On Sat, Oct 3, 2020 at 11:30 PM Michel Lespinasse <walken@xxxxxxxxxx> wrote: > Unrelated to the above: copy_from_user and copy_to_user should not be > called with mmap_lock held; it may be worth adding these assertions > too (probably in separate patches) ? We already have that: All (hopefully?) the userspace accessors call might_fault(), and that does might_lock_read(¤t->mm->mmap_lock) (if we're not running in a lazytlb kernel thread or KERNEL_DS is on or we're in IRQ context or page faults have explicitly been disabled). But another place where lockdep asserts should be added is find_vma(); there are currently several architectures that sometimes improperly call that with no lock held: SPARC's arch_validate_prot(): https://lore.kernel.org/linux-mm/CAG48ez3YsfTfOFKa-Po58e4PNp7FK54MFbkK3aUPSRt3LWtxQA@xxxxxxxxxxxxxx/ nios2 sys_cacheflush(): https://lore.kernel.org/linux-mm/CAG48ez3hxeXU29UGWRH-gRXX2jb5Lc==npbXFt8UDrWO4eHZdQ@xxxxxxxxxxxxxx/ nds32 sys_cacheflush(): https://lore.kernel.org/linux-mm/CAG48ez1UnQEMok9rqFQC4XHBaMmBe=eaedu8Z_RXdjFHTna_LA@xxxxxxxxxxxxxx/
