umber-kernel/drivers/usb/chipidea
Mario Peter f4fbf2d475 usb: chipidea: udc: fix DMA and SG cleanup in _ep_nuke()
[ Upstream commit cea2a1257a3b5ea3e769a445b34af13e6aa5a123 ]

The ChipIdea UDC driver can encounter "not page aligned sg buffer"
errors when a USB device is reconnected after being disconnected
during an active transfer. This occurs because _ep_nuke() returns
requests to the gadget layer without properly unmapping DMA buffers
or cleaning up scatter-gather bounce buffers.

Root cause:
When a disconnect happens during a multi-segment DMA transfer, the
request's num_mapped_sgs field and sgt.sgl pointer remain set with
stale values. The request is returned to the gadget driver with status
-ESHUTDOWN but still has active DMA state. If the gadget driver reuses
this request on reconnect without reinitializing it, the stale DMA
state causes _hardware_enqueue() to skip DMA mapping (seeing non-zero
num_mapped_sgs) and attempt to use freed/invalid DMA addresses,
leading to alignment errors and potential memory corruption.

The normal completion path via _hardware_dequeue() properly calls
usb_gadget_unmap_request_by_dev() and sglist_do_debounce() before
returning the request. The _ep_nuke() path must do the same cleanup
to ensure requests are returned in a clean, reusable state.

Fix:
Add DMA unmapping and bounce buffer cleanup to _ep_nuke() to mirror
the cleanup sequence in _hardware_dequeue():
- Call usb_gadget_unmap_request_by_dev() if num_mapped_sgs is set
- Call sglist_do_debounce() with copy=false if bounce buffer exists

This ensures that when requests are returned due to endpoint shutdown,
they don't retain stale DMA mappings. The 'false' parameter to
sglist_do_debounce() prevents copying data back (appropriate for
shutdown path where transfer was aborted).

Signed-off-by: Mario Peter <mario.peter@leica-geosystems.com>
Reviewed-by: Xu Yang <xu.yang_2@nxp.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Link: https://patch.msgid.link/20260108165902.795354-1-mario.peter@leica-geosystems.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04 07:20:35 -05:00
..
Kconfig
Makefile
bits.h
ci.h usb: chipidea: udc: limit usb request length to max 16KB 2024-10-04 15:13:58 +02:00
ci_hdrc_imx.c usb: chipidea: imx: improve usbmisc_imx7d_pullup() 2025-08-13 17:19:10 +02:00
ci_hdrc_imx.h usb: chipidea: imx: add imx_usbmisc_pullup() hook 2025-06-19 12:28:25 +02:00
ci_hdrc_msm.c usb: Switch back to struct platform_driver::remove() 2024-10-04 15:13:03 +02:00
ci_hdrc_npcm.c usb: Switch back to struct platform_driver::remove() 2024-10-04 15:13:03 +02:00
ci_hdrc_pci.c
ci_hdrc_tegra.c usb: Switch back to struct platform_driver::remove() 2024-10-04 15:13:03 +02:00
ci_hdrc_usb2.c usb: Switch back to struct platform_driver::remove() 2024-10-04 15:13:03 +02:00
core.c usb: Use (of|device)_property_present() for non-boolean properties 2024-11-05 13:29:26 +01:00
debug.c
host.c USB: Use str_enable_disable-like helpers 2025-01-15 18:28:13 +01:00
host.h
otg.c
otg.h
otg_fsm.c USB: chipidea: Switch to use hrtimer_setup() 2025-02-18 11:19:01 +01:00
otg_fsm.h
trace.c
trace.h
udc.c usb: chipidea: udc: fix DMA and SG cleanup in _ep_nuke() 2026-03-04 07:20:35 -05:00
udc.h usb: chipidea: udc: create bounce buffer for problem sglist entries if possible 2024-10-04 15:13:58 +02:00
ulpi.c
usbmisc_imx.c usb: chipidea: imx: improve usbmisc_imx7d_pullup() 2025-08-13 17:19:10 +02:00