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Commit f307ab6d authored by Lorenzo Stoakes's avatar Lorenzo Stoakes Committed by Linus Torvalds
Browse files

mm: replace access_process_vm() write parameter with gup_flags 



This removes the 'write' argument from access_process_vm() and replaces
it with 'gup_flags' as use of this function previously silently implied
FOLL_FORCE, whereas after this patch callers explicitly pass this flag.

We make this explicit as use of FOLL_FORCE can result in surprising
behaviour (and hence bugs) within the mm subsystem.

Signed-off-by: default avatarLorenzo Stoakes <lstoakes@gmail.com>
Acked-by: default avatarJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6347e8d5

arch/alpha/kernel/ptrace.c

+6 −3
Original line number Diff line number Diff line
@@ -157,14 +157,16 @@ put_reg(struct task_struct *task, unsigned long regno, unsigned long data) 
static inline int

read_int(struct task_struct *task, unsigned long addr, int * data)

{

	int copied = access_process_vm(task, addr, data, sizeof(int), 0);

	int copied = access_process_vm(task, addr, data, sizeof(int),

			FOLL_FORCE);

	return (copied == sizeof(int)) ? 0 : -EIO;

}



static inline int

write_int(struct task_struct *task, unsigned long addr, int data)

{

	int copied = access_process_vm(task, addr, &data, sizeof(int), 1);

	int copied = access_process_vm(task, addr, &data, sizeof(int),

			FOLL_FORCE | FOLL_WRITE);

	return (copied == sizeof(int)) ? 0 : -EIO;

}
@@ -281,7 +283,8 @@ long arch_ptrace(struct task_struct *child, long request, 
	/* When I and D space are separate, these will need to be fixed.  */

	case PTRACE_PEEKTEXT: /* read word at location addr. */

	case PTRACE_PEEKDATA:

		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);

		copied = access_process_vm(child, addr, &tmp, sizeof(tmp),

				FOLL_FORCE);

		ret = -EIO;

		if (copied != sizeof(tmp))

			break;

arch/blackfin/kernel/ptrace.c

+3 −2
Original line number Diff line number Diff line
@@ -271,7 +271,7 @@ long arch_ptrace(struct task_struct *child, long request, 
			case BFIN_MEM_ACCESS_CORE:

			case BFIN_MEM_ACCESS_CORE_ONLY:

				copied = access_process_vm(child, addr, &tmp,

				                           to_copy, 0);

							   to_copy, FOLL_FORCE);

				if (copied)

					break;
@@ -324,7 +324,8 @@ long arch_ptrace(struct task_struct *child, long request, 
			case BFIN_MEM_ACCESS_CORE:

			case BFIN_MEM_ACCESS_CORE_ONLY:

				copied = access_process_vm(child, addr, &data,

				                           to_copy, 1);

				                           to_copy,

							   FOLL_FORCE | FOLL_WRITE);

				break;

			case BFIN_MEM_ACCESS_DMA:

				if (safe_dma_memcpy(paddr, &data, to_copy))

arch/cris/arch-v32/kernel/ptrace.c

+2 −2
Original line number Diff line number Diff line
@@ -147,7 +147,7 @@ long arch_ptrace(struct task_struct *child, long request, 
				/* The trampoline page is globally mapped, no page table to traverse.*/

				tmp = *(unsigned long*)addr;

			} else {

				copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);

				copied = access_process_vm(child, addr, &tmp, sizeof(tmp), FOLL_FORCE);



				if (copied != sizeof(tmp))

					break;
@@ -279,7 +279,7 @@ static int insn_size(struct task_struct *child, unsigned long pc) 
  int opsize = 0;



  /* Read the opcode at pc (do what PTRACE_PEEKTEXT would do). */

  copied = access_process_vm(child, pc, &opcode, sizeof(opcode), 0);

  copied = access_process_vm(child, pc, &opcode, sizeof(opcode), FOLL_FORCE);

  if (copied != sizeof(opcode))

    return 0;

arch/ia64/kernel/ptrace.c

+9 −5
Original line number Diff line number Diff line
@@ -453,7 +453,7 @@ ia64_peek (struct task_struct *child, struct switch_stack *child_stack, 
			return 0;

		}

	}

	copied = access_process_vm(child, addr, &ret, sizeof(ret), 0);

	copied = access_process_vm(child, addr, &ret, sizeof(ret), FOLL_FORCE);

	if (copied != sizeof(ret))

		return -EIO;

	*val = ret;
@@ -489,7 +489,8 @@ ia64_poke (struct task_struct *child, struct switch_stack *child_stack, 
				*ia64_rse_skip_regs(krbs, regnum) = val;

			}

		}

	} else if (access_process_vm(child, addr, &val, sizeof(val), 1)

	} else if (access_process_vm(child, addr, &val, sizeof(val),

				FOLL_FORCE | FOLL_WRITE)

		   != sizeof(val))

		return -EIO;

	return 0;
@@ -543,7 +544,8 @@ ia64_sync_user_rbs (struct task_struct *child, struct switch_stack *sw, 
		ret = ia64_peek(child, sw, user_rbs_end, addr, &val);

		if (ret < 0)

			return ret;

		if (access_process_vm(child, addr, &val, sizeof(val), 1)

		if (access_process_vm(child, addr, &val, sizeof(val),

				FOLL_FORCE | FOLL_WRITE)

		    != sizeof(val))

			return -EIO;

	}
@@ -559,7 +561,8 @@ ia64_sync_kernel_rbs (struct task_struct *child, struct switch_stack *sw, 


	/* now copy word for word from user rbs to kernel rbs: */

	for (addr = user_rbs_start; addr < user_rbs_end; addr += 8) {

		if (access_process_vm(child, addr, &val, sizeof(val), 0)

		if (access_process_vm(child, addr, &val, sizeof(val),

				FOLL_FORCE)

				!= sizeof(val))

			return -EIO;
@@ -1156,7 +1159,8 @@ arch_ptrace (struct task_struct *child, long request, 
	case PTRACE_PEEKTEXT:

	case PTRACE_PEEKDATA:

		/* read word at location addr */

		if (access_process_vm(child, addr, &data, sizeof(data), 0)

		if (access_process_vm(child, addr, &data, sizeof(data),

				FOLL_FORCE)

		    != sizeof(data))

			return -EIO;

		/* ensure return value is not mistaken for error code */

arch/m32r/kernel/ptrace.c

+10 −5
Original line number Diff line number Diff line
@@ -493,7 +493,8 @@ unregister_all_debug_traps(struct task_struct *child) 
	int i;



	for (i = 0; i < p->nr_trap; i++)

		access_process_vm(child, p->addr[i], &p->insn[i], sizeof(p->insn[i]), 1);

		access_process_vm(child, p->addr[i], &p->insn[i], sizeof(p->insn[i]),

				FOLL_FORCE | FOLL_WRITE);

	p->nr_trap = 0;

}
@@ -537,7 +538,8 @@ embed_debug_trap(struct task_struct *child, unsigned long next_pc) 
	unsigned long next_insn, code;

	unsigned long addr = next_pc & ~3;



	if (access_process_vm(child, addr, &next_insn, sizeof(next_insn), 0)

	if (access_process_vm(child, addr, &next_insn, sizeof(next_insn),

			FOLL_FORCE)

	    != sizeof(next_insn)) {

		return -1; /* error */

	}
@@ -546,7 +548,8 @@ embed_debug_trap(struct task_struct *child, unsigned long next_pc) 
	if (register_debug_trap(child, next_pc, next_insn, &code)) {

		return -1; /* error */

	}

	if (access_process_vm(child, addr, &code, sizeof(code), 1)

	if (access_process_vm(child, addr, &code, sizeof(code),

			FOLL_FORCE | FOLL_WRITE)

	    != sizeof(code)) {

		return -1; /* error */

	}
@@ -562,7 +565,8 @@ withdraw_debug_trap(struct pt_regs *regs) 
 	addr = (regs->bpc - 2) & ~3;

	regs->bpc -= 2;

	if (unregister_debug_trap(current, addr, &code)) {

	    access_process_vm(current, addr, &code, sizeof(code), 1);

	    access_process_vm(current, addr, &code, sizeof(code),

		    FOLL_FORCE | FOLL_WRITE);

	    invalidate_cache();

	}

}
@@ -589,7 +593,8 @@ void user_enable_single_step(struct task_struct *child) 
	/* Compute next pc.  */

	pc = get_stack_long(child, PT_BPC);



	if (access_process_vm(child, pc&~3, &insn, sizeof(insn), 0)

	if (access_process_vm(child, pc&~3, &insn, sizeof(insn),

			FOLL_FORCE)

	    != sizeof(insn))

		return;