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  1. WiredTiger
  2. WT-6049

Fix eviction evicting uncommitted changes

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      Found this while working on WT-5676, but was able to show the problem in develop with a relatively short workload.  To reproduce, put the attached Python script into bench/workgen/runner and run it via gdb --args python rwstress.py .  It takes about 20 seconds overall.  Sometimes I see malloc complaints like: corrupted size vs. prev_size or double free or corruption (!prev) .  Other times assertions.  But invariably, __split_multi_inmem_ _and _wt_split_rewrite are in the stack.

      (gdb) bt
      #0  0x00007ffff7a22e97 in raise () from /lib/x86_64-linux-gnu/libc.so.6
      #1  0x00007ffff7a24801 in abort () from /lib/x86_64-linux-gnu/libc.so.6
      #2  0x00007ffff67559ac in __wt_abort (session=session@entry=0x7ffff48c4868)
          at ../src/os_common/os_abort.c:30
      #3  0x00007ffff667f290 in __split_multi_inmem (
          session=session@entry=0x7ffff48c4868, orig=orig@entry=0x7ffe3009cb20, 
          multi=multi@entry=0x7fff58883f90, ref=0x7fff5821d220)
          at ../src/btree/bt_split.c:1469
      #4  0x00007ffff668b0d9 in __wt_split_rewrite (
          session=session@entry=0x7ffff48c4868, ref=ref@entry=0x7fff38920150, 
          multi=0x7fff58883f90) at ../src/btree/bt_split.c:2273
      #5  0x00007ffff6720a9f in __evict_page_dirty_update (evict_flags=0, 
          ref=0x7fff38920150, session=0x7ffff48c4868)
          at ../src/evict/evict_page.c:394
      #6  __wt_evict (session=session@entry=0x7ffff48c4868, 
          ref=ref@entry=0x7fff38920150, 
          previous_state=previous_state@entry=3 '\003', flags=flags@entry=0)
          at ../src/evict/evict_page.c:219
      #7  0x00007ffff671848d in __evict_page (session=session@entry=0x7ffff48c4868, 
          is_server=is_server@entry=false) at ../src/evict/evict_lru.c:2263
      #8  0x00007ffff6719730 in __wt_cache_eviction_worker (
          session=session@entry=0x7ffff48c4868, busy=<optimized out>, 
          readonly=readonly@entry=false, pct_full=<optimized out>)
          at ../src/evict/evict_lru.c:2350
      #9  0x00007ffff66441ca in __wt_cache_eviction_check (didworkp=0x0, 
          readonly=false, busy=<optimized out>, session=0x7ffff48c4868)
          at ../src/include/cache.i:427
      #10 __cursor_enter (session=0x7ffff48c4868) at ../src/include/cursor.i:165
      #11 __cursor_func_init (cbt=0x555556593f00, reenter=<optimized out>)
          at ../src/include/cursor.i:395
      #12 0x00007ffff6647d1e in __wt_btcur_search (cbt=cbt@entry=0x555556593f00)
          at ../src/btree/bt_cursor.c:568
      #13 0x00007ffff66e6a7f in __curfile_search (cursor=0x555556593f00)
          at ../src/cursor/cur_file.c:200
      #14 0x00007ffff59103cd in workgen::ThreadRunner::op_run (this=0x555555f31cc0, 
          op=0x555555e859f8) at ../../../bench/workgen/workgen.cxx:896
      #15 0x00007ffff5910d5d in workgen::ThreadRunner::run (this=0x555555f31cc0)
          at ../../../bench/workgen/workgen.cxx:625
      #16 0x00007ffff5910f09 in workgen::thread_runner_main (arg=0x555555f31cc0)
          at ../../../bench/workgen/workgen.cxx:118
      #17 0x00007ffff77cc6db in start_thread ()
         from /lib/x86_64-linux-gnu/libpthread.so.0
      #18 0x00007ffff7b0588f in clone () from /lib/x86_64-linux-gnu/libc.so.6
      (gdb) up
      #1  0x00007ffff7a24801 in abort () from /lib/x86_64-linux-gnu/libc.so.6
      (gdb) up
      #2  0x00007ffff67559ac in __wt_abort (session=session@entry=0x7ffff48c4868)
          at ../src/os_common/os_abort.c:30
      30	    abort();
      (gdb) up
      #3  0x00007ffff667f290 in __split_multi_inmem (
          session=session@entry=0x7ffff48c4868, orig=orig@entry=0x7ffe3009cb20, 
          multi=multi@entry=0x7fff58883f90, ref=0x7fff5821d220)
          at ../src/btree/bt_split.c:1469
      1469	            WT_ASSERT(session, upd != supd->onpage_upd);
      (gdb) p upd
      $1 = (WT_UPDATE *) 0x7ffe98b1f300
      (gdb) p supd->onpage_upd
      $2 = (WT_UPDATE *) 0x7ffe98b1f300 

      This workload populates a table and then runs a couple hundred worker threads to insert/update/read, then stops after 10 seconds.  After the 10 seconds, gdb reports one or two worker threads as exited, and at that point one of the remaining ones malloc-error-aborts, assert-aborts or SEGVs.

      Here's another stack where malloc detects the error, very similar:

      double free or corruption (!prev)
      Thread 61 "python" received signal SIGABRT, Aborted.
      [Switching to Thread 0x7fff3f7fe700 (LWP 13417)]
      0x00007ffff7a22e97 in raise () from /lib/x86_64-linux-gnu/libc.so.6
      (gdb) bt
      #0  0x00007ffff7a22e97 in raise () from /lib/x86_64-linux-gnu/libc.so.6
      #1  0x00007ffff7a24801 in abort () from /lib/x86_64-linux-gnu/libc.so.6
      #2  0x00007ffff7a6d897 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
      #3  0x00007ffff7a7490a in ?? () from /lib/x86_64-linux-gnu/libc.so.6
      #4  0x00007ffff7a7be84 in free () from /lib/x86_64-linux-gnu/libc.so.6
      #5  0x00007ffff676f1c3 in __wt_free_int (session=session@entry=0x7ffff4a303f0, p_arg=p_arg@entry=0x7fff3f7fd888)
          at ../src/os_common/os_alloc.c:301
      #6  0x00007ffff6687b59 in __wt_free_update_list (session=session@entry=0x7ffff4a303f0, 
          updp=updp@entry=0x7fff4443d060) at ../src/btree/bt_discard.c:443
      #7  0x00007ffff66a5f74 in __split_multi_inmem_final (session=session@entry=0x7ffff4a303f0, 
          orig=orig@entry=0x7ffeb09b0800, multi=multi@entry=0x7fff441ebdc0) at ../src/btree/bt_split.c:1578
      #8  0x00007ffff66aee8e in __wt_split_rewrite (session=session@entry=0x7ffff4a303f0, ref=ref@entry=0x7ffe1879a060, 
          multi=0x7fff441ebdc0) at ../src/btree/bt_split.c:2280
      #9  0x00007ffff673f57d in __evict_page_dirty_update (evict_flags=0, ref=0x7ffe1879a060, session=0x7ffff4a303f0)
          at ../src/evict/evict_page.c:394
      #10 __wt_evict (session=session@entry=0x7ffff4a303f0, ref=ref@entry=0x7ffe1879a060, 
          previous_state=previous_state@entry=3 '\003', flags=flags@entry=0) at ../src/evict/evict_page.c:219
      #11 0x00007ffff673790c in __evict_page (session=session@entry=0x7ffff4a303f0, is_server=is_server@entry=false)
          at ../src/evict/evict_lru.c:2263
      #12 0x00007ffff6738a52 in __wt_cache_eviction_worker (session=session@entry=0x7ffff4a303f0, busy=<optimized out>, 
          readonly=readonly@entry=true, pct_full=<optimized out>) at ../src/evict/evict_lru.c:2350
      #13 0x00007ffff67bf94f in __wt_cache_eviction_check (didworkp=0x0, readonly=true, busy=<optimized out>, 
          session=0x7ffff4a303f0) at ../src/include/cache.i:427
      #14 __wt_txn_begin (cfg=0x7fff3f7fdb90, session=0x7ffff4a303f0) at ../src/include/txn.i:931
      #15 __session_begin_transaction (wt_session=0x7ffff4a303f0, config=<optimized out>)
          at ../src/session/session_api.c:1627
      #16 0x00007ffff5b8b386 in workgen::ThreadRunner::op_run (this=0x555555f36218, op=0x555555f0f718)
          at ../../../bench/workgen/workgen.cxx:881
      #17 0x00007ffff5b8bd5d in workgen::ThreadRunner::run (this=0x555555f36218)
          at ../../../bench/workgen/workgen.cxx:625
      #18 0x00007ffff5b8bf09 in workgen::thread_runner_main (arg=0x555555f36218)
          at ../../../bench/workgen/workgen.cxx:118
      #19 0x00007ffff77cc6db in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
      #20 0x00007ffff7b0588f in clone () from /lib/x86_64-linux-gnu/libc.so.6 

      This seems easily reproducible in the develop branch.

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            Assignee:
            chenhao.qu Chenhao Qu
            Reporter:
            donald.anderson Donald Anderson
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              Created:
              Updated:
              Resolved: