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@linar... 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 780971318810d..1a0005a8fadb2 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; }