id = 1302
title = "Per-thread logging flag must be made immutable"
state = "closed"
created_at = "2022-11-07T12:30:06.554Z"
closed_at = "2022-11-08T16:37:08.335Z"
labels = ["kind::Bug"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/1302"
host-os = "Fedora 35"
host-arch = "x86"
qemu-version = "QEMU emulator version 7.1.50 (v7.1.0-1678-g466e81ff1201)"
guest-os = "n/a"
guest-arch = "n/a"
description = """The problem is that the code assumes it isn't possible to switch from global logging to per-thread logging and vice-versa per design, but it lags appropriate checks to enforce it. Enabling or disabling per-thread logging at runtime from the monitor causes unexpected results."""
reproduce = """Enabling per-thread logging at runtime:

1. Start QEMU : `./qemu-system-x86_64 -S -monitor stdio -D qemu.log.%d`
2. Enable per-thread logging from the HMP monitor : `(qemu) log tid`
3. Fails with `Filename template with '%d' required for 'tid'` even though such a template was passed with `-D`.

Disabling per-thread logging at runtime:

1. Start QEMU : `./qemu-system-x86_64 -S -monitor stdio -D qemu.log.%d -d tid,cpu_reset`
2. Disable per-thread logging from the HMP monitor: `(qemu) log cpu_reset`
3. QEMU creates a log file with a bogus `qemu.log.%d` name."""
additional = """[Series](https://patchew.org/QEMU/20221104120059.678470-1-groug@kaod.org/) posted and already reviewed by @rth7680 ."""