On Sun 2018-09-16 11:34:14, Pavel Machek wrote: > Hi! > > > > Any ideas? > > > > Hmm. Is this new? > > > > > 2018-09-10T18:47:54.532837-07:00 dragon kernel: [ 31.472371] kernel BUG at ../kernel/dma/swiotlb.c:521! > > > > nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; > > [...] > > BUG_ON(!nslots) > > > > > 2018-09-10T18:47:54.613655-07:00 dragon kernel: [ 31.490325] swiotlb_alloc+0x88/0x170 > > > 2018-09-10T18:47:54.613656-07:00 dragon kernel: [ 31.490329] ? __kmalloc+0x1cc/0x200 > > > 2018-09-10T18:47:54.613657-07:00 dragon kernel: [ 31.491652] iwl_pcie_txq_alloc+0x1d4/0x3b0 [iwlwifi] > > > > There are two calls to dma_alloc_coherent() here, should those even hit > > swiotlb? The sizes of those should be > > * 256 x 128 (32k) > > * 32 x 256 (8k) [TFH, unlikely to be the case here] > > * 256 x 256 (65k) [TFH] > > * 32 x 64 (2k) > > * 256 x 64 (16k) > > > > > > IO_TLB_SHIFT is 11, so we get 2k alignment, so even the smallest size > > (32*64) should result in nslots being 1? > > > > In fact, unless the driver passed *ZERO* as the size, this should never > > happen (hence the BUG_ON), since ALIGN() would take care of rounding up > > any smaller allocation here. > > > > Presumably you can reproduce this pretty easily (and I don't know what > > specific model of NIC you have etc.), so perhaps you can do something > > like this? > > > > https://p.sipsolutions.net/aa0dccd7a60fe176.txt > > That results in: ... if I'm not mistaken. Tested on top of today's > mainline. (-rc3.95 :-) Hold on. I was confused by my build system. Let me retry. Are you sure you are not mistaking WARN and WARN_ON? -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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