[vlc-devel] [PATCH 1/2] compat: Workaround sendmsg bug on some ArmV8 Android devices

Rémi Denis-Courmont remi at remlab.net
Fri Mar 29 21:11:05 CET 2019

Le perjantaina 29. maaliskuuta 2019, 15.22.51 EET Hugo Beauzée-Luyssen a écrit 
> > And FWIW, I don't agree with the assessment that bugs in libc syscall
> > wrappers cannot be coded around - especially if you target only one
> > specific ISA.
> I can't see anything obviously wrong in the syscall wrapper:
> https://android.googlesource.com/platform/bionic.git/+/refs/heads/master/li
> bc/arch-arm64/syscalls/sendmsg.S But I can't say I'm fluent with Assembly
> *at all*
> I can't see anything in the libc's logs that points me to a fix there, hence
> the feeling that the issue is more on the kernel level.

Implying that you can see something wrong with the kernel code? If there was a 
sign-expansion bug in the Linux system call dispatch on AArch64, it would 
would affect a lot more system calls than just sendmsg on an old Android. If 
there was a sign-expansion bug in the sengmsg system call itself, it would 
affect all 64-bits platforms, some of which have been in broad use for longer 
than Android has even existed.

This rather questions if the alleged bug is even specific to AArch64 & sendmsg.


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