
> But I still think there should be another issue in the code.
> 

Can you, please, attach the log or try to find any fault injections? 
Them may point exactly to the root case.


With regards,
Pavel Skripkin