* [PATCH] selftests: ublk: add rotating auto_buf index regression test
[not found] <20260730010910.799346-3-yangxiuwei@kylinos.cn>
@ 2026-07-30 2:40 ` Yang Xiuwei
2026-07-31 16:24 ` Ming Lei
2026-08-04 2:40 ` Jens Axboe
0 siblings, 2 replies; 6+ messages in thread
From: Yang Xiuwei @ 2026-07-30 2:40 UTC (permalink / raw)
To: Ming Lei, Jens Axboe, Shuah Khan
Cc: linux-block, linux-kselftest, Caleb Sander Mateos, Yang Xiuwei
Batch AUTO_BUF_REG COMMIT must unregister the old auto_buf index before
storing the next one. Fixed per-tag indexing (A == B) masks bugs that
clear after overwriting io->buf.
Add kublk --rotate_auto_buf so each tag alternates between two sparse
buffer indices, and test_batch_04.sh to exercise that path. Without the
driver fix, the request ref stays stuck and I/O hangs; the test uses a
short timeout and kills the ublk daemon to recover. With the fix, a
small write completes quickly.
Signed-off-by: Yang Xiuwei <yangxiuwei@kylinos.cn>
---
tools/testing/selftests/ublk/Makefile | 1 +
tools/testing/selftests/ublk/batch.c | 2 +-
tools/testing/selftests/ublk/kublk.c | 19 +++++++-
tools/testing/selftests/ublk/kublk.h | 19 +++++++-
tools/testing/selftests/ublk/test_batch_04.sh | 44 +++++++++++++++++++
5 files changed, 82 insertions(+), 3 deletions(-)
create mode 100755 tools/testing/selftests/ublk/test_batch_04.sh
diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile
index 6e4fe8d1fed1..b5d757aa7ee8 100644
--- a/tools/testing/selftests/ublk/Makefile
+++ b/tools/testing/selftests/ublk/Makefile
@@ -23,6 +23,7 @@ TEST_PROGS += test_generic_17.sh
TEST_PROGS += test_batch_01.sh
TEST_PROGS += test_batch_02.sh
TEST_PROGS += test_batch_03.sh
+TEST_PROGS += test_batch_04.sh
TEST_PROGS += test_null_01.sh
TEST_PROGS += test_null_02.sh
diff --git a/tools/testing/selftests/ublk/batch.c b/tools/testing/selftests/ublk/batch.c
index a54025b00917..d8d9ebed5979 100644
--- a/tools/testing/selftests/ublk/batch.c
+++ b/tools/testing/selftests/ublk/batch.c
@@ -535,7 +535,7 @@ void ublk_batch_complete_io(struct ublk_thread *t, struct ublk_queue *q,
elem = (struct ublk_batch_elem *)(cb->elem + cb->done * t->commit_buf_elem_size);
elem->tag = tag;
- elem->buf_index = ublk_batch_io_buf_idx(t, q, tag);
+ elem->buf_index = ublk_batch_io_buf_idx_next(t, q, tag);
elem->result = res;
if (!ublk_queue_no_buf(q))
diff --git a/tools/testing/selftests/ublk/kublk.c b/tools/testing/selftests/ublk/kublk.c
index 0b23c09daea5..10320d9f73d1 100644
--- a/tools/testing/selftests/ublk/kublk.c
+++ b/tools/testing/selftests/ublk/kublk.c
@@ -540,9 +540,14 @@ static int ublk_thread_init(struct ublk_thread *t, unsigned long long extra_flag
unsigned max_nr_ios_per_thread = nr_ios / dev->nthreads;
max_nr_ios_per_thread += !!(nr_ios % dev->nthreads);
+ t->auto_buf_stride = max_nr_ios_per_thread;
t->nr_bufs = max_nr_ios_per_thread;
+ if ((extra_flags & UBLKS_Q_ROTATE_AUTO_BUF) &&
+ (dev->dev_info.flags & UBLK_F_AUTO_BUF_REG))
+ t->nr_bufs *= 2;
} else {
t->nr_bufs = 0;
+ t->auto_buf_stride = 0;
}
if (ublk_dev_batch_io(dev))
@@ -1436,6 +1441,8 @@ static int ublk_start_daemon(const struct dev_ctx *ctx, struct ublk_dev *dev)
extra_flags = UBLKS_Q_AUTO_BUF_REG_FALLBACK;
if (ctx->no_ublk_fixed_fd)
extra_flags |= UBLKS_Q_NO_UBLK_FIXED_FD;
+ if (ctx->rotate_auto_buf)
+ extra_flags |= UBLKS_Q_ROTATE_AUTO_BUF;
for (i = 0; i < dinfo->nr_hw_queues; i++) {
dev->q[i].dev = dev;
@@ -2067,7 +2074,7 @@ static void __cmd_create_help(char *exe, bool recovery)
printf("\t[--nthreads threads] [--per_io_tasks]\n");
printf("\t[--integrity_capable] [--integrity_reftag] [--metadata_size SIZE] "
"[--pi_offset OFFSET] [--csum_type ip|t10dif|nvme] [--tag_size SIZE]\n");
- printf("\t[--batch|-b] [--no_auto_part_scan]\n");
+ printf("\t[--batch|-b] [--rotate_auto_buf] [--no_auto_part_scan]\n");
printf("\t[target options] [backfile1] [backfile2] ...\n");
printf("\tdefault: nr_queues=2(max 32), depth=128(max 1024), dev_id=-1(auto allocation)\n");
printf("\tdefault: nthreads=nr_queues");
@@ -2141,6 +2148,7 @@ int main(int argc, char *argv[])
{ "tag_size", 1, NULL, 0 },
{ "safe", 0, NULL, 0 },
{ "batch", 0, NULL, 'b'},
+ { "rotate_auto_buf", 0, NULL, 0 },
{ "no_auto_part_scan", 0, NULL, 0 },
{ "shmem_zc", 0, NULL, 0 },
{ "htlb", 1, NULL, 0 },
@@ -2228,6 +2236,8 @@ int main(int argc, char *argv[])
ctx.flags |= UBLK_F_AUTO_BUF_REG;
if (!strcmp(longopts[option_idx].name, "auto_zc_fallback"))
ctx.auto_zc_fallback = 1;
+ if (!strcmp(longopts[option_idx].name, "rotate_auto_buf"))
+ ctx.rotate_auto_buf = 1;
if (!strcmp(longopts[option_idx].name, "nthreads"))
ctx.nthreads = strtol(optarg, NULL, 10);
if (!strcmp(longopts[option_idx].name, "per_io_tasks"))
@@ -2335,6 +2345,13 @@ int main(int argc, char *argv[])
return -EINVAL;
}
+ if (ctx.rotate_auto_buf &&
+ !((ctx.flags & UBLK_F_AUTO_BUF_REG) &&
+ (ctx.flags & UBLK_F_BATCH_IO))) {
+ ublk_err("rotate_auto_buf requires --auto_zc and --batch\n");
+ return -EINVAL;
+ }
+
i = optind;
while (i < argc && ctx.nr_files < MAX_BACK_FILES) {
ctx.files[ctx.nr_files++] = argv[i++];
diff --git a/tools/testing/selftests/ublk/kublk.h b/tools/testing/selftests/ublk/kublk.h
index 742c41d77df1..188b97f0cb95 100644
--- a/tools/testing/selftests/ublk/kublk.h
+++ b/tools/testing/selftests/ublk/kublk.h
@@ -82,6 +82,7 @@ struct dev_ctx {
unsigned int safe_stop:1;
unsigned int no_auto_part_scan:1;
unsigned int rdonly_shmem_buf:1;
+ unsigned int rotate_auto_buf:1;
__u32 integrity_flags;
__u8 metadata_size;
__u8 pi_offset;
@@ -134,6 +135,7 @@ struct ublk_io {
unsigned short buf_index;
unsigned short tgt_ios;
+ unsigned char auto_buf_phase;
void *private_data;
};
@@ -184,6 +186,7 @@ struct ublk_queue {
#define UBLKS_Q_AUTO_BUF_REG_FALLBACK (1ULL << 63)
#define UBLKS_Q_NO_UBLK_FIXED_FD (1ULL << 62)
#define UBLKS_Q_PREPARED (1ULL << 61)
+#define UBLKS_Q_ROTATE_AUTO_BUF (1ULL << 60)
__u64 flags;
int ublk_fd; /* cached ublk char device fd */
__u8 metadata_size;
@@ -232,6 +235,7 @@ struct ublk_thread {
unsigned int io_inflight;
unsigned short nr_bufs;
+ unsigned short auto_buf_stride;
/* followings are for BATCH_IO */
unsigned short commit_buf_start;
@@ -550,7 +554,20 @@ static inline unsigned short ublk_batch_io_buf_idx(
const struct ublk_thread *t, const struct ublk_queue *q,
unsigned tag)
{
- return ublk_queue_idx_in_thread(t, q) * q->q_depth + tag;
+ unsigned short base = ublk_queue_idx_in_thread(t, q) * q->q_depth + tag;
+
+ if (q->flags & UBLKS_Q_ROTATE_AUTO_BUF)
+ return base + q->ios[tag].auto_buf_phase * t->auto_buf_stride;
+ return base;
+}
+
+static inline unsigned short ublk_batch_io_buf_idx_next(
+ const struct ublk_thread *t, struct ublk_queue *q,
+ unsigned tag)
+{
+ if (q->flags & UBLKS_Q_ROTATE_AUTO_BUF)
+ q->ios[tag].auto_buf_phase ^= 1;
+ return ublk_batch_io_buf_idx(t, q, tag);
}
/* Queue UBLK_U_IO_PREP_IO_CMDS for a specific queue with batch elements */
diff --git a/tools/testing/selftests/ublk/test_batch_04.sh b/tools/testing/selftests/ublk/test_batch_04.sh
new file mode 100755
index 000000000000..cd5e1ff9d630
--- /dev/null
+++ b/tools/testing/selftests/ublk/test_batch_04.sh
@@ -0,0 +1,44 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# --rotate_auto_buf: COMMIT must unregister old auto_buf index before store.
+
+. "$(cd "$(dirname "$0")" && pwd)"/test_common.sh
+
+ERR_CODE=0
+
+if ! _have_feature "BATCH_IO" || ! _have_feature "AUTO_BUF_REG"; then
+ exit "$UBLK_SKIP_CODE"
+fi
+if ! _have_program fio || ! _have_program timeout; then
+ exit "$UBLK_SKIP_CODE"
+fi
+
+_prep_test "generic" "batch auto_buf unregister with rotating index"
+
+_create_backfile 0 64M
+
+dev_id=$(_add_ublk_dev_no_settle -t loop -q 1 --nthreads 1 -b --auto_zc \
+ --rotate_auto_buf "${UBLK_BACKFILES[0]}")
+_check_add_dev $TID $?
+
+for ((i = 0; i < 50; i++)); do
+ [ -b /dev/ublkb"${dev_id}" ] && break
+ sleep 0.1
+done
+[ -b /dev/ublkb"${dev_id}" ] || { _cleanup_test; _show_result $TID 1; }
+
+timeout -k 2 5 fio --name=job1 --filename=/dev/ublkb"${dev_id}" \
+ --ioengine=libaio --rw=write --direct=1 --bs=4k --iodepth=1 --size=64k \
+ > /dev/null 2>&1
+ERR_CODE=$?
+
+if [ "$ERR_CODE" -ne 0 ]; then
+ kill -9 "$(_get_ublk_daemon_pid "$dev_id" 2>/dev/null)" 2>/dev/null || true
+ sleep 0.5
+ pkill -9 fio 2>/dev/null || true
+ ERR_CODE=1
+fi
+
+_cleanup_test
+_show_result $TID $ERR_CODE
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread