linux-stable.git/drivers/usb/core/message.c, branch linux-5.10.y Linux kernel stable tree USB: core: Limit the length of unkillable synchronous timeouts 2026-04-18T08:30:55+00:00 Alan Stern stern@rowland.harvard.edu 2026-02-18T03:10:32+00:00 4e86f5b79e62ded7e3c3ebd688cf5775e618148a commit 1015c27a5e1a63efae2b18a9901494474b4d1dc3 upstream. The usb_control_msg(), usb_bulk_msg(), and usb_interrupt_msg() APIs in usbcore allow unlimited timeout durations. And since they use uninterruptible waits, this leaves open the possibility of hanging a task for an indefinitely long time, with no way to kill it short of unplugging the target device. To prevent this sort of problem, enforce a maximum limit on the length of these unkillable timeouts. The limit chosen here, somewhat arbitrarily, is 60 seconds. On many systems (although not all) this is short enough to avoid triggering the kernel's hung-task detector. In addition, clear up the ambiguity of negative timeout values by treating them the same as 0, i.e., using the maximum allowed timeout. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Link: https://lore.kernel.org/linux-usb/3acfe838-6334-4f6d-be7c-4bb01704b33d@rowland.harvard.edu/ Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") CC: stable@vger.kernel.org Link: https://patch.msgid.link/15fc9773-a007-47b0-a703-df89a8cf83dd@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1015c27a5e1a63efae2b18a9901494474b4d1dc3 upstream.

The usb_control_msg(), usb_bulk_msg(), and usb_interrupt_msg() APIs in
usbcore allow unlimited timeout durations.  And since they use
uninterruptible waits, this leaves open the possibility of hanging a
task for an indefinitely long time, with no way to kill it short of
unplugging the target device.

To prevent this sort of problem, enforce a maximum limit on the length
of these unkillable timeouts.  The limit chosen here, somewhat
arbitrarily, is 60 seconds.  On many systems (although not all) this
is short enough to avoid triggering the kernel's hung-task detector.

In addition, clear up the ambiguity of negative timeout values by
treating them the same as 0, i.e., using the maximum allowed timeout.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/linux-usb/3acfe838-6334-4f6d-be7c-4bb01704b33d@rowland.harvard.edu/
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
CC: stable@vger.kernel.org
Link: https://patch.msgid.link/15fc9773-a007-47b0-a703-df89a8cf83dd@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: usbcore: Introduce usb_bulk_msg_killable() 2026-04-18T08:30:55+00:00 Alan Stern stern@rowland.harvard.edu 2026-02-18T03:07:47+00:00 c6780266ca6257b340daa66ac1b5aca5027a4ba2 commit 416909962e7cdf29fd01ac523c953f37708df93d upstream. The synchronous message API in usbcore (usb_control_msg(), usb_bulk_msg(), and so on) uses uninterruptible waits. However, drivers may call these routines in the context of a user thread, which means it ought to be possible to at least kill them. For this reason, introduce a new usb_bulk_msg_killable() function which behaves the same as usb_bulk_msg() except for using wait_for_completion_killable_timeout() instead of wait_for_completion_timeout(). The same can be done later for usb_control_msg() later on, if it turns out to be needed. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Suggested-by: Oliver Neukum <oneukum@suse.com> Link: https://lore.kernel.org/linux-usb/3acfe838-6334-4f6d-be7c-4bb01704b33d@rowland.harvard.edu/ Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") CC: stable@vger.kernel.org Link: https://patch.msgid.link/248628b4-cc83-4e81-a620-3ce4e0376d41@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 416909962e7cdf29fd01ac523c953f37708df93d upstream.

The synchronous message API in usbcore (usb_control_msg(),
usb_bulk_msg(), and so on) uses uninterruptible waits.  However,
drivers may call these routines in the context of a user thread, which
means it ought to be possible to at least kill them.

For this reason, introduce a new usb_bulk_msg_killable() function
which behaves the same as usb_bulk_msg() except for using
wait_for_completion_killable_timeout() instead of
wait_for_completion_timeout().  The same can be done later for
usb_control_msg() later on, if it turns out to be needed.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Suggested-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/linux-usb/3acfe838-6334-4f6d-be7c-4bb01704b33d@rowland.harvard.edu/
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
CC: stable@vger.kernel.org
Link: https://patch.msgid.link/248628b4-cc83-4e81-a620-3ce4e0376d41@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: Fix descriptor count when handling invalid MBIM extended descriptor 2026-01-19T12:11:27+00:00 Seungjin Bae eeodqql09@gmail.com 2025-09-28T18:56:11+00:00 9a636b8a22db57980da76decc5a23feb0b955868 [ Upstream commit 5570ad1423ee60f6e972dadb63fb2e5f90a54cbe ] In cdc_parse_cdc_header(), the check for the USB_CDC_MBIM_EXTENDED_TYPE descriptor was using 'break' upon detecting an invalid length. This was incorrect because 'break' only exits the switch statement, causing the code to fall through to cnt++, thus incorrectly incrementing the count of parsed descriptors for a descriptor that was actually invalid and being discarded. This patch changes 'break' to 'goto next_desc;' to ensure that the logic skips the counter increment and correctly proceeds to the next descriptor in the buffer. This maintains an accurate count of only the successfully parsed descriptors. Fixes: e4c6fb7794982 ("usbnet: move the CDC parser into USB core") Signed-off-by: Seungjin Bae <eeodqql09@gmail.com> Link: https://lore.kernel.org/r/20250928185611.764589-1-eeodqql09@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 5570ad1423ee60f6e972dadb63fb2e5f90a54cbe ]

In cdc_parse_cdc_header(), the check for the USB_CDC_MBIM_EXTENDED_TYPE
descriptor was using 'break' upon detecting an invalid length.

This was incorrect because 'break' only exits the switch statement,
causing the code to fall through to cnt++, thus incorrectly
incrementing the count of parsed descriptors for a descriptor that was
actually invalid and being discarded.

This patch changes 'break' to 'goto next_desc;' to ensure that the
logic skips the counter increment and correctly proceeds to the next
descriptor in the buffer. This maintains an accurate count of only
the successfully parsed descriptors.

Fixes: e4c6fb7794982 ("usbnet: move the CDC parser into USB core")
Signed-off-by: Seungjin Bae <eeodqql09@gmail.com>
Link: https://lore.kernel.org/r/20250928185611.764589-1-eeodqql09@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
USB: core: Change usb_get_device_descriptor() API 2023-09-19T10:20:23+00:00 Alan Stern stern@rowland.harvard.edu 2023-08-04T19:12:21+00:00 6ceffc2ecf3de8acdce2202db1c32d8c520a230e commit de28e469da75359a2bb8cd8778b78aa64b1be1f4 upstream. The usb_get_device_descriptor() routine reads the device descriptor from the udev device and stores it directly in udev->descriptor. This interface is error prone, because the USB subsystem expects in-memory copies of a device's descriptors to be immutable once the device has been initialized. The interface is changed so that the device descriptor is left in a kmalloc-ed buffer, not copied into the usb_device structure. A pointer to the buffer is returned to the caller, who is then responsible for kfree-ing it. The corresponding changes needed in the various callers are fairly small. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Link: https://lore.kernel.org/r/d0111bb6-56c1-4f90-adf2-6cfe152f6561@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit de28e469da75359a2bb8cd8778b78aa64b1be1f4 upstream.

The usb_get_device_descriptor() routine reads the device descriptor
from the udev device and stores it directly in udev->descriptor.  This
interface is error prone, because the USB subsystem expects in-memory
copies of a device's descriptors to be immutable once the device has
been initialized.

The interface is changed so that the device descriptor is left in a
kmalloc-ed buffer, not copied into the usb_device structure.  A
pointer to the buffer is returned to the caller, who is then
responsible for kfree-ing it.  The corresponding changes needed in the
various callers are fairly small.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/d0111bb6-56c1-4f90-adf2-6cfe152f6561@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: core: Avoid WARNings for 0-length descriptor requests 2021-08-26T12:35:34+00:00 Alan Stern stern@rowland.harvard.edu 2021-06-07T15:23:07+00:00 ba6c1b004ac5aaee418ce84acbecdc4d89a67bbe [ Upstream commit 60dfe484cef45293e631b3a6e8995f1689818172 ] The USB core has utility routines to retrieve various types of descriptors. These routines will now provoke a WARN if they are asked to retrieve 0 bytes (USB "receive" requests must not have zero length), so avert this by checking the size argument at the start. CC: Johan Hovold <johan@kernel.org> Reported-and-tested-by: syzbot+7dbcd9ff34dc4ed45240@syzkaller.appspotmail.com Reviewed-by: Johan Hovold <johan@kernel.org> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Link: https://lore.kernel.org/r/20210607152307.GD1768031@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 60dfe484cef45293e631b3a6e8995f1689818172 ]

The USB core has utility routines to retrieve various types of
descriptors.  These routines will now provoke a WARN if they are asked
to retrieve 0 bytes (USB "receive" requests must not have zero
length), so avert this by checking the size argument at the start.

CC: Johan Hovold <johan@kernel.org>
Reported-and-tested-by: syzbot+7dbcd9ff34dc4ed45240@syzkaller.appspotmail.com
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20210607152307.GD1768031@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Merge tag 'dma-mapping-5.10' of git://git.infradead.org/users/hch/dma-mapping 2020-10-15T21:43:29+00:00 Linus Torvalds torvalds@linux-foundation.org 2020-10-15T21:43:29+00:00 5a32c3413d3340f90c82c84b375ad4b335a59f28 Pull dma-mapping updates from Christoph Hellwig: - rework the non-coherent DMA allocator - move private definitions out of <linux/dma-mapping.h> - lower CMA_ALIGNMENT (Paul Cercueil) - remove the omap1 dma address translation in favor of the common code - make dma-direct aware of multiple dma offset ranges (Jim Quinlan) - support per-node DMA CMA areas (Barry Song) - increase the default seg boundary limit (Nicolin Chen) - misc fixes (Robin Murphy, Thomas Tai, Xu Wang) - various cleanups * tag 'dma-mapping-5.10' of git://git.infradead.org/users/hch/dma-mapping: (63 commits) ARM/ixp4xx: add a missing include of dma-map-ops.h dma-direct: simplify the DMA_ATTR_NO_KERNEL_MAPPING handling dma-direct: factor out a dma_direct_alloc_from_pool helper dma-direct check for highmem pages in dma_direct_alloc_pages dma-mapping: merge <linux/dma-noncoherent.h> into <linux/dma-map-ops.h> dma-mapping: move large parts of <linux/dma-direct.h> to kernel/dma dma-mapping: move dma-debug.h to kernel/dma/ dma-mapping: remove <asm/dma-contiguous.h> dma-mapping: merge <linux/dma-contiguous.h> into <linux/dma-map-ops.h> dma-contiguous: remove dma_contiguous_set_default dma-contiguous: remove dev_set_cma_area dma-contiguous: remove dma_declare_contiguous dma-mapping: split <linux/dma-mapping.h> cma: decrease CMA_ALIGNMENT lower limit to 2 firewire-ohci: use dma_alloc_pages dma-iommu: implement ->alloc_noncoherent dma-mapping: add new {alloc,free}_noncoherent dma_map_ops methods dma-mapping: add a new dma_alloc_pages API dma-mapping: remove dma_cache_sync 53c700: convert to dma_alloc_noncoherent ... 
Pull dma-mapping updates from Christoph Hellwig:

 - rework the non-coherent DMA allocator

 - move private definitions out of <linux/dma-mapping.h>

 - lower CMA_ALIGNMENT (Paul Cercueil)

 - remove the omap1 dma address translation in favor of the common code

 - make dma-direct aware of multiple dma offset ranges (Jim Quinlan)

 - support per-node DMA CMA areas (Barry Song)

 - increase the default seg boundary limit (Nicolin Chen)

 - misc fixes (Robin Murphy, Thomas Tai, Xu Wang)

 - various cleanups

* tag 'dma-mapping-5.10' of git://git.infradead.org/users/hch/dma-mapping: (63 commits)
  ARM/ixp4xx: add a missing include of dma-map-ops.h
  dma-direct: simplify the DMA_ATTR_NO_KERNEL_MAPPING handling
  dma-direct: factor out a dma_direct_alloc_from_pool helper
  dma-direct check for highmem pages in dma_direct_alloc_pages
  dma-mapping: merge <linux/dma-noncoherent.h> into <linux/dma-map-ops.h>
  dma-mapping: move large parts of <linux/dma-direct.h> to kernel/dma
  dma-mapping: move dma-debug.h to kernel/dma/
  dma-mapping: remove <asm/dma-contiguous.h>
  dma-mapping: merge <linux/dma-contiguous.h> into <linux/dma-map-ops.h>
  dma-contiguous: remove dma_contiguous_set_default
  dma-contiguous: remove dev_set_cma_area
  dma-contiguous: remove dma_declare_contiguous
  dma-mapping: split <linux/dma-mapping.h>
  cma: decrease CMA_ALIGNMENT lower limit to 2
  firewire-ohci: use dma_alloc_pages
  dma-iommu: implement ->alloc_noncoherent
  dma-mapping: add new {alloc,free}_noncoherent dma_map_ops methods
  dma-mapping: add a new dma_alloc_pages API
  dma-mapping: remove dma_cache_sync
  53c700: convert to dma_alloc_noncoherent
  ...
USB: correct API of usb_control_msg_send/recv 2020-09-25T14:33:58+00:00 Oliver Neukum oneukum@suse.com 2020-09-23T13:43:42+00:00 ddd1198e3e0935066d6e309180d49f64ef4fa702 They need to specify how memory is to be allocated, as control messages need to work in contexts that require GFP_NOIO. Signed-off-by: Oliver Neukum <oneukum@suse.com> Link: https://lore.kernel.org/r/20200923134348.23862-9-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
They need to specify how memory is to be allocated,
as control messages need to work in contexts that require GFP_NOIO.

Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20200923134348.23862-9-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge branch 'master' of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into dma-mapping-for-next 2020-09-25T04:19:19+00:00 Christoph Hellwig hch@lst.de 2020-09-25T04:19:19+00:00 8c1c6c7588b2faf9dd45fb3cfb7497fd09bbfe7c Pull in the latest 5.9 tree for the commit to revert the V4L2_FLAG_MEMORY_NON_CONSISTENT uapi addition. 
Pull in the latest 5.9 tree for the commit to revert the
V4L2_FLAG_MEMORY_NON_CONSISTENT uapi addition.
usb: don't inherity DMA properties for USB devices 2020-09-17T16:43:25+00:00 Christoph Hellwig hch@lst.de 2020-09-10T16:03:49+00:00 6eb0233ec2d0df288fe8515d5b0b2b15562e05bb As the comment in usb_alloc_dev correctly states, drivers can't use the DMA API on usb device, and at least calling dma_set_mask on them is highly dangerous. Unlike what the comment states upper level drivers also can't really use the presence of a dma mask to check for DMA support, as the dma_mask is set by default for most busses. Setting the dma_mask comes from "[PATCH] usbcore dma updates (and doc)" in BitKeeper times, as it seems like it was primarily for setting the NETIF_F_HIGHDMA flag in USB drivers, something that has long been fixed up since. Setting the dma_pfn_offset comes from commit b44bbc46a8bb ("usb: core: setup dma_pfn_offset for USB devices and, interfaces"), which worked around the fact that the scsi_calculate_bounce_limits functions wasn't going through the proper driver interface to query DMA information, but that function was removed in commit 21e07dba9fb1 ("scsi: reduce use of block bounce buffers") years ago. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
As the comment in usb_alloc_dev correctly states, drivers can't use
the DMA API on usb device, and at least calling dma_set_mask on them
is highly dangerous.  Unlike what the comment states upper level drivers
also can't really use the presence of a dma mask to check for DMA
support, as the dma_mask is set by default for most busses.

Setting the dma_mask comes from "[PATCH] usbcore dma updates (and doc)"
in BitKeeper times, as it seems like it was primarily for setting the
NETIF_F_HIGHDMA flag in USB drivers, something that has long been
fixed up since.

Setting the dma_pfn_offset comes from commit b44bbc46a8bb
("usb: core: setup dma_pfn_offset for USB devices and, interfaces"),
which worked around the fact that the scsi_calculate_bounce_limits
functions wasn't going through the proper driver interface to query
DMA information, but that function was removed in commit 21e07dba9fb1
("scsi: reduce use of block bounce buffers") years ago.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: core: message.c: use usb_control_msg_send() in a few places 2020-09-16T09:02:35+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2020-09-14T15:37:48+00:00 297e84c04d76b9fdbac463e6378f5db7e9283ecd There are a few calls to usb_control_msg() that can be converted to use usb_control_msg_send() instead, so do that in order to make the error checking a bit simpler. Cc: Alan Stern <stern@rowland.harvard.edu> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20200914153756.3412156-4-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
There are a few calls to usb_control_msg() that can be converted to use
usb_control_msg_send() instead, so do that in order to make the error
checking a bit simpler.

Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200914153756.3412156-4-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>