[PATCH v3 6/6] USB: forbid memory allocation with I/O during bus reset
From: Ming Lei <hidden>
Date: 2012-10-29 12:26:49
Also in:
linux-mm, linux-pm, lkml
Subsystem:
the rest, usb subsystem · Maintainers:
Linus Torvalds, Greg Kroah-Hartman
If one storage interface or usb network interface(iSCSI case) exists in current configuration, memory allocation with GFP_KERNEL during usb_device_reset() might trigger I/O transfer on the storage interface itself and cause deadlock because the 'us->dev_mutex' is held in .pre_reset() and the storage interface can't do I/O transfer when the reset is triggered by other interface, or the error handling can't be completed if the reset is triggered by the storage itself(error handling path). Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Oliver Neukum <redacted> Signed-off-by: Ming Lei <redacted> --- v3: - check usbnet device or usb mass storage device by 'dev->power.memalloc_noio_resume' as suggested by Alan Stern --- drivers/usb/core/hub.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 5b131b6..5aea807 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c@@ -5044,6 +5044,8 @@ int usb_reset_device(struct usb_device *udev) { int ret; int i; + unsigned int uninitialized_var(noio_flag); + bool noio_set = false; struct usb_host_config *config = udev->actconfig; if (udev->state == USB_STATE_NOTATTACHED ||
@@ -5053,6 +5055,17 @@ int usb_reset_device(struct usb_device *udev) return -EINVAL; } + /* + * Don't allocate memory with GFP_KERNEL in current + * context to avoid possible deadlock if usb mass + * storage interface or usbnet interface(iSCSI case) + * is included in current configuration. + */ + if (pm_runtime_get_memalloc_noio(&udev->dev)) { + memalloc_noio_save(noio_flag); + noio_set = true; + } + /* Prevent autosuspend during the reset */ usb_autoresume_device(udev);
@@ -5097,6 +5110,8 @@ int usb_reset_device(struct usb_device *udev) } usb_autosuspend_device(udev); + if (noio_set) + memalloc_noio_restore(noio_flag); return ret; } EXPORT_SYMBOL_GPL(usb_reset_device);
--
1.7.9.5
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>