• J
    block: Make blk_get_backing_dev_info() safe without open bdev · b1d2dc56
    Jan Kara 提交于
    Currenly blk_get_backing_dev_info() is not safe to be called when the
    block device is not open as bdev->bd_disk is NULL in that case. However
    inode_to_bdi() uses this function and may be call called from flusher
    worker or other writeback related functions without bdev being open
    which leads to crashes such as:
    
    [113031.075540] Unable to handle kernel paging request for data at address 0x00000000
    [113031.075614] Faulting instruction address: 0xc0000000003692e0
    0:mon> t
    [c0000000fb65f900] c00000000036cb6c writeback_sb_inodes+0x30c/0x590
    [c0000000fb65fa10] c00000000036ced4 __writeback_inodes_wb+0xe4/0x150
    [c0000000fb65fa70] c00000000036d33c wb_writeback+0x30c/0x450
    [c0000000fb65fb40] c00000000036e198 wb_workfn+0x268/0x580
    [c0000000fb65fc50] c0000000000f3470 process_one_work+0x1e0/0x590
    [c0000000fb65fce0] c0000000000f38c8 worker_thread+0xa8/0x660
    [c0000000fb65fd80] c0000000000fc4b0 kthread+0x110/0x130
    [c0000000fb65fe30] c0000000000098f0 ret_from_kernel_thread+0x5c/0x6c
    Signed-off-by: NJens Axboe <axboe@fb.com>
    b1d2dc56
blk-core.c 91.3 KB