Jason Gunthorpe 71fb40ae9b drm/ttm: remove ttm_bo_vm_insert_huge() ... [ Upstream commit 0d97950953 ] The huge page functionality in TTM does not work safely because PUD and PMD entries do not have a special bit. get_user_pages_fast() considers any page that passed pmd_huge() as usable: if (unlikely(pmd_trans_huge(pmd) || pmd_huge(pmd) || pmd_devmap(pmd))) { And vmf_insert_pfn_pmd_prot() unconditionally sets entry = pmd_mkhuge(pfn_t_pmd(pfn, prot)); eg on x86 the page will be _PAGE_PRESENT | PAGE_PSE. As such gup_huge_pmd() will try to deref a struct page: head = try_grab_compound_head(pmd_page(orig), refs, flags); and thus crash. Thomas further notices that the drivers are not expecting the struct page to be used by anything - in particular the refcount incr above will cause them to malfunction. Thus everything about this is not able to fully work correctly considering GUP_fast. Delete it entirely. It can return someday along with a proper PMD/PUD_SPECIAL bit in the page table itself to gate GUP_fast. Fixes: 314b6580ad ("drm/ttm, drm/vmwgfx: Support huge TTM pagefaults") Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Thomas Hellström <thomas.helllstrom@linux.intel.com> Reviewed-by: Christian König <christian.koenig@amd.com> [danvet: Update subject per Thomas' &Christian's review] Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/0-v2-a44694790652+4ac-ttm_pmd_jgg@nvidia.com Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-11-18 19:17:08 +01:00
..
acpi	ACPI: tools: fix compilation error	2021-10-07 19:18:19 +02:00
asm-generic	asm-generic: build fixes for v5.15	2021-10-08 11:57:54 -07:00
clocksource
crypto	Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6	2021-08-30 12:57:10 -07:00
drm	drm/ttm: remove ttm_bo_vm_insert_huge()	2021-11-18 19:17:08 +01:00
dt-bindings	linux-watchdog 5.15-rc1 tag	2021-09-07 13:52:46 -07:00
keys
kunit	kunit: fix kernel-doc warnings due to mismatched arg names	2021-10-06 17:54:07 -06:00
kvm	KVM: arm64: Fix PMU probe ordering	2021-09-20 12:43:34 +01:00
linux	net: dsa: felix: fix broken VLAN-tagged PTP under VLAN-aware bridge	2021-11-18 19:17:06 +01:00
math-emu
media	media: videobuf2: rework vb2_mem_ops API	2021-11-18 19:16:13 +01:00
memory	memory: renesas-rpc-if: Correct QSPI data transfer in Manual mode	2021-11-18 19:16:01 +01:00
misc
net	sctp: subtract sctphdr len in sctp_transport_pl_hlen	2021-11-18 19:16:43 +01:00
pcmcia
ras
rdma	RDMA/core: Set sgtable nents when using ib_dma_virt_map_sg()	2021-11-18 19:16:52 +01:00
scsi	scsi: core: Avoid leaving shost->last_reset with stale value if EH does not run	2021-11-18 19:15:51 +01:00
soc	net: dsa: tag_ocelot_8021q: break circular dependency with ocelot switch lib	2021-10-12 17:35:18 -07:00
sound	ASoC: topology: Fix stub for snd_soc_tplg_component_remove()	2021-11-18 19:16:55 +01:00
target
trace	block-5.15-2021-10-17	2021-10-17 19:25:20 -10:00
uapi	ethtool: fix ethtool msg len calculation for pause stats	2021-11-18 19:17:06 +01:00
vdso
video
xen	xen/privcmd: drop "pages" parameter from xen_remap_pfn()	2021-10-05 08:20:27 +02:00