Details
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Bug
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Status: Closed (View Workflow)
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Critical
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Resolution: Fixed
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10.6.16, 10.10.7, 10.11.6, 11.0.4, 11.1.3, 11.2.2, 10.6.17, 10.11.7
Description
While the testing of MDEV-33588, mleich encountered an rr replay trace where the purge_coordinator_task is trying to parse arbitrary data in the middle of an undo log record. I narrowed it down to the following code in purge_sys_t::choose_next_log():
const trx_undo_rec_t *undo_rec= |
trx_undo_page_get_first_rec(b, hdr_page_no, hdr_offset);
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Here, b is undo log page 13, and hdr_page_no and hdr_offset are related to that. I think that we would benefit from some testing with the following patch to catch the root cause of the corruption sooner:
@@ -134,8 +134,9 @@ trx_undo_page_get_first_rec(const buf_block_t *block, uint32_t page_no,
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uint16_t offset)
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{
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uint16_t start= trx_undo_page_get_start(block, page_no, offset);
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- return start == trx_undo_page_get_end(block, page_no, offset)
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- ? nullptr : block->page.frame + start;
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+ uint16_t end= trx_undo_page_get_end(block, page_no, offset);
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+ ut_ad(start <= end);
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+ return start >= end ? nullptr : block->page.frame + start;
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}
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/** Get the last undo log record on a page. |
In the trace that I analyzed, we would be reading an invalid start value that points outside the page frame.
Attachments
Issue Links
- is caused by
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- Closed
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- relates to
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- Needs Feedback
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- Closed
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