"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nblock: fix deadlock between bd_link_disk_holder and partition scan\n\n'open_mutex' of gendisk is used to protect open/close block devices. But\nin bd_link_disk_holder(), it is used to protect the creation of symlink\nbetween holding disk and slave bdev, which introduces some issues.\n\nWhen bd_link_disk_holder() is called, the driver is usually in the process\nof initialization/modification and may suspend submitting io. At this\ntime, any io hold 'open_mutex', such as scanning partitions, can cause\ndeadlocks. For example, in raid:\n\nT1 T2\nbdev_open_by_dev\n lock open_mutex [1]\n ...\n efi_partition\n ...\n md_submit_bio\n\t\t\t\tmd_ioctl mddev_syspend\n\t\t\t\t -> suspend all io\n\t\t\t\t md_add_new_disk\n\t\t\t\t bind_rdev_to_array\n\t\t\t\t bd_link_disk_holder\n\t\t\t\t try lock open_mutex [2]\n md_handle_request\n -> wait mddev_resume\n\nT1 scan partition, T2 add a new device to raid. T1 waits for T2 to resume\nmddev, but T2 waits for open_mutex held by T1. Deadlock occurs.\n\nFix it by introducing a local mutex 'blk_holder_mutex' to replace\n'open_mutex'."
