| Message ID | 20230703200404.20361-1-ddrokosov@sberdevices.ru |
|---|---|
| State | New |
| Headers | show |
| Series | [v1] clk: meson: change usleep_range() to udelay() for atomic context | expand |
diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c index 56ec2210f1ad..eef6f37c8d8d 100644 --- a/drivers/clk/meson/clk-pll.c +++ b/drivers/clk/meson/clk-pll.c @@ -367,9 +367,9 @@ static int meson_clk_pll_enable(struct clk_hw *hw) * 3. enable the lock detect module */ if (MESON_PARM_APPLICABLE(&pll->current_en)) { - usleep_range(10, 20); + udelay(10); meson_parm_write(clk->map, &pll->current_en, 1); - usleep_range(40, 50); + udelay(40); }; if (MESON_PARM_APPLICABLE(&pll->l_detect)) {
The function meson_clk_pll_enable() can be invoked under the enable_lock spinlock from the clk core logic (please refer to drivers/clk/clk.c:clk_core_enable_lock()), which risks a kernel panic during the usleep_range() call: BUG: scheduling while atomic: kworker/u4:2/36/0x00000002 Modules linked in: g_ffs usb_f_fs libcomposite CPU: 1 PID: 36 Comm: kworker/u4:2 Not tainted 6.4.0-rc5 #273 Workqueue: events_unbound async_run_entry_fn Call trace: dump_backtrace+0x9c/0x128 show_stack+0x20/0x38 dump_stack_lvl+0x48/0x60 dump_stack+0x18/0x28 __schedule_bug+0x58/0x78 __schedule+0x828/0xa88 schedule+0x64/0xd8 schedule_hrtimeout_range_clock+0xd0/0x208 schedule_hrtimeout_range+0x1c/0x30 usleep_range_state+0x6c/0xa8 meson_clk_pll_enable+0x1f4/0x310 clk_core_enable+0x78/0x200 clk_core_enable+0x58/0x200 clk_core_enable+0x58/0x200 clk_core_enable+0x58/0x200 clk_enable+0x34/0x60 Considering that this code is expected to be used in an atomic context, it is required to use the udelay() function instead of usleep_range() for the atomic context safety. Fixes: b6ec400aa153 ("clk: meson: introduce new pll power-on sequence for A1 SoC family") Reported-by: Jan Dakinevich <yvdakinevich@sberdevices.ru> Signed-off-by: Dmitry Rokosov <ddrokosov@sberdevices.ru> Signed-off-by: Jan Dakinevich <yvdakinevich@sberdevices.ru> --- drivers/clk/meson/clk-pll.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)