Hi Milan, On Tue, Apr 15, 2025 at 05:01:15PM +0200, Milan Broz wrote: > Hi, > > I tried upstream stable git and bisect, this is the conclusion: > > - upstream 6.1.134 is still broken > > - bisect points to this patch > (Patch cannot be easily reverted, it need some other patches, anyway, it can > be used as reference what need to be backported) > > 476c1dfefab8b98ae9c3e3ad283c2ac10d30c774 is the first bad commit > commit 476c1dfefab8b98ae9c3e3ad283c2ac10d30c774 > Author: David Howells <dhowe...@redhat.com> > Date: Fri May 26 22:41:40 2023 +0100 > > mm: Don't pin ZERO_PAGE in pin_user_pages() > > [ Upstream commit c8070b78751955e59b42457b974bea4a4fe00187 ] > > Make pin_user_pages*() leave a ZERO_PAGE unpinned if it extracts a pointer > to it from the page tables and make unpin_user_page*() correspondingly > ignore a ZERO_PAGE when unpinning. We don't want to risk overrunning a > zero page's refcount as we're only allowed ~2 million pins on it - > something that userspace can conceivably trigger. > > Add a pair of functions to test whether a page or a folio is a ZERO_PAGE. > > Signed-off-by: David Howells <dhowe...@redhat.com> > cc: Christoph Hellwig <h...@infradead.org> > cc: David Hildenbrand <da...@redhat.com> > cc: Lorenzo Stoakes <lstoa...@gmail.com> > cc: Andrew Morton <a...@linux-foundation.org> > cc: Jens Axboe <ax...@kernel.dk> > cc: Al Viro <v...@zeniv.linux.org.uk> > cc: Matthew Wilcox <wi...@infradead.org> > cc: Jan Kara <j...@suse.cz> > cc: Jeff Layton <jlay...@kernel.org> > cc: Jason Gunthorpe <j...@nvidia.com> > cc: Logan Gunthorpe <log...@deltatee.com> > cc: Hillf Danton <hdan...@sina.com> > cc: Christian Brauner <brau...@kernel.org> > cc: Linus Torvalds <torva...@linux-foundation.org> > cc: linux-fsde...@vger.kernel.org > cc: linux-bl...@vger.kernel.org > cc: linux-ker...@vger.kernel.org > cc: linux...@kvack.org > Reviewed-by: Lorenzo Stoakes <lstoa...@gmail.com> > Reviewed-by: Christoph Hellwig <h...@lst.de> > Acked-by: David Hildenbrand <da...@redhat.com> > Link: > https://lore.kernel.org/r/20230526214142.958751-2-dhowe...@redhat.com > Signed-off-by: Jens Axboe <ax...@kernel.dk> > Stable-dep-of: bddf10d26e6e ("uprobes: Reject the shared zeropage in > uprobe_write_opcode()") > Signed-off-by: Sasha Levin <sas...@kernel.org> > > Documentation/core-api/pin_user_pages.rst | 6 ++++++ > include/linux/mm.h | 26 ++++++++++++++++++++++++-- > mm/gup.c | 31 > ++++++++++++++++++++++++++++++- > 3 files changed, 60 insertions(+), 3 deletions(-) > > If you are going to write a mail to upstream kernel list, please cc me.
Thanks for doing that work, I will forward the bug report now upstream (and sure will include you on CC). Regards, Salvatore
