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  1. WiredTiger
  2. WT-4618

Don't hijack other sessions in __wt_verbose_dump_txn

    • Type: Icon: Bug Bug
    • Resolution: Fixed
    • Priority: Icon: Major - P3 Major - P3
    • WT3.2.0, 4.1.10
    • Affects Version/s: None
    • Component/s: None
    • Labels:
    • Storage Engines
    • 8
    • Storage Engines 2019-03-25

      When debugging WT-4324, I recently added a call to wt_verbose_dump_txn to dump the global txn information and the txns in each session. After doing so, many runs of the test/checkpoint test started dumping core with seg faults, assertion failures, etc.

      The most common stack looks like this:

      #0  0x00000000004d9239 in __wt_bt_read (session=0x7f3ba7762550, 
          addr=0x7f3b947d7cc0 "\200\201\344\030\332", <incomplete sequence \307>, 
          addr_size=7) at ../src/btree/bt_io.c:54
      #1  0x00000000004e6aee in __page_read (session=0x7f3ba7762550, ref=0xc5e100, 
          flags=1032) at ../src/btree/bt_read.c:496
      #2  0x00000000004e745d in __wt_page_in_func (session=0x7f3ba7762550, 
          ref=0xc5e100, flags=1032, func=0x5da610 <__func__.33775> "__wt_row_search", 
          line=453) at ../src/btree/bt_read.c:672
      #3  0x000000000051a773 in __wt_page_swap_func (session=0x7f3ba7762550, 
          held=0xc54d48, want=0xc5e100, flags=1024, 
          func=0x5da610 <__func__.33775> "__wt_row_search", line=453)
          at ../src/include/btree.i:1702
      #4  0x000000000051bdc1 in __wt_row_search (session=0x7f3ba7762550, 
          srch_key=0xc84550, leaf=0x0, cbt=0xc84450, insert=true, restore=false)
          at ../src/btree/row_srch.c:452
      #5  0x00000000004ca96e in __cursor_row_search (session=0x7f3ba7762550, 
          cbt=0xc84450, leaf=0x0, insert=true) at ../src/btree/bt_cursor.c:397
      (gdb) p dsk
      $1 = (const WT_PAGE_HEADER *) 0x0

      I will attach the tiny diff that causes the problem and a script to reproduce it. I have been running on kodkod.

        1. 4618.diff
          0.6 kB
        2. rckpt.sh
          0.7 kB

            michael.cahill@mongodb.com Michael Cahill (Inactive)
            sue.loverso@mongodb.com Susan LoVerso
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