https://bugzilla.kernel.org/show_bug.cgi?id=206619
Bug ID: 206619 Summary: reboot hung since request_firmware Product: ACPI Version: 2.5 Kernel Version: 4.19 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Power-Off Assignee: acpi_power-...@kernel-bugs.osdl.org Reporter: zhaoqia...@xiaomi.com Regression: No I got an issue in reboot pressure test,reboot command called by user first,all userspace task has been killed,then a kworker thread grab cpu then invoking request_firmware,but since uevent thread has been killed,request_firmware will never load successfully,blocked in "wait_for_completion_killable_timeout" ,before wait complete,this thread has calling usermodehelper_read_trylock and held "umhelper_sem" lock,at this time,init reboot continue to running,try to __usermodehelper_disable,this needs hold umhelper_sem,but it's held by kworker,casue reboot process blocked until request_firmware timeout and release umhelper_sem,if timeout not be setting,this timeout maybe MAX_JIFFY_OFFSET,so i think it's a risk. -- You are receiving this mail because: You are watching the assignee of the bug. _______________________________________________ acpi-bugzilla mailing list acpi-bugzilla@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/acpi-bugzilla