DAOS-19495 object: fix segfault on max epoch query in a transaction - #18858
Merged
Conversation
daos_obj_query_max_epoch() has neither dkey nor akey, but dc_tx_attach() cached it as a read with nr=1, so dc_tx_add_read() left dcsr_nr=1 while dcr_iods stayed NULL. The commit then crashed dereferencing dcr_iods in dc_tx_cpd_sub_reqs_size(). Record it as an object level read (nr=0) and force nr=0 whenever no dkey is given. Add DTX42 regression test. Signed-off-by: Mohamad Chaarawi <mohamad.chaarawi@hpe.com>
|
Ticket title is 'SEGV seen in DTX operation involving daos_obj_query_max_epoch' |
mchaarawi
marked this pull request as ready for review
August 13, 2026 12:46
wangshilong
previously approved these changes
Aug 13, 2026
Nasf-Fan
reviewed
Aug 14, 2026
| if (dkey == NULL) | ||
| /* Set read TS on object shard, without dkey there is no akey/iod to record. */ | ||
| if (dkey == NULL) { | ||
| nr = 0; |
Contributor
There was a problem hiding this comment.
Why need this since the patch has already checked if (qu->flags == 0) at line 3553?
Contributor
Author
There was a problem hiding this comment.
you are right, this is redundant. ill remove
Signed-off-by: Mohamad Chaarawi <mohamad.chaarawi@hpe.com>
Nasf-Fan
approved these changes
Aug 16, 2026
6 tasks
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
daos_obj_query_max_epoch() has neither dkey nor akey, but dc_tx_attach() cached it as a read with nr=1, so dc_tx_add_read() left dcsr_nr=1 while dcr_iods stayed NULL. The commit then crashed dereferencing dcr_iods in dc_tx_cpd_sub_reqs_size(). Record it as an object level read (nr=0) and force nr=0 whenever no dkey is given. Add DTX42 regression test.
Steps for the author:
After all prior steps are complete: