From 824dea7e53116af0ff722aaf2f9b21f564b3bfd2 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Wed, 16 Apr 2014 14:08:12 +0200 Subject: erts: Add etp commands for alloc_util block and carrier inspection etp-block etp-block2mbc etp-carrier-blocks --- erts/etc/unix/etp-commands.in | 150 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 149 insertions(+), 1 deletion(-) diff --git a/erts/etc/unix/etp-commands.in b/erts/etc/unix/etp-commands.in index 9e39764195..53c1e24a57 100644 --- a/erts/etc/unix/etp-commands.in +++ b/erts/etc/unix/etp-commands.in @@ -1,7 +1,7 @@ # # %CopyrightBegin% # -# Copyright Ericsson AB 2005-2012. All Rights Reserved. +# Copyright Ericsson AB 2005-2014. All Rights Reserved. # # The contents of this file are subject to the Erlang Public License, # Version 1.1, (the "License"); you may not use this file except in @@ -3176,6 +3176,154 @@ define etp-thr source @ERL_TOP@/erts/etc/unix/etp-thr.py end +############################################################################ +# erl_alloc_util (blocks and carriers) +# + +define etp-block-size-1 +# +# In: (Block_t*) in $arg0 +# Out: Byte size in $etp_blk_sz +# + if ($arg0)->bhdr & 1 + # Free block + set $etp_blk_sz = ($arg0)->bhdr & ~7 + else + # Allocated block + if !$etp_MBC_ABLK_SZ_MASK + if etp_arch_bits == 64 + set $etp_MBC_ABLK_OFFSET_SHIFT = (64 - 24) + else + set $etp_MBC_ABLK_OFFSET_SHIFT = (32 - 9) + end + set $etp_MBC_ABLK_SZ_MASK = ~(~0 << $etp_MBC_ABLK_OFFSET_SHIFT) & ~7 + end + set $etp_blk_sz = ($arg0)->bhdr & $etp_MBC_ABLK_SZ_MASK + end +end + +define etp-block2mbc-1 +# +# In: (Block_t*) in $arg0 +# Out: (Carrier_t*) in $etp-mbc +# + if (($arg0)->bhdr) & 1 + # Free block + set $etp_mbc = ($arg0)->u.carrier + else + # Allocated block + if !$etp_MBC_ABLK_OFFSET_SHIFT + if etp_arch_bits == 64 + set $etp_MBC_ABLK_OFFSET_SHIFT = (64 - 24) + else + set $etp_MBC_ABLK_OFFSET_SHIFT = (32 - 9) + end + end + set $etp_mbc = (Carrier_t*) ((((UWord)($arg0)) & (~0 << 18)) - ((($arg0)->bhdr >> $etp_MBC_ABLK_OFFSET_SHIFT) << 18)) + end +end + +define etp-block2mbc + etp-block2mbc-1 ((Block_t*)$arg0) + print $etp_mbc +end + +document etp-block2mbc +%--------------------------------------------------------------------------- +% Print pointer to multiblock carrier containing the argument (Block_t*) +%--------------------------------------------------------------------------- +end + +define etp-block + etp-block-size-1 ((Block_t*)$arg0) + if ((Block_t*)$arg0)->bhdr & 1 + printf "%#lx: FREE sz=%#x\n", ($arg0), $etp_blk_sz + else + printf "%#lx: ALLOCATED sz=%#x\n", ($arg0), $etp_blk_sz + end +end + +document etp-block +%--------------------------------------------------------------------------- +% Print memory block (Block_t*) +%--------------------------------------------------------------------------- +end + +define etp-carrier-blocks + set $etp_crr = (Carrier_t*) $arg0 + set $etp_alc = (Allctr_t*)($etp_crr->allctr.counter & ~7) + set $etp_blk = (Block_t*) ((char*)$etp_crr + $etp_alc->mbc_header_size) + set $etp_prev_blk = 0 + set $etp_error_cnt = 0 + set $etp_ablk_cnt = 0 + set $etp_fblk_cnt = 0 + + if $argc == 2 + set $etp_be_silent = $arg1 + else + set $etp_be_silent = 0 + end + + while 1 + if !$etp_be_silent + etp-block $etp_blk + else + etp-block-size-1 $etp_blk + end + etp-block2mbc-1 $etp_blk + if $etp_mbc != $etp_crr + printf "ERROR: Invalid carrier pointer %#lx in block at %#lx\n", $etp_mbc, $etp_blk + set $etp_error_cnt = $etp_error_cnt + 1 + end + if $etp_prev_blk + if ($etp_prev_blk->bhdr & 1) + # Prev is FREE + if ($etp_blk->bhdr & 1) + printf "ERROR: Adjacent FREE blocks at %#lx and %#lx\n", $etp_prev_blk, $etp_blk + set $etp_error_cnt = $etp_error_cnt + 1 + end + if !($etp_blk->bhdr & 2) + printf "ERROR: Missing PREV_FREE_BLK_HDR_FLG (2) in block at %#lx\n", $etp_blk + set $etp_error_cnt = $etp_error_cnt + 1 + end + end + end + if $etp_blk->bhdr & 1 + set $etp_fblk_cnt = $etp_fblk_cnt + 1 + else + set $etp_ablk_cnt = $etp_ablk_cnt + 1 + end + if $etp_blk->bhdr & 4 + # Last block + loop_break + end + # All free blocks except the last have a footer + if ($etp_blk->bhdr & 1) && ((UWord*)((char*)$etp_blk + $etp_blk_sz))[-1] != $etp_blk_sz + printf "ERROR: Invalid footer of free block at %#lx\n", $etp_blk + end + set $etp_prev_blk = $etp_blk + set $etp_blk = (Block_t*) ((char*)$etp_blk + $etp_blk_sz) + end + + if ((char*)$etp_blk + $etp_blk_sz) != ((char*)$etp_crr + ($etp_crr->chdr & ~7)) + printf "ERROR: Last block not at end of carrier\n" + set $etp_error_cnt = $etp_error_cnt + 1 + end + printf "Allocated blocks: %u\n", $etp_ablk_cnt + printf "Free blocks: %u\n", $etp_fblk_cnt + if $etp_error_cnt + printf "%u ERRORs reported above\n", $etp-error-cnt + end +end + +document etp-carrier-blocks +%--------------------------------------------------------------------------- +% Check and (maybe) print all memory blocks in carrier +% Args: (Carrier_t*) [1=be_silent] +%--------------------------------------------------------------------------- +end + + ############################################################################ # Toolbox parameter handling # -- cgit v1.2.3 From a652d1d882d6f4ddb46a23bf550cb8d12e403e8c Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Tue, 29 Apr 2014 15:24:41 +0200 Subject: Fix race between ETS table deletion and unfixation Symptom: VM crash running mnesia_SUITE Scenario: Process A terminates while still having fixed table T and process B "at the same time" deletes table T with ets:delete/1 or by terminating. Problem: A table scheduled for deallocation do only have a valid 'common' part. The unfix-table-at-process-exit code tried to read the hash-specific part of such a table. Solution: Must back off if DB_DELETE flag is set. Since: R16B --- erts/emulator/beam/erl_db.c | 62 ++++++++++++++++++++++++--------------------- 1 file changed, 33 insertions(+), 29 deletions(-) diff --git a/erts/emulator/beam/erl_db.c b/erts/emulator/beam/erl_db.c index a5d67571e2..8f246ffa07 100644 --- a/erts/emulator/beam/erl_db.c +++ b/erts/emulator/beam/erl_db.c @@ -259,10 +259,11 @@ static void schedule_free_dbtable(DbTable* tb) /* * NON-SMP case: Caller is *not* allowed to access the *tb * structure after this function has returned! - * SMP case: Caller is allowed to access the *tb structure - * until the bif has returned (we typically - * need to unlock the table lock after this - * function has returned). + * SMP case: Caller is allowed to access the *common* part of the *tb + * structure until the bif has returned (we typically need to + * unlock the table lock after this function has returned). + * Caller is *not* allowed to access the specialized part + * (hash or tree) of *tb after this function has returned. */ ASSERT(erts_refc_read(&tb->common.ref, 0) == 0); erts_schedule_thr_prgr_later_cleanup_op(free_dbtable, @@ -3279,34 +3280,37 @@ erts_db_process_exiting(Process *c_p, ErtsProcLocks c_p_locks) } erts_smp_rwmtx_runlock(mmtl); if (tb) { - int reds; - DbFixation** pp; + int reds = 0; db_lock(tb, LCK_WRITE_REC); - #ifdef ERTS_SMP - erts_smp_mtx_lock(&tb->common.fixlock); - #endif - reds = 10; - - for (pp = &tb->common.fixations; *pp != NULL; - pp = &(*pp)->next) { - if ((*pp)->pid == pid) { - DbFixation* fix = *pp; - erts_aint_t diff = -((erts_aint_t) fix->counter); - erts_refc_add(&tb->common.ref,diff,0); - *pp = fix->next; - erts_db_free(ERTS_ALC_T_DB_FIXATION, - tb, fix, sizeof(DbFixation)); - ERTS_ETS_MISC_MEM_ADD(-sizeof(DbFixation)); - break; + if (!(tb->common.status & DB_DELETE)) { + DbFixation** pp; + + #ifdef ERTS_SMP + erts_smp_mtx_lock(&tb->common.fixlock); + #endif + reds = 10; + + for (pp = &tb->common.fixations; *pp != NULL; + pp = &(*pp)->next) { + if ((*pp)->pid == pid) { + DbFixation* fix = *pp; + erts_aint_t diff = -((erts_aint_t) fix->counter); + erts_refc_add(&tb->common.ref,diff,0); + *pp = fix->next; + erts_db_free(ERTS_ALC_T_DB_FIXATION, + tb, fix, sizeof(DbFixation)); + ERTS_ETS_MISC_MEM_ADD(-sizeof(DbFixation)); + break; + } + } + #ifdef ERTS_SMP + erts_smp_mtx_unlock(&tb->common.fixlock); + #endif + if (!IS_FIXED(tb) && IS_HASH_TABLE(tb->common.status)) { + db_unfix_table_hash(&(tb->hash)); + reds += 40; } - } - #ifdef ERTS_SMP - erts_smp_mtx_unlock(&tb->common.fixlock); - #endif - if (!IS_FIXED(tb) && IS_HASH_TABLE(tb->common.status)) { - db_unfix_table_hash(&(tb->hash)); - reds += 40; } db_unlock(tb, LCK_WRITE_REC); BUMP_REDS(c_p, reds); -- cgit v1.2.3