Re: master c0bb1aac10: Fix reader memory leak upon error (bug#56623)

[Lars Ingebrigtsen <larsi@gnus.org>]

Mattias Engdegård <mattiase@acm.org> writes:

>     Fix reader memory leak upon error (bug#56623)
>
>     Reported by Tom Gillespie; error found by Greg Hendershott.
>
>     * src/lread.c (read_stack_reset): New.
>     (read0): Reset read stack when unwinding from an error.

I have no idea whether it's this commit or not, but fns-tests.el is
segfaulting now (and it didn't yesterday).

I haven't tried to debug any further; perhaps it's obvious what the
problem may be.

double free or corruption (!prev)
Backtrace:
../src/emacs(+0x18e2b1)[0x5556c76b12b1]
../src/emacs(+0x4846c)[0x5556c756b46c]
../src/emacs(+0x48999)[0x5556c756b999]
../src/emacs(+0x18c79d)[0x5556c76af79d]
../src/emacs(+0x18c889)[0x5556c76af889]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x14140)[0x7f7457a41140]
/lib/x86_64-linux-gnu/libc.so.6(gsignal+0x141)[0x7f74576d5ce1]
/lib/x86_64-linux-gnu/libc.so.6(abort+0x123)[0x7f74576bf537]
/lib/x86_64-linux-gnu/libc.so.6(+0x7e768)[0x7f7457718768]
/lib/x86_64-linux-gnu/libc.so.6(+0x85a5a)[0x7f745771fa5a]
/lib/x86_64-linux-gnu/libc.so.6(+0x8709c)[0x7f745772109c]
../src/emacs(+0x2a0719)[0x5556c77c3719]
../src/emacs(+0x1f7978)[0x5556c771a978]
../src/emacs(+0x228525)[0x5556c774b525]
../src/emacs(+0x229a20)[0x5556c774ca20]
../src/emacs(+0x1f8473)[0x5556c771b473]
../src/emacs(+0x22a380)[0x5556c774d380]
../src/emacs(+0x22af7e)[0x5556c774df7e]
../src/emacs(+0x23d645)[0x5556c7760645]
../src/emacs(+0x1fd737)[0x5556c7720737]
../src/emacs(+0x1fc18d)[0x5556c771f18d]
../src/emacs(+0x1fe767)[0x5556c7721767]
../src/emacs(+0x1f6cf7)[0x5556c7719cf7]
../src/emacs(+0x16d6d6)[0x5556c76906d6]
../src/emacs(+0x1f6c51)[0x5556c7719c51]
../src/emacs(+0x16cce8)[0x5556c768fce8]
../src/emacs(+0x173bb3)[0x5556c7696bb3]
../src/emacs(+0x173f2c)[0x5556c7696f2c]
../src/emacs(+0x51190)[0x5556c7574190]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xea)[0x7f74576c0d0a]
../src/emacs(+0x516ba)[0x5556c75746ba]