Re: kern/56804: panic: drm2 overreleasing kref

[Patrick Welche <prlw1%talktalk.net@localhost>]

The following reply was made to PR kern/56804; it has been noted by GNATS.

From: Patrick Welche <prlw1%talktalk.net@localhost>
To: Taylor R Campbell <riastradh%NetBSD.org@localhost>
Cc: prlw1%cam.ac.uk@localhost, gnats-bugs%NetBSD.org@localhost
Subject: Re: kern/56804: panic: drm2 overreleasing kref
Date: Thu, 26 May 2022 12:21:20 +0100

 On Wed, May 25, 2022 at 01:02:33AM +0000, Taylor R Campbell wrote:
 > If you still have the core dump, can you share dmesg, and print what
 > `ret' is in frame #8?  I want to see how nouveau_bo_init failed.
 
 ret = -12  = -ENOMEM
 
 Looking at sys/external/bsd/drm2/dist/drm/ttm/ttm_bo.c ttm_bo_init_reserved()
 
    1313 	ret = ttm_mem_global_alloc(mem_glob, acc_size, ctx);
    1314 	if (ret) {
    1315 		pr_err("Out of kernel memory\n");
    1316 		if (destroy)
    1317 			(*destroy)(bo);
    1318 		else
    1319 			kfree(bo);
    1320 		return -ENOMEM;
    1321 	}
 
 nouveau_bo_init():
 struct nouveau_bo *nvbo;
 acc_size = ttm_bo_dma_acc_size(nvbo->bo.bdev, size, sizeof(*nvbo));
 
 should be "small"?
 
 Something which has puzzled me on this box is that it has
 
 [   1.0000000] total memory = 65469 MB
 [   1.0000000] avail memory = 63426 MB
 
 yet it struggles to build (-j24) libreoffice with objdir on tmpfs,
 with processes stuck in biowait swapping. I am not sure I understand
 what "16G Inact" means in "top" as naively I am surprised that so
 little is free that swapping is necessary... When not building,
 e.g.  now, I see 740K Inact 37G Free which makes more sense.
 
 This panic had happened during a pbulk run.
 
 
 [   2.7572726] nouveau0: info: NVIDIA GK104 (0e4000a2)
 [   2.8772749] nouveau0: info: bios: version 80.04.09.00.01
 [   2.8872727] nouveau0: interrupting at msi8 vec 0 (nouveau0)
 [   2.8872727] nouveau0: info: fb: 2048 MiB GDDR5
 [   2.9672727] Zone  kernel: Available graphics memory: 22684942 KiB
 [   2.9672727] Zone   dma32: Available graphics memory: 2097152 KiB
 [   2.9813498] nouveau0: info: DRM: VRAM: 2048 MiB
 [   2.9813498] nouveau0: info: DRM: GART: 1048576 MiB
 [   2.9908122] nouveau0: info: DRM: TMDS table version 2.0
 [   2.9908122] nouveau0: info: DRM: DCB version 4.0
 [   3.0006277] nouveau0: info: DRM: DCB outp 00: 01000f02 00020030
 [   3.0006277] nouveau0: info: DRM: DCB outp 01: 02000f00 00000000
 [   3.0124439] nouveau0: info: DRM: DCB outp 02: 08011f82 00020030
 [   3.0183527] nouveau0: info: DRM: DCB outp 03: 02022f62 00020010
 [   3.0183527] nouveau0: info: DRM: DCB outp 04: 04833fb6 0f420010
 [   3.0301683] nouveau0: info: DRM: DCB outp 05: 04033f72 00020010
 [   3.0301683] nouveau0: info: DRM: DCB conn 00: 00001030
 [   3.0412027] nouveau0: info: DRM: DCB conn 01: 00020131
 [   3.0412027] nouveau0: info: DRM: DCB conn 02: 00010261
 [   3.0514536] nouveau0: info: DRM: DCB conn 03: 00002346
 [   3.0572741] nouveau0: info: DRM: MM: using COPY for buffer copies
 [   3.0572741] kern info: [drm] Supports vblank timestamp caching Rev 2 (21.10.2
 013).
 [   3.0738254] kern info: [drm] Driver supports precise vblank timestamp query.
 [   3.1072742] nouveaufb0 at nouveau0
 [   3.1072742] kern info: [drm] Initialized nouveau 1.3.1 20120801 for nouveau0 
 on minor 0
 [   3.1213511] nouveaufb0: framebuffer at 0xe8260000, size 3840x2160, depth 32, 
 stride 15360
 [   3.1672733] no data for est. mode 640x480x67