* [bug report] mm/gup.c: Fix return value for __gup_longterm_locked()
@ 2022-08-25 7:49 Dan Carpenter
2022-08-27 22:36 ` Shigeru Yoshida
0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2022-08-25 7:49 UTC (permalink / raw)
To: syoshida; +Cc: linux-mm
Hello Shigeru Yoshida,
The patch 35f9c4607f9e: "mm/gup.c: Fix return value for
__gup_longterm_locked()" from Aug 22, 2022, leads to the following
Smatch static checker warning:
mm/gup.c:2089 __gup_longterm_locked()
error: uninitialized symbol 'rc'.
mm/gup.c
2064 static long __gup_longterm_locked(struct mm_struct *mm,
2065 unsigned long start,
2066 unsigned long nr_pages,
2067 struct page **pages,
2068 struct vm_area_struct **vmas,
2069 unsigned int gup_flags)
2070 {
2071 unsigned int flags;
2072 long rc, nr_pinned_pages;
2073
2074 if (!(gup_flags & FOLL_LONGTERM))
2075 return __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
2076 NULL, gup_flags);
2077 flags = memalloc_pin_save();
2078 do {
2079 nr_pinned_pages = __get_user_pages_locked(mm, start, nr_pages,
2080 pages, vmas, NULL,
2081 gup_flags);
2082 if (nr_pinned_pages <= 0)
This doesn't work if if fails on the first iteration. But also I'm
surprised that we are return -EAGAIN on subsequent iterations...
2083 break;
2084 rc = check_and_migrate_movable_pages(nr_pinned_pages, pages,
2085 gup_flags);
2086 } while (rc == -EAGAIN);
2087 memalloc_pin_restore(flags);
2088
--> 2089 return rc ? rc : nr_pinned_pages;
2090 }
regards,
dan carpenter
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [bug report] mm/gup.c: Fix return value for __gup_longterm_locked()
2022-08-25 7:49 [bug report] mm/gup.c: Fix return value for __gup_longterm_locked() Dan Carpenter
@ 2022-08-27 22:36 ` Shigeru Yoshida
0 siblings, 0 replies; 2+ messages in thread
From: Shigeru Yoshida @ 2022-08-27 22:36 UTC (permalink / raw)
To: dan.carpenter; +Cc: linux-mm
Hi Dan,
On Thu, 25 Aug 2022 10:49:27 +0300, Dan Carpenter wrote:
> Hello Shigeru Yoshida,
>
> The patch 35f9c4607f9e: "mm/gup.c: Fix return value for
> __gup_longterm_locked()" from Aug 22, 2022, leads to the following
> Smatch static checker warning:
>
> mm/gup.c:2089 __gup_longterm_locked()
> error: uninitialized symbol 'rc'.
>
> mm/gup.c
> 2064 static long __gup_longterm_locked(struct mm_struct *mm,
> 2065 unsigned long start,
> 2066 unsigned long nr_pages,
> 2067 struct page **pages,
> 2068 struct vm_area_struct **vmas,
> 2069 unsigned int gup_flags)
> 2070 {
> 2071 unsigned int flags;
> 2072 long rc, nr_pinned_pages;
> 2073
> 2074 if (!(gup_flags & FOLL_LONGTERM))
> 2075 return __get_user_pages_locked(mm, start, nr_pages, pages, vmas,
> 2076 NULL, gup_flags);
> 2077 flags = memalloc_pin_save();
> 2078 do {
> 2079 nr_pinned_pages = __get_user_pages_locked(mm, start, nr_pages,
> 2080 pages, vmas, NULL,
> 2081 gup_flags);
> 2082 if (nr_pinned_pages <= 0)
>
>
> This doesn't work if if fails on the first iteration. But also I'm
> surprised that we are return -EAGAIN on subsequent iterations...
Sorry for late response and thanks for your bug report. Yes, that's
my fault. I'll prepare the patch.
Thanks,
Shigeru
>
> 2083 break;
> 2084 rc = check_and_migrate_movable_pages(nr_pinned_pages, pages,
> 2085 gup_flags);
> 2086 } while (rc == -EAGAIN);
> 2087 memalloc_pin_restore(flags);
> 2088
> --> 2089 return rc ? rc : nr_pinned_pages;
> 2090 }
>
> regards,
> dan carpenter
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2022-08-27 22:37 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-08-25 7:49 [bug report] mm/gup.c: Fix return value for __gup_longterm_locked() Dan Carpenter
2022-08-27 22:36 ` Shigeru Yoshida
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox