Messages in this thread Patch in this message | | | Date | Sun, 20 Jun 2021 10:26:34 +0200 | From | Dominik Brodowski <> | Subject | v5.13-rcX regression - NULL pointer dereference - MFD and software node API |
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Over a month ago, Andy Shevchenko reported and fixed a NULL pointer dereference issue introduced by commit 42e59982917a ("mfd: core: Add support for software nodes") in v5.13-rc1: https://lore.kernel.org/lkml/20210510141552.57045-1-andriy.shevchenko@linux.intel.com/
A bisect shows that it is indeed commit 42e59982917a which causes boot to fail due to a NULL pointer dereference on my work laptop, where "intel-lpss" is bound to 00:15.0 Signal processing controller: Intel Corporation Sunrise Point-LP Serial IO I2C Controller #0 (rev 21) and fails to bind to INT3446:
[ 6.048087] intel-lpss 0000:00:15.0: enabling device (0000 -> 0002) [ 6.050625] idma64 idma64.0: Found Intel integrated DMA 64-bit [ 6.109112] intel-lpss 0000:00:15.1: enabling device (0000 -> 0002) [ 6.111348] idma64 idma64.1: Found Intel integrated DMA 64-bit [ 6.172229] intel-lpss 0000:00:15.2: enabling device (0000 -> 0002) [ 6.174353] idma64 idma64.2: Found Intel integrated DMA 64-bit [ 6.231865] intel-lpss 0000:00:15.3: enabling device (0000 -> 0002) [ 6.233845] idma64 idma64.3: Found Intel integrated DMA 64-bit [ 6.287492] ACPI Warning: SystemMemory range 0x00000000FE028000-0x00000000FE0281FF conflicts with OpRegion 0x00000000FE028000-0x00000000FE028207 (\_SB.PCI0.GEXP.BAR0) (20210331/utaddress-204) [ 6.287704] ACPI: OSL: Resource conflict; ACPI support missing from driver? [ 6.289760] intel-lpss: probe of INT3446:00 failed with error -16
Unfortunately, the patch by Andy Shevchenko (applied on top of Linus' tree) does not fix the issue. A complete revert, however, does fix the issue, and allows my laptop to boot again.
In my opinion, it is unfortunate that although it has been known for over a month that commit 42e59982917a is broken, the bugfix (though probably not far-reaching enough) has not yet progressed upstream.
Thanks, Dominik
[PATCH] Revert "mfd: core: Add support for software nodes"
This reverts commit 42e59982917a25ad254b74e6e8decee5e684763d.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c index 6f02b8022c6d..7a052e61280e 100644 --- a/drivers/mfd/mfd-core.c +++ b/drivers/mfd/mfd-core.c @@ -226,12 +226,6 @@ static int mfd_add_device(struct device *parent, int id, goto fail_of_entry; } - if (cell->swnode) { - ret = device_add_software_node(&pdev->dev, cell->swnode); - if (ret) - goto fail_of_entry; - } - for (r = 0; r < cell->num_resources; r++) { res[r].name = cell->resources[r].name; res[r].flags = cell->resources[r].flags; @@ -292,7 +286,6 @@ static int mfd_add_device(struct device *parent, int id, list_del(&of_entry->list); kfree(of_entry); } - device_remove_software_node(&pdev->dev); fail_alias: regulator_bulk_unregister_supply_alias(&pdev->dev, cell->parent_supplies, @@ -361,8 +354,6 @@ static int mfd_remove_devices_fn(struct device *dev, void *data) regulator_bulk_unregister_supply_alias(dev, cell->parent_supplies, cell->num_parent_supplies); - device_remove_software_node(&pdev->dev); - platform_device_unregister(pdev); return 0; }
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