This reverts commit ffd603f214.
Commit ffd603f214 ("usb: gadget: u_serial: Add null pointer check in
gs_start_io") adds null pointer checks at the beginning of the
gs_start_io() function to prevent a null pointer dereference. However,
these checks are redundant because the function's comment already
requires callers to hold the port_lock and ensure port.tty and port_usb
are not null. All existing callers already follow these rules.
The true cause of the null pointer dereference is a race condition. When
gs_start_io() calls either gs_start_rx() or gs_start_tx(), the port_lock
is temporarily released for usb_ep_queue(). This allows port.tty and
port_usb to be cleared.
Fixes: ffd603f214 ("usb: gadget: u_serial: Add null pointer check in gs_start_io")
Cc: stable <stable@kernel.org>
Signed-off-by: Kuen-Han Tsai <khtsai@google.com>
Reviewed-by: Prashanth K <prashanth.k@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250617050844.1848232-1-khtsai@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Replace ternary (condition ? "enable" : "disable") syntax with helpers
from string_choices.h because:
1. Simple function call with one argument is easier to read. Ternary
operator has three arguments and with wrapping might lead to quite
long code.
2. Is slightly shorter thus also easier to read.
3. It brings uniformity in the text - same string.
4. Allows deduping by the linker, which results in a smaller binary
file.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250114-str-enable-disable-usb-v1-5-c8405df47c19@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Considering that in some extreme cases, when performing the
unbinding operation, gserial_disconnect has cleared gser->ioport,
which triggers gadget reconfiguration, and then calls gs_read_complete,
resulting in access to a null pointer. Therefore, ep is disabled before
gserial_disconnect sets port to null to prevent this from happening.
Call trace:
gs_read_complete+0x58/0x240
usb_gadget_giveback_request+0x40/0x160
dwc3_remove_requests+0x170/0x484
dwc3_ep0_out_start+0xb0/0x1d4
__dwc3_gadget_start+0x25c/0x720
kretprobe_trampoline.cfi_jt+0x0/0x8
kretprobe_trampoline.cfi_jt+0x0/0x8
udc_bind_to_driver+0x1d8/0x300
usb_gadget_probe_driver+0xa8/0x1dc
gadget_dev_desc_UDC_store+0x13c/0x188
configfs_write_iter+0x160/0x1f4
vfs_write+0x2d0/0x40c
ksys_write+0x7c/0xf0
__arm64_sys_write+0x20/0x30
invoke_syscall+0x60/0x150
el0_svc_common+0x8c/0xf8
do_el0_svc+0x28/0xa0
el0_svc+0x24/0x84
Fixes: c1dca562be ("usb gadget: split out serial core")
Cc: stable <stable@kernel.org>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lianqin Hu <hulianqin@vivo.com>
Link: https://lore.kernel.org/r/TYUPR06MB621733B5AC690DBDF80A0DCCD2042@TYUPR06MB6217.apcprd06.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Considering that in some extreme cases,
when u_serial driver is accessed by multiple threads,
Thread A is executing the open operation and calling the gs_open,
Thread B is executing the disconnect operation and calling the
gserial_disconnect function,The port->port_usb pointer will be set to NULL.
E.g.
Thread A Thread B
gs_open() gadget_unbind_driver()
gs_start_io() composite_disconnect()
gs_start_rx() gserial_disconnect()
... ...
spin_unlock(&port->port_lock)
status = usb_ep_queue() spin_lock(&port->port_lock)
spin_lock(&port->port_lock) port->port_usb = NULL
gs_free_requests(port->port_usb->in) spin_unlock(&port->port_lock)
Crash
This causes thread A to access a null pointer (port->port_usb is null)
when calling the gs_free_requests function, causing a crash.
If port_usb is NULL, the release request will be skipped as it
will be done by gserial_disconnect.
So add a null pointer check to gs_start_io before attempting
to access the value of the pointer port->port_usb.
Call trace:
gs_start_io+0x164/0x25c
gs_open+0x108/0x13c
tty_open+0x314/0x638
chrdev_open+0x1b8/0x258
do_dentry_open+0x2c4/0x700
vfs_open+0x2c/0x3c
path_openat+0xa64/0xc60
do_filp_open+0xb8/0x164
do_sys_openat2+0x84/0xf0
__arm64_sys_openat+0x70/0x9c
invoke_syscall+0x58/0x114
el0_svc_common+0x80/0xe0
do_el0_svc+0x1c/0x28
el0_svc+0x38/0x68
Fixes: c1dca562be ("usb gadget: split out serial core")
Cc: stable@vger.kernel.org
Suggested-by: Prashanth K <quic_prashk@quicinc.com>
Signed-off-by: Lianqin Hu <hulianqin@vivo.com>
Acked-by: Prashanth K <quic_prashk@quicinc.com>
Link: https://lore.kernel.org/r/TYUPR06MB62178DC3473F9E1A537DCD02D2362@TYUPR06MB6217.apcprd06.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Upstream commit aba3a8d01d ("usb: gadget: u_serial: add suspend
resume callbacks") added started_delayed flag, so that new ports
which are opened after USB suspend can start IO while resuming.
But if the port was already opened, and gadget suspend kicks in
afterwards, start_delayed will never be set. This causes resume
to bail out before calling gs_start_io(). Fix this by setting
start_delayed during suspend.
Fixes: aba3a8d01d ("usb: gadget: u_serial: add suspend resume callbacks")
Cc: stable@vger.kernel.org
Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
Link: https://lore.kernel.org/r/20240730125754.576326-1-quic_prashk@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If gs_close has cleared port->port.tty and gs_start_io is called
afterwards, then the function tty_wakeup will attempt to access the value
of the pointer port->port.tty which will cause a null pointer
dereference error.
To avoid this, add a null pointer check to gs_start_io before attempting
to access the value of the pointer port->port.tty.
Signed-off-by: Kuen-Han Tsai <khtsai@google.com>
Message-ID: <20230602070009.1353946-1-khtsai@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When serial console over USB is enabled, gs_console_connect
queues gs_console_work, where it acquires the spinlock and
queues the usb request, and this request goes to gadget layer.
Now consider a situation where gadget layer prints something
to dmesg, this will eventually call gs_console_write() which
requires cons->lock. And this causes spinlock recursion. Avoid
this by excluding usb_ep_queue from the spinlock.
spin_lock_irqsave //needs cons->lock
gs_console_write
.
.
_printk
__warn_printk
dev_warn/pr_err
.
.
[USB Gadget Layer]
.
.
usb_ep_queue
gs_console_work
__gs_console_push // acquires cons->lock
process_one_work
Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
Link: https://lore.kernel.org/r/1683638872-6885-1-git-send-email-quic_prashk@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Consider a case where gserial_disconnect has already cleared
gser->ioport. And if gserial_suspend gets called afterwards,
it will lead to accessing of gser->ioport and thus causing
null pointer dereference.
Avoid this by adding a null pointer check. Added a static
spinlock to prevent gser->ioport from becoming null after
the newly added null pointer check.
Fixes: aba3a8d01d ("usb: gadget: u_serial: add suspend resume callbacks")
Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
Link: https://lore.kernel.org/r/1683278317-11774-1-git-send-email-quic_prashk@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The commit aba3a8d01d ("usb: gadget: u_serial: add suspend resume
callbacks") set/cleared the suspended flag in USB bus suspend/resume
only. But, when a USB cable is disconnected in the suspend, since some
controllers will not detect USB bus resume, the suspended flag is not
cleared. After that, user cannot send any data. To fix the issue,
clears the suspended flag in the gserial_disconnect().
Fixes: aba3a8d01d ("usb: gadget: u_serial: add suspend resume callbacks")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Linh Phung <linh.phung.jy@renesas.com>
Tested-by: Tam Nguyen <tam.nguyen.xa@renesas.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Add suspend resume callbacks to handle the case seen when the bus is
suspended by the HOST, and the device opens the port (cat /dev/ttyGS0).
Gadget controller (like DWC2) doesn't accept usb requests to be queued in
this case (when in L2 state), from the gs_open() call. Error log is printed
- configfs-gadget gadget: acm ttyGS0 can't notify serial state, -11
If the HOST resumes (opens) the bus, the port still isn't functional.
Use suspend/resume callbacks to monitor the gadget suspended state by using
'suspended' flag. In case the port gets opened (cat /dev/ttyGS0), the I/O
stream will be delayed until the bus gets resumed by the HOST.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Symptom: application opens /dev/ttyGS0 and starts sending (writing) to
it while either USB cable is not connected, or nobody listens on the
other side of the cable. If driver circular buffer overflows before
connection is established, no data will be written to the USB layer
until/unless /dev/ttyGS0 is closed and re-opened again by the
application (the latter besides having no means of being notified about
the event of establishing of the connection.)
Fix: on open and/or connect, kick Tx to flush circular buffer data to
USB layer.
Signed-off-by: Sergey Organov <sorganov@gmail.com>
Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Remove home-made waiting mechanism from gs_open() and rely on
portmaster's mutex to do the job.
Note: This releases thread waiting on close() when another thread
open()s simultaneously.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Insert markers in console stream marking places where data
is missing. This makes the hole in the data stand out clearly
instead of glueing together unrelated messages.
Example output as seen from USB host side:
[ 0.064078] pinctrl core: registered pin 16 (UART3_RTS_N PC0) on 70000868.pinmux
[ 0.064130] pinctrl
[missed 114987 bytes]
[ 4.302299] udevd[134]: starting version 3.2.5
[ 4.306845] random: udevd: uninitialized urandom read (16 bytes read)
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Allow configuring more than one console using USB serial or ACM gadget.
By default, only first (ttyGS0) is a console, but this may be changed
using function's new "console" attribute.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Prevent OBEX serial port from ever becoming a console. Console messages
will definitely break the protocol, and since you have to instantiate
the port making it explicitly for OBEX, there is no point in allowing
console to break it by mistake.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Rewrite console support to fix a few shortcomings of the old code
preventing its use with multiple ports. This removes some duplicated
code and replaces a custom kthread with simpler workqueue item.
Only port ttyGS0 gets to be a console for now.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Ladislav Michl <ladis@linux-mips.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Switch RX processing from tasklet to (delayed) work queue. This allows
receiver more room to process incoming data and prevents flood of
"ttyGS0: RX not scheduled?" messages on HS receive on slow CPU.
A side effect is 2.4MB/s zmodem transfer speed (up from 1.8MB/s)
on my test board.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
The kernel FIFO implementation, kfifo, provides interfaces to manipulate
a first-in-first-out circular buffer. Use kfifo instead of the homemade
one to make the code more concise and readable.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.
Update the drivers/usb/ and include/linux/usb* files with the correct
SPDX license identifier based on the license text in the file itself.
The SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.
This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Addresses-Coverity-ID: 1350962
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
When the gadget serial device has no associated TTY, do not pass any
received data into the TTY layer for processing; simply drop it instead.
This prevents the TTY layer from calling back into the gadget serial
driver, which will then crash in e.g. gs_write_room() due to lack of
gadget serial device to TTY association (i.e. a NULL pointer dereference).
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Check for bad pointer that may result because of kthread_create failure.
This check is needed since the gserial setup callback function
(gs_console_setup()) is only freeing the info->con_buf in case of
kthread_create failure which will result into bad info->console_thread
pointer.
Without checking info->console_thread pointer validity in the
gserial_console_exit() function, before calling kthread_stop(), the
rmmod will generate Kernel Oops.
Signed-off-by: Bogdan Mirea <Bogdan-Stefan_mirea@mentor.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
