Date: Wed, 26 Jul 2017 16:42:32 +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-11@freebsd.org Subject: svn commit: r321548 - stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <201707261642.v6QGgWg3076540@repo.freebsd.org>
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Author: mav Date: Wed Jul 26 16:42:32 2017 New Revision: 321548 URL: https://svnweb.freebsd.org/changeset/base/321548 Log: MFC r318822: MFC r316913: 7869 panic in bpobj_space(): null pointer dereference illumos/illumos-gate@a3905a45920de250d181b66ac0b6b71bd200d9ef https://github.com/illumos/illumos-gate/commit/a3905a45920de250d181b66ac0b6b71bd200d9ef https://www.illumos.org/issues/7869 The issue fixed by this patch is a race condition in the deadlist code. A thread executing an administrative command that uses `dsl_deadlist_space_range()` holds the lock of the whole `deadlist_t` to protect the access of all its entries that the deadlist contains in an avl tree. Sync threads trying to insert a new entry in the deadlist (through `dsl_deadlist_insert()` -> `dle_enqueue()`) do not hold the deadlist lock at that moment. If the `dle_bpobj` is the empty bpobj (our sentinel value), we close and reopen it. Between these two operations, it is possible for the `dsl_deadlist_space_range()` thread to dereference that bpobj which is `NULL` during that window. Threads should hold the a deadlist's `dl_lock` when they manipulate its internal data so scenarios like the one above are avoided. In addition, threads should also hold the bpobj lock whenever they are allocating the subobj list of a bpobj, and not just when they actually insert the subobj to the list. This way we can avoid potential memory leaks. Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: Dan Kimmel <dan.kimmel@delphix.com> Reviewed by: Steve Gonczi <steve.gonczi@delphix.com> Reviewed by: John Kennedy <john.kennedy@delphix.com> Reviewed by: George Melikov <mail@gmelikov.ru> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@omniti.com> Author: Serapheim Dimitropoulos <serapheim@delphix.com> Modified: stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c ============================================================================== --- stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c Wed Jul 26 16:35:17 2017 (r321547) +++ stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/bpobj.c Wed Jul 26 16:42:32 2017 (r321548) @@ -20,7 +20,7 @@ */ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. - * Copyright (c) 2011, 2014 by Delphix. All rights reserved. + * Copyright (c) 2011, 2016 by Delphix. All rights reserved. * Copyright (c) 2014 Integros [integros.com] */ @@ -395,6 +395,7 @@ bpobj_enqueue_subobj(bpobj_t *bpo, uint64_t subobj, dm return; } + mutex_enter(&bpo->bpo_lock); dmu_buf_will_dirty(bpo->bpo_dbuf, tx); if (bpo->bpo_phys->bpo_subobjs == 0) { bpo->bpo_phys->bpo_subobjs = dmu_object_alloc(bpo->bpo_os, @@ -406,7 +407,6 @@ bpobj_enqueue_subobj(bpobj_t *bpo, uint64_t subobj, dm ASSERT0(dmu_object_info(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs, &doi)); ASSERT3U(doi.doi_type, ==, DMU_OT_BPOBJ_SUBOBJ); - mutex_enter(&bpo->bpo_lock); dmu_write(bpo->bpo_os, bpo->bpo_phys->bpo_subobjs, bpo->bpo_phys->bpo_num_subobjs * sizeof (subobj), sizeof (subobj), &subobj, tx); Modified: stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c ============================================================================== --- stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c Wed Jul 26 16:35:17 2017 (r321547) +++ stable/11/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_deadlist.c Wed Jul 26 16:42:32 2017 (r321548) @@ -72,6 +72,8 @@ dsl_deadlist_load_tree(dsl_deadlist_t *dl) zap_cursor_t zc; zap_attribute_t za; + ASSERT(MUTEX_HELD(&dl->dl_lock)); + ASSERT(!dl->dl_oldfmt); if (dl->dl_havetree) return; @@ -182,6 +184,7 @@ static void dle_enqueue(dsl_deadlist_t *dl, dsl_deadlist_entry_t *dle, const blkptr_t *bp, dmu_tx_t *tx) { + ASSERT(MUTEX_HELD(&dl->dl_lock)); if (dle->dle_bpobj.bpo_object == dmu_objset_pool(dl->dl_os)->dp_empty_bpobj) { uint64_t obj = bpobj_alloc(dl->dl_os, SPA_OLD_MAXBLOCKSIZE, tx); @@ -198,6 +201,7 @@ static void dle_enqueue_subobj(dsl_deadlist_t *dl, dsl_deadlist_entry_t *dle, uint64_t obj, dmu_tx_t *tx) { + ASSERT(MUTEX_HELD(&dl->dl_lock)); if (dle->dle_bpobj.bpo_object != dmu_objset_pool(dl->dl_os)->dp_empty_bpobj) { bpobj_enqueue_subobj(&dle->dle_bpobj, obj, tx); @@ -222,15 +226,14 @@ dsl_deadlist_insert(dsl_deadlist_t *dl, const blkptr_t return; } + mutex_enter(&dl->dl_lock); dsl_deadlist_load_tree(dl); dmu_buf_will_dirty(dl->dl_dbuf, tx); - mutex_enter(&dl->dl_lock); dl->dl_phys->dl_used += bp_get_dsize_sync(dmu_objset_spa(dl->dl_os), bp); dl->dl_phys->dl_comp += BP_GET_PSIZE(bp); dl->dl_phys->dl_uncomp += BP_GET_UCSIZE(bp); - mutex_exit(&dl->dl_lock); dle_tofind.dle_mintxg = bp->blk_birth; dle = avl_find(&dl->dl_tree, &dle_tofind, &where); @@ -239,6 +242,7 @@ dsl_deadlist_insert(dsl_deadlist_t *dl, const blkptr_t else dle = AVL_PREV(&dl->dl_tree, dle); dle_enqueue(dl, dle, bp, tx); + mutex_exit(&dl->dl_lock); } /* @@ -254,16 +258,19 @@ dsl_deadlist_add_key(dsl_deadlist_t *dl, uint64_t mint if (dl->dl_oldfmt) return; - dsl_deadlist_load_tree(dl); - dle = kmem_alloc(sizeof (*dle), KM_SLEEP); dle->dle_mintxg = mintxg; + + mutex_enter(&dl->dl_lock); + dsl_deadlist_load_tree(dl); + obj = bpobj_alloc_empty(dl->dl_os, SPA_OLD_MAXBLOCKSIZE, tx); VERIFY3U(0, ==, bpobj_open(&dle->dle_bpobj, dl->dl_os, obj)); avl_add(&dl->dl_tree, dle); VERIFY3U(0, ==, zap_add_int_key(dl->dl_os, dl->dl_object, mintxg, obj, tx)); + mutex_exit(&dl->dl_lock); } /* @@ -278,6 +285,7 @@ dsl_deadlist_remove_key(dsl_deadlist_t *dl, uint64_t m if (dl->dl_oldfmt) return; + mutex_enter(&dl->dl_lock); dsl_deadlist_load_tree(dl); dle_tofind.dle_mintxg = mintxg; @@ -291,6 +299,7 @@ dsl_deadlist_remove_key(dsl_deadlist_t *dl, uint64_t m kmem_free(dle, sizeof (*dle)); VERIFY3U(0, ==, zap_remove_int(dl->dl_os, dl->dl_object, mintxg, tx)); + mutex_exit(&dl->dl_lock); } /* @@ -334,6 +343,7 @@ dsl_deadlist_clone(dsl_deadlist_t *dl, uint64_t maxtxg return (newobj); } + mutex_enter(&dl->dl_lock); dsl_deadlist_load_tree(dl); for (dle = avl_first(&dl->dl_tree); dle; @@ -347,6 +357,7 @@ dsl_deadlist_clone(dsl_deadlist_t *dl, uint64_t maxtxg VERIFY3U(0, ==, zap_add_int_key(dl->dl_os, newobj, dle->dle_mintxg, obj, tx)); } + mutex_exit(&dl->dl_lock); return (newobj); } @@ -424,6 +435,8 @@ dsl_deadlist_insert_bpobj(dsl_deadlist_t *dl, uint64_t uint64_t used, comp, uncomp; bpobj_t bpo; + ASSERT(MUTEX_HELD(&dl->dl_lock)); + VERIFY3U(0, ==, bpobj_open(&bpo, dl->dl_os, obj)); VERIFY3U(0, ==, bpobj_space(&bpo, &used, &comp, &uncomp)); bpobj_close(&bpo); @@ -431,11 +444,9 @@ dsl_deadlist_insert_bpobj(dsl_deadlist_t *dl, uint64_t dsl_deadlist_load_tree(dl); dmu_buf_will_dirty(dl->dl_dbuf, tx); - mutex_enter(&dl->dl_lock); dl->dl_phys->dl_used += used; dl->dl_phys->dl_comp += comp; dl->dl_phys->dl_uncomp += uncomp; - mutex_exit(&dl->dl_lock); dle_tofind.dle_mintxg = birth; dle = avl_find(&dl->dl_tree, &dle_tofind, &where); @@ -475,6 +486,7 @@ dsl_deadlist_merge(dsl_deadlist_t *dl, uint64_t obj, d return; } + mutex_enter(&dl->dl_lock); for (zap_cursor_init(&zc, dl->dl_os, obj); zap_cursor_retrieve(&zc, &za) == 0; zap_cursor_advance(&zc)) { @@ -489,6 +501,7 @@ dsl_deadlist_merge(dsl_deadlist_t *dl, uint64_t obj, d dmu_buf_will_dirty(bonus, tx); bzero(dlp, sizeof (*dlp)); dmu_buf_rele(bonus, FTAG); + mutex_exit(&dl->dl_lock); } /* @@ -503,6 +516,8 @@ dsl_deadlist_move_bpobj(dsl_deadlist_t *dl, bpobj_t *b avl_index_t where; ASSERT(!dl->dl_oldfmt); + + mutex_enter(&dl->dl_lock); dmu_buf_will_dirty(dl->dl_dbuf, tx); dsl_deadlist_load_tree(dl); @@ -518,14 +533,12 @@ dsl_deadlist_move_bpobj(dsl_deadlist_t *dl, bpobj_t *b VERIFY3U(0, ==, bpobj_space(&dle->dle_bpobj, &used, &comp, &uncomp)); - mutex_enter(&dl->dl_lock); ASSERT3U(dl->dl_phys->dl_used, >=, used); ASSERT3U(dl->dl_phys->dl_comp, >=, comp); ASSERT3U(dl->dl_phys->dl_uncomp, >=, uncomp); dl->dl_phys->dl_used -= used; dl->dl_phys->dl_comp -= comp; dl->dl_phys->dl_uncomp -= uncomp; - mutex_exit(&dl->dl_lock); VERIFY3U(0, ==, zap_remove_int(dl->dl_os, dl->dl_object, dle->dle_mintxg, tx)); @@ -536,4 +549,5 @@ dsl_deadlist_move_bpobj(dsl_deadlist_t *dl, bpobj_t *b kmem_free(dle, sizeof (*dle)); dle = dle_next; } + mutex_exit(&dl->dl_lock); }
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