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Diffstat (limited to 'mailinglist/output_launchpad/1832281')
| -rw-r--r-- | mailinglist/output_launchpad/1832281 | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/mailinglist/output_launchpad/1832281 b/mailinglist/output_launchpad/1832281 new file mode 100644 index 00000000..50095875 --- /dev/null +++ b/mailinglist/output_launchpad/1832281 @@ -0,0 +1,84 @@ +tcg bug master / 4.0.0 v8 operation >>> and |= + +vm guest is linux, executed with tcg +running this Node.js snippet leads to + +$ node +> a = undefined +undefined +> a >>> 0 +4294967295 + +host node +$ node +> a = undefined +undefined +> a >>> 0 +0 + +same with |= + +node +Welcome to Node.js v12.4.0. +Type ".help" for more information. +> let buffer +undefined +> buffer |= 0 +0 + +vm with tcg: + +$ ./out/Release/node --version +v12.4.0 +./out/Release/node -e "let buffer; buffer |= 0; console.log(buffer);" +-1 + + +vm guest is debian x86_64 latest release +vm guest is started with ./x86_64-softmmu/qemu-system-x86_64 -vnc :0 -cdrom debian-9.9.0-amd64-netinst.iso -m 4G -smp cores=6,threads=1,sockets=1 -nic user,hostfwd=tcp:ipv4addr:2233-:22 -cpu qemu64 debian.img + +git tag v4.0.0 and master, commit a578cdfbdd8f9beff5ced52b7826ddb1669abbbf, for building qemu-system-x86_64 was used. + +Node.js as compiled on the vm guest (v12.4.0 / master) + + +see also +https://github.com/nodejs/node/issues/19348#issuecomment-500465502 + +I need further assistance to track down the cause of the bug. + +Kind regards +Manuel + +This might be the same underlying problem as LP:1815423 which also mentions some issues with Javascript calculations involving arithmetic operations on a js "undefined" value. That bug has a C-only reproduce case so is probably a good place to start for anybody interesting in investigating and fixing it. + + +https://<email address hidden>/ is a patch which I think probably fixes this bug -- could you test it? (I don't have an x86 vm with node.js in it to test with.) + +Hi Peter, + +I will try the tag and report back. + +result: + +node +Welcome to Node.js v12.4.0. +Type ".help" for more information. +> a = undefined +undefined +> a >>> 0 +0 +> let buffer +undefined +> buffer |= 0 +0 + + +Thanks for the patch :-) + +Thanks a lot for testing it! + + +Patch had been included here: +https://git.qemu.org/?p=qemu.git;a=commitdiff;h=1e8a98b53867f61da9c + |