[RF] Fix dangling stack normSet after xRooNode::BuildHistogram - #22932
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guitargeek wants to merge 2 commits into
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[RF] Fix dangling stack normSet after xRooNode::BuildHistogram#22932guitargeek wants to merge 2 commits into
guitargeek wants to merge 2 commits into
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Expose setProxyNormSet so that external code can make an object forget a normalization set previously passed to `getVal()`. This is needed when that set may not outlive the object (e.g. it lived on the caller's stack), since the proxies only keep a bare pointer to it. Symmetric to the already-public `RooAbsPdf::setActiveNormSet`. 🤖 Done with the help of AI.
BuildHistogram evaluates the model with a stack-local `normSet`. RooFit proxies only cache a bare pointer to the last normalization set and re-use it later (e.g. RooProduct::evaluate reads back _compRSet.nset()), so once `normSet` goes out of scope those proxies dangle into freed stack memory. A subsequent evaluation then reads it, reported by valgrind as "use of uninitialised value" in RooAbsReal::getValV (nset->uniqueId()). `sterilize()` was meant to forget the passed normSet, but in >=6.27 that code is disabled (the uniqueId invalidity check only guards `RooAbsPdf::_normSet`, not the proxy pointers) and it only walks clients, whereas getVal() propagates the normSet down to the servers of the evaluated function. Reset the proxy normSet on the whole server tree of every function we called getVal() on, before `normSet` is destroyed. 🤖 Done with the help of AI.
Test Results 23 files 23 suites 3d 14h 29m 43s ⏱️ For more details on these failures, see this check. Results for commit 79ad705. |
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BuildHistogram evaluates the model with a stack-local
normSet. RooFit proxies only cache a bare pointer to the last normalization set and re-use it later (e.g. RooProduct::evaluate reads back _compRSet.nset()), so oncenormSetgoes out of scope those proxies dangle into freed stack memory. A subsequent evaluation then reads it, reported by valgrind as "use of uninitialised value" in RooAbsReal::getValV (nset->uniqueId()).sterilize()was meant to forget the passed normSet, but in >=6.27 that code is disabled (the uniqueId invalidity check only guardsRooAbsPdf::_normSet, not the proxy pointers) and it only walks clients, whereas getVal() propagates the normSet down to the servers of the evaluated function. Reset the proxy normSet on the whole server tree of every function we called getVal() on, beforenormSetis destroyed.Thanks @TomasDado for reporting the problem!
FYI, @will-cern. If this works, I'll also submit it upstream to your xRooFit repo.