From: Stephen Boyd <swboyd@chromium.org>
To: gregkh@linuxfoundation.org, satya priya <skakit@codeaurora.org>
Cc: mgautam@codeaurora.org, linux-arm-msm@vger.kernel.org,
linux-serial@vger.kernel.org, akashast@codeaurora.org,
rojay@codeaurora.org, msavaliy@qti.qualcomm.com,
satya priya <skakit@codeaurora.org>
Subject: Re: [PATCH V2 1/2] tty: serial: qcom_geni_serial: Allocate port->rx_fifo buffer in probe
Date: Fri, 28 Feb 2020 15:01:29 -0800 [thread overview]
Message-ID: <158293088963.112031.11417422453396901116@swboyd.mtv.corp.google.com> (raw)
In-Reply-To: <1582638862-9344-2-git-send-email-skakit@codeaurora.org>
Quoting satya priya (2020-02-25 05:54:21)
> To fix the RX cancel command failure, rx_fifo buffer needs to be
> flushed in stop_rx() by calling handle_rx().
>
> If set_termios is called before startup, by this time memory is not
> allocated to port->rx_fifo buffer, which leads to a NULL pointer
> dereference.
Also, clearly set_termios() isn't being called in the warning stack that
I sent last round:
pc : handle_rx_uart+0x64/0x278
lr : qcom_geni_serial_handle_rx+0x84/0x90
sp : ffffff814348f960
x29: ffffff814348f960 x28: ffffffd01ac24288
x27: 0000000000000018 x26: 0000000000000002
x25: 0000000000000001 x24: ffffff8146341348
x23: ffffff8146341000 x22: ffffffd01accc978
x21: ffffff8146341000 x20: 0000000000000001
x19: 0000000000000001 x18: ffffffd01b22d000
x17: 0000000000008000 x16: 00000000000000b0
x15: ffffffd01afdbdd0 x14: ffffffd01b3edde0
x13: ffffffd01b7fb000 x12: 0000000000000001
x11: 0000000000000000 x10: 0000000000000000
x9 : ffffffd010344780 x8 : 0000000000000000
x7 : ffffffd019d8e768 x6 : 0000000000000000
x5 : ffffffd01adbb000 x4 : 0000000000008004
x3 : 0000000000000001 x2 : 0000000000000001
x1 : 0000000000000001 x0 : ffffffd01accc978
Call trace:
handle_rx_uart+0x64/0x278
qcom_geni_serial_handle_rx+0x84/0x90
qcom_geni_serial_stop_rx+0x110/0x180
qcom_geni_serial_port_setup+0x68/0x1b0
qcom_geni_serial_startup+0x24/0x70
uart_startup+0x164/0x28c
uart_port_activate+0x6c/0xbc
tty_port_open+0xa8/0x114
uart_open+0x28/0x38
ttyport_open+0x7c/0x164
serdev_device_open+0x38/0xe4
hci_uart_register_device+0x54/0x2e8 [hci_uart]
qca_serdev_probe+0x1c4/0x374 [hci_uart]
serdev_drv_probe+0x3c/0x64
really_probe+0x144/0x3f8
driver_probe_device+0x70/0x140
__driver_attach_async_helper+0x7c/0xa8
async_run_entry_fn+0x60/0x178
process_one_work+0x33c/0x640
worker_thread+0x2a0/0x470
kthread+0x128/0x138
ret_from_fork+0x10/0x18
Code: 1aca096a 911e0129 b940012b 7100054a (b800450b)
This shows that uart_startup() is the one that is calling
qcom_geni_serial_startup() and that's running the newly added cancel
path. So even if we allocate the buffer in probe vs. in startup we're
going to flip a buffer full of junk that we're trying to cancel out of
the fifo into the tty layer. That seems wrong. We should have a
different qcom_geni_serial_stop_rx() function that knows we're starting
up vs. handling a normal rx event and call something besides handle_rx()
because that pushes bytes up into the tty layer.
>
> To avoid this NULL pointer dereference allocate memory to port->rx_fifo
> in probe itself.
>
next prev parent reply other threads:[~2020-02-28 23:01 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-25 13:54 [PATCH V2 0/2] Fix RX cancel command failure satya priya
2020-02-25 13:54 ` [PATCH V2 1/2] tty: serial: qcom_geni_serial: Allocate port->rx_fifo buffer in probe satya priya
2020-02-28 22:54 ` Stephen Boyd
2020-03-04 13:38 ` skakit
2020-02-28 23:01 ` Stephen Boyd [this message]
2020-03-04 13:34 ` skakit
2020-03-04 17:48 ` Stephen Boyd
2020-02-25 13:54 ` [PATCH V2 2/2] tty: serial: qcom_geni_serial: Fix RX cancel command failure satya priya
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=158293088963.112031.11417422453396901116@swboyd.mtv.corp.google.com \
--to=swboyd@chromium.org \
--cc=akashast@codeaurora.org \
--cc=gregkh@linuxfoundation.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=mgautam@codeaurora.org \
--cc=msavaliy@qti.qualcomm.com \
--cc=rojay@codeaurora.org \
--cc=skakit@codeaurora.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).