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Manivannan Sadhasivam 7948fab26b watchdog: qcom: Avoid context switch in restart handler
The use of msleep() in the restart handler will cause scheduler to
induce a context switch which is not desirable. This generates below
warning on SDX55 when WDT is the only available restart source:

[   39.800188] reboot: Restarting system
[   39.804115] ------------[ cut here ]------------
[   39.807855] WARNING: CPU: 0 PID: 678 at kernel/rcu/tree_plugin.h:297 rcu_note_context_switch+0x190/0x764
[   39.812538] Modules linked in:
[   39.821954] CPU: 0 PID: 678 Comm: reboot Not tainted 5.10.0-rc1-00063-g33a9990d1d66-dirty #47
[   39.824854] Hardware name: Generic DT based system
[   39.833470] [<c0310fbc>] (unwind_backtrace) from [<c030c544>] (show_stack+0x10/0x14)
[   39.838154] [<c030c544>] (show_stack) from [<c0c218f0>] (dump_stack+0x8c/0xa0)
[   39.846049] [<c0c218f0>] (dump_stack) from [<c0322f80>] (__warn+0xd8/0xf0)
[   39.853058] [<c0322f80>] (__warn) from [<c0c1dc08>] (warn_slowpath_fmt+0x64/0xc8)
[   39.859925] [<c0c1dc08>] (warn_slowpath_fmt) from [<c038b6f4>] (rcu_note_context_switch+0x190/0x764)
[   39.867503] [<c038b6f4>] (rcu_note_context_switch) from [<c0c2aa3c>] (__schedule+0x84/0x640)
[   39.876685] [<c0c2aa3c>] (__schedule) from [<c0c2b050>] (schedule+0x58/0x10c)
[   39.885095] [<c0c2b050>] (schedule) from [<c0c2eed0>] (schedule_timeout+0x1e8/0x3d4)
[   39.892135] [<c0c2eed0>] (schedule_timeout) from [<c039ad40>] (msleep+0x2c/0x38)
[   39.899947] [<c039ad40>] (msleep) from [<c0a59d0c>] (qcom_wdt_restart+0xc4/0xcc)
[   39.907319] [<c0a59d0c>] (qcom_wdt_restart) from [<c0a58290>] (watchdog_restart_notifier+0x18/0x28)
[   39.914715] [<c0a58290>] (watchdog_restart_notifier) from [<c03468e0>] (atomic_notifier_call_chain+0x60/0x84)
[   39.923487] [<c03468e0>] (atomic_notifier_call_chain) from [<c030ae64>] (machine_restart+0x78/0x7c)
[   39.933551] [<c030ae64>] (machine_restart) from [<c0348048>] (__do_sys_reboot+0xdc/0x1e0)
[   39.942397] [<c0348048>] (__do_sys_reboot) from [<c0300060>] (ret_fast_syscall+0x0/0x54)
[   39.950721] Exception stack(0xc3e0bfa8 to 0xc3e0bff0)
[   39.958855] bfa0:                   0001221c bed2fe24 fee1dead 28121969 01234567 00000000
[   39.963832] bfc0: 0001221c bed2fe24 00000003 00000058 000225e0 00000000 00000000 00000000
[   39.971985] bfe0: b6e62560 bed2fc84 00010fd8 b6e62580
[   39.980124] ---[ end trace 3f578288bad866e4 ]---

Hence, replace msleep() with mdelay() to fix this issue.

Fixes: 05e487d905 ("watchdog: qcom: register a restart notifier")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20201207060005.21293-1-manivannan.sadhasivam@linaro.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-12-17 06:46:25 +01:00
Documentation Bugfixes for ARM, x86 and tools. 2020-12-12 10:08:16 -08:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
arch Bugfixes for ARM, x86 and tools. 2020-12-12 10:08:16 -08:00
block block-5.10-2020-12-05 2020-12-05 14:45:30 -08:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto drivers-5.10-2020-10-12 2020-10-13 13:04:41 -07:00
drivers watchdog: qcom: Avoid context switch in restart handler 2020-12-17 06:46:25 +01:00
fs io_uring-5.10-2020-12-11 2020-12-12 09:45:01 -08:00
include xen: branch for v5.10-rc8 2020-12-12 10:02:03 -08:00
init initramfs: fix clang build failure 2020-12-11 14:02:14 -08:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel bpf: Fix enum names for bpf_this_cpu_ptr() and bpf_per_cpu_ptr() helpers 2020-12-11 14:19:07 -08:00
lib selftest/fpu: avoid clang warning 2020-12-11 14:02:14 -08:00
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net Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2020-12-10 14:29:30 -08:00
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scripts Kbuild fixes for v5.10 (2nd) 2020-12-06 10:31:39 -08:00
security selinux/stable-5.10 PR 20201113 2020-11-14 12:04:02 -08:00
sound ALSA: hda/realtek: Add mute LED quirk to yet another HP x360 model 2020-11-28 10:00:51 +01:00
tools Bugfixes for ARM, x86 and tools. 2020-12-12 10:08:16 -08:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt kvm: x86/mmu: Support dirty logging for the TDP MMU 2020-10-23 03:42:13 -04:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
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.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
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Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-12-10 15:30:13 -08:00
Makefile Linux 5.10-rc7 2020-12-06 14:25:12 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.