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| author | Emilio G. Cota | 2018-08-19 11:13:35 +0200 |
|---|---|---|
| committer | Paolo Bonzini | 2018-08-23 18:46:25 +0200 |
| commit | 068a5ea02f62853116788a2c42d8851a94bb7567 (patch) | |
| tree | 0e7c635241a440b1aeee6dd853077fad928a40d4 /cpus-common.c | |
| parent | spapr: do not use CPU_FOREACH_REVERSE (diff) | |
| download | qemu-068a5ea02f62853116788a2c42d8851a94bb7567.tar.gz qemu-068a5ea02f62853116788a2c42d8851a94bb7567.tar.xz qemu-068a5ea02f62853116788a2c42d8851a94bb7567.zip | |
qom: convert the CPU list to RCU
Iterating over the list without using atomics is undefined behaviour,
since the list can be modified concurrently by other threads (e.g.
every time a new thread is created in user-mode).
Fix it by implementing the CPU list as an RCU QTAILQ. This requires
a little bit of extra work to traverse list in reverse order (see
previous patch), but other than that the conversion is trivial.
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <20180819091335.22863-12-cota@braap.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'cpus-common.c')
| -rw-r--r-- | cpus-common.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/cpus-common.c b/cpus-common.c index 59f751ecf9..98dd8c6ff1 100644 --- a/cpus-common.c +++ b/cpus-common.c @@ -84,7 +84,7 @@ void cpu_list_add(CPUState *cpu) } else { assert(!cpu_index_auto_assigned); } - QTAILQ_INSERT_TAIL(&cpus, cpu, node); + QTAILQ_INSERT_TAIL_RCU(&cpus, cpu, node); qemu_mutex_unlock(&qemu_cpu_list_lock); finish_safe_work(cpu); @@ -101,7 +101,7 @@ void cpu_list_remove(CPUState *cpu) assert(!(cpu_index_auto_assigned && cpu != QTAILQ_LAST(&cpus, CPUTailQ))); - QTAILQ_REMOVE(&cpus, cpu, node); + QTAILQ_REMOVE_RCU(&cpus, cpu, node); cpu->cpu_index = UNASSIGNED_CPU_INDEX; qemu_mutex_unlock(&qemu_cpu_list_lock); } |