| Message ID | 20210818193117.Fn2hT%akpm@linux-foundation.org |
|---|---|
| State | New |
| Headers | show |
| Series | + mm-remove-bogus-vm_bug_on.patch added to -mm tree | expand |
--- a/mm/filemap.c~mm-remove-bogus-vm_bug_on +++ a/mm/filemap.c @@ -2038,7 +2038,6 @@ unsigned find_lock_entries(struct addres if (!xa_is_value(page)) { if (page->index < start) goto put; - VM_BUG_ON_PAGE(page->index != xas.xa_index, page); if (page->index + thp_nr_pages(page) - 1 > end) goto put; if (!trylock_page(page))
The patch titled Subject: mm/filemap.c: remove bogus VM_BUG_ON has been added to the -mm tree. Its filename is mm-remove-bogus-vm_bug_on.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-remove-bogus-vm_bug_on.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-remove-bogus-vm_bug_on.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: "Matthew Wilcox (Oracle)" <willy@infradead.org> Subject: mm/filemap.c: remove bogus VM_BUG_ON It is not safe to check page->index without holding the page lock. It can be changed if the page is moved between the swap cache and the page cache for a shmem file, for example. There is a VM_BUG_ON below which checks page->index is correct after taking the page lock. Link: https://lkml.kernel.org/r/20210818144932.940640-1-willy@infradead.org Fixes: 5c211ba29deb ("mm: add and use find_lock_entries") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reported-by: <syzbot+c87be4f669d920c76330@syzkaller.appspotmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- mm/filemap.c | 1 - 1 file changed, 1 deletion(-)