From: Leo Yan <leo.yan@linaro.org>
To: Andy Gross <agross@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Stephen Boyd <swboyd@chromium.org>,
Nicolas Dechesne <nicolas.dechesne@linaro.org>,
Jeffrey Hugo <jeffrey.l.hugo@gmail.com>,
linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v2 0/2] tty: serial: msm_serial: Fix lockup issues
Date: Wed, 27 Nov 2019 22:15:42 +0800 [thread overview]
Message-ID: <20191127141544.4277-1-leo.yan@linaro.org> (raw)
This patch set is to address two msm serial driver's lockup issues.
The first lockup issue is a well known and common issue which is caused
by recursive locking between normal printing and the kernel debugging
facilities (e.g. sysrq and oops). Patch 0001 follows up other drivers
general approach to fix this lockup issue.
The second lockup issue is related with msm serial driver's specific
implementation. Since the serial driver invokes dma related operations
after has acquired spinlock, then the dma functions might allocat dma
descriptors and when the system has very less free memory the kernel
tries to print out warning, this leads to recursive output and causes
deadlock. Patch 0002 is used to resolve this deadlock issue.
These two patches have been tested on DB410c with backported on 4.14.96,
they also have been verified with mainline kernel for boot testing.
Changes from v1:
* Added 'Fixes' tags for two patches (Jeffrey Hugo).
* Added cover letter for more clear context description (Jeffrey Hugo).
Leo Yan (2):
tty: serial: msm_serial: Fix lockup for sysrq and oops
tty: serial: msm_serial: Fix deadlock caused by recursive output
drivers/tty/serial/msm_serial.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
--
2.17.1
next reply other threads:[~2019-11-27 14:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-27 14:15 Leo Yan [this message]
2019-11-27 14:15 ` [PATCH v2 1/2] tty: serial: msm_serial: Fix lockup for sysrq and oops Leo Yan
2019-12-02 16:37 ` Jeffrey Hugo
2019-12-05 0:40 ` Doug Anderson
2019-12-27 6:44 ` Leo Yan
2019-11-27 14:15 ` [PATCH v2 2/2] tty: serial: msm_serial: Fix deadlock caused by recursive output Leo Yan
2019-12-02 16:40 ` Jeffrey Hugo
2019-12-03 8:23 ` Leo Yan
2019-12-03 22:42 ` Jeffrey Hugo
2019-12-04 16:13 ` Leo Yan
2019-12-16 18:49 ` Jeffrey Hugo
2019-12-27 5:52 ` Leo Yan
[not found] ` <CAD9cdQ6ROYf6B2PkQYJds_80-0dA=Jcew=TCNCSB=r+WEUNvdQ@mail.gmail.com>
2019-12-16 18:50 ` Jeffrey Hugo
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=20191127141544.4277-1-leo.yan@linaro.org \
--to=leo.yan@linaro.org \
--cc=agross@kernel.org \
--cc=bjorn.andersson@linaro.org \
--cc=gregkh@linuxfoundation.org \
--cc=jeffrey.l.hugo@gmail.com \
--cc=jslaby@suse.com \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
--cc=nicolas.dechesne@linaro.org \
--cc=swboyd@chromium.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).