[BUG] NULL pointer in dev_pm_opp_put_regulators

From: Krzysztof Kozlowski
Date: Wed Jan 20 2021 - 03:02:45 EST


Hi,

Today's next fails to boot on Exynos5422 Odroid HC1 board:

[ 6.409023] Unable to handle kernel NULL pointer dereference at virtual address 00000004
[ 6.417199] pgd = (ptrval)
[ 6.419748] [00000004] *pgd=00000000
[ 6.423499] Internal error: Oops: 805 [#1] PREEMPT SMP ARM
[ 6.428724] Modules linked in:
[ 6.431752] CPU: 5 PID: 1 Comm: swapper/0 Not tainted 5.11.0-rc4-next-20210120 #2
[ 6.439209] Hardware name: Samsung Exynos (Flattened Device Tree)
[ 6.445273] PC is at dev_pm_opp_put_regulators+0xb4/0x114
...
[ 6.680370] [<c086f51c>] (dev_pm_opp_put_regulators) from [<c08d5d48>] (exynos_bus_probe+0x45c/0x620)
[ 6.689556] [<c08d5d48>] (exynos_bus_probe) from [<c06b49a8>] (platform_probe+0x80/0xc0)
[ 6.697614] [<c06b49a8>] (platform_probe) from [<c06b1ab4>] (really_probe+0x1d4/0x500)
[ 6.705499] [<c06b1ab4>] (really_probe) from [<c06b1e58>] (driver_probe_device+0x78/0x1dc)
[ 6.713731] [<c06b1e58>] (driver_probe_device) from [<c06b236c>] (device_driver_attach+0x58/0x60)
[ 6.722571] [<c06b236c>] (device_driver_attach) from [<c06b2470>] (__driver_attach+0xfc/0x160)
[ 6.731149] [<c06b2470>] (__driver_attach) from [<c06af85c>] (bus_for_each_dev+0x68/0xb4)
[ 6.739294] [<c06af85c>] (bus_for_each_dev) from [<c06b0b5c>] (bus_add_driver+0x158/0x214)
[ 6.747526] [<c06b0b5c>] (bus_add_driver) from [<c06b3314>] (driver_register+0x78/0x110)
[ 6.755585] [<c06b3314>] (driver_register) from [<c0102464>] (do_one_initcall+0x8c/0x430)
[ 6.763731] [<c0102464>] (do_one_initcall) from [<c11010e4>] (kernel_init_freeable+0x190/0x1e0)
[ 6.772397] [<c11010e4>] (kernel_init_freeable) from [<c0b4fc50>] (kernel_init+0x8/0x120)
[ 6.780542] [<c0b4fc50>] (kernel_init) from [<c010011c>] (ret_from_fork+0x14/0x38)

https://krzk.eu/#/builders/21/builds/2862/steps/15/logs/serial0

I did not do a bisect but the last commit touching these parts was:

commit 302c014726dbd9fcde852985528c139d2214a1f2
Author: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Date: Tue Jan 19 11:58:58 2021 +0530
opp: Prepare for ->set_opp() helper to work without regulators

Maybe you have some idea of cause?

Best regards,
Krzysztof