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Re: bdrv_drained_begin deadlock with io-threads
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From: |
Dietmar Maurer |
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Subject: |
Re: bdrv_drained_begin deadlock with io-threads |
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Date: |
Tue, 31 Mar 2020 11:17:47 +0200 (CEST) |
Inside exec.c, there is a race:
-------
static bool prepare_mmio_access(MemoryRegion *mr)
{
bool unlocked = !qemu_mutex_iothread_locked();
bool release_lock = false;
if (unlocked && mr->global_locking) {
qemu_mutex_lock_iothread();
------
IMHO, checking for unlocked that way is wrong. Should use some kind
of _trylock instead?