RFR: 8256594: Unexpected warning: SIGSEGV handler flags expected:SA_RESTART|SA_SIGINFO found:SA_RESTART|SA_SIGINFO

[David Holmes]

On Thu, 19 Nov 2020 10:33:39 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> In the recent POSIX signal code cleanup (JDK-8253742) I misunderstood the role of the SIGNIFICANT_SIGNAL_MASK and removing its application causes -Xcheck:jni to report errors with the signal handler due to an unexpected bit in the sigaction.sa_flags field.
>> 
>> This fix restores the masking of that flag, for Linux only, and more clearly indicating what it is. I also augmented the flag printing code to show when an unexpected flag is present (and so avoid the mysterious "expected X found X" message).
>> 
>> See bug report for more details.
>> 
>> Thanks.
>
> LGTM.
> 
> Note that a maybe more elegant approach - avoiding the double definition of known flags - would have been, in the print loop, to store the checked flags in a mask. And then test for ~mask at the final step.
> 
> The numeric comparison of flags in check_jni - which requires this SA_RESTORER_FLAG_MASK workaround - is a bit grating. Would have been better to compare just known flags. But this is old coding.
> 
> All idle nitpicking :) Patch is fine.
> 
> ..Thomas

Can I get a second review ASAP please as this is causing quite a bit of noise in the testing.
Thanks.

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PR: https://git.openjdk.java.net/jdk/pull/1309