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</o:shapelayout></xml><![endif]--></head><body lang=ZH-CN link="#0563C1" vlink="#954F72" style='word-wrap:break-word;text-justify-trim:punctuation'><div class=WordSection1><p class=MsoNormal><span lang=EN-US>Hi Christoph,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:10.5pt;mso-para-margin-left:1.0gd'><span lang=EN-US>Recently when I use kernel5.15 with android, an issue related to bow_target is found with below log:<o:p></o:p></span></p><p class=MsoNormal style='margin-left:10.5pt;mso-para-margin-left:1.0gd'><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'>[ 8.935429][ T1] kobject_add_internal failed for bow (error: -2 parent: (null))</span><span lang=EN-US style='font-family:Consolas'><o:p></o:p></span></p><p class=MsoNormal style='margin-left:10.5pt;mso-para-margin-left:1.0gd'><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:10.5pt;mso-para-margin-left:1.0gd'><span lang=EN-US>The call trace to the preceding log is as below:<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'>dm_ctl_ioctl<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'> -> ctl_ioctl<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'> -> lookup_ioctl // returns the table_load function pointer<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'> table_load<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'> -> populate_table<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'> -> dm_table_add_target<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'> -> dm_bow_ctr<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'> -> kobject_init_and_add<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'> -> kobject_add_varg<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'> -> kobject_add_internal<o:p></o:p></span></p><p class=MsoNormal style='margin-left:10.5pt;mso-para-margin-left:1.0gd'><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:10.5pt;mso-para-margin-left:1.0gd'><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:10.5pt;mso-para-margin-left:1.0gd'><span lang=EN-US>Compared to kernel5.10, then I found it’s related to below patch. The gendisk, it’s not registered yet, its kobject is not in sysfs, so its child “bow” kobject cannot be added to the kernel.<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'>commit 89f871af1b26d98d983cba7ed0e86effa45ba5f8<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'>Author: Christoph Hellwig <a href="mailto:hch@lst.de"><span style='color:#0070C0'>hch@lst.de</span></a><o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'>Date: Wed Aug 4 11:41:46 2021 +0200<o:p></o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:21.0pt;mso-para-margin-left:2.0gd'><span lang=EN-US style='font-family:Consolas;color:#0070C0'> dm: delay registering the gendisk<o:p></o:p></span></p><p class=MsoNormal style='margin-left:10.5pt;mso-para-margin-left:1.0gd'><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:10.5pt;mso-para-margin-left:1.0gd'><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:10.5pt;mso-para-margin-left:1.0gd'><span lang=EN-US>Is this an issue? if it is, is there any patch to fix it? if it is not, then what is the right way to use the bow_target in userspace?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Best Regards,<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US>Zhu Faqiang.<o:p></o:p></span></p></div></body></html>