A non-first waiter can potentially spin in the for loop of
rwsem_down_write_slowpath() without sleeping but fail to acquire the
lock even if the rwsem is free if the following sequence happens:
Non-first RT waiter First waiter Lock holder
------------------- ------------ -----------
Acquire wait_lock
rwsem_try_write_lock():
Set handoff bit if RT or
wait too long
Set waiter->handoff_set
Release wait_lock
Acquire wait_lock
Inherit waiter->handoff_set
Release wait_lock
Clear owner
Release lock
if (waiter.handoff_set) {
rwsem_spin_on_owner(();
if (OWNER_NULL)
goto trylock_again;
}
trylock_again:
Acquire wait_lock
rwsem_try_write_lock():
if (first->handoff_set && (waiter != first))
return false;
Release wait_lock
A non-first waiter cannot really acquire the rwsem even if it mistakenly
believes that it can spin on OWNER_NULL value. If that waiter happens
to be an RT task running on the same CPU as the first waiter, it can
block the first waiter from acquiring the rwsem leading to live lock.
Fix this problem by making sure that a non-first waiter cannot spin in
the slowpath loop without sleeping.
Fixes: d257cc8cb8d5 ("locking/rwsem: Make handoff bit handling more consistent")
Reviewed-and-tested-by: Mukesh Ojha <quic_mojha(a)quicinc.com>
Signed-off-by: Waiman Long <longman(a)redhat.com>
Cc: stable(a)vger.kernel.org
---
kernel/locking/rwsem.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index 44873594de03..be2df9ea7c30 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -624,18 +624,16 @@ static inline bool rwsem_try_write_lock(struct rw_semaphore *sem,
*/
if (first->handoff_set && (waiter != first))
return false;
-
- /*
- * First waiter can inherit a previously set handoff
- * bit and spin on rwsem if lock acquisition fails.
- */
- if (waiter == first)
- waiter->handoff_set = true;
}
new = count;
if (count & RWSEM_LOCK_MASK) {
+ /*
+ * A waiter (first or not) can set the handoff bit
+ * if it is an RT task or wait in the wait queue
+ * for too long.
+ */
if (has_handoff || (!rt_task(waiter->task) &&
!time_after(jiffies, waiter->timeout)))
return false;
@@ -651,11 +649,12 @@ static inline bool rwsem_try_write_lock(struct rw_semaphore *sem,
} while (!atomic_long_try_cmpxchg_acquire(&sem->count, &count, new));
/*
- * We have either acquired the lock with handoff bit cleared or
- * set the handoff bit.
+ * We have either acquired the lock with handoff bit cleared or set
+ * the handoff bit. Only the first waiter can have its handoff_set
+ * set here to enable optimistic spinning in slowpath loop.
*/
if (new & RWSEM_FLAG_HANDOFF) {
- waiter->handoff_set = true;
+ first->handoff_set = true;
lockevent_inc(rwsem_wlock_handoff);
return false;
}
--
2.31.1
In Google internal bug 265639009 we've received an (as yet) unreproducible
crash report from an aarch64 GKI 5.10.149-android13 running device.
AFAICT the source code is at:
https://android.googlesource.com/kernel/common/+/refs/tags/ASB-2022-12-05_1…
The call stack is:
ncm_close() -> ncm_notify() -> ncm_do_notify()
with the crash at:
ncm_do_notify+0x98/0x270
Code: 79000d0b b9000a6c f940012a f9400269 (b9405d4b)
Which I believe disassembles to (I don't know ARM assembly, but it looks sane enough to me...):
// halfword (16-bit) store presumably to event->wLength (at offset 6 of struct usb_cdc_notification)
0B 0D 00 79 strh w11, [x8, #6]
// word (32-bit) store presumably to req->Length (at offset 8 of struct usb_request)
6C 0A 00 B9 str w12, [x19, #8]
// x10 (NULL) was read here from offset 0 of valid pointer x9
// IMHO we're reading 'cdev->gadget' and getting NULL
// gadget is indeed at offset 0 of struct usb_composite_dev
2A 01 40 F9 ldr x10, [x9]
// loading req->buf pointer, which is at offset 0 of struct usb_request
69 02 40 F9 ldr x9, [x19]
// x10 is null, crash, appears to be attempt to read cdev->gadget->max_speed
4B 5D 40 B9 ldr w11, [x10, #0x5c]
which seems to line up with ncm_do_notify() case NCM_NOTIFY_SPEED code fragment:
event->wLength = cpu_to_le16(8);
req->length = NCM_STATUS_BYTECOUNT;
/* SPEED_CHANGE data is up/down speeds in bits/sec */
data = req->buf + sizeof *event;
data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget));
My analysis of registers and NULL ptr deref crash offset
(Unable to handle kernel NULL pointer dereference at virtual address 000000000000005c)
heavily suggests that the crash is due to 'cdev->gadget' being NULL when executing:
data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget));
which calls:
ncm_bitrate(NULL)
which then calls:
gadget_is_superspeed(NULL)
which reads
((struct usb_gadget *)NULL)->max_speed
and hits a panic.
AFAICT, if I'm counting right, the offset of max_speed is indeed 0x5C.
(remember there's a GKI KABI reservation of 16 bytes in struct work_struct)
It's not at all clear to me how this is all supposed to work...
but returning 0 seems much better than panic-ing...
Cc: Felipe Balbi <balbi(a)kernel.org>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Lorenzo Colitti <lorenzo(a)google.com>
Cc: Carlos Llamas <cmllamas(a)google.com>
Cc: stable(a)vger.kernel.org
Signed-off-by: Maciej Żenczykowski <maze(a)google.com>
---
drivers/usb/gadget/function/f_ncm.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c
index c36bcfa0e9b4..424bb3b666db 100644
--- a/drivers/usb/gadget/function/f_ncm.c
+++ b/drivers/usb/gadget/function/f_ncm.c
@@ -83,7 +83,9 @@ static inline struct f_ncm *func_to_ncm(struct usb_function *f)
/* peak (theoretical) bulk transfer rate in bits-per-second */
static inline unsigned ncm_bitrate(struct usb_gadget *g)
{
- if (gadget_is_superspeed(g) && g->speed >= USB_SPEED_SUPER_PLUS)
+ if (!g)
+ return 0;
+ else if (gadget_is_superspeed(g) && g->speed >= USB_SPEED_SUPER_PLUS)
return 4250000000U;
else if (gadget_is_superspeed(g) && g->speed == USB_SPEED_SUPER)
return 3750000000U;
--
2.39.0.314.g84b9a713c41-goog
Update the altmode "active" state when we receive Acks for Enter and
Exit Mode commands. Having the right state is necessary to change Pin
Assignments using the 'pin_assignment" sysfs file.
Fixes: 0e3bb7d6894d ("usb: typec: Add driver for DisplayPort alternate mode")
Cc: stable(a)vger.kernel.org
Cc: Heikki Krogerus <heikki.krogerus(a)linux.intel.com>
Signed-off-by: Prashant Malani <pmalani(a)chromium.org>
---
drivers/usb/typec/altmodes/displayport.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
index 06fb4732f8cd..bc1c556944d6 100644
--- a/drivers/usb/typec/altmodes/displayport.c
+++ b/drivers/usb/typec/altmodes/displayport.c
@@ -277,9 +277,11 @@ static int dp_altmode_vdm(struct typec_altmode *alt,
case CMDT_RSP_ACK:
switch (cmd) {
case CMD_ENTER_MODE:
+ typec_altmode_update_active(alt, true);
dp->state = DP_STATE_UPDATE;
break;
case CMD_EXIT_MODE:
+ typec_altmode_update_active(alt, false);
dp->data.status = 0;
dp->data.conf = 0;
break;
--
2.39.0.314.g84b9a713c41-goog
The memory for "llcc_driv_data" is allocated by the LLCC driver. But when
it is passed as "pvt_info" to the EDAC core, it will get freed during the
qcom_edac driver release. So when the qcom_edac driver gets probed again,
it will try to use the freed data leading to the use-after-free bug.
Hence, do not pass "llcc_driv_data" as pvt_info but rather reference it
using the "platform_data" in the qcom_edac driver.
Cc: <stable(a)vger.kernel.org> # 4.20
Fixes: 27450653f1db ("drivers: edac: Add EDAC driver support for QCOM SoCs")
Tested-by: Steev Klimaszewski <steev(a)kali.org> # Thinkpad X13s
Tested-by: Andrew Halaney <ahalaney(a)redhat.com> # sa8540p-ride
Reported-by: Steev Klimaszewski <steev(a)kali.org>
Reviewed-by: Borislav Petkov (AMD) <bp(a)alien8.de>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam(a)linaro.org>
---
drivers/edac/qcom_edac.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/edac/qcom_edac.c b/drivers/edac/qcom_edac.c
index 9e77fa84e84f..3256254c3722 100644
--- a/drivers/edac/qcom_edac.c
+++ b/drivers/edac/qcom_edac.c
@@ -252,7 +252,7 @@ dump_syn_reg_values(struct llcc_drv_data *drv, u32 bank, int err_type)
static int
dump_syn_reg(struct edac_device_ctl_info *edev_ctl, int err_type, u32 bank)
{
- struct llcc_drv_data *drv = edev_ctl->pvt_info;
+ struct llcc_drv_data *drv = edev_ctl->dev->platform_data;
int ret;
ret = dump_syn_reg_values(drv, bank, err_type);
@@ -289,7 +289,7 @@ static irqreturn_t
llcc_ecc_irq_handler(int irq, void *edev_ctl)
{
struct edac_device_ctl_info *edac_dev_ctl = edev_ctl;
- struct llcc_drv_data *drv = edac_dev_ctl->pvt_info;
+ struct llcc_drv_data *drv = edac_dev_ctl->dev->platform_data;
irqreturn_t irq_rc = IRQ_NONE;
u32 drp_error, trp_error, i;
int ret;
@@ -358,7 +358,6 @@ static int qcom_llcc_edac_probe(struct platform_device *pdev)
edev_ctl->dev_name = dev_name(dev);
edev_ctl->ctl_name = "llcc";
edev_ctl->panic_on_ue = LLCC_ERP_PANIC_ON_UE;
- edev_ctl->pvt_info = llcc_driv_data;
rc = edac_device_add_device(edev_ctl);
if (rc)
--
2.25.1
Requesting an interrupt with IRQF_ONESHOT will run the primary handler
in the hard-IRQ context even in the force-threaded mode. The
force-threaded mode is used by PREEMPT_RT in order to avoid acquiring
sleeping locks (spinlock_t) in hard-IRQ context. This combination
makes it impossible and leads to "sleeping while atomic" warnings.
Use one interrupt handler for both handlers (primary and secondary)
and drop the IRQF_ONESHOT flag which is not needed.
Fixes: e359b4411c283 ("serial: stm32: fix threaded interrupt handling")
Reviewed-by: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
Tested-by: Valentin Caron <valentin.caron(a)foss.st.com> # V3
Signed-off-by: Marek Vasut <marex(a)denx.de>
Cc: stable(a)vger.kernel.org
---
Cc: Alexandre Torgue <alexandre.torgue(a)foss.st.com>
Cc: Erwan Le Ray <erwan.leray(a)foss.st.com>
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Jiri Slaby <jirislaby(a)kernel.org>
Cc: Maxime Coquelin <mcoquelin.stm32(a)gmail.com>
Cc: Sebastian Andrzej Siewior <bigeasy(a)linutronix.de>
Cc: Thomas Gleixner <tglx(a)linutronix.de>
Cc: Valentin Caron <valentin.caron(a)foss.st.com>
Cc: linux-arm-kernel(a)lists.infradead.org
Cc: linux-stm32(a)st-md-mailman.stormreply.com
To: linux-serial(a)vger.kernel.org
---
V2: - Update patch subject, was:
serial: stm32: Move hard IRQ handling to threaded interrupt context
- Use request_irq() instead, rename the IRQ handler function
V3: - Update the commit message per suggestion from Sebastian
- Add RB from Sebastian
- Add Fixes tag
V4: - Remove uart_console() deadlock check from
stm32_usart_of_dma_rx_probe()
- Use plain spin_lock()/spin_unlock() instead of the
_irqsave/_irqrestore variants in IRQ handler
- Add TB from Valentin
V5: - Add CC stable@
- Do not move the sr variable, removes one useless hunk from the patch
V6: - Replace uart_unlock_and_check_sysrq_irqrestore with uart_unlock_and_check_sysrq
and drop last instance of flags
---
drivers/tty/serial/stm32-usart.c | 33 +++++---------------------------
1 file changed, 5 insertions(+), 28 deletions(-)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index a1490033aa164..409e91d6829a5 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -797,25 +797,11 @@ static irqreturn_t stm32_usart_interrupt(int irq, void *ptr)
spin_unlock(&port->lock);
}
- if (stm32_usart_rx_dma_enabled(port))
- return IRQ_WAKE_THREAD;
- else
- return IRQ_HANDLED;
-}
-
-static irqreturn_t stm32_usart_threaded_interrupt(int irq, void *ptr)
-{
- struct uart_port *port = ptr;
- struct tty_port *tport = &port->state->port;
- struct stm32_port *stm32_port = to_stm32_port(port);
- unsigned int size;
- unsigned long flags;
-
/* Receiver timeout irq for DMA RX */
- if (!stm32_port->throttled) {
- spin_lock_irqsave(&port->lock, flags);
+ if (stm32_usart_rx_dma_enabled(port) && !stm32_port->throttled) {
+ spin_lock(&port->lock);
size = stm32_usart_receive_chars(port, false);
- uart_unlock_and_check_sysrq_irqrestore(port, flags);
+ uart_unlock_and_check_sysrq(port);
if (size)
tty_flip_buffer_push(tport);
}
@@ -1015,10 +1001,8 @@ static int stm32_usart_startup(struct uart_port *port)
u32 val;
int ret;
- ret = request_threaded_irq(port->irq, stm32_usart_interrupt,
- stm32_usart_threaded_interrupt,
- IRQF_ONESHOT | IRQF_NO_SUSPEND,
- name, port);
+ ret = request_irq(port->irq, stm32_usart_interrupt,
+ IRQF_NO_SUSPEND, name, port);
if (ret)
return ret;
@@ -1601,13 +1585,6 @@ static int stm32_usart_of_dma_rx_probe(struct stm32_port *stm32port,
struct dma_slave_config config;
int ret;
- /*
- * Using DMA and threaded handler for the console could lead to
- * deadlocks.
- */
- if (uart_console(port))
- return -ENODEV;
-
stm32port->rx_buf = dma_alloc_coherent(dev, RX_BUF_L,
&stm32port->rx_dma_buf,
GFP_KERNEL);
--
2.39.0
This is a note to let you know that I've just added the patch titled
mei: me: add meteor lake point M DID
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From 0c4d68261717f89fa8c4f98a6967c3832fcb3ad0 Mon Sep 17 00:00:00 2001
From: Alexander Usyskin <alexander.usyskin(a)intel.com>
Date: Tue, 13 Dec 2022 00:02:47 +0200
Subject: mei: me: add meteor lake point M DID
Add Meteor Lake Point M device id.
Cc: <stable(a)vger.kernel.org>
Signed-off-by: Alexander Usyskin <alexander.usyskin(a)intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler(a)intel.com>
Link: https://lore.kernel.org/r/20221212220247.286019-2-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
---
drivers/misc/mei/hw-me-regs.h | 2 ++
drivers/misc/mei/pci-me.c | 2 ++
2 files changed, 4 insertions(+)
diff --git a/drivers/misc/mei/hw-me-regs.h b/drivers/misc/mei/hw-me-regs.h
index 99966cd3e7d8..bdc65d50b945 100644
--- a/drivers/misc/mei/hw-me-regs.h
+++ b/drivers/misc/mei/hw-me-regs.h
@@ -111,6 +111,8 @@
#define MEI_DEV_ID_RPL_S 0x7A68 /* Raptor Lake Point S */
+#define MEI_DEV_ID_MTL_M 0x7E70 /* Meteor Lake Point M */
+
/*
* MEI HW Section
*/
diff --git a/drivers/misc/mei/pci-me.c b/drivers/misc/mei/pci-me.c
index 704cd0caa172..5bf0d50d55a0 100644
--- a/drivers/misc/mei/pci-me.c
+++ b/drivers/misc/mei/pci-me.c
@@ -118,6 +118,8 @@ static const struct pci_device_id mei_me_pci_tbl[] = {
{MEI_PCI_DEVICE(MEI_DEV_ID_RPL_S, MEI_ME_PCH15_CFG)},
+ {MEI_PCI_DEVICE(MEI_DEV_ID_MTL_M, MEI_ME_PCH15_CFG)},
+
/* required last entry */
{0, }
};
--
2.39.1