Why hasn't the patch "r8152: Fix a deadlock by doubly PM resume" back ported to stable branches?

[Heyi Guo]

Hi all,

We found that below bug fix patch had not been back ported to stable 
branches, like linux-5.10.y. Is there any special reason?

commit 776ac63a986d211286230c4fd70f85390eabedcd
Author:     Takashi Iwai <tiwai@xxxxxxx>
AuthorDate: Wed Jul 14 19:00:22 2021 +0200
Commit:     David S. Miller <davem@xxxxxxxxxxxxx>
CommitDate: Wed Jul 14 14:57:55 2021 -0700

    r8152: Fix a deadlock by doubly PM resume

    r8152 driver sets up the MAC address at reset-resume, while
    rtl8152_set_mac_address() has the temporary autopm get/put. This may
    lead to a deadlock as the PM lock has been already taken for the
    execution of the runtime PM callback.

    This patch adds the workaround to avoid the superfluous autpm when
    called from rtl8152_reset_resume().

    Link: https://bugzilla.suse.com/show_bug.cgi?id=1186194
    Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>

Thanks,

Guo, Heyi