On 09/30/2019 05:39 PM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: bb2aee77 Add linux-next specific files for 20190926 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=13385ca3600000 > kernel config: https://syzkaller.appspot.com/x/.config?x=e60af4ac5a01e964 > dashboard link: > https://syzkaller.appspot.com/bug?extid=24c12fa8d218ed26011a > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12abc2a3600000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11712c05600000 > > The bug was bisected to: > > commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4 > Author: Mike Christie <mchri...@redhat.com> > Date: Sun Aug 4 19:10:06 2019 +0000 > > nbd: fix max number of supported devs > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1226f3c5600000 > final crash: https://syzkaller.appspot.com/x/report.txt?x=1126f3c5600000 > console output: https://syzkaller.appspot.com/x/log.txt?x=1626f3c5600000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+24c12fa8d218ed260...@syzkaller.appspotmail.com > Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs") > > INFO: task syz-executor390:8778 can't die for more than 143 seconds. > syz-executor390 D27432 8778 8777 0x00004004 > Call Trace: > context_switch kernel/sched/core.c:3384 [inline] > __schedule+0x828/0x1c20 kernel/sched/core.c:4065 > schedule+0xd9/0x260 kernel/sched/core.c:4132 > schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871 > do_wait_for_common kernel/sched/completion.c:83 [inline] > __wait_for_common kernel/sched/completion.c:104 [inline] > wait_for_common kernel/sched/completion.c:115 [inline] > wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136 > flush_workqueue+0x40f/0x14c0 kernel/workqueue.c:2826 > nbd_start_device_ioctl drivers/block/nbd.c:1272 [inline] > __nbd_ioctl drivers/block/nbd.c:1347 [inline] > nbd_ioctl+0xb2e/0xc44 drivers/block/nbd.c:1387 > __blkdev_driver_ioctl block/ioctl.c:304 [inline] > blkdev_ioctl+0xedb/0x1c20 block/ioctl.c:606 > block_ioctl+0xee/0x130 fs/block_dev.c:1954 > vfs_ioctl fs/ioctl.c:47 [inline] > file_ioctl fs/ioctl.c:539 [inline] > do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:726 > ksys_ioctl+0xab/0xd0 fs/ioctl.c:743 > __do_sys_ioctl fs/ioctl.c:750 [inline] > __se_sys_ioctl fs/ioctl.c:748 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:748 > do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x4452d9 > Code: Bad RIP value. > RSP: 002b:00007ffde928d288 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004452d9 > RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000004 > RBP: 0000000000000000 R08: 00000000004025b0 R09: 00000000004025b0 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402520 > R13: 00000000004025b0 R14: 0000000000000000 R15: 0000000000000000 > INFO: task syz-executor390:8778 blocked for more than 143 seconds. > Not tainted 5.3.0-next-20190926 #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > syz-executor390 D27432 8778 8777 0x00004004 > Call Trace: > context_switch kernel/sched/core.c:3384 [inline] > __schedule+0x828/0x1c20 kernel/sched/core.c:4065 > schedule+0xd9/0x260 kernel/sched/core.c:4132 > schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871 > do_wait_for_common kernel/sched/completion.c:83 [inline] > __wait_for_common kernel/sched/completion.c:104 [inline] > wait_for_common kernel/sched/completion.c:115 [inline] > wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136 > flush_workqueue+0x40f/0x14c0 kernel/workqueue.c:2826 > nbd_start_device_ioctl drivers/block/nbd.c:1272 [inline] > __nbd_ioctl drivers/block/nbd.c:1347 [inline] > nbd_ioctl+0xb2e/0xc44 drivers/block/nbd.c:1387 > __blkdev_driver_ioctl block/ioctl.c:304 [inline] > blkdev_ioctl+0xedb/0x1c20 block/ioctl.c:606 > block_ioctl+0xee/0x130 fs/block_dev.c:1954 > vfs_ioctl fs/ioctl.c:47 [inline] > file_ioctl fs/ioctl.c:539 [inline] > do_vfs_ioctl+0xdb6/0x13e0 fs/ioctl.c:726 > ksys_ioctl+0xab/0xd0 fs/ioctl.c:743 > __do_sys_ioctl fs/ioctl.c:750 [inline] > __se_sys_ioctl fs/ioctl.c:748 [inline] > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:748 > do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x4452d9 > Code: Bad RIP value. > RSP: 002b:00007ffde928d288 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004452d9 > RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000004 > RBP: 0000000000000000 R08: 00000000004025b0 R09: 00000000004025b0 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402520 > R13: 00000000004025b0 R14: 0000000000000000 R15: 0000000000000000 >
I will send a fix for this. I had assumed that for every socket type a kernel_sock_shutdown would break us out of sock_recvmsg call, but it looks like that's not the case.
