This is a note to let you know that I've just added the patch titled
mm/gup: explicitly define and check internal GUP flags, disallow FOLL_TOUCH
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-gup-explicitly-define-and-check-internal-gup-flag.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d64d15556b61253f6109226a4c039ace736a218f
Author: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Date: Tue Oct 3 00:14:52 2023 +0100
mm/gup: explicitly define and check internal GUP flags, disallow FOLL_TOUCH
[ Upstream commit 0f20bba1688bdf3b32df0162511a67d4eda15790 ]
Rather than open-coding a list of internal GUP flags in
is_valid_gup_args(), define which ones are internal.
In addition, explicitly check to see if the user passed in FOLL_TOUCH
somehow, as this appears to have been accidentally excluded.
Link: https://lkml.kernel.org/r/971e013dfe20915612ea8b704e801d7aef9a66b6.1696288092.git.lstoakes@xxxxxxxxx
Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Richard Cochran <richardcochran@xxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Stable-dep-of: 631426ba1d45 ("mm/madvise: make MADV_POPULATE_(READ|WRITE) handle VM_FAULT_RETRY properly")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/mm/gup.c b/mm/gup.c
index 2f8a2d89fde19..b21b33d1787e1 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2227,12 +2227,11 @@ static bool is_valid_gup_args(struct page **pages, int *locked,
/*
* These flags not allowed to be specified externally to the gup
* interfaces:
- * - FOLL_PIN/FOLL_TRIED/FOLL_FAST_ONLY are internal only
+ * - FOLL_TOUCH/FOLL_PIN/FOLL_TRIED/FOLL_FAST_ONLY are internal only
* - FOLL_REMOTE is internal only and used on follow_page()
* - FOLL_UNLOCKABLE is internal only and used if locked is !NULL
*/
- if (WARN_ON_ONCE(gup_flags & (FOLL_PIN | FOLL_TRIED | FOLL_UNLOCKABLE |
- FOLL_REMOTE | FOLL_FAST_ONLY)))
+ if (WARN_ON_ONCE(gup_flags & INTERNAL_GUP_FLAGS))
return false;
gup_flags |= to_set;
diff --git a/mm/internal.h b/mm/internal.h
index 30cf724ddbce3..50cf76d30a88f 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -964,6 +964,9 @@ enum {
FOLL_UNLOCKABLE = 1 << 21,
};
+#define INTERNAL_GUP_FLAGS (FOLL_TOUCH | FOLL_TRIED | FOLL_REMOTE | FOLL_PIN | \
+ FOLL_FAST_ONLY | FOLL_UNLOCKABLE)
+
/*
* Indicates for which pages that are write-protected in the page table,
* whether GUP has to trigger unsharing via FAULT_FLAG_UNSHARE such that the
