On Mon, Feb 05, 2024 at 11:11:06AM +0000, Richard Purdie wrote:
> On Mon, 2024-02-05 at 13:05 +1000, Richard Henderson wrote:
> > On 1/26/24 23:52, Richard Purdie wrote:
> > > On Fri, 2024-01-26 at 16:33 +0300, Michael Tokarev wrote:
> > > > 26.01.2024 16:03, Richard Purdie wrote:
> > > > > I've run into a problem with this change.
> > > > >
> > > > > We (Yocto Project) upgraded to qemu 8.2.0 recently and after that we
> > > > > started seeing errors cross compiling webkitgtk on x86_64 for x86_64
> > > > > during the introspection code which runs under user mode qemu.
> > > >
> > > > Besides your observations, please be aware there's quite a few issues
> > > > in 8.2.0.
> > > > Please take a look at
> > > > https://gitlab.com/mjt0k/qemu/-/commits/staging-8.2/
> > > > (and https://gitlab.com/qemu-project/qemu/-/commits/staging-8.2/ which
> > > > is updated
> > > > less often) for fixes already queued up, if you haven't looked there
> > > > already.
> > > > 8.2.1 stable/bugfix release is scheduled for the beginning of the next
> > > > week.
> > >
> > > Thanks.
> > >
> > > I should note that I did test the staging-8.2 branch and nothing there
> > > helped. The issue was also present with master as of yesterday.
> > >
> > > https://bugzilla.yoctoproject.org/show_bug.cgi?id=15367 is Yocto
> > > Projects tracking of the issue which has the commits for master and
> > > staging-8.2 that I tested.
> >
> > The yocto logs referenced here are not helpful for reproducing the problem.
>
> It took me a couple of days I didn't have to workout which commit
> caused it, which versions showed the issue and how to work around it.
>
> It looks host kernel specific since it doesn't happen on some systems
> so even with the binaries/command/environment vars, it may not be
> enough.
>
> I was hoping the indication of the cause might help point to the fix as
> there is quite a bit of work in trying to extract this into a
> reproducer. The failure is 20 mins into a webkitgtk compile on a remote
> CI system which no longer has the context on it.
>
> > Please extract a binary to run, inputs, and command-line.
>
> I wish I could say that to the bug reports I get! :)
>
> I'll do my best but finding the time is going to be a challenge.
>
> Cheers,
>
> Richard
I just ran into a similar crash and could reproduce it with
5005aed8a7e7 alpha-linux-user as follows:
#include <fcntl.h>
#include <sys/shm.h>
int main(void)
{
shmat(shmget(IPC_PRIVATE, 1836016, IPC_CREAT | 0600), (void
*)0x20000804000, 0);
open("/proc/self/maps", O_RDONLY);
}
Apparently an mmap() is missing for shmat() when g>h and shmaddr is
specified. The mismatch between the host's and the guest's view of the
mapping's tail appears to be causing the SEGV.
