4.15-stable review patch. If anyone has any objections, please let me know.
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From: Enric Balletbo i Serra enric.balletbo@collabora.com
commit bff52352e0ccc2481f2b6b0d612ff8ff56c50f3a upstream.
dwc3_of_simple_dev_pm_ops has never been used since commit a0d8c4cfdf31 ("usb: dwc3: of-simple: set dev_pm_ops"), but this commit has brought and oops when unbind the device due this sequence:
dwc3_of_simple_remove -> clk_disable ... -> pm_runtime_put_sync -> dwc3_of_simple_runtime_suspend -> clk_disable (again)
This double call to clk_core_disable causes a kernel oops like this:
WARNING: CPU: 1 PID: 4022 at drivers/clk/clk.c:656 clk_core_disable+0x78/0x80 CPU: 1 PID: 4022 Comm: bash Not tainted 4.15.0-rc4+ #44 Hardware name: Google Kevin (DT) pstate: 80000085 (Nzcv daIf -PAN -UAO) pc : clk_core_disable+0x78/0x80 lr : clk_core_disable_lock+0x20/0x38 sp : ffff00000bbf3a90 ... Call trace: clk_core_disable+0x78/0x80 clk_disable+0x1c/0x30 dwc3_of_simple_runtime_suspend+0x30/0x50 pm_generic_runtime_suspend+0x28/0x40
This patch fixes the unbalanced clk disable call by setting the num_clocks variable to zero once the clocks were disabled.
Fixes: a0d8c4cfdf31 ("usb: dwc3: of-simple: set dev_pm_ops") Signed-off-by: Enric Balletbo i Serra enric.balletbo@collabora.com Signed-off-by: Felipe Balbi felipe.balbi@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/dwc3/dwc3-of-simple.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/usb/dwc3/dwc3-of-simple.c +++ b/drivers/usb/dwc3/dwc3-of-simple.c @@ -143,6 +143,7 @@ static int dwc3_of_simple_remove(struct clk_disable_unprepare(simple->clks[i]); clk_put(simple->clks[i]); } + simple->num_clocks = 0;
reset_control_assert(simple->resets); reset_control_put(simple->resets);