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mm: replace access_process_vm() write parameter with gup_flags

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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: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Lorenzo Stoakes
2016-10-13 01:20:20 +01:00
committed by Linus Torvalds
parent 6347e8d5bc
commit f307ab6dce
17 changed files with 84 additions and 54 deletions
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9
arch/alpha/kernel/ptrace.c
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@@ -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;