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| author | Frank Ch. Eigler <fche@redhat.com> | 2022-08-15 06:20:10 -0400 |
|---|---|---|
| committer | Frank Ch. Eigler <fche@redhat.com> | 2022-08-15 06:20:10 -0400 |
| commit | 31d6b1fe74ab89138b4d256742997b730dc5cba8 (patch) | |
| tree | a96f449cdd963d67a0befdce4adc76d697e96663 | |
| parent | b713edb9a7f3da8e4dd28ac69a1665ed493ca504 (diff) | |
| download | elfutils-31d6b1fe74ab89138b4d256742997b730dc5cba8.tar.gz | |
PR29474: debuginfod
Previous code sometimes confused debuginfod with concurrent queries
targeting the same RPM. One thread fetching & prefetching, the other
thread misinterpreted the sudden presence of its target file in the
fdcache as a mere unnecessary prefetch duplicate. But if it was the
other thread's target file, previous code would -skip- it completely,
resulting in a 404 error. New code allows the other thread to also
decompress the target file and return it, and still continue to its
own prefetching process for other files.
There's a performance trade-off here. Another option would be for the
other thread to check the fdcache regularly and abort its own
prefetch/fetch/prefetch loop early in case of a sudden target file
hit. That'd save CPU probably but it'd stop prefetching of later
segments of the input archive, which could save future time.
Automated testing is too time/load sensitive to attempt. Confirmed
working with Martin's stress tester.
Reported-By: Martin Liška <mliska@suse.cz>
Signed-Off-By: Frank Ch. Eigler <fche@redhat.com>
| -rw-r--r-- | debuginfod/ChangeLog | 6 | ||||
| -rw-r--r-- | debuginfod/debuginfod.cxx | 3 |
2 files changed, 8 insertions, 1 deletions
diff --git a/debuginfod/ChangeLog b/debuginfod/ChangeLog index a8b5d7f4..7cc9bcaf 100644 --- a/debuginfod/ChangeLog +++ b/debuginfod/ChangeLog @@ -1,3 +1,9 @@ +2022-08-15 Frank Ch. Eigler <fche@redhat.com> + + PR29474 + * debuginfod.cxx (handle_buildid_r_match): Don't trigger false-404's + for concurrently prefetched target files. + 2022-08-02 Josef Cejka <jcejka@suse.de> * debuginfod.cxx (groom): Don't evaluate regex unless needed. diff --git a/debuginfod/debuginfod.cxx b/debuginfod/debuginfod.cxx index a089d0bd..9245be53 100644 --- a/debuginfod/debuginfod.cxx +++ b/debuginfod/debuginfod.cxx @@ -1742,7 +1742,8 @@ handle_buildid_r_match (bool internal_req_p, if ((r == 0) && (fn != b_source1)) // stage 1 continue; - if (fdcache.probe (b_source0, fn)) // skip if already interned + if (fdcache.probe (b_source0, fn) && // skip if already interned + fn != b_source1) // but only if we'd just be prefetching, PR29474 continue; // extract this file to a temporary file |