RFR: 8374807: Crash in MethodData::extra_data_lock()+0x0 when running -XX:+TraceDeoptimization -XX:-ProfileTraps -XX:-TieredCompilation -Xcomp -version

[SendaoYan]

On Sat, 10 Jan 2026 00:08:12 GMT, Guanqiang Han <ghan at openjdk.org> wrote:

> Please review this change. Thanks!
> 
> Description:
> 
> This change fixes a crash in Deoptimization::uncommon_trap_inner when running with -XX:+TraceDeoptimization -XX:-ProfileTraps -XX:-TieredCompilation -Xcomp.
> 
> With -XX:-ProfileTraps, create_if_missing is set to false.
> https://github.com/openjdk/jdk/blob/74faf033127ab3a5e28be75b91e662c589f81084/src/hotspot/share/runtime/deoptimization.cpp#L2121-L2122
> 
> When create_if_missing is false, new mdo can not be created when m()->method_data() return null, so get_method_data() may return null .
> https://github.com/openjdk/jdk/blob/74faf033127ab3a5e28be75b91e662c589f81084/src/hotspot/share/runtime/deoptimization.cpp#L1911-L1912
> 
> and trap_mdo can be null as a result
> https://github.com/openjdk/jdk/blob/74faf033127ab3a5e28be75b91e662c589f81084/src/hotspot/share/runtime/deoptimization.cpp#L2134-L2136
> 
> The crash happens here because trap_mdo is null
> https://github.com/openjdk/jdk/blob/74faf033127ab3a5e28be75b91e662c589f81084/src/hotspot/share/runtime/deoptimization.cpp#L2157
> 
> Fix:
> 
> The fix makes acquisition of extra_data_lock conditional on trap_mdo being non-null, preserving the required lock ordering (extra_data_lock before ttyLocker) when an MDO exists.
> 
> Test:
> 
> GHA

test/hotspot/jtreg/compiler/uncommontrap/TestPrintDiagnosticsWithoutProfileTraps.java line 29:

> 27:  * @summary Regression test for -XX:+TraceDeoptimization -XX:-ProfileTraps -XX:-TieredCompilation -Xcomp crash
> 28:  * @requires vm.debug
> 29:  * @run main/othervm -XX:+TraceDeoptimization -XX:-ProfileTraps -XX:-TieredCompilation -Xcomp compiler.uncommontrap.TestPrintDiagnosticsWithoutProfileTraps

Should we split this line to two or three lines.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29147#discussion_r2693077929