Fix intermittent shutdown SIGSEGV: reset content downloader handle in UnloadAllExtensions - #909
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ExtensionManager::Uninit() runs twice on shutdown (via AzureDeviceUpdateCoreInterface_Destroy and via ExtensionManager_Uninit). UnloadAllExtensions() dlclose'd the content downloader library but left the static _contentDownloader handle and its V2 contract flag set, so the second call did dlsym(_contentDownloader, "Cleanup") on the freed handle. glibc's do_lookup_x then walked a freed link_map and crashed intermittently with SIGSEGV inside ld.so during agent shutdown (exit-only; agent restarts fine). Reset _contentDownloader and its contract version after the dlclose loop so a repeat unload is a no-op. Root-caused from a symbolized device core. Add a regression test (Uninit twice must not reuse the handle) and fix the existing "Uninit clears ... downloader library state" test, which had asserted the buggy "not cleared" behavior. Pristine 1.4.0 bug (upstream), not introduced by the omnect port. Signed-off-by: Jan Zachmann 50990105+JanZachmann@users.noreply.github.com
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Fixes #908
What
Fix the intermittent shutdown
SIGSEGVinld.so:ExtensionManager::Uninit()runs twice at shutdown, and the second
UnloadAllExtensions()diddlsym(_contentDownloader, "Cleanup")on a content-downloader handle the firstcall had already
dlclosed.do_lookup_xthen walked a freedlink_map.Fix
Reset
_contentDownloaderand its contract version after thedlcloseloop, sothe second unload is a no-op.
Tests
Uninit()calls must not reuse the handle."Uninit clears ... downloader library state"test, whichasserted the buggy "not cleared" behaviour.
Root-caused from a symbolized core; details in the linked issue.