From mboxrd@z Thu Jan 1 00:00:00 1970 From: m.szyprowski@samsung.com (Marek Szyprowski) Date: Mon, 09 Oct 2017 14:20:01 +0200 Subject: arm64: 4.14 of_match_node() issues In-Reply-To: References: <5d2ff063-1f7e-0200-cc02-99804f7d9219@suse.de> <20171009092409.GB5127@arm.com> <66956548-fa7a-332a-8045-8202ae0aa564@arm.com> Message-ID: <42630b8b-8987-57ff-be7e-79af7294856e@samsung.com> To: linus-amlogic@lists.infradead.org List-Id: linus-amlogic.lists.infradead.org Hi All, On 2017-10-09 14:04, Robin Murphy wrote: > On 09/10/17 11:58, Robin Murphy wrote: >> On 09/10/17 10:24, Will Deacon wrote: >>> Hi Andreas, >>> >>> On Sat, Oct 07, 2017 at 02:42:13AM +0200, Andreas F?rber wrote: >>>> Since 4.14-rc1 I am seeing frequent oopses during module loading (e.g., >>>> MMC, USB) from initrd on aarch64. Symptoms are similar to this in -rc3: >>>> >>>> [ OK ] Started udev Coldplug all Devices. >>>> [ 10.117775] usbcore: registered new interface driver usbfs >>>> [ 10.118235] Unable to handle kernel paging request at virtual address >>>> ffff000008e5abc0 >>>> [ 10.118238] Mem abort info: >>>> [ 10.118245] Exception class = DABT (current EL), IL = 32 bits >>>> [ 10.118249] SET = 0, FnV = 0 >>>> [ 10.118253] EA = 0, S1PTW = 0 >>>> [ 10.118256] Data abort info: >>>> [ 10.118261] ISV = 0, ISS = 0x00000006 >>>> [ 10.118264] CM = 0, WnR = 0 >>>> [ 10.118274] swapper pgtable: 4k pages, 48-bit VAs, pgd = ffff0000094a5000 >>>> [ 10.118279] [ffff000008e5abc0] *pgd=00000000bfffe003, >>>> *pud=00000000bfffd003, *pmd=0000000000000000 >>>> [ 10.118299] Internal error: Oops: 96000006 [#1] SMP >>>> [ 10.118305] Modules linked in: fixed usbcore(+) sunxi_mmc mmc_core >>>> phy_sun4i_usb sg >>>> [ 10.118341] CPU: 3 PID: 49 Comm: kworker/3:1 Not tainted >>>> 4.14.0-rc3-2.gf27997b-default #1 >>>> [ 10.118345] Hardware name: sunxi sunxi/sunxi, BIOS 2017.05-rc1 04/13/2017 >>>> [ 10.118369] Workqueue: events deferred_probe_work_func >>>> [ 10.118378] task: ffff80007c8f4000 task.stack: ffff0000099d8000 >>>> [ 10.118394] PC is at __of_match_node.part.1+0x48/0x88 >>>> [ 10.118403] LR is at of_match_node+0x40/0x70 >>>> [ 10.118411] pc : [] lr : [] >>> [...] >>> >>>> This has been observed on Pine64 (>60%; also by Stefan) and Odroid-C2; >>>> my other arm64 boards such as Raspberry Pi 3 have not run into this so >>>> far. No such problems on 32-bit boards. >>>> >>>> This is using the openSUSE config: >>>> https://kernel.opensuse.org/cgit/kernel-source/plain/config/arm64/default >>> Hmm, hard to know what to suggest without a concrete reproducer. Do you know >>> which driver is being probed in the log above? Also, does this still break >>> if you pass "keepinitrd" on the cmdline? Finally, can you dump the kernel >>> virtual memory layout, please? >> FWIW, this looks a lot like what happens when a built-in driver's >> of_match_table is marked __init, but for whatever reason (deferred probe >> etc.) winds up getting poked by a module load after it no longer exists. > Heh, synchronicity... > > https://lists.linuxfoundation.org/pipermail/iommu/2017-October/024572.html > > Looks like we either have to revert plenty of patches from the const > brigade, avoid freeing init, or come up with some way to make the driver > core cleverer about the whole deal :( It's not that bad. I did a quick check with # git grep "of_device_id.*init" and Exynos SYSMMU driver was the only candidate for a fix. Maybe someone else should double check that list to make sure that there is no other platform device/driver related code there. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland