Date: Thu, 12 Dec 2019 00:29:48 +0000 (UTC) From: Alexander Motin <mav@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r355636 - stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <201912120029.xBC0TmAJ021932@repo.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: mav Date: Thu Dec 12 00:29:48 2019 New Revision: 355636 URL: https://svnweb.freebsd.org/changeset/base/355636 Log: MFC r355182: Fix use-after-free in case of L2ARC prefetch failure. In case L2ARC read failed, l2arc_read_done() creates _different_ ZIO to read data from the original storage device. Unfortunately pointer to the failed ZIO remains in hdr->b_l1hdr.b_acb->acb_zio_head, and if some other read try to bump the ZIO priority, it will crash. The problem is reproducible by corrupting L2ARC content and reading some data with prefetch if l2arc_noprefetch tunable is changed to 0. With the default setting the issue is probably not reproducible now. Modified: stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c ============================================================================== --- stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Thu Dec 12 00:14:01 2019 (r355635) +++ stable/12/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c Thu Dec 12 00:29:48 2019 (r355636) @@ -7886,7 +7886,6 @@ l2arc_read_done(zio_t *zio) zio->io_private = hdr; arc_read_done(zio); } else { - mutex_exit(hash_lock); /* * Buffer didn't survive caching. Increment stats and * reissue to the original storage device. @@ -7909,11 +7908,17 @@ l2arc_read_done(zio_t *zio) ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL); - zio_nowait(zio_read(pio, zio->io_spa, zio->io_bp, + zio = zio_read(pio, zio->io_spa, zio->io_bp, hdr->b_l1hdr.b_pabd, zio->io_size, arc_read_done, hdr, zio->io_priority, cb->l2rcb_flags, - &cb->l2rcb_zb)); - } + &cb->l2rcb_zb); + for (struct arc_callback *acb = hdr->b_l1hdr.b_acb; + acb != NULL; acb = acb->acb_next) + acb->acb_zio_head = zio; + mutex_exit(hash_lock); + zio_nowait(zio); + } else + mutex_exit(hash_lock); } kmem_free(cb, sizeof (l2arc_read_callback_t));
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201912120029.xBC0TmAJ021932>