Re: 2b5d1c29f6c4 ("drm/nouveau/disp: PIOR DP uses GPIO for HPD, not PMGR AUX interrupts")

From: Karol Herbst
Date: Mon Aug 14 2023 - 10:21:09 EST

On Mon, Aug 14, 2023 at 3:35 PM Takashi Iwai <tiwai@xxxxxxx> wrote:
>
> On Mon, 14 Aug 2023 15:19:11 +0200,
> Karol Herbst wrote:
> >
> > On Mon, Aug 14, 2023 at 2:56 PM Karol Herbst <kherbst@xxxxxxxxxx> wrote:
> > >
> > > On Mon, Aug 14, 2023 at 2:48 PM Takashi Iwai <tiwai@xxxxxxx> wrote:
> > > >
> > > > On Mon, 14 Aug 2023 14:38:18 +0200,
> > > > Karol Herbst wrote:
> > > > >
> > > > > On Wed, Aug 9, 2023 at 6:16 PM Takashi Iwai <tiwai@xxxxxxx> wrote:
> > > > > >
> > > > > > On Wed, 09 Aug 2023 16:46:38 +0200,
> > > > > > Takashi Iwai wrote:
> > > > > > >
> > > > > > > On Wed, 09 Aug 2023 15:13:23 +0200,
> > > > > > > Takashi Iwai wrote:
> > > > > > > >
> > > > > > > > On Wed, 09 Aug 2023 14:19:23 +0200,
> > > > > > > > Karol Herbst wrote:
> > > > > > > > >
> > > > > > > > > On Wed, Aug 9, 2023 at 1:46 PM Takashi Iwai <tiwai@xxxxxxx> wrote:
> > > > > > > > > >
> > > > > > > > > > On Wed, 09 Aug 2023 13:42:09 +0200,
> > > > > > > > > > Karol Herbst wrote:
> > > > > > > > > > >
> > > > > > > > > > > On Wed, Aug 9, 2023 at 11:22 AM Takashi Iwai <tiwai@xxxxxxx> wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > On Tue, 08 Aug 2023 12:39:32 +0200,
> > > > > > > > > > > > Karol Herbst wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Mon, Aug 7, 2023 at 5:05 PM Borislav Petkov <bp@xxxxxxxxx> wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Mon, Aug 07, 2023 at 01:49:42PM +0200, Karol Herbst wrote:
> > > > > > > > > > > > > > > in what way does it stop? Just not progressing? That would be kinda
> > > > > > > > > > > > > > > concerning. Mind tracing with what arguments `nvkm_uevent_add` is
> > > > > > > > > > > > > > > called with and without that patch?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Well, me dumping those args I guess made the box not freeze before
> > > > > > > > > > > > > > catching a #PF over serial. Does that help?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > ....
> > > > > > > > > > > > > > [ 3.410135] Unpacking initramfs...
> > > > > > > > > > > > > > [ 3.416319] software IO TLB: mapped [mem 0x00000000a877d000-0x00000000ac77d000] (64MB)
> > > > > > > > > > > > > > [ 3.418227] Initialise system trusted keyrings
> > > > > > > > > > > > > > [ 3.432273] workingset: timestamp_bits=56 max_order=22 bucket_order=0
> > > > > > > > > > > > > > [ 3.439006] ntfs: driver 2.1.32 [Flags: R/W].
> > > > > > > > > > > > > > [ 3.443368] fuse: init (API version 7.38)
> > > > > > > > > > > > > > [ 3.447601] 9p: Installing v9fs 9p2000 file system support
> > > > > > > > > > > > > > [ 3.453223] Key type asymmetric registered
> > > > > > > > > > > > > > [ 3.457332] Asymmetric key parser 'x509' registered
> > > > > > > > > > > > > > [ 3.462236] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 250)
> > > > > > > > > > > > > > [ 3.475865] efifb: probing for efifb
> > > > > > > > > > > > > > [ 3.479458] efifb: framebuffer at 0xf9000000, using 1920k, total 1920k
> > > > > > > > > > > > > > [ 3.485969] efifb: mode is 800x600x32, linelength=3200, pages=1
> > > > > > > > > > > > > > [ 3.491872] efifb: scrolling: redraw
> > > > > > > > > > > > > > [ 3.495438] efifb: Truecolor: size=8:8:8:8, shift=24:16:8:0
> > > > > > > > > > > > > > [ 3.502349] Console: switching to colour frame buffer device 100x37
> > > > > > > > > > > > > > [ 3.509564] fb0: EFI VGA frame buffer device
> > > > > > > > > > > > > > [ 3.514013] ACPI: \_PR_.CP00: Found 4 idle states
> > > > > > > > > > > > > > [ 3.518850] ACPI: \_PR_.CP01: Found 4 idle states
> > > > > > > > > > > > > > [ 3.523687] ACPI: \_PR_.CP02: Found 4 idle states
> > > > > > > > > > > > > > [ 3.528515] ACPI: \_PR_.CP03: Found 4 idle states
> > > > > > > > > > > > > > [ 3.533346] ACPI: \_PR_.CP04: Found 4 idle states
> > > > > > > > > > > > > > [ 3.538173] ACPI: \_PR_.CP05: Found 4 idle states
> > > > > > > > > > > > > > [ 3.543003] ACPI: \_PR_.CP06: Found 4 idle states
> > > > > > > > > > > > > > [ 3.544219] Freeing initrd memory: 8196K
> > > > > > > > > > > > > > [ 3.547844] ACPI: \_PR_.CP07: Found 4 idle states
> > > > > > > > > > > > > > [ 3.609542] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
> > > > > > > > > > > > > > [ 3.616224] 00:05: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
> > > > > > > > > > > > > > [ 3.625552] serial 0000:00:16.3: enabling device (0000 -> 0003)
> > > > > > > > > > > > > > [ 3.633034] 0000:00:16.3: ttyS1 at I/O 0xf0a0 (irq = 17, base_baud = 115200) is a 16550A
> > > > > > > > > > > > > > [ 3.642451] Linux agpgart interface v0.103
> > > > > > > > > > > > > > [ 3.647141] ACPI: bus type drm_connector registered
> > > > > > > > > > > > > > [ 3.653261] Console: switching to colour dummy device 80x25
> > > > > > > > > > > > > > [ 3.659092] nouveau 0000:03:00.0: vgaarb: deactivate vga console
> > > > > > > > > > > > > > [ 3.665174] nouveau 0000:03:00.0: NVIDIA GT218 (0a8c00b1)
> > > > > > > > > > > > > > [ 3.784585] nouveau 0000:03:00.0: bios: version 70.18.83.00.08
> > > > > > > > > > > > > > [ 3.792244] nouveau 0000:03:00.0: fb: 512 MiB DDR3
> > > > > > > > > > > > > > [ 3.948786] nouveau 0000:03:00.0: DRM: VRAM: 512 MiB
> > > > > > > > > > > > > > [ 3.953755] nouveau 0000:03:00.0: DRM: GART: 1048576 MiB
> > > > > > > > > > > > > > [ 3.959073] nouveau 0000:03:00.0: DRM: TMDS table version 2.0
> > > > > > > > > > > > > > [ 3.964808] nouveau 0000:03:00.0: DRM: DCB version 4.0
> > > > > > > > > > > > > > [ 3.969938] nouveau 0000:03:00.0: DRM: DCB outp 00: 02000360 00000000
> > > > > > > > > > > > > > [ 3.976367] nouveau 0000:03:00.0: DRM: DCB outp 01: 02000362 00020010
> > > > > > > > > > > > > > [ 3.982792] nouveau 0000:03:00.0: DRM: DCB outp 02: 028003a6 0f220010
> > > > > > > > > > > > > > [ 3.989223] nouveau 0000:03:00.0: DRM: DCB outp 03: 01011380 00000000
> > > > > > > > > > > > > > [ 3.995647] nouveau 0000:03:00.0: DRM: DCB outp 04: 08011382 00020010
> > > > > > > > > > > > > > [ 4.002076] nouveau 0000:03:00.0: DRM: DCB outp 05: 088113c6 0f220010
> > > > > > > > > > > > > > [ 4.008511] nouveau 0000:03:00.0: DRM: DCB conn 00: 00101064
> > > > > > > > > > > > > > [ 4.014151] nouveau 0000:03:00.0: DRM: DCB conn 01: 00202165
> > > > > > > > > > > > > > [ 4.021710] nvkm_uevent_add: uevent: 0xffff888100242100, event: 0xffff8881022de1a0, id: 0x0, bits: 0x1, func: 0x0000000000000000
> > > > > > > > > > > > > > [ 4.033680] nvkm_uevent_add: uevent: 0xffff888100242300, event: 0xffff8881022de1a0, id: 0x0, bits: 0x1, func: 0x0000000000000000
> > > > > > > > > > > > > > [ 4.045429] nouveau 0000:03:00.0: DRM: MM: using COPY for buffer copies
> > > > > > > > > > > > > > [ 4.052059] stackdepot: allocating hash table of 1048576 entries via kvcalloc
> > > > > > > > > > > > > > [ 4.067191] nvkm_uevent_add: uevent: 0xffff888100242800, event: 0xffff888104b3e260, id: 0x0, bits: 0x1, func: 0x0000000000000000
> > > > > > > > > > > > > > [ 4.078936] nvkm_uevent_add: uevent: 0xffff888100242900, event: 0xffff888104b3e260, id: 0x1, bits: 0x1, func: 0x0000000000000000
> > > > > > > > > > > > > > [ 4.090514] nvkm_uevent_add: uevent: 0xffff888100242a00, event: 0xffff888102091f28, id: 0x1, bits: 0x3, func: 0xffffffff8177b700
> > > > > > > > > > > > > > [ 4.102118] tsc: Refined TSC clocksource calibration: 3591.345 MHz
> > > > > > > > > > > > > > [ 4.108342] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x33c4635c383, max_idle_ns: 440795314831 ns
> > > > > > > > > > > > > > [ 4.108401] nvkm_uevent_add: uevent: 0xffff8881020b6000, event: 0xffff888102091f28, id: 0xf, bits: 0x3, func: 0xffffffff8177b700
> > > > > > > > > > > > > > [ 4.129864] clocksource: Switched to clocksource tsc
> > > > > > > > > > > > > > [ 4.131478] [drm] Initialized nouveau 1.3.1 20120801 for 0000:03:00.0 on minor 0
> > > > > > > > > > > > > > [ 4.143806] BUG: kernel NULL pointer dereference, address: 0000000000000020
> > > > > > > > > > > > >
> > > > > > > > > > > > > ahh, that would have been good to know :) Mind figuring out what's
> > > > > > > > > > > > > exactly NULL inside nvif_object_mthd? Or rather what line
> > > > > > > > > > > > > `nvif_object_mthd+0x136` belongs to, then it should be easy to figure
> > > > > > > > > > > > > out what's wrong here.
> > > > > > > > > > > >
> > > > > > > > > > > > FWIW, we've hit the bug on openSUSE Tumbleweed 6.4.8 kernel:
> > > > > > > > > > > > https://bugzilla.suse.com/show_bug.cgi?id=1214073
> > > > > > > > > > > > Confirmed that reverting the patch cured the issue.
> > > > > > > > > > > >
> > > > > > > > > > > > FWIW, loading nouveau showed a refcount_t warning just before the NULL
> > > > > > > > > > > > dereference:
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > mh, I wonder if one of those `return -EINVAL;` branches is hit where
> > > > > > > > > > > it wasn't before. Could some of you check if `nvkm_uconn_uevent`
> > > > > > > > > > > returns -EINVAL with that patch where it didn't before? I wonder if
> > > > > > > > > > > it's the `if (&outp->head == &conn->disp->outps) return -EINVAL;` and
> > > > > > > > > > > if remove that fixes the crash?
> > > > > > > > > >
> > > > > > > > > > Please give a patch, then I can build a kernel and let the reporter
> > > > > > > > > > testing it :)
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > > attached a patch.
> > > > > > > >
> > > > > > > > Thanks. Now I'm building a test kernel and asked the reporter for
> > > > > > > > testing it.
> > > > > > >
> > > > > > > And the result was negative, the boot still hanged up.
> > > > > >
> > > > > > And below is another log from the 6.4.8 kernel with KASAN-enabled.
> > > > > > Some memory corruption seems happening.
> > > > > >
> > > > > > [ 228.422919] nouveau 0000:02:00.0: DRM: DCB conn 01: 0000a146
> > > > > > [ 228.428674] nouveau 0000:02:00.0: DRM: MM: using M2MF for buffer copies
> > > > > > [ 228.436682] ==================================================================
> > > > > > [ 228.436698] BUG: KASAN: slab-use-after-free in drm_connector_list_iter_next+0x176/0x320
> > > > > > [ 228.436715] Read of size 4 at addr ffff8881731ce050 by task modprobe/6174
> > > > > >
> > > > > > [ 228.436728] CPU: 0 PID: 6174 Comm: modprobe Not tainted 6.4.9-4.g5b9ad20-default #1 openSUSE Tumbleweed (unreleased) d0a6841e538b38d17513f6942fb58770372b54fd
> > > > > > [ 228.436740] Hardware name: Apple Inc. MacBook5,1/Mac-F42D89C8, BIOS MB51.88Z.007D.B03.0904271443 04/27/09
> > > > > > [ 228.436747] Call Trace:
> > > > > > [ 228.436753] <TASK>
> > > > > > [ 228.436759] dump_stack_lvl+0x47/0x60
> > > > > > [ 228.436773] print_report+0xcf/0x640
> > > > > > [ 228.436784] ? __pfx__raw_spin_lock_irqsave+0x10/0x10
> > > > > > [ 228.436797] ? drm_connector_list_iter_next+0x176/0x320
> > > > > > [ 228.436807] kasan_report+0xb1/0xe0
> > > > > > [ 228.436817] ? drm_connector_list_iter_next+0x176/0x320
> > > > > > [ 228.436828] kasan_check_range+0x105/0x1b0
> > > > > > [ 228.436837] drm_connector_list_iter_next+0x176/0x320
> > > > > > [ 228.436848] ? __pfx_drm_connector_list_iter_next+0x10/0x10
> > > > > > [ 228.436859] ? __kmem_cache_free+0x18a/0x2c0
> > > > > > [ 228.436868] nouveau_connector_create+0x170/0x1cd0 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.437540] ? drm_encoder_init+0xbe/0x140
> > > > > > [ 228.437554] ? __pfx_nouveau_connector_create+0x10/0x10 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438137] ? nvif_outp_ctor+0x2d9/0x430 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438236] nv50_display_create+0xe54/0x30d0 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438236] nouveau_display_create+0x903/0x10c0 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438236] nouveau_drm_device_init+0x3a4/0x19e0 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438236] ? __pfx_nouveau_drm_device_init+0x10/0x10 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438236] ? __pfx_pci_update_current_state+0x10/0x10
> > > > > > [ 228.438236] ? __kasan_check_byte+0x13/0x50
> > > > > > [ 228.438236] nouveau_drm_probe+0x1a2/0x6b0 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438236] ? __pfx__raw_spin_lock_irqsave+0x10/0x10
> > > > > > [ 228.438236] ? __pfx_nouveau_drm_probe+0x10/0x10 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438236] ? __pfx_nouveau_drm_probe+0x10/0x10 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438236] local_pci_probe+0xdd/0x190
> > > > > > [ 228.438236] pci_device_probe+0x23a/0x770
> > > > > > [ 228.438236] ? kernfs_add_one+0x2d8/0x450
> > > > > > [ 228.438236] ? kernfs_get.part.0+0x4c/0x70
> > > > > > [ 228.438236] ? __pfx_pci_device_probe+0x10/0x10
> > > > > > [ 228.438236] ? kernfs_create_link+0x15f/0x230
> > > > > > [ 228.438236] ? kernfs_put+0x1c/0x40
> > > > > > [ 228.438236] ? sysfs_do_create_link_sd+0x8e/0x100
> > > > > > [ 228.438236] really_probe+0x3e2/0xb80
> > > > > > [ 228.438236] __driver_probe_device+0x18c/0x450
> > > > > > [ 228.438236] ? __pfx_klist_iter_init_node+0x10/0x10
> > > > > > [ 228.438236] driver_probe_device+0x4a/0x120
> > > > > > [ 228.438236] __driver_attach+0x1e1/0x4a0
> > > > > > [ 228.438236] ? __pfx___driver_attach+0x10/0x10
> > > > > > [ 228.438236] bus_for_each_dev+0xf4/0x170
> > > > > > [ 228.438236] ? __pfx__raw_spin_lock+0x10/0x10
> > > > > > [ 228.438236] ? __pfx_bus_for_each_dev+0x10/0x10
> > > > > > [ 228.438236] bus_add_driver+0x29e/0x570
> > > > > > [ 228.438236] ? __pfx_nouveau_drm_init+0x10/0x10 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438236] ? __pfx_nouveau_drm_init+0x10/0x10 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438236] driver_register+0x134/0x460
> > > > > > [ 228.438236] ? __pfx_nouveau_drm_init+0x10/0x10 [nouveau d0287dfba9984367c331e8149297392f67038244]
> > > > > > [ 228.438236] do_one_initcall+0x8e/0x310
> > > > > > [ 228.438236] ? __pfx_do_one_initcall+0x10/0x10
> > > > > > [ 228.438236] ? __kmem_cache_alloc_node+0x1b9/0x3b0
> > > > > > [ 228.438236] ? do_init_module+0x4b/0x730
> > > > > > [ 228.438236] ? kasan_unpoison+0x44/0x70
> > > > > > [ 228.438236] do_init_module+0x238/0x730
> > > > > > [ 228.438236] load_module+0x5b41/0x6dd0
> > > > > > [ 228.438236] ? __pfx_load_module+0x10/0x10
> > > > > > [ 228.438236] ? _raw_spin_lock+0x85/0xe0
> > > > > > [ 228.438236] ? __pfx__raw_spin_lock+0x10/0x10
> > > > > > [ 228.438236] ? find_vmap_area+0xab/0xe0
> > > > > > [ 228.438236] ? __do_sys_init_module+0x1df/0x210
> > > > > > [ 228.438236] __do_sys_init_module+0x1df/0x210
> > > > > > [ 228.438236] ? __pfx___do_sys_init_module+0x10/0x10
> > > > > > [ 228.438236] ? syscall_exit_to_user_mode+0x1b/0x40
> > > > > > [ 228.438236] ? do_syscall_64+0x6c/0x90
> > > > > > [ 228.438236] ? __pfx_ksys_read+0x10/0x10
> > > > > > [ 228.438236] do_syscall_64+0x60/0x90
> > > > > > [ 228.438236] ? syscall_exit_to_user_mode+0x1b/0x40
> > > > > > [ 228.438236] ? do_syscall_64+0x6c/0x90
> > > > > > [ 228.438236] ? syscall_exit_to_user_mode+0x1b/0x40
> > > > > > [ 228.438236] ? do_syscall_64+0x6c/0x90
> > > > > > [ 228.438236] ? exc_page_fault+0x62/0xd0
> > > > > > [ 228.438236] entry_SYSCALL_64_after_hwframe+0x77/0xe1
> > > > > > [ 228.438236] RIP: 0033:0x7f91ce119a5e
> > > > > > [ 228.438236] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 49 89 ca b8 af 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 7a 03 0d 00 f7 d8 64 89 01 48
> > > > > > [ 228.438236] RSP: 002b:00007ffce2813538 EFLAGS: 00000246 ORIG_RAX: 00000000000000af
> > > > > > [ 228.438236] RAX: ffffffffffffffda RBX: 00005588462def10 RCX: 00007f91ce119a5e
> > > > > > [ 228.438236] RDX: 00005588462e39c0 RSI: 0000000000fda8b2 RDI: 00007f91cc371010
> > > > > > [ 228.438236] RBP: 00005588462e39c0 R08: 00005588462e3ce0 R09: 0000000000000000
> > > > > > [ 228.438236] R10: 000000000005af11 R11: 0000000000000246 R12: 0000000000040000
> > > > > > [ 228.438236] R13: 0000000000000000 R14: 0000000000000009 R15: 00005588462de7c0
> > > > > > [ 228.438236] </TASK>
> > > > > >
> > > > > > [ 228.438236] Allocated by task 6174:
> > > > > > [ 228.438236] kasan_save_stack+0x20/0x40
> > > > > > [ 228.438236] kasan_set_track+0x25/0x30
> > > > > > [ 228.438236] __kasan_kmalloc+0xaa/0xb0
> > > > > > [ 228.438236] nouveau_connector_create+0x386/0x1cd0 [nouveau]
> > > > > > [ 228.438236] nv50_display_create+0xe54/0x30d0 [nouveau]
> > > > > > [ 228.438236] nouveau_display_create+0x903/0x10c0 [nouveau]
> > > > > > [ 228.438236] nouveau_drm_device_init+0x3a4/0x19e0 [nouveau]
> > > > > > [ 228.438236] nouveau_drm_probe+0x1a2/0x6b0 [nouveau]
> > > > > > [ 228.438236] local_pci_probe+0xdd/0x190
> > > > > > [ 228.438236] pci_device_probe+0x23a/0x770
> > > > > > [ 228.438236] really_probe+0x3e2/0xb80
> > > > > > [ 228.438236] __driver_probe_device+0x18c/0x450
> > > > > > [ 228.438236] driver_probe_device+0x4a/0x120
> > > > > > [ 228.438236] __driver_attach+0x1e1/0x4a0
> > > > > > [ 228.438236] bus_for_each_dev+0xf4/0x170
> > > > > > [ 228.438236] bus_add_driver+0x29e/0x570
> > > > > > [ 228.438236] driver_register+0x134/0x460
> > > > > > [ 228.438236] do_one_initcall+0x8e/0x310
> > > > > > [ 228.438236] do_init_module+0x238/0x730
> > > > > > [ 228.438236] load_module+0x5b41/0x6dd0
> > > > > > [ 228.438236] __do_sys_init_module+0x1df/0x210
> > > > > > [ 228.438236] do_syscall_64+0x60/0x90
> > > > > > [ 228.438236] entry_SYSCALL_64_after_hwframe+0x77/0xe1
> > > > > >
> > > > > > [ 228.438236] Freed by task 6174:
> > > > > > [ 228.438236] kasan_save_stack+0x20/0x40
> > > > > > [ 228.438236] kasan_set_track+0x25/0x30
> > > > > > [ 228.438236] kasan_save_free_info+0x2e/0x50
> > > > > > [ 228.438236] ____kasan_slab_free+0x169/0x1c0
> > > > > > [ 228.438236] slab_free_freelist_hook+0xcd/0x190
> > > > > > [ 228.438236] __kmem_cache_free+0x18a/0x2c0
> > > > > > [ 228.438236] nouveau_connector_create+0x1423/0x1cd0 [nouveau]
> > > > > > [ 228.438236] nv50_display_create+0xe54/0x30d0 [nouveau]
> > > > > > [ 228.438236] nouveau_display_create+0x903/0x10c0 [nouveau]
> > > > > > [ 228.438236] nouveau_drm_device_init+0x3a4/0x19e0 [nouveau]
> > > > > > [ 228.438236] nouveau_drm_probe+0x1a2/0x6b0 [nouveau]
> > > > > > [ 228.438236] local_pci_probe+0xdd/0x190
> > > > > > [ 228.438236] pci_device_probe+0x23a/0x770
> > > > > > [ 228.438236] really_probe+0x3e2/0xb80
> > > > > > [ 228.438236] __driver_probe_device+0x18c/0x450
> > > > > > [ 228.438236] driver_probe_device+0x4a/0x120
> > > > > > [ 228.438236] __driver_attach+0x1e1/0x4a0
> > > > > > [ 228.438236] bus_for_each_dev+0xf4/0x170
> > > > > > [ 228.438236] bus_add_driver+0x29e/0x570
> > > > > > [ 228.438236] driver_register+0x134/0x460
> > > > > > [ 228.438236] do_one_initcall+0x8e/0x310
> > > > > > [ 228.438236] do_init_module+0x238/0x730
> > > > > > [ 228.438236] load_module+0x5b41/0x6dd0
> > > > > > [ 228.438236] __do_sys_init_module+0x1df/0x210
> > > > > > [ 228.438236] do_syscall_64+0x60/0x90
> > > > > > [ 228.438236] entry_SYSCALL_64_after_hwframe+0x77/0xe1
> > > > > >
> > > > > > [ 228.438236] The buggy address belongs to the object at ffff8881731ce000
> > > > > > which belongs to the cache kmalloc-4k of size 4096
> > > > > > [ 228.438236] The buggy address is located 80 bytes inside of
> > > > > > freed 4096-byte region [ffff8881731ce000, ffff8881731cf000)
> > > > > >
> > > > > > [ 228.438236] The buggy address belongs to the physical page:
> > > > > > [ 228.438236] page:00000000d1c274b4 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1731c8
> > > > > > [ 228.438236] head:00000000d1c274b4 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
> > > > > > [ 228.438236] flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff)
> > > > > > [ 228.438236] page_type: 0xffffffff()
> > > > > > [ 228.438236] raw: 0017ffffc0010200 ffff888100042140 dead000000000122 0000000000000000
> > > > > > [ 228.438236] raw: 0000000000000000 0000000080040004 00000001ffffffff 0000000000000000
> > > > > > [ 228.438236] page dumped because: kasan: bad access detected
> > > > > >
> > > > > > [ 228.438236] Memory state around the buggy address:
> > > > > > [ 228.438236] ffff8881731cdf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > > > > > [ 228.438236] ffff8881731cdf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> > > > > > [ 228.438236] >ffff8881731ce000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > > > > > [ 228.438236] ^
> > > > > > [ 228.438236] ffff8881731ce080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > > > > > [ 228.438236] ffff8881731ce100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > > > > > [ 228.438236] ==================================================================
> > > > > >
> > > > >
> > > > > mind resolving those to file lines via decode_stacktrace.sh or
> > > > > something, because looking at it, it makes no sense really.
> > > >
> > > > I don't own the machine, so it's a bit difficult from my side,
> > > > unfortunately.
> > > >
> >
> > also, you don't need to run it on the same machine if it's all
> > distribution packaged. As long as you have the exact same binary
> > available you can resolve the lines. Or just use gdb:
> > https://docs.kernel.org/admin-guide/bug-hunting.html#gdb
>
> Unfortunately it's not possible, as it's a moving target (following
> the upstream development), and the rpm packages used for the report
> are already gone. What I can get now won't match any longer.
>
> But now I wonder whether this can be reproduced by injecting an
> error artificially.
>

uhh, nvm. I was blind and I didn't see those lines of code:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/gpu/drm/nouveau/nouveau_connector.c?h=v6.5-rc6#n1403

Those lines probably should only be called after all error checks,
I'll see if it's safe to do so.

>
> Takashi
>