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hw/ufs: avoid double unref of wrapped scsi-hd

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ufs_init_scsi_device() creates an internal scsi-hd and adds it as a
child of lu->bus. qdev_realize_and_unref() then drops the construction
reference, leaving the bus child ownership to tear it down.

ufs_lu_unrealize() still unrefs lu->scsi_dev directly. If the UFS
controller is ejected through ACPI PCI hotplug, the scsi-hd object can be
finalized there and then the bus child removal RCU callback later unrefs
the same object again.

Keep lu->scsi_dev as a borrowed pointer and clear it during unrealize
without unreffing it.

Add a qtest that ejects the UFS controller through the x86 ACPI PCI
hotplug eject register. On an ASAN build, the test reproduces the UAF
before the fix.

Fixes: 096434fea1 ("hw/ufs: Modify lu.c to share codes with SCSI subsystem")
Cc: qemu-stable@nongnu.org
Signed-off-by: Jia Jia <physicalmtea@gmail.com>
Signed-off-by: Jeuk Kim <jeuk20.kim@samsung.com>
This commit is contained in:
Jia Jia
2026-05-31 09:34:52 +08:00
committed by Jeuk Kim
parent f893c46c39
commit 90aacd5bc4
2 changed files with 19 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
hw/ufs/lu.c
View File

@@ -530,11 +530,8 @@ static void ufs_lu_unrealize(DeviceState *dev)
{
UfsLu *lu = DO_UPCAST(UfsLu, qdev, dev);
if (lu->scsi_dev) {
object_unref(OBJECT(lu->scsi_dev));
lu->scsi_dev = NULL;
}
}
static void ufs_lu_class_init(ObjectClass *oc, const void *data)
{

18
tests/qtest/ufs-test.c
View File

@@ -34,6 +34,8 @@
#define TEST_QID 0
#define QUEUE_SIZE 32
#define UFS_MCQ_MAX_QNUM 32
#define ACPI_PCIHP_ADDR 0xae00
#define PCI_EJ_BASE 0x0008
typedef struct QUfs QUfs;
@@ -635,6 +637,17 @@ static void ufstest_reg_read(void *obj, void *data, QGuestAllocator *alloc)
qpci_iounmap(&ufs->dev, ufs->bar);
}
static void ufstest_acpi_eject(void *obj, void *data, QGuestAllocator *alloc)
{
QUfs *ufs = obj;
QTestState *qts = ufs->dev.bus->qts;
qtest_outl(qts, ACPI_PCIHP_ADDR + PCI_EJ_BASE, 1 << 4);
qtest_qmp_assert_success(qts, "{ 'execute': 'query-status' }");
g_usleep(3 * G_USEC_PER_SEC);
qtest_qmp_assert_success(qts, "{ 'execute': 'query-status' }");
}
static void ufstest_init(void *obj, void *data, QGuestAllocator *alloc)
{
QUfs *ufs = obj;
@@ -1682,6 +1695,7 @@ static void ufs_register_nodes(void)
"mcq=false,nutrs=32,nutmrs=8,"
"wb-max-size=1024,"
"wb-min-size=256" };
QOSGraphTestOptions acpi_eject_test_opts = { .subprocess = true };
add_qpci_address(&edge_opts, &(QPCIAddress){ .devfn = QPCI_DEVFN(4, 0) });
@@ -1700,6 +1714,10 @@ static void ufs_register_nodes(void)
g_test_message("Skipping ufs io tests for ppc64");
return;
}
if (!strcmp(arch, "i386") || !strcmp(arch, "x86_64")) {
qos_add_test("acpi-eject", "ufs", ufstest_acpi_eject,
&acpi_eject_test_opts);
}
qos_add_test("init", "ufs", ufstest_init, NULL);
qos_add_test("legacy-read-write", "ufs", ufstest_read_write, &io_test_opts);
qos_add_test("mcq-read-write", "ufs", ufstest_read_write, &mcq_test_opts);