Yaya48
cf256aa081
Upstream: https://gitlab.com/qemu-project/qemu.git Upstream-Commit: d2e570cc0f97b936902a5b1b86b73c0f5998b475
116 lines
3.2 KiB
C
116 lines
3.2 KiB
C
/*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*
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* BlockAcctStats latency histogram locking regression test
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*
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* Copyright (c) 2026 Virtuozzo International GmbH.
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*
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* Regression test for missing stats->lock in
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* block_latency_histogram_set()/block_latency_histograms_clear(),
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* racing block_account_one_io() reading the same fields from an
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* iothread. Aborts reliably before the fix, passes after it.
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*/
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#include "qemu/osdep.h"
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#include "block/block.h"
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#include "block/accounting.h"
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#include "system/block-backend.h"
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#include "system/block-backend-io.h"
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#include "qapi/error.h"
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#include "qemu/main-loop.h"
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#include "qemu/thread.h"
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#define RACE_DURATION_MS 2000
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#define NUM_READER_THREADS 8
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static bool stop_workers;
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/*
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* Different bin counts, so the writer's g_free()/g_new() churn can be
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* caught mid-update. Values are small enough (nanoseconds) that plain
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* back-to-back start/done calls exercise every bin without sleeping.
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*/
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static uint64List boundaries_a[] = {
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{ .next = &boundaries_a[1], .value = 1000 },
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{ .next = &boundaries_a[2], .value = 5000 },
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{ .next = NULL, .value = 50000 },
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};
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static uint64List boundaries_b[] = {
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{ .next = &boundaries_b[1], .value = 800 },
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{ .next = &boundaries_b[2], .value = 3000 },
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{ .next = &boundaries_b[3], .value = 20000 },
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{ .next = NULL, .value = 200000 },
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};
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static void *writer_thread(void *opaque)
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{
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BlockAcctStats *stats = opaque;
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while (!qatomic_read(&stop_workers)) {
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block_latency_histogram_set(stats, BLOCK_ACCT_READ, boundaries_a);
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block_latency_histogram_set(stats, BLOCK_ACCT_READ, boundaries_b);
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block_latency_histograms_clear(stats);
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}
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return NULL;
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}
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static void *reader_thread(void *opaque)
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{
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BlockAcctStats *stats = opaque;
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while (!qatomic_read(&stop_workers)) {
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BlockAcctCookie cookie;
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block_acct_start(stats, &cookie, 4096, BLOCK_ACCT_READ);
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block_acct_done(stats, &cookie);
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}
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return NULL;
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}
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static void test_latency_histogram_race(void)
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{
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BlockBackend *blk = blk_new(qemu_get_aio_context(),
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BLK_PERM_ALL, BLK_PERM_ALL);
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BlockAcctStats *stats = blk_get_stats(blk);
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QemuThread writer, readers[NUM_READER_THREADS];
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int i;
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/* Histogram has to be enabled (bins != NULL) before racing it. */
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g_assert(block_latency_histogram_set(stats, BLOCK_ACCT_READ,
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boundaries_a) == 0);
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stop_workers = false;
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qemu_thread_create(&writer, "hist-writer", writer_thread, stats,
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QEMU_THREAD_JOINABLE);
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for (i = 0; i < NUM_READER_THREADS; i++) {
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qemu_thread_create(&readers[i], "hist-reader", reader_thread, stats,
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QEMU_THREAD_JOINABLE);
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}
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g_usleep(RACE_DURATION_MS * 1000);
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qatomic_set(&stop_workers, true);
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qemu_thread_join(&writer);
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for (i = 0; i < NUM_READER_THREADS; i++) {
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qemu_thread_join(&readers[i]);
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}
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blk_unref(blk);
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}
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int main(int argc, char **argv)
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{
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bdrv_init();
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qemu_init_main_loop(&error_abort);
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g_test_init(&argc, &argv, NULL);
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g_test_add_func("/block-accounting/latency_histogram_race",
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test_latency_histogram_race);
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return g_test_run();
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}
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