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usb: uas: fix urb unmapping issue when the uas device is remove during ongoing data transfer

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When a UAS device is unplugged during data transfer, there is
a probability of a system panic occurring. The root cause is
an access to an invalid memory address during URB callback handling.
Specifically, this happens when the dma_direct_unmap_sg() function
is called within the usb_hcd_unmap_urb_for_dma() interface, but the
sg->dma_address field is 0 and the sg data structure has already been
freed.

The SCSI driver sends transfer commands by invoking uas_queuecommand_lck()
in uas.c, using the uas_submit_urbs() function to submit requests to USB.
Within the uas_submit_urbs() implementation, three URBs (sense_urb,
data_urb, and cmd_urb) are sequentially submitted. Device removal may
occur at any point during uas_submit_urbs execution, which may result
in URB submission failure. However, some URBs might have been successfully
submitted before the failure, and uas_submit_urbs will return the -ENODEV
error code in this case. The current error handling directly calls
scsi_done(). In the SCSI driver, this eventually triggers scsi_complete()
to invoke scsi_end_request() for releasing the sgtable. The successfully
submitted URBs, when being unlinked to giveback, call
usb_hcd_unmap_urb_for_dma() in hcd.c, leading to exceptions during sg
unmapping operations since the sg data structure has already been freed.

This patch modifies the error condition check in the uas_submit_urbs()
function. When a UAS device is removed but one or more URBs have already
been successfully submitted to USB, it avoids immediately invoking
scsi_done() and save the cmnd to devinfo->cmnd array. If the successfully
submitted URBs is completed before devinfo->resetting being set, then
the scsi_done() function will be called within uas_try_complete() after
all pending URB operations are finalized. Otherwise, the scsi_done()
function will be called within uas_zap_pending(), which is executed after
usb_kill_anchored_urbs().

The error handling only takes effect when uas_queuecommand_lck() calls
uas_submit_urbs() and returns the error value -ENODEV . In this case,
the device is disconnected, and the flow proceeds to uas_disconnect(),
where uas_zap_pending() is invoked to call uas_try_complete().

Fixes: eb2a86ae8c ("USB: UAS: fix disconnect by unplugging a hub")
Cc: stable <stable@kernel.org>
Signed-off-by: Yu Chen <chenyu45@xiaomi.com>
Signed-off-by: Owen Gu <guhuinan@xiaomi.com>
Acked-by: Oliver Neukum <oneukum@suse.com>
Link: https://patch.msgid.link/20251120123336.3328-1-guhuinan@xiaomi.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Owen Gu
2025-11-20 20:33:36 +08:00
committed by Greg Kroah-Hartman
parent e4037689a3
commit 26d56a9fcb
1 changed files with 5 additions and 0 deletions
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5
drivers/usb/storage/uas.c
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@@ -698,6 +698,10 @@ static int uas_queuecommand_lck(struct scsi_cmnd *cmnd)
* of queueing, no matter how fatal the error
*/
if (err == -ENODEV) {
if (cmdinfo->state & (COMMAND_INFLIGHT | DATA_IN_URB_INFLIGHT |
DATA_OUT_URB_INFLIGHT))
goto out;
set_host_byte(cmnd, DID_NO_CONNECT);
scsi_done(cmnd);
goto zombie;
@@ -711,6 +715,7 @@ static int uas_queuecommand_lck(struct scsi_cmnd *cmnd)
uas_add_work(cmnd);
}
out:
devinfo->cmnd[idx] = cmnd;
zombie:
spin_unlock_irqrestore(&devinfo->lock, flags);