* re: ACPI / debugger: Add IO interface to access debugger functionalities
@ 2015-12-22 19:48 Dan Carpenter
2015-12-24 5:45 ` Zheng, Lv
2015-12-25 0:21 ` Zheng, Lv
0 siblings, 2 replies; 3+ messages in thread
From: Dan Carpenter @ 2015-12-22 19:48 UTC (permalink / raw)
To: lv.zheng; +Cc: linux-acpi
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
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: ACPI / debugger: Add IO interface to access debugger functionalities
2015-12-22 19:48 ACPI / debugger: Add IO interface to access debugger functionalities Dan Carpenter
@ 2015-12-24 5:45 ` Zheng, Lv
2015-12-25 0:21 ` Zheng, Lv
1 sibling, 0 replies; 3+ messages in thread
From: Zheng, Lv @ 2015-12-24 5:45 UTC (permalink / raw)
To: Dan Carpenter; +Cc: linux-acpi@vger.kernel.org
Hi,
Thanks for the report.
> -----Original Message-----
> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-
> owner@vger.kernel.org] On Behalf Of Dan Carpenter
> Sent: Wednesday, December 23, 2015 3:49 AM
> To: Zheng, Lv <lv.zheng@intel.com>
> Cc: linux-acpi@vger.kernel.org
> Subject: re: ACPI / debugger: Add IO interface to access debugger
> functionalities
>
> 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 }
> 520 pr_debug("Debugger thread initialized.\n");
> 521
> 522 mutex_lock(&acpi_aml_io.lock);
[Lv Zheng]
Here the lock is held again.
I also noticed that the above line should be put under the locking environment:
> 519 acpi_aml_io.flags |= ACPI_AML_OPENED;
Thanks for the report.
I'll submit a fix for this.
Best regards
-Lv
> 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
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 3+ messages in thread
* RE: ACPI / debugger: Add IO interface to access debugger functionalities
2015-12-22 19:48 ACPI / debugger: Add IO interface to access debugger functionalities Dan Carpenter
2015-12-24 5:45 ` Zheng, Lv
@ 2015-12-25 0:21 ` Zheng, Lv
1 sibling, 0 replies; 3+ messages in thread
From: Zheng, Lv @ 2015-12-25 0:21 UTC (permalink / raw)
To: Dan Carpenter; +Cc: linux-acpi@vger.kernel.org
Hi,
> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-
> owner@vger.kernel.org] On Behalf Of Dan Carpenter
> Subject: re: ACPI / debugger: Add IO interface to access debugger
> functionalities
>
> 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.
[Lv Zheng]
Oops.
This is indeed a problem.
I'll send another fix for this.
Thanks and best regards
-Lv
>
> 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
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 3+ messages in thread
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