Merge "mm: Fix sleeping while atomic during speculative page fault" (6e625d33) · Commits · e / devices / android_kernel_fairphone_FP5

arch/arm64/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -189,6 +189,7 @@ config ARM64
		select SWIOTLB
		select SYSCTL_EXCEPTION_TRACE
		select THREAD_INFO_IN_TASK
		select ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT
		help
		ARM 64-bit (AArch64) Linux support.

arch/arm64/mm/fault.c

+23 −3

Original line number	Diff line number	Diff line
		@@ -406,10 +406,9 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re
		#define VM_FAULT_BADMAP 0x010000
		#define VM_FAULT_BADACCESS 0x020000

		static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr,
		static int __do_page_fault(struct vm_area_struct *vma, unsigned long addr,
		unsigned int mm_flags, unsigned long vm_flags)
		{
		struct vm_area_struct *vma = find_vma(mm, addr);

		if (unlikely(!vma))
		return VM_FAULT_BADMAP;
		@@ -456,6 +455,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
		vm_fault_t fault, major = 0;
		unsigned long vm_flags = VM_READ \| VM_WRITE \| VM_EXEC;
		unsigned int mm_flags = FAULT_FLAG_ALLOW_RETRY \| FAULT_FLAG_KILLABLE;
		struct vm_area_struct *vma = NULL;

		if (kprobe_page_fault(regs, esr))
		return 0;
		@@ -495,6 +495,14 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,

		perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);

		/*
		* let's try a speculative page fault without grabbing the
		* mmap_sem.
		*/
		fault = handle_speculative_fault(mm, addr, mm_flags, &vma);
		if (fault != VM_FAULT_RETRY)
		goto done;

		/*
		* As per x86, we may deadlock here. However, since the kernel only
		* validly references user space from well defined areas of the code,
		@@ -519,7 +527,10 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
		#endif
		}

		fault = __do_page_fault(mm, addr, mm_flags, vm_flags);
		if (!vma \|\| !can_reuse_spf_vma(vma, addr))
		vma = find_vma(mm, addr);

		fault = __do_page_fault(vma, addr, mm_flags, vm_flags);
		major \|= fault & VM_FAULT_MAJOR;

		if (fault & VM_FAULT_RETRY) {
		@@ -542,11 +553,20 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
		if (mm_flags & FAULT_FLAG_ALLOW_RETRY) {
		mm_flags &= ~FAULT_FLAG_ALLOW_RETRY;
		mm_flags \|= FAULT_FLAG_TRIED;

		/*
		* Do not try to reuse this vma and fetch it
		* again since we will release the mmap_sem.
		*/
		vma = NULL;

		goto retry;
		}
		}
		up_read(&mm->mmap_sem);

		done:

		/*
		* Handle the "normal" (no error) case first.
		*/

fs/proc/task_mmu.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -1277,8 +1277,11 @@ static ssize_t clear_refs_write(struct file file, const char __user buf,
		goto out_mm;
		}
		for (vma = mm->mmap; vma; vma = vma->vm_next) {
		vma->vm_flags &= ~VM_SOFTDIRTY;
		vm_write_begin(vma);
		WRITE_ONCE(vma->vm_flags,
		vma->vm_flags & ~VM_SOFTDIRTY);
		vma_set_page_prot(vma);
		vm_write_end(vma);
		}
		downgrade_write(&mm->mmap_sem);
		break;

fs/userfaultfd.c

+13 −4

Original line number	Diff line number	Diff line
		@@ -675,8 +675,11 @@ int dup_userfaultfd(struct vm_area_struct vma, struct list_head fcs)

		octx = vma->vm_userfaultfd_ctx.ctx;
		if (!octx \|\| !(octx->features & UFFD_FEATURE_EVENT_FORK)) {
		vm_write_begin(vma);
		vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
		vma->vm_flags &= ~(VM_UFFD_WP \| VM_UFFD_MISSING);
		WRITE_ONCE(vma->vm_flags,
		vma->vm_flags & ~(VM_UFFD_WP \| VM_UFFD_MISSING));
		vm_write_end(vma);
		return 0;
		}

		@@ -919,8 +922,10 @@ static int userfaultfd_release(struct inode inode, struct file file)
		else
		prev = vma;
		}
		vma->vm_flags = new_flags;
		vm_write_begin(vma);
		WRITE_ONCE(vma->vm_flags, new_flags);
		vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
		vm_write_end(vma);
		}
		up_write(&mm->mmap_sem);
		mmput(mm);
		@@ -1487,8 +1492,10 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
		* the next vma was merged into the current one and
		* the current one has not been updated yet.
		*/
		vma->vm_flags = new_flags;
		vm_write_begin(vma);
		WRITE_ONCE(vma->vm_flags, new_flags);
		vma->vm_userfaultfd_ctx.ctx = ctx;
		vm_write_end(vma);

		skip:
		prev = vma;
		@@ -1650,8 +1657,10 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
		* the next vma was merged into the current one and
		* the current one has not been updated yet.
		*/
		vma->vm_flags = new_flags;
		vm_write_begin(vma);
		WRITE_ONCE(vma->vm_flags, new_flags);
		vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
		vm_write_end(vma);

		skip:
		prev = vma;

include/linux/hugetlb_inline.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -8,7 +8,7 @@

		static inline bool is_vm_hugetlb_page(struct vm_area_struct *vma)
		{
		return !!(vma->vm_flags & VM_HUGETLB);
		return !!(READ_ONCE(vma->vm_flags) & VM_HUGETLB);
		}

		#else