qemu commit 80422b0: tcg.c crash in temp_load

[Alberto Ortega]

As discussed in #1803160 I'm opening a new ticket for the new bug.

QEMU version:
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qemu from git, master branch commit 80422b00196a7af4c6efb628fae0ad8b644e98af

Summary:
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TCG crashes in i386 and x86_64 when it tries to execute some specific illegal instructions. When running full OS emulation, both the guest system and QEMU crash.

$ qemu-i386 tcg_crash1.elf
/home/alberto/Documents/qemu/tcg/tcg.c:2863: tcg fatal error
qemu: uncaught target signal 11 (Segmentation fault) - core dumped
zsh: segmentation fault (core dumped) ./qemu/build/i386-linux-user/qemu-i386 tcg_crash1.elf

Invalid instructions:

f0 invalid
40 inc eax
a7 cmpsd dword [esi], dword ptr es:[edi]
48 dec eax

Testcase:
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Find ELF file attached.

[Peter Maydell (pmaydell)]

(Still repros as of commit d37bfe142382fa82585.)

[Peter Maydell (pmaydell)]

I've sent patch https://patchwork.ozlabs.org/patch/1068003/ to the list which fixes this. (There might be other failures to check for bogus LOCK prefixes elsewhere, though.)

[Peter Maydell (pmaydell)]

The patch from comment #3 is now in git master and will be in the 4.0 release.