Huan, Thanks for your response. On 3/11/25 3:12 PM, Huan Yang wrote: > > 在 2025/3/11 14:40, Bingbu Cao 写道: >> [You don't often get email from bingbu.cao@xxxxxxxxxxxxxxx. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] >> >> Huan Yang and Vivek, >> >> I am trying to use udmabuf for my test, and I cannot vmap the udmabuf >> buffers now. vmap_pfn_apply() will report a warning to complain that >> the pfns are invalid. >> I dump the pfn numbers as below: >> [ 3365.399641] pg[0] pfn 1148695 >> [ 3365.399642] pg[1] pfn 1145057 >> [ 3365.399642] pg[2] pfn 1134070 >> [ 3365.399643] pg[3] pfn 1148700 >> [ 3365.399643] pg[4] pfn 1144871 >> [ 3365.399643] pg[5] pfn 1408686 >> [ 3365.399643] pg[6] pfn 1408683 >> ... >> [ 3365.399660] WARNING: CPU: 3 PID: 2772 at mm/vmalloc.c:3489 vmap_pfn_apply+0xb7/0xd0 >> [ 3365.399667] Modules linked in:... >> [ 3365.399750] CPU: 3 UID: 0 PID: 2772 Comm: drm-test Not tainted 6.13.0-rc2-rvp #845 >> [ 3365.399752] Hardware name: Intel Corporation Client Platform/xxxx, BIOS xxxFWI1.R00.3221.D83.2408120121 08/12/2024 >> [ 3365.399753] RIP: 0010:vmap_pfn_apply+0xb7/0xd0 >> [ 3365.399755] Code: 5b 41 5c 41 5d 5d c3 cc cc cc cc 48 21 c3 eb d1 48 21 c3 48 23 3d 31 c0 26 02 eb c5 48 c7 c7 c4 3c 20 a8 e8 5b c0 d8 ff eb 8a <0f> 0b b8 ea ff ff ff 5b 41 5c 41 5d 5d c3 cc cc cc cc 0f 1f 80 00 >> [ 3365.399756] RSP: 0018:ffffb9b50c32fad0 EFLAGS: 00010202 >> [ 3365.399757] RAX: 0000000000000001 RBX: 0000000000118717 RCX: 0000000000000000 >> [ 3365.399758] RDX: 0000000080000000 RSI: ffffb9b50c358000 RDI: 00000000ffffffff >> [ 3365.399758] RBP: ffffb9b50c32fae8 R08: ffffb9b50c32fbd0 R09: 0000000000000001 >> [ 3365.399759] R10: ffff941602479288 R11: 0000000000000000 R12: ffffb9b50c32fbd0 >> [ 3365.399759] R13: ffff941618665ac0 R14: ffffb9b50c358000 R15: ffff941618665ac8 >> [ 3365.399760] FS: 00007ff9e9ddd740(0000) GS:ffff94196f780000(0000) knlGS:0000000000000000 >> [ 3365.399760] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [ 3365.399761] CR2: 000055fda5dc69d9 CR3: 00000001544de003 CR4: 0000000000f72ef0 >> [ 3365.399762] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> [ 3365.399762] DR3: 0000000000000000 DR6: 00000000ffff07f0 DR7: 0000000000000400 >> [ 3365.399763] PKRU: 55555554 >> [ 3365.399763] Call Trace: >> [ 3365.399765] <TASK> >> [ 3365.399769] ? show_regs+0x6d/0x80 >> [ 3365.399773] ? __warn+0x97/0x160 >> [ 3365.399777] ? vmap_pfn_apply+0xb7/0xd0 >> [ 3365.399777] ? report_bug+0x1ec/0x240 >> [ 3365.399782] ? handle_bug+0x63/0xa0 >> [ 3365.399784] ? exc_invalid_op+0x1d/0x80 >> [ 3365.399785] ? asm_exc_invalid_op+0x1f/0x30 >> [ 3365.399790] ? vmap_pfn_apply+0xb7/0xd0 >> [ 3365.399791] __apply_to_page_range+0x522/0x8a0 >> [ 3365.399794] ? __pfx_vmap_pfn_apply+0x10/0x10 >> [ 3365.399795] apply_to_page_range+0x18/0x20 >> [ 3365.399796] vmap_pfn+0x77/0xd0 >> [ 3365.399797] vmap_udmabuf+0xc5/0x110 >> [ 3365.399802] dma_buf_vmap+0x96/0x130 >> >> I did an experiment to revert 18d7de823b7150344d242c3677e65d68c5271b04, >> then I can vmap the pages. Could you help what's wrong with that? > > Sorry for that, as I reviewed pfn_valid, that's someting wired: > > /** > * pfn_valid - check if there is a valid memory map entry for a PFN > * @pfn: the page frame number to check > * > * Check if there is a valid memory map entry aka struct page for the @pfn. > * Note, that availability of the memory map entry does not imply that > * there is actual usable memory at that @pfn. The struct page may > * represent a hole or an unusable page frame. > * > * Return: 1 for PFNs that have memory map entries and 0 otherwise > */ > > So, if pfn valid, it's return 1, else 0. So mean, only 1 is a valid pfn. But vmap_pfn_apply in there: > > static int vmap_pfn_apply(pte_t *pte, unsigned long addr, void *private) > { > struct vmap_pfn_data *data = private; > unsigned long pfn = data->pfns[data->idx]; > pte_t ptent; > > if (WARN_ON_ONCE(pfn_valid(pfn))) > return -EINVAL; > > ptent = pte_mkspecial(pfn_pte(pfn, data->prot)); > set_pte_at(&init_mm, addr, pte, ptent); > > data->idx++; > return 0; > } > > Do it give a wrong check? maybe should fix by: I guess not, it looks more like warning when you trying to vmap a pfn which already took a valid entry in pte. However, the MM code is so complex for me, just my guess. :) > > static int vmap_pfn_apply(pte_t *pte, unsigned long addr, void *private) > { > struct vmap_pfn_data *data = private; > unsigned long pfn = data->pfns[data->idx]; > pte_t ptent; > > - if (WARN_ON_ONCE(pfn_valid(pfn))) > + if (WARN_ON_ONCE(!pfn_valid(pfn))) > return -EINVAL; > > ptent = pte_mkspecial(pfn_pte(pfn, data->prot)); > set_pte_at(&init_mm, addr, pte, ptent); > > data->idx++; > return 0; > } > > Please help me check it, also, you can apply this and then check it.:) > >> >> >> -- >> Best regards, >> Bingbu Cao -- Best regards, Bingbu Cao
