Hello Lv Zheng,
The patch 8cfb0cdf07e2: "ACPI / debugger: Add IO interface to access
debugger functionalities" from Dec 3, 2015, leads to the following
static checker warning:
drivers/acpi/acpi_dbg.c:533 acpi_aml_open()
error: double unlock 'mutex:&acpi_aml_io.lock'
drivers/acpi/acpi_dbg.c
498 } else {
499 /*
500 * No writer is allowed unless the debugger thread is
501 * ready.
502 */
503 if (!(acpi_aml_io.flags & ACPI_AML_OPENED)) {
504 ret = -ENODEV;
505 goto err_lock;
Holding lock.
506 }
507 }
508 if (acpi_aml_active_reader == file) {
509 pr_debug("Opening debugger interface.\n");
510 mutex_unlock(&acpi_aml_io.lock);
511
512 pr_debug("Initializing debugger thread.\n");
513 status = acpi_initialize_debugger();
514 if (ACPI_FAILURE(status)) {
515 pr_err("Failed to initialize debugger.\n");
516 ret = -EINVAL;
517 goto err_lock;
Not holding lock.
518 }
519 acpi_aml_io.flags |= ACPI_AML_OPENED;
520 pr_debug("Debugger thread initialized.\n");
521
522 mutex_lock(&acpi_aml_io.lock);
523 acpi_aml_io.out_crc.head = acpi_aml_io.out_crc.tail = 0;
524 acpi_aml_io.in_crc.head = acpi_aml_io.in_crc.tail = 0;
525 pr_debug("Debugger interface opened.\n");
526 }
527 acpi_aml_io.users++;
528 err_lock:
529 if (IS_ERR_VALUE(ret)) {
530 if (acpi_aml_active_reader == file)
531 acpi_aml_active_reader = NULL;
532 }
533 mutex_unlock(&acpi_aml_io.lock);
Double onlock.
534 return ret;
535 }
regards,
dan carpenter
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