• Yu Kuai's avatar
    block, bfq: fix null pointer dereference in bfq_bio_bfqg() · 1340f027
    Yu Kuai authored
    [ Upstream commit f02be900 ]
    
    Out test found a following problem in kernel 5.10, and the same problem
    should exist in mainline:
    
    BUG: kernel NULL pointer dereference, address: 0000000000000094
    PGD 0 P4D 0
    Oops: 0000 [#1] SMP
    CPU: 7 PID: 155 Comm: kworker/7:1 Not tainted 5.10.0-01932-g19e0ace2ca1d-dirty 4
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-b4
    Workqueue: kthrotld blk_throtl_dispatch_work_fn
    RIP: 0010:bfq_bio_bfqg+0x52/0xc0
    Code: 94 00 00 00 00 75 2e 48 8b 40 30 48 83 05 35 06 c8 0b 01 48 85 c0 74 3d 4b
    RSP: 0018:ffffc90001a1fba0 EFLAGS: 00010002
    RAX: ffff888100d60400 RBX: ffff8881132e7000 RCX: 0000000000000000
    RDX: 0000000000000017 RSI: ffff888103580a18 RDI: ffff888103580a18
    RBP: ffff8881132e7000 R08: 0000000000000000 R09: ffffc90001a1fe10
    R10: 0000000000000a20 R11: 0000000000034320 R12: 0000000000000000
    R13: ffff888103580a18 R14: ffff888114447000 R15: 0000000000000000
    FS:  0...
    1340f027
bfq-cgroup.c 39.8 KB