mirror of
https://github.com/torvalds/linux.git
synced 2026-09-18 16:48:03 +02:00
4a19f7ab59
In amdxdna_insert_pages(), vm_flags_mod() sets VM_MIXEDMAP and clears
VM_PFNMAP. If an unprivileged userspace process mmaps a non-imported GEM
object and then calls madvise(MADV_DONTNEED), the PTEs will be
successfully cleared because VM_MIXEDMAP allows this (unlike VM_PFNMAP).
When userspace subsequently accesses the memory, drm_gem_shmem_fault()
handles the page fault and attempts to map the backing shmem page via
vmf_insert_pfn() which calls vmf_insert_pfn_prot(). Because the backing
shmem page is normal system memory (pfn_valid(pfn) is true) and the VMA
now has VM_MIXEDMAP set, won't this predictably trigger the explicit
assertion BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn))
Fix by removing the vm_flags_mod() call and replacing the vm_insert_pages()
pre-population with the handle_mm_fault() loop that was already used for
the import (dma-buf) path.
Fixes:
|
||
|---|---|---|
| .. | ||
| amdxdna | ||
| ethosu | ||
| habanalabs | ||
| ivpu | ||
| qaic | ||
| rocket | ||
| drm_accel.c | ||
| Kconfig | ||
| Makefile | ||