Messages in this thread | | | Subject | Re: [PATCH v4 4/4] thermal: core: Add notifications call in the framework | From | Marek Szyprowski <> | Date | Wed, 15 Jul 2020 08:09:25 +0200 |
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Hi Daniel,
On 15.07.2020 01:20, Daniel Lezcano wrote: > On 13/07/2020 22:32, Daniel Lezcano wrote: >> On 13/07/2020 11:31, Marek Szyprowski wrote: >>> On 07.07.2020 11:15, Marek Szyprowski wrote: >>>> On 06.07.2020 15:46, Daniel Lezcano wrote: >>>>> On 06/07/2020 15:17, Marek Szyprowski wrote: >>>>>> On 06.07.2020 12:55, Daniel Lezcano wrote: >>>>>>> The generic netlink protocol is implemented but the different >>>>>>> notification functions are not yet connected to the core code. >>>>>>> >>>>>>> These changes add the notification calls in the different >>>>>>> corresponding places. >>>>>>> >>>>>>> Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org> >>>>>>> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> >>>>>> This patch landed in today's linux-next 20200706 as commit 5df786e46560 >>>>>> ("thermal: core: Add notifications call in the framework"). Sadly it >>>>>> breaks booting various Samsung Exynos based boards. Here is an example >>>>>> log from Odroid U3 board: >>>>>> >>>>>> Unable to handle kernel NULL pointer dereference at virtual address >>>>>> 00000010 >>>>>> pgd = (ptrval) >>>>>> [00000010] *pgd=00000000 >>>>>> Internal error: Oops: 5 [#1] PREEMPT SMP ARM >>>>>> Modules linked in: >>>>>> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.8.0-rc3-00015-g5df786e46560 >>>>>> #1146 >>>>>> Hardware name: Samsung Exynos (Flattened Device Tree) >>>>>> PC is at kmem_cache_alloc+0x13c/0x418 >>>>>> LR is at kmem_cache_alloc+0x48/0x418 >>>>>> pc : [<c02b5cac>] lr : [<c02b5bb8>] psr: 20000053 >>>>>> ... >>>>>> Flags: nzCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment none >>>>>> Control: 10c5387d Table: 4000404a DAC: 00000051 >>>>>> Process swapper/0 (pid: 1, stack limit = 0x(ptrval)) >>>>>> Stack: (0xee8f1cf8 to 0xee8f2000) >>>>>> ... >>>>>> [<c02b5cac>] (kmem_cache_alloc) from [<c08cd170>] >>>>>> (__alloc_skb+0x5c/0x170) >>>>>> [<c08cd170>] (__alloc_skb) from [<c07ec19c>] >>>>>> (thermal_genl_send_event+0x24/0x174) >>>>>> [<c07ec19c>] (thermal_genl_send_event) from [<c07ec648>] >>>>>> (thermal_notify_tz_create+0x58/0x74) >>>>>> [<c07ec648>] (thermal_notify_tz_create) from [<c07e9058>] >>>>>> (thermal_zone_device_register+0x358/0x650) >>>>>> [<c07e9058>] (thermal_zone_device_register) from [<c1028d34>] >>>>>> (of_parse_thermal_zones+0x304/0x7a4) >>>>>> [<c1028d34>] (of_parse_thermal_zones) from [<c1028964>] >>>>>> (thermal_init+0xdc/0x154) >>>>>> [<c1028964>] (thermal_init) from [<c0102378>] >>>>>> (do_one_initcall+0x8c/0x424) >>>>>> [<c0102378>] (do_one_initcall) from [<c1001158>] >>>>>> (kernel_init_freeable+0x190/0x204) >>>>>> [<c1001158>] (kernel_init_freeable) from [<c0ab85f4>] >>>>>> (kernel_init+0x8/0x118) >>>>>> [<c0ab85f4>] (kernel_init) from [<c0100114>] (ret_from_fork+0x14/0x20) >>>>>> >>>>>> Reverting it on top of linux-next fixes the boot issue. I will >>>>>> investigate it further soon. >>>>> Thanks for reporting this. >>>>> >>>>> Can you send the addr2line result and code it points to ? >>>> addr2line of c02b5cac (kmem_cache_alloc+0x13c/0x418) points to >>>> mm/slub.c +2839, but I'm not sure if we can trust it. imho it looks >>>> like some trashed memory somewhere, but I don't have time right now to >>>> analyze it further now... >>> Just one more thing I've noticed. The crash happens only if the kernel >>> is compiled with old GCC (tested with arm-linux-gnueabi-gcc (Linaro GCC >>> 4.9-2017.01) 4.9.4). If I compile kernel with newed GCC (like >>> arm-linux-gnueabi-gcc (Linaro GCC 6.4-2017.11) 6.4.1 20171012), it works >>> fine... >>> >>> This happens also with Linux next-20200710, which again got this commit. >> So I finally succeed to reproduce on an ARM64 with a recent compiler, >> earlycon, and the option CONFIG_INIT_ON_ALLOC_DEFAULT_ON. > > Finally, narrowed down the issue. > > - genetlink initialization is done at subsys initcall. > - thermal netlink init is done at core initcall > - netlink is done at core initcall > > By changing the order: > > - netlink and genetlink at core initcall > - thermal init at postcore initcall > > That fixes the problem. I confirm that such change fixes the issue! Feel free to add:
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
to the final patch.
> The genetlink initcall order is from 2005 and > IMO it makes sense to come right after the netlink initialization. > > It is acceptable to have the thermal init at the postcore initcall. It > is very recently we moved from fs_initcall to core_initcall. > > Thanks to Arnd who give me a direction to look at. Best regards
-- Marek Szyprowski, PhD Samsung R&D Institute Poland
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