* FAILED: patch "[PATCH] usb: xhci: bail out of setup if the controller is" failed to apply to 5.10-stable tree
@ 2026-08-31 12:21 gregkh
2026-09-01 11:19 ` [PATCH 5.10.y] usb: xhci: bail out of setup if the controller is inaccessible Sasha Levin
0 siblings, 1 reply; 2+ messages in thread
From: gregkh @ 2026-08-31 12:21 UTC (permalink / raw)
To: leitao, gregkh, mathias.nyman; +Cc: stable
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 78203d5b54a40f0e36196ebf31c9c7a380fc8811
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026083123-overbuilt-setback-14b9@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 78203d5b54a40f0e36196ebf31c9c7a380fc8811 Mon Sep 17 00:00:00 2001
From: Breno Leitao <leitao@debian.org>
Date: Thu, 6 Aug 2026 17:21:06 +0300
Subject: [PATCH] usb: xhci: bail out of setup if the controller is
inaccessible
xhci_gen_setup() locates the operational registers using the capability
length read from the very first register:
xhci->op_regs = hcd->regs +
HC_LENGTH(readl(&xhci->cap_regs->hc_capbase));
If the controller is dead or has dropped off the bus, that read returns
~0, HC_LENGTH() truncates it to 0xff, and op_regs ends up 0xff bytes
past the page-aligned MMIO base, i.e. unaligned. The first access
through it, xhci_halt() -> xhci_handshake() reading op_regs->status, is
then an unaligned readl() on device memory. arm64 faults on unaligned
device accesses, so instead of xhci_handshake() catching the all-ones
value and returning -ENODEV, setup oopses:
xhci-pci-renesas 0005:08:00.0: Unable to change power state from D3cold to D0, device inaccessible
xhci-pci-renesas 0005:08:00.0: xHCI Host Controller
xhci-pci-renesas 0005:08:00.0: new USB bus registered, assigned bus number 1
Unable to handle kernel paging request at virtual address ffff80030a770103
ESR = 0x0000000096000021
FSC = 0x21: alignment fault
Internal error: Oops: 0000000096000021 [#1] SMP
pc : xhci_halt [xhci_hcd]
Call trace:
xhci_halt
xhci_gen_setup
xhci_pci_setup
usb_add_hcd
usb_hcd_pci_probe
xhci_pci_common_probe
xhci_pci_renesas_probe
This was hit with a Renesas uPD720201 that failed to power up ("Unable
to change power state from D3cold to D0, device inaccessible") yet still
reached the HCD probe path.
Read the capability register once, and if it reads back the all-ones
value (as xhci_handshake() and xhci_reset() already test for), abort
setup with -ENODEV before op_regs is derived from it. Reading it once
also avoids re-reading a register that may change under a concurrent
hot-removal.
Fixes: 66d4eadd8d06 ("USB: xhci: BIOS handoff and HW initialization.")
Cc: stable@vger.kernel.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20260806142113.2436238-11-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 71c25c2e71b9..4473b3cd1d36 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -5434,6 +5434,7 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
struct device *dev = hcd->self.sysdev;
int retval;
u32 hcs_params1;
+ u32 hc_capbase;
/* Accept arbitrarily long scatter-gather lists */
hcd->self.sg_tablesize = ~0;
@@ -5454,15 +5455,19 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
mutex_init(&xhci->mutex);
xhci->main_hcd = hcd;
xhci->cap_regs = hcd->regs;
- xhci->op_regs = hcd->regs +
- HC_LENGTH(readl(&xhci->cap_regs->hc_capbase));
+ hc_capbase = readl(&xhci->cap_regs->hc_capbase);
+ if (hc_capbase == U32_MAX) {
+ xhci_warn(xhci, "Host controller not accessible, removed?\n");
+ return -ENODEV;
+ }
+ xhci->op_regs = hcd->regs + HC_LENGTH(hc_capbase);
xhci->run_regs = hcd->regs +
(readl(&xhci->cap_regs->run_regs_off) & RTSOFF_MASK);
/* Cache read-only capability registers */
hcs_params1 = readl(&xhci->cap_regs->hcs_params1);
xhci->hcs_params2 = readl(&xhci->cap_regs->hcs_params2);
xhci->hcs_params3 = readl(&xhci->cap_regs->hcs_params3);
- xhci->hci_version = HC_VERSION(readl(&xhci->cap_regs->hc_capbase));
+ xhci->hci_version = HC_VERSION(hc_capbase);
xhci->hcc_params = readl(&xhci->cap_regs->hcc_params);
if (xhci->hci_version > 0x100)
xhci->hcc_params2 = readl(&xhci->cap_regs->hcc_params2);
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH 5.10.y] usb: xhci: bail out of setup if the controller is inaccessible
2026-08-31 12:21 FAILED: patch "[PATCH] usb: xhci: bail out of setup if the controller is" failed to apply to 5.10-stable tree gregkh
@ 2026-09-01 11:19 ` Sasha Levin
0 siblings, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2026-09-01 11:19 UTC (permalink / raw)
To: stable; +Cc: Breno Leitao, Mathias Nyman, Greg Kroah-Hartman, Sasha Levin
From: Breno Leitao <leitao@debian.org>
[ Upstream commit 78203d5b54a40f0e36196ebf31c9c7a380fc8811 ]
xhci_gen_setup() locates the operational registers using the capability
length read from the very first register:
xhci->op_regs = hcd->regs +
HC_LENGTH(readl(&xhci->cap_regs->hc_capbase));
If the controller is dead or has dropped off the bus, that read returns
~0, HC_LENGTH() truncates it to 0xff, and op_regs ends up 0xff bytes
past the page-aligned MMIO base, i.e. unaligned. The first access
through it, xhci_halt() -> xhci_handshake() reading op_regs->status, is
then an unaligned readl() on device memory. arm64 faults on unaligned
device accesses, so instead of xhci_handshake() catching the all-ones
value and returning -ENODEV, setup oopses:
xhci-pci-renesas 0005:08:00.0: Unable to change power state from D3cold to D0, device inaccessible
xhci-pci-renesas 0005:08:00.0: xHCI Host Controller
xhci-pci-renesas 0005:08:00.0: new USB bus registered, assigned bus number 1
Unable to handle kernel paging request at virtual address ffff80030a770103
ESR = 0x0000000096000021
FSC = 0x21: alignment fault
Internal error: Oops: 0000000096000021 [#1] SMP
pc : xhci_halt [xhci_hcd]
Call trace:
xhci_halt
xhci_gen_setup
xhci_pci_setup
usb_add_hcd
usb_hcd_pci_probe
xhci_pci_common_probe
xhci_pci_renesas_probe
This was hit with a Renesas uPD720201 that failed to power up ("Unable
to change power state from D3cold to D0, device inaccessible") yet still
reached the HCD probe path.
Read the capability register once, and if it reads back the all-ones
value (as xhci_handshake() and xhci_reset() already test for), abort
setup with -ENODEV before op_regs is derived from it. Reading it once
also avoids re-reading a register that may change under a concurrent
hot-removal.
Fixes: 66d4eadd8d06 ("USB: xhci: BIOS handoff and HW initialization.")
Cc: stable@vger.kernel.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20260806142113.2436238-11-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ adapted the double hc_capbase register read via hcc_params/hci_version to use a single new local hc_capbase variable ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/host/xhci.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 2cc27dba08e2d..81b1fb22dc932 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -5243,6 +5243,7 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
struct device *dev = hcd->self.sysdev;
unsigned int minor_rev;
int retval;
+ u32 hc_capbase;
/* Accept arbitrarily long scatter-gather lists */
hcd->self.sg_tablesize = ~0;
@@ -5309,16 +5310,19 @@ int xhci_gen_setup(struct usb_hcd *hcd, xhci_get_quirks_t get_quirks)
mutex_init(&xhci->mutex);
xhci->cap_regs = hcd->regs;
- xhci->op_regs = hcd->regs +
- HC_LENGTH(readl(&xhci->cap_regs->hc_capbase));
+ hc_capbase = readl(&xhci->cap_regs->hc_capbase);
+ if (hc_capbase == U32_MAX) {
+ xhci_warn(xhci, "Host controller not accessible, removed?\n");
+ return -ENODEV;
+ }
+ xhci->op_regs = hcd->regs + HC_LENGTH(hc_capbase);
xhci->run_regs = hcd->regs +
(readl(&xhci->cap_regs->run_regs_off) & RTSOFF_MASK);
/* Cache read-only capability registers */
xhci->hcs_params1 = readl(&xhci->cap_regs->hcs_params1);
xhci->hcs_params2 = readl(&xhci->cap_regs->hcs_params2);
xhci->hcs_params3 = readl(&xhci->cap_regs->hcs_params3);
- xhci->hcc_params = readl(&xhci->cap_regs->hc_capbase);
- xhci->hci_version = HC_VERSION(xhci->hcc_params);
+ xhci->hci_version = HC_VERSION(hc_capbase);
xhci->hcc_params = readl(&xhci->cap_regs->hcc_params);
if (xhci->hci_version > 0x100)
xhci->hcc_params2 = readl(&xhci->cap_regs->hcc_params2);
--
2.53.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-09-01 11:19 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-08-31 12:21 FAILED: patch "[PATCH] usb: xhci: bail out of setup if the controller is" failed to apply to 5.10-stable tree gregkh
2026-09-01 11:19 ` [PATCH 5.10.y] usb: xhci: bail out of setup if the controller is inaccessible Sasha Levin
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox