Re: platform-device-test on 6.6 causes "(null)' : is not initialized, yet kobject_get() is being called"

[Maxime Ripard]

On Fri, Dec 01, 2023 at 03:35:26PM +0000, Richard Fitzgerald wrote:
> On 28/11/23 14:42, Maxime Ripard wrote:
> > Hi,
> > 
> > On Wed, Nov 15, 2023 at 01:28:13PM +0000, Richard Fitzgerald wrote:
> > > Target platform: Aaeon Whiskeylake UpXtreme (Celeron CPU)
> > > Target OS: Debian 11 (non-graphical install)
> > > 
> > > Kernel: v6.6.1 from
> > > git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
> > > branch: linux-6.6.y
> > > at commit 8afabe2118a9 ("Linux 6.6.1")
> > > 
> > > defconfig attached.
> > > 
> > > CONFIG_DM_KUNIT_TEST=m
> > > 
> > > gcc (Debian 10.2.1-6) 10.2.1 20210110
> > > 
> > > loading the module to run the test causes kobject_get() to WARN:
> > > 
> > > sudo modprobe platform-device-test
> > > 
> > > [   82.595238] KTAP version 1
> > > [   82.595252] 1..1
> > > [   82.595487]     KTAP version 1
> > > [   82.595489]     # Subtest: platform-device-devm
> > > [   82.595490]     # module: platform_device_test
> > > [   82.595493]     1..4
> > > [   82.596130]     ok 1 platform_device_devm_register_unregister_test
> > > [   82.596314]     ok 2
> > > platform_device_devm_register_get_unregister_with_devm_test
> > > [   82.596387] ------------[ cut here ]------------
> > > [   82.596395] kobject: '(null)' (0000000067030afc): is not initialized, yet
> > > kobject_get() is being called.
> > > [   82.596410] WARNING: CPU: 1 PID: 654 at lib/kobject.c:637
> > > kobject_get+0x4c/0x70
> > > [   82.596415] Modules linked in: platform_device_test(E+)
> > > x86_pkg_temp_thermal(E) intel_powerclamp(E) coretemp(E) crc32_pclmul(E)
> > > ghash_clmulni_intel(E) sha512_ssse3(E) sha512_generic(E) nls_ascii(E)
> > > nls_cp437(E) vfat(E) fat(E) aesni_intel(E) libaes(E) crypto_simd(E)
> > > cryptd(E) mei_wdt(E) mei_hdcp(E) snd_hda_codec_hdmi(E) watchdog(E) rapl(E)
> > > intel_rapl_msr(E) snd_hda_codec_cs8409(E) snd_hda_codec_generic(E)
> > > intel_cstate(E) ledtrig_audio(E) snd_hda_intel(E) snd_intel_dspcfg(E)
> > > intel_uncore(E) snd_hda_codec(E) processor_thermal_device_pci_legacy(E)
> > > processor_thermal_device(E) snd_hda_core(E) processor_thermal_rfim(E)
> > > efi_pstore(E) pcspkr(E) mei_me(E) wmi_bmof(E) snd_pcm(E)
> > > processor_thermal_mbox(E) processor_thermal_rapl(E) snd_timer(E)
> > > intel_rapl_common(E) int340x_thermal_zone(E) snd(E) intel_soc_dts_iosf(E)
> > > mei(E) intel_pch_thermal(E) soundcore(E) tpm_crb(E) evdev(E) tpm_tis(E)
> > > tpm_tis_core(E) tpm(E) intel_pmc_core(E) acpi_pad(E) rng_core(E) acpi_tad(E)
> > > button(E) msr(E) fuse(E) configfs(E) efivarfs(E) ip_tables(E)
> > > [   82.596473]  x_tables(E) autofs4(E) ext4(E) crc32c_generic(E) crc16(E)
> > > mbcache(E) jbd2(E) spi_pxa2xx_platform(E) dw_dmac(E) dw_dmac_core(E)
> > > mmc_block(E) i915(E) drm_buddy(E) ttm(E) intel_gtt(E) drm_display_helper(E)
> > > drm_kms_helper(E) sdhci_pci(E) xhci_pci(E) drm(E) crct10dif_pclmul(E)
> > > cqhci(E) crct10dif_common(E) intel_lpss_pci(E) crc32c_intel(E) sdhci(E)
> > > intel_lpss(E) xhci_hcd(E) i2c_i801(E) cec(E) i2c_smbus(E) idma64(E)
> > > mmc_core(E) usbcore(E) usb_common(E) fan(E) video(E) wmi(E)
> > > [   82.596508] CPU: 1 PID: 654 Comm: kunit_try_catch Tainted: G   E    N
> > > 6.6.1-test #1
> > > [   82.596510] Hardware name: AAEON UP-WHL01/UP-WHL01, BIOS UPW1AM19
> > > 11/10/2020
> > > [   82.596512] RIP: 0010:kobject_get+0x4c/0x70
> > > [   82.596515] Code: 44 24 38 85 c0 74 3b 78 25 83 c0 01 78 20 4c 89 e0 41
> > > 5c c3 cc cc cc cc 48 8b 37 48 89 fa 48 c7 c7 80 a6 a1 92 e8 64 2a 68 ff <0f>
> > > 0b eb c4 be 01 00 00 00 e8 26 08 af ff 4c 89 e0 41 5c c3 cc cc
> > > [   82.596517] RSP: 0018:ffffa2cf814e7d40 EFLAGS: 00010286
> > > [   82.596519] RAX: 0000000000000000 RBX: ffffffffc111c510 RCX:
> > > ffff8e28e3c9c888
> > > [   82.596521] RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI:
> > > ffff8e28e3c9c880
> > > [   82.596522] RBP: ffff8e27843e48c0 R08: 0000000000000000 R09:
> > > 00000000ffffefff
> > > [   82.596524] R10: ffffa2cf814e7be0 R11: ffffffff92cd2788 R12:
> > > ffffffffc111c510
> > > [   82.596525] R13: 0000000000000000 R14: 0000000000000000 R15:
> > > ffff8e2784968da0
> > > [   82.596526] FS:  0000000000000000(0000) GS:ffff8e28e3c80000(0000)
> > > knlGS:0000000000000000
> > > [   82.596528] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > [   82.596530] CR2: 0000558fd9288c70 CR3: 000000002b020003 CR4:
> > > 00000000003706e0
> > > [   82.596531] Call Trace:
> > > [   82.596532]  <TASK>
> > > [   82.596534]  ? __warn+0x84/0x170
> > > [   82.596538]  ? kobject_get+0x4c/0x70
> > > [   82.596541]  ? report_bug+0x198/0x1b0
> > > [   82.596545]  ? handle_bug+0x3c/0x70
> > > [   82.596547]  ? exc_invalid_op+0x18/0x70
> > > [   82.596549]  ? asm_exc_invalid_op+0x1a/0x20
> > > [   82.596554]  ? kobject_get+0x4c/0x70
> > > [   82.596557]  kobject_add_internal+0x30/0x2b0
> > > [   82.596560]  kobject_add+0x7e/0xf0
> > > [   82.596565]  kobject_create_and_add+0x51/0x90
> > > [   82.596567]  module_add_driver+0xfe/0x110
> > > [   82.596571]  bus_add_driver+0x130/0x220
> > > [   82.596575]  ? __pfx_kunit_generic_run_threadfn_adapter+0x10/0x10
> > > [   82.596578]  driver_register+0x60/0x120
> > > [   82.596581]
> > > probed_platform_device_devm_register_unregister_test+0x40/0x3e0
> > > [platform_device_test]
> > > [   82.596587]  ? platform_device_devm_init+0x74/0xd0 [platform_device_test]
> > > [   82.596593]  ? __pfx_kunit_generic_run_threadfn_adapter+0x10/0x10
> > > [   82.596595]  kunit_generic_run_threadfn_adapter+0x17/0x30
> > > [   82.596597]  kthread+0xf4/0x130
> > > [   82.596600]  ? __pfx_kthread+0x10/0x10
> > > [   82.596604]  ret_from_fork+0x31/0x50
> > > [   82.596606]  ? __pfx_kthread+0x10/0x10
> > > [   82.596609]  ret_from_fork_asm+0x1b/0x30
> > > [   82.596615]  </TASK>
> > > [   82.596616] irq event stamp: 975
> > > [   82.596618] hardirqs last  enabled at (981): [<ffffffff9193aa6d>]
> > > console_unlock+0x10d/0x130
> > > [   82.596621] hardirqs last disabled at (986): [<ffffffff9193aa52>]
> > > console_unlock+0xf2/0x130
> > > [   82.596624] softirqs last  enabled at (0): [<ffffffff9188890f>]
> > > copy_process+0xa8f/0x2080
> > > [   82.596626] softirqs last disabled at (0): [<0000000000000000>] 0x0
> > > [   82.596628] ---[ end trace 0000000000000000 ]---
> > 
> > It's not entirely clear to me what could be happening here, but it looks
> > similar to the issue that Marco was fixing here:
> > https://lore.kernel.org/linux-kselftest/20231128101627.65399-1-marpagan@xxxxxxxxxx/
> > 
> > Could you test with that fix and see if it still happens?
> > 
> > Thanks!
> > Maxime
> 
> Yes, Marco's patch fixes it.

Awesome, thanks for the report and for testing :)

Maxime

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