Running sha224_kunit on a KMSAN-enabled kernel results in a crash in
kmsan_internal_set_shadow_origin():
BUG: unable to handle page fault for address: ffffbc3840291000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0
Oops: 0000 [#1] SMP NOPTI
CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G N 6.17.0-rc3 #10 PREEMPT(voluntary)
Tainted: [N]=TEST
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100
[...]
Call Trace:
<TASK>
__msan_memset+0xee/0x1a0
sha224_final+0x9e/0x350
test_hash_buffer_overruns+0x46f/0x5f0
? kmsan_get_shadow_origin_ptr+0x46/0xa0
? __pfx_test_hash_buffer_overruns+0x10/0x10
kunit_try_run_case+0x198/0xa00
This occurs when memset() is called on a buffer that is not 4-byte
aligned and extends to the end of a guard page, i.e. the next page is
unmapped.
The bug is that the loop at the end of
kmsan_internal_set_shadow_origin() accesses the wrong shadow memory
bytes when the address is not 4-byte aligned. Since each 4 bytes are
associated with an origin, it rounds the address and size so that it can
access all the origins that contain the buffer. However, when it checks
the corresponding shadow bytes for a particular origin, it incorrectly
uses the original unrounded shadow address. This results in reads from
shadow memory beyond the end of the buffer's shadow memory, which
crashes when that memory is not mapped.
To fix this, correctly align the shadow address before accessing the 4
shadow bytes corresponding to each origin.
Fixes: 2ef3cec44c60 ("kmsan: do not wipe out origin when doing partial unpoisoning")
Cc: stable(a)vger.kernel.org
Signed-off-by: Eric Biggers <ebiggers(a)kernel.org>
---
mm/kmsan/core.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/mm/kmsan/core.c b/mm/kmsan/core.c
index 1ea711786c522..8bca7fece47f0 100644
--- a/mm/kmsan/core.c
+++ b/mm/kmsan/core.c
@@ -193,11 +193,12 @@ depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id)
void kmsan_internal_set_shadow_origin(void *addr, size_t size, int b,
u32 origin, bool checked)
{
u64 address = (u64)addr;
- u32 *shadow_start, *origin_start;
+ void *shadow_start;
+ u32 *aligned_shadow, *origin_start;
size_t pad = 0;
KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(addr, size));
shadow_start = kmsan_get_metadata(addr, KMSAN_META_SHADOW);
if (!shadow_start) {
@@ -212,13 +213,16 @@ void kmsan_internal_set_shadow_origin(void *addr, size_t size, int b,
}
return;
}
__memset(shadow_start, b, size);
- if (!IS_ALIGNED(address, KMSAN_ORIGIN_SIZE)) {
+ if (IS_ALIGNED(address, KMSAN_ORIGIN_SIZE)) {
+ aligned_shadow = shadow_start;
+ } else {
pad = address % KMSAN_ORIGIN_SIZE;
address -= pad;
+ aligned_shadow = shadow_start - pad;
size += pad;
}
size = ALIGN(size, KMSAN_ORIGIN_SIZE);
origin_start =
(u32 *)kmsan_get_metadata((void *)address, KMSAN_META_ORIGIN);
@@ -228,11 +232,11 @@ void kmsan_internal_set_shadow_origin(void *addr, size_t size, int b,
* and unconditionally overwrite the old origin slot.
* If the new origin is zero, overwrite the old origin slot iff the
* corresponding shadow slot is zero.
*/
for (int i = 0; i < size / KMSAN_ORIGIN_SIZE; i++) {
- if (origin || !shadow_start[i])
+ if (origin || !aligned_shadow[i])
origin_start[i] = origin;
}
}
struct page *kmsan_vmalloc_to_page_or_null(void *vaddr)
base-commit: 1b237f190eb3d36f52dffe07a40b5eb210280e00
--
2.50.1
The patch below does not apply to the 5.4-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(a)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-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 535fd4c98452c87537a40610abba45daf5761ec6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025091722-chatter-dyslexia-7db3@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 535fd4c98452c87537a40610abba45daf5761ec6 Mon Sep 17 00:00:00 2001
From: Hugo Villeneuve <hvilleneuve(a)dimonoff.com>
Date: Thu, 31 Jul 2025 08:44:50 -0400
Subject: [PATCH] serial: sc16is7xx: fix bug in flow control levels init
When trying to set MCR[2], XON1 is incorrectly accessed instead. And when
writing to the TCR register to configure flow control levels, we are
incorrectly writing to the MSR register. The default value of $00 is then
used for TCR, which means that selectable trigger levels in FCR are used
in place of TCR.
TCR/TLR access requires EFR[4] (enable enhanced functions) and MCR[2]
to be set. EFR[4] is already set in probe().
MCR access requires LCR[7] to be zero.
Since LCR is set to $BF when trying to set MCR[2], XON1 is incorrectly
accessed instead because MCR shares the same address space as XON1.
Since MCR[2] is unmodified and still zero, when writing to TCR we are in
fact writing to MSR because TCR/TLR registers share the same address space
as MSR/SPR.
Fix by first removing useless reconfiguration of EFR[4] (enable enhanced
functions), as it is already enabled in sc16is7xx_probe() since commit
43c51bb573aa ("sc16is7xx: make sure device is in suspend once probed").
Now LCR is $00, which means that MCR access is enabled.
Also remove regcache_cache_bypass() calls since we no longer access the
enhanced registers set, and TCR is already declared as volatile (in fact
by declaring MSR as volatile, which shares the same address).
Finally disable access to TCR/TLR registers after modifying them by
clearing MCR[2].
Note: the comment about "... and internal clock div" is wrong and can be
ignored/removed as access to internal clock div registers (DLL/DLH)
is permitted only when LCR[7] is logic 1, not when enhanced features
is enabled. And DLL/DLH access is not needed in sc16is7xx_startup().
Fixes: dfeae619d781 ("serial: sc16is7xx")
Cc: stable(a)vger.kernel.org
Signed-off-by: Hugo Villeneuve <hvilleneuve(a)dimonoff.com>
Link: https://lore.kernel.org/r/20250731124451.1108864-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 3f38fba8f6ea..a668e0bb26b3 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1177,17 +1177,6 @@ static int sc16is7xx_startup(struct uart_port *port)
sc16is7xx_port_write(port, SC16IS7XX_FCR_REG,
SC16IS7XX_FCR_FIFO_BIT);
- /* Enable EFR */
- sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
- SC16IS7XX_LCR_CONF_MODE_B);
-
- regcache_cache_bypass(one->regmap, true);
-
- /* Enable write access to enhanced features and internal clock div */
- sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
- SC16IS7XX_EFR_ENABLE_BIT,
- SC16IS7XX_EFR_ENABLE_BIT);
-
/* Enable TCR/TLR */
sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
SC16IS7XX_MCR_TCRTLR_BIT,
@@ -1199,7 +1188,8 @@ static int sc16is7xx_startup(struct uart_port *port)
SC16IS7XX_TCR_RX_RESUME(24) |
SC16IS7XX_TCR_RX_HALT(48));
- regcache_cache_bypass(one->regmap, false);
+ /* Disable TCR/TLR access */
+ sc16is7xx_port_update(port, SC16IS7XX_MCR_REG, SC16IS7XX_MCR_TCRTLR_BIT, 0);
/* Now, initialize the UART */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_WORD_LEN_8);
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(a)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 535fd4c98452c87537a40610abba45daf5761ec6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025091721-speak-detoxify-e6fe@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 535fd4c98452c87537a40610abba45daf5761ec6 Mon Sep 17 00:00:00 2001
From: Hugo Villeneuve <hvilleneuve(a)dimonoff.com>
Date: Thu, 31 Jul 2025 08:44:50 -0400
Subject: [PATCH] serial: sc16is7xx: fix bug in flow control levels init
When trying to set MCR[2], XON1 is incorrectly accessed instead. And when
writing to the TCR register to configure flow control levels, we are
incorrectly writing to the MSR register. The default value of $00 is then
used for TCR, which means that selectable trigger levels in FCR are used
in place of TCR.
TCR/TLR access requires EFR[4] (enable enhanced functions) and MCR[2]
to be set. EFR[4] is already set in probe().
MCR access requires LCR[7] to be zero.
Since LCR is set to $BF when trying to set MCR[2], XON1 is incorrectly
accessed instead because MCR shares the same address space as XON1.
Since MCR[2] is unmodified and still zero, when writing to TCR we are in
fact writing to MSR because TCR/TLR registers share the same address space
as MSR/SPR.
Fix by first removing useless reconfiguration of EFR[4] (enable enhanced
functions), as it is already enabled in sc16is7xx_probe() since commit
43c51bb573aa ("sc16is7xx: make sure device is in suspend once probed").
Now LCR is $00, which means that MCR access is enabled.
Also remove regcache_cache_bypass() calls since we no longer access the
enhanced registers set, and TCR is already declared as volatile (in fact
by declaring MSR as volatile, which shares the same address).
Finally disable access to TCR/TLR registers after modifying them by
clearing MCR[2].
Note: the comment about "... and internal clock div" is wrong and can be
ignored/removed as access to internal clock div registers (DLL/DLH)
is permitted only when LCR[7] is logic 1, not when enhanced features
is enabled. And DLL/DLH access is not needed in sc16is7xx_startup().
Fixes: dfeae619d781 ("serial: sc16is7xx")
Cc: stable(a)vger.kernel.org
Signed-off-by: Hugo Villeneuve <hvilleneuve(a)dimonoff.com>
Link: https://lore.kernel.org/r/20250731124451.1108864-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 3f38fba8f6ea..a668e0bb26b3 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1177,17 +1177,6 @@ static int sc16is7xx_startup(struct uart_port *port)
sc16is7xx_port_write(port, SC16IS7XX_FCR_REG,
SC16IS7XX_FCR_FIFO_BIT);
- /* Enable EFR */
- sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
- SC16IS7XX_LCR_CONF_MODE_B);
-
- regcache_cache_bypass(one->regmap, true);
-
- /* Enable write access to enhanced features and internal clock div */
- sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
- SC16IS7XX_EFR_ENABLE_BIT,
- SC16IS7XX_EFR_ENABLE_BIT);
-
/* Enable TCR/TLR */
sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
SC16IS7XX_MCR_TCRTLR_BIT,
@@ -1199,7 +1188,8 @@ static int sc16is7xx_startup(struct uart_port *port)
SC16IS7XX_TCR_RX_RESUME(24) |
SC16IS7XX_TCR_RX_HALT(48));
- regcache_cache_bypass(one->regmap, false);
+ /* Disable TCR/TLR access */
+ sc16is7xx_port_update(port, SC16IS7XX_MCR_REG, SC16IS7XX_MCR_TCRTLR_BIT, 0);
/* Now, initialize the UART */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_WORD_LEN_8);
The patch below does not apply to the 5.15-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(a)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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 535fd4c98452c87537a40610abba45daf5761ec6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025091721-moonwalk-barrack-423e@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 535fd4c98452c87537a40610abba45daf5761ec6 Mon Sep 17 00:00:00 2001
From: Hugo Villeneuve <hvilleneuve(a)dimonoff.com>
Date: Thu, 31 Jul 2025 08:44:50 -0400
Subject: [PATCH] serial: sc16is7xx: fix bug in flow control levels init
When trying to set MCR[2], XON1 is incorrectly accessed instead. And when
writing to the TCR register to configure flow control levels, we are
incorrectly writing to the MSR register. The default value of $00 is then
used for TCR, which means that selectable trigger levels in FCR are used
in place of TCR.
TCR/TLR access requires EFR[4] (enable enhanced functions) and MCR[2]
to be set. EFR[4] is already set in probe().
MCR access requires LCR[7] to be zero.
Since LCR is set to $BF when trying to set MCR[2], XON1 is incorrectly
accessed instead because MCR shares the same address space as XON1.
Since MCR[2] is unmodified and still zero, when writing to TCR we are in
fact writing to MSR because TCR/TLR registers share the same address space
as MSR/SPR.
Fix by first removing useless reconfiguration of EFR[4] (enable enhanced
functions), as it is already enabled in sc16is7xx_probe() since commit
43c51bb573aa ("sc16is7xx: make sure device is in suspend once probed").
Now LCR is $00, which means that MCR access is enabled.
Also remove regcache_cache_bypass() calls since we no longer access the
enhanced registers set, and TCR is already declared as volatile (in fact
by declaring MSR as volatile, which shares the same address).
Finally disable access to TCR/TLR registers after modifying them by
clearing MCR[2].
Note: the comment about "... and internal clock div" is wrong and can be
ignored/removed as access to internal clock div registers (DLL/DLH)
is permitted only when LCR[7] is logic 1, not when enhanced features
is enabled. And DLL/DLH access is not needed in sc16is7xx_startup().
Fixes: dfeae619d781 ("serial: sc16is7xx")
Cc: stable(a)vger.kernel.org
Signed-off-by: Hugo Villeneuve <hvilleneuve(a)dimonoff.com>
Link: https://lore.kernel.org/r/20250731124451.1108864-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 3f38fba8f6ea..a668e0bb26b3 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1177,17 +1177,6 @@ static int sc16is7xx_startup(struct uart_port *port)
sc16is7xx_port_write(port, SC16IS7XX_FCR_REG,
SC16IS7XX_FCR_FIFO_BIT);
- /* Enable EFR */
- sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
- SC16IS7XX_LCR_CONF_MODE_B);
-
- regcache_cache_bypass(one->regmap, true);
-
- /* Enable write access to enhanced features and internal clock div */
- sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
- SC16IS7XX_EFR_ENABLE_BIT,
- SC16IS7XX_EFR_ENABLE_BIT);
-
/* Enable TCR/TLR */
sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
SC16IS7XX_MCR_TCRTLR_BIT,
@@ -1199,7 +1188,8 @@ static int sc16is7xx_startup(struct uart_port *port)
SC16IS7XX_TCR_RX_RESUME(24) |
SC16IS7XX_TCR_RX_HALT(48));
- regcache_cache_bypass(one->regmap, false);
+ /* Disable TCR/TLR access */
+ sc16is7xx_port_update(port, SC16IS7XX_MCR_REG, SC16IS7XX_MCR_TCRTLR_BIT, 0);
/* Now, initialize the UART */
sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_WORD_LEN_8);
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(a)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 a5c98e8b1398534ae1feb6e95e2d3ee5215538ed
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025091731-subtotal-outcome-6092@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a5c98e8b1398534ae1feb6e95e2d3ee5215538ed Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman(a)linux.intel.com>
Date: Tue, 2 Sep 2025 13:53:05 +0300
Subject: [PATCH] xhci: dbc: Fix full DbC transfer ring after several
reconnects
Pending requests will be flushed on disconnect, and the corresponding
TRBs will be turned into No-op TRBs, which are ignored by the xHC
controller once it starts processing the ring.
If the USB debug cable repeatedly disconnects before ring is started
then the ring will eventually be filled with No-op TRBs.
No new transfers can be queued when the ring is full, and driver will
print the following error message:
"xhci_hcd 0000:00:14.0: failed to queue trbs"
This is a normal case for 'in' transfers where TRBs are always enqueued
in advance, ready to take on incoming data. If no data arrives, and
device is disconnected, then ring dequeue will remain at beginning of
the ring while enqueue points to first free TRB after last cancelled
No-op TRB.
s
Solve this by reinitializing the rings when the debug cable disconnects
and DbC is leaving the configured state.
Clear the whole ring buffer and set enqueue and dequeue to the beginning
of ring, and set cycle bit to its initial state.
Cc: stable(a)vger.kernel.org
Fixes: dfba2174dc42 ("usb: xhci: Add DbC support in xHCI driver")
Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com>
Link: https://lore.kernel.org/r/20250902105306.877476-3-mathias.nyman@linux.intel…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/usb/host/xhci-dbgcap.c b/drivers/usb/host/xhci-dbgcap.c
index d0faff233e3e..63edf2d8f245 100644
--- a/drivers/usb/host/xhci-dbgcap.c
+++ b/drivers/usb/host/xhci-dbgcap.c
@@ -462,6 +462,25 @@ static void xhci_dbc_ring_init(struct xhci_ring *ring)
xhci_initialize_ring_info(ring);
}
+static int xhci_dbc_reinit_ep_rings(struct xhci_dbc *dbc)
+{
+ struct xhci_ring *in_ring = dbc->eps[BULK_IN].ring;
+ struct xhci_ring *out_ring = dbc->eps[BULK_OUT].ring;
+
+ if (!in_ring || !out_ring || !dbc->ctx) {
+ dev_warn(dbc->dev, "Can't re-init unallocated endpoints\n");
+ return -ENODEV;
+ }
+
+ xhci_dbc_ring_init(in_ring);
+ xhci_dbc_ring_init(out_ring);
+
+ /* set ep context enqueue, dequeue, and cycle to initial values */
+ xhci_dbc_init_ep_contexts(dbc);
+
+ return 0;
+}
+
static struct xhci_ring *
xhci_dbc_ring_alloc(struct device *dev, enum xhci_ring_type type, gfp_t flags)
{
@@ -885,7 +904,7 @@ static enum evtreturn xhci_dbc_do_handle_events(struct xhci_dbc *dbc)
dev_info(dbc->dev, "DbC cable unplugged\n");
dbc->state = DS_ENABLED;
xhci_dbc_flush_requests(dbc);
-
+ xhci_dbc_reinit_ep_rings(dbc);
return EVT_DISC;
}
@@ -895,7 +914,7 @@ static enum evtreturn xhci_dbc_do_handle_events(struct xhci_dbc *dbc)
writel(portsc, &dbc->regs->portsc);
dbc->state = DS_ENABLED;
xhci_dbc_flush_requests(dbc);
-
+ xhci_dbc_reinit_ep_rings(dbc);
return EVT_DISC;
}
The patch below does not apply to the 5.15-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(a)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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x a5c98e8b1398534ae1feb6e95e2d3ee5215538ed
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025091747-thirstily-dispose-3727@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a5c98e8b1398534ae1feb6e95e2d3ee5215538ed Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman(a)linux.intel.com>
Date: Tue, 2 Sep 2025 13:53:05 +0300
Subject: [PATCH] xhci: dbc: Fix full DbC transfer ring after several
reconnects
Pending requests will be flushed on disconnect, and the corresponding
TRBs will be turned into No-op TRBs, which are ignored by the xHC
controller once it starts processing the ring.
If the USB debug cable repeatedly disconnects before ring is started
then the ring will eventually be filled with No-op TRBs.
No new transfers can be queued when the ring is full, and driver will
print the following error message:
"xhci_hcd 0000:00:14.0: failed to queue trbs"
This is a normal case for 'in' transfers where TRBs are always enqueued
in advance, ready to take on incoming data. If no data arrives, and
device is disconnected, then ring dequeue will remain at beginning of
the ring while enqueue points to first free TRB after last cancelled
No-op TRB.
s
Solve this by reinitializing the rings when the debug cable disconnects
and DbC is leaving the configured state.
Clear the whole ring buffer and set enqueue and dequeue to the beginning
of ring, and set cycle bit to its initial state.
Cc: stable(a)vger.kernel.org
Fixes: dfba2174dc42 ("usb: xhci: Add DbC support in xHCI driver")
Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com>
Link: https://lore.kernel.org/r/20250902105306.877476-3-mathias.nyman@linux.intel…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/usb/host/xhci-dbgcap.c b/drivers/usb/host/xhci-dbgcap.c
index d0faff233e3e..63edf2d8f245 100644
--- a/drivers/usb/host/xhci-dbgcap.c
+++ b/drivers/usb/host/xhci-dbgcap.c
@@ -462,6 +462,25 @@ static void xhci_dbc_ring_init(struct xhci_ring *ring)
xhci_initialize_ring_info(ring);
}
+static int xhci_dbc_reinit_ep_rings(struct xhci_dbc *dbc)
+{
+ struct xhci_ring *in_ring = dbc->eps[BULK_IN].ring;
+ struct xhci_ring *out_ring = dbc->eps[BULK_OUT].ring;
+
+ if (!in_ring || !out_ring || !dbc->ctx) {
+ dev_warn(dbc->dev, "Can't re-init unallocated endpoints\n");
+ return -ENODEV;
+ }
+
+ xhci_dbc_ring_init(in_ring);
+ xhci_dbc_ring_init(out_ring);
+
+ /* set ep context enqueue, dequeue, and cycle to initial values */
+ xhci_dbc_init_ep_contexts(dbc);
+
+ return 0;
+}
+
static struct xhci_ring *
xhci_dbc_ring_alloc(struct device *dev, enum xhci_ring_type type, gfp_t flags)
{
@@ -885,7 +904,7 @@ static enum evtreturn xhci_dbc_do_handle_events(struct xhci_dbc *dbc)
dev_info(dbc->dev, "DbC cable unplugged\n");
dbc->state = DS_ENABLED;
xhci_dbc_flush_requests(dbc);
-
+ xhci_dbc_reinit_ep_rings(dbc);
return EVT_DISC;
}
@@ -895,7 +914,7 @@ static enum evtreturn xhci_dbc_do_handle_events(struct xhci_dbc *dbc)
writel(portsc, &dbc->regs->portsc);
dbc->state = DS_ENABLED;
xhci_dbc_flush_requests(dbc);
-
+ xhci_dbc_reinit_ep_rings(dbc);
return EVT_DISC;
}
The patch below does not apply to the 6.1-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(a)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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x a5c98e8b1398534ae1feb6e95e2d3ee5215538ed
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025091706-savings-chatroom-9c46@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From a5c98e8b1398534ae1feb6e95e2d3ee5215538ed Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman(a)linux.intel.com>
Date: Tue, 2 Sep 2025 13:53:05 +0300
Subject: [PATCH] xhci: dbc: Fix full DbC transfer ring after several
reconnects
Pending requests will be flushed on disconnect, and the corresponding
TRBs will be turned into No-op TRBs, which are ignored by the xHC
controller once it starts processing the ring.
If the USB debug cable repeatedly disconnects before ring is started
then the ring will eventually be filled with No-op TRBs.
No new transfers can be queued when the ring is full, and driver will
print the following error message:
"xhci_hcd 0000:00:14.0: failed to queue trbs"
This is a normal case for 'in' transfers where TRBs are always enqueued
in advance, ready to take on incoming data. If no data arrives, and
device is disconnected, then ring dequeue will remain at beginning of
the ring while enqueue points to first free TRB after last cancelled
No-op TRB.
s
Solve this by reinitializing the rings when the debug cable disconnects
and DbC is leaving the configured state.
Clear the whole ring buffer and set enqueue and dequeue to the beginning
of ring, and set cycle bit to its initial state.
Cc: stable(a)vger.kernel.org
Fixes: dfba2174dc42 ("usb: xhci: Add DbC support in xHCI driver")
Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com>
Link: https://lore.kernel.org/r/20250902105306.877476-3-mathias.nyman@linux.intel…
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
diff --git a/drivers/usb/host/xhci-dbgcap.c b/drivers/usb/host/xhci-dbgcap.c
index d0faff233e3e..63edf2d8f245 100644
--- a/drivers/usb/host/xhci-dbgcap.c
+++ b/drivers/usb/host/xhci-dbgcap.c
@@ -462,6 +462,25 @@ static void xhci_dbc_ring_init(struct xhci_ring *ring)
xhci_initialize_ring_info(ring);
}
+static int xhci_dbc_reinit_ep_rings(struct xhci_dbc *dbc)
+{
+ struct xhci_ring *in_ring = dbc->eps[BULK_IN].ring;
+ struct xhci_ring *out_ring = dbc->eps[BULK_OUT].ring;
+
+ if (!in_ring || !out_ring || !dbc->ctx) {
+ dev_warn(dbc->dev, "Can't re-init unallocated endpoints\n");
+ return -ENODEV;
+ }
+
+ xhci_dbc_ring_init(in_ring);
+ xhci_dbc_ring_init(out_ring);
+
+ /* set ep context enqueue, dequeue, and cycle to initial values */
+ xhci_dbc_init_ep_contexts(dbc);
+
+ return 0;
+}
+
static struct xhci_ring *
xhci_dbc_ring_alloc(struct device *dev, enum xhci_ring_type type, gfp_t flags)
{
@@ -885,7 +904,7 @@ static enum evtreturn xhci_dbc_do_handle_events(struct xhci_dbc *dbc)
dev_info(dbc->dev, "DbC cable unplugged\n");
dbc->state = DS_ENABLED;
xhci_dbc_flush_requests(dbc);
-
+ xhci_dbc_reinit_ep_rings(dbc);
return EVT_DISC;
}
@@ -895,7 +914,7 @@ static enum evtreturn xhci_dbc_do_handle_events(struct xhci_dbc *dbc)
writel(portsc, &dbc->regs->portsc);
dbc->state = DS_ENABLED;
xhci_dbc_flush_requests(dbc);
-
+ xhci_dbc_reinit_ep_rings(dbc);
return EVT_DISC;
}