From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4EB8C28371; Thu, 26 Sep 2024 21:04:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727384649; cv=none; b=mFMZwMZIeXtrqpM3JsoINkmCdQJAtOv4gQFijFYDiO26J6Jssd4nBMJPrcjDLHOHblkmC3UNv8b2TEg3HvNoJLRy0x8CJ6aAWAULa4yMinLID1Sx0bpbg+yCoSwasAMFR3J9IYksIooV7MYSMc3TNO/j8XG8APaWMkoXLOpM9+o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727384649; c=relaxed/simple; bh=VvBdKj+W2U5/Yt/pOj/u0EVQCdwIdQoRAskCLA2c6hI=; h=Date:To:From:Subject:Message-Id; b=lFvnMWUhz2OuNGehbmA4S2ZFkXDwTx1KZRB81ZEfefz2C6FGF+iSYxx6lInYA+IF1tBGBjEHYcO78l0NHLix2zy7MJhWXPj46RM0TUQYQGSPp0/Pgx10nrdFzMb3FQu3CEU8Ls5jT/r/F3/RQ2P8L7fxK6BlnXob5rCNLqvfZ6Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=LNYjgQjZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="LNYjgQjZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CA507C4CEC7; Thu, 26 Sep 2024 21:04:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1727384648; bh=VvBdKj+W2U5/Yt/pOj/u0EVQCdwIdQoRAskCLA2c6hI=; h=Date:To:From:Subject:From; b=LNYjgQjZnpfWjPjOSs/HWbBuSxDuBaAHz3voi1FFc+kbI01KgzpWyp07tzdNhA4/V 4XY7NX3louEvO8pXU80ubkkcx/LRTAVi+5R/4/HY5xV7OyOHARlm3AaJg11q0lvh+Y HrGPAAsz5xgtIyOPO8cqt5nY1GSgwzk760iLcClc= Date: Thu, 26 Sep 2024 14:04:08 -0700 To: mm-commits@vger.kernel.org,willy@infradead.org,vivek.kasireddy@intel.com,stable@vger.kernel.org,peterx@redhat.com,muchun.song@linux.dev,jgg@nvidia.com,david@redhat.com,steven.sistare@oracle.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-filemap-fix-filemap_get_folios_contig-thp-panic.patch removed from -mm tree Message-Id: <20240926210408.CA507C4CEC7@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/filemap: fix filemap_get_folios_contig THP panic has been removed from the -mm tree. Its filename was mm-filemap-fix-filemap_get_folios_contig-thp-panic.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Steve Sistare Subject: mm/filemap: fix filemap_get_folios_contig THP panic Date: Tue, 3 Sep 2024 07:25:17 -0700 Patch series "memfd-pin huge page fixes". Fix multiple bugs that occur when using memfd_pin_folios with hugetlb pages and THP. The hugetlb bugs only bite when the page is not yet faulted in when memfd_pin_folios is called. The THP bug bites when the starting offset passed to memfd_pin_folios is not huge page aligned. See the commit messages for details. This patch (of 5): memfd_pin_folios on memory backed by THP panics if the requested start offset is not huge page aligned: BUG: kernel NULL pointer dereference, address: 0000000000000036 RIP: 0010:filemap_get_folios_contig+0xdf/0x290 RSP: 0018:ffffc9002092fbe8 EFLAGS: 00010202 RAX: 0000000000000002 RBX: 0000000000000002 RCX: 0000000000000002 The fault occurs here, because xas_load returns a folio with value 2: filemap_get_folios_contig() for (folio = xas_load(&xas); folio && xas.xa_index <= end; folio = xas_next(&xas)) { ... if (!folio_try_get(folio)) <-- BOOM "2" is an xarray sibling entry. We get it because memfd_pin_folios does not round the indices passed to filemap_get_folios_contig to huge page boundaries for THP, so we load from the middle of a huge page range see a sibling. (It does round for hugetlbfs, at the is_file_hugepages test). To fix, if the folio is a sibling, then return the next index as the starting point for the next call to filemap_get_folios_contig. Link: https://lkml.kernel.org/r/1725373521-451395-1-git-send-email-steven.sistare@oracle.com Link: https://lkml.kernel.org/r/1725373521-451395-2-git-send-email-steven.sistare@oracle.com Fixes: 89c1905d9c14 ("mm/gup: introduce memfd_pin_folios() for pinning memfd folios") Signed-off-by: Steve Sistare Cc: David Hildenbrand Cc: Jason Gunthorpe Cc: Matthew Wilcox Cc: Muchun Song Cc: Peter Xu Cc: Vivek Kasireddy Cc: Signed-off-by: Andrew Morton --- mm/filemap.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/mm/filemap.c~mm-filemap-fix-filemap_get_folios_contig-thp-panic +++ a/mm/filemap.c @@ -2196,6 +2196,10 @@ unsigned filemap_get_folios_contig(struc if (xa_is_value(folio)) goto update_start; + /* If we landed in the middle of a THP, continue at its end. */ + if (xa_is_sibling(folio)) + goto update_start; + if (!folio_try_get(folio)) goto retry; _ Patches currently in -mm which might be from steven.sistare@oracle.com are