On 11.01.25 02:00, Hillf Danton wrote:
On Fri, 10 Jan 2025 17:35:25 +0100 David Hildenbrand <david@xxxxxxxxxx>
On 31.12.24 09:41, Hillf Danton wrote:
On Fri, 27 Dec 2024 20:56:21 -0800
syzbot has found a reproducer for the following issue on:
HEAD commit: 8155b4ef3466 Add linux-next specific files for 20241220
git tree: linux-next
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1652fadf980000
#syz test
--- x/mm/filemap.c
+++ y/mm/filemap.c
@@ -3636,6 +3636,10 @@ static vm_fault_t filemap_map_folio_rang
continue;
skip:
if (count) {
+ for (unsigned int i = 0; i < count; i++) {
+ if (page_folio(page + i) != folio)
+ goto out;
+ }
IIRC, count <= nr_pages. Wouldn't that mean that we somehow pass in
nr_pages that already exceeds the given folio+start?
When I last looked at this, I was not able to spot the error in the
caller :(
This is a debug patch at the first place, and this hunk overlaps with the
next one.
Yeah, I was rather wondering if you had any clue why that hunk might
help on its own.
--
Cheers,
David / dhildenb
