| From 79f5aa544334dfdc27c7b4b79c8b042c219d0dd4 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Mon, 7 Dec 2020 11:30:05 +0530 |
| Subject: watchdog: qcom: Avoid context switch in restart handler |
| |
| From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> |
| |
| [ Upstream commit 7948fab26bcc468aa2a76462f441291b5fb0d5c7 ] |
| |
| 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: 05e487d905ab ("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> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/watchdog/qcom-wdt.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c |
| index 4f47b5e909566..8b88824a88dc2 100644 |
| --- a/drivers/watchdog/qcom-wdt.c |
| +++ b/drivers/watchdog/qcom-wdt.c |
| @@ -121,7 +121,7 @@ static int qcom_wdt_restart(struct watchdog_device *wdd, unsigned long action, |
| */ |
| wmb(); |
| |
| - msleep(150); |
| + mdelay(150); |
| return 0; |
| } |
| |
| -- |
| 2.27.0 |
| |
