On Mon, Jun 15, 2020 at 09:15:40AM +0200, Krzysztof Kozlowski wrote:
On Sun, Jun 14, 2020 at 06:48:04PM +0300, Vladimir Oltean wrote:
On Sun, 14 Jun 2020 at 13:57, Krzysztof Kozlowski krzk@kernel.org wrote:
If interrupt comes late, during probe error path or device remove (could be triggered with CONFIG_DEBUG_SHIRQ), the interrupt handler dspi_interrupt() will access registers with the clock being disabled. This leads to external abort on non-linefetch on Toradex Colibri VF50 module (with Vybrid VF5xx):
$ echo 4002d000.spi > /sys/devices/platform/soc/40000000.bus/4002d000.spi/driver/unbind Unhandled fault: external abort on non-linefetch (0x1008) at 0x8887f02c Internal error: : 1008 [#1] ARM CPU: 0 PID: 136 Comm: sh Not tainted 5.7.0-next-20200610-00009-g5c913fa0f9c5-dirty #74 Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree) (regmap_mmio_read32le) from [<8061885c>] (regmap_mmio_read+0x48/0x68) (regmap_mmio_read) from [<8060e3b8>] (_regmap_bus_reg_read+0x24/0x28) (_regmap_bus_reg_read) from [<80611c50>] (_regmap_read+0x70/0x1c0) (_regmap_read) from [<80611dec>] (regmap_read+0x4c/0x6c) (regmap_read) from [<80678ca0>] (dspi_interrupt+0x3c/0xa8) (dspi_interrupt) from [<8017acec>] (free_irq+0x26c/0x3cc) (free_irq) from [<8017dcec>] (devm_irq_release+0x1c/0x20) (devm_irq_release) from [<805f98ec>] (release_nodes+0x1e4/0x298) (release_nodes) from [<805f9ac8>] (devres_release_all+0x40/0x60) (devres_release_all) from [<805f5134>] (device_release_driver_internal+0x108/0x1ac) (device_release_driver_internal) from [<805f521c>] (device_driver_detach+0x20/0x24)The resource-managed framework should not be used for interrupt handling, because the resource will be released too late - after disabling clocks. The interrupt handler is not prepared for such case.
Fixes: 349ad66c0ab0 ("spi:Add Freescale DSPI driver for Vybrid VF610 platform") Cc: stable@vger.kernel.org Signed-off-by: Krzysztof Kozlowski krzk@kernel.org
I don't buy this argument that "the resource-managed framework should not be used for interrupt handling". What is it there for, then?
It was created long time ago for memory allocations and since then people ported to all other possibilities and used in drivers. Just because you can do something, does not necessarily mean that you should...
Could you just call disable_irq before clk_disable_unprepare instead of this massive rework?
This massive rework is 9 insertions and 4 deletions, indeed I made impressive, huge commit with significant impact. disable_irq() could work as well so if this is preferred, no problem from my side.
disable_irq() should fix real world case but won't fix DEBUG_SHIRQ. I'll rework it as well but then we go to bigger change again.
Best regards, Krzysztof