Messages in this thread | | | From | xiaojun.zhao141@gmail ... | Date | Wed, 14 Apr 2021 11:55:48 +0800 | Subject | the qemu-nbd process automatically exit with the commit 43347d56c 'livepatch: send a fake signal to all blocking tasks' |
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I found the qemu-nbd process(started with qemu-nbd -t -c /dev/nbd0 nbd.qcow2) will automatically exit when I patched for functions of the nbd with livepatch.
The nbd relative source: static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev) { struct nbd_config *config = nbd->config; int ret; ret = nbd_start_device(nbd); if (ret) return ret; if (max_part) bdev->bd_invalidated = 1; mutex_unlock(&nbd->config_lock); ret = wait_event_interruptible(config->recv_wq, atomic_read(&config->recv_threads) == 0); if (ret) sock_shutdown(nbd); flush_workqueue(nbd->recv_workq); mutex_lock(&nbd->config_lock); nbd_bdev_reset(bdev); /* user requested, ignore socket errors */ if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags)) ret = 0; if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags)) ret = -ETIMEDOUT; return ret; }
When the nbd waits for atomic_read(&config->recv_threads) == 0, the klp will send a fake signal to it then the qemu-nbd process exits. And the signal of sysfs to control this action was removed in the commit 10b3d52790e 'livepatch: Remove signal sysfs attribute'. Are there other ways to control this action? How?
Thanks very much.
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