Re: Fw:Re: [PATCH] fs: nilfs2: fix memory leak in nilfs sysfs create device group

[Pavel Skripkin]

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