Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 24 Apr 2009 20:59:19 -0700
From:      Artem Belevich <fbsdlist@src.cx>
To:        Ryan Stone <rysto32@gmail.com>
Cc:        freebsd-current@freebsd.org, Ben Kelly <ben@wanderview.com>
Subject:   Re: [patch] zfs livelock and thread priorities
Message-ID:  <ed91d4a80904242059n3642a40aud55df6d1b6a1695@mail.gmail.com>
In-Reply-To: <bc2d970904241947r50576efbgc93164a9e4dd297d@mail.gmail.com>
References:  <DC9F2088-A0AF-467D-8574-F24A045ABD81@wanderview.com> <49C2CFF6.8070608@egr.msu.edu> <BDABA909-C2AE-4A55-869B-CA01BE778A82@wanderview.com> <ed91d4a80904131636u18c90474w7cdaa57bc7000e02@mail.gmail.com> <08D7DC2A-68BE-47B6-8D5D-5DE6B48F87E5@wanderview.com> <AC3C4C3F-40C6-4AF9-BAF3-2C4D1E444839@wanderview.com> <ed91d4a80904142135n429dea52o672abf51116fa707@mail.gmail.com> <ed91d4a80904241816r28531a04r2dc70fa8960d430e@mail.gmail.com> <bc2d970904241947r50576efbgc93164a9e4dd297d@mail.gmail.com>

next in thread | previous in thread | raw e-mail | index | archive | help
Ah! Indeed.

> va_list va;
> va_start(ap, fmt);
> va_copy(va, ap);
> vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, va);
> vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);

We also need va_end(va) to clear up after va_copy();

I'll give it a try.

Thanks,
--Artem



On Fri, Apr 24, 2009 at 7:47 PM, Ryan Stone <rysto32@gmail.com> wrote:
> The crash happens because vsnprintf is called twice on the same va_list.
> That's not legal.=A0 It happens to work on i386, but it will crash on amd=
64.
> The patch should instead do:
>
> va_list va;
> va_start(ap, fmt);
> va_copy(va, ap);
> vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, va);
> vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
>
> Ryan Stone
>
>



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?ed91d4a80904242059n3642a40aud55df6d1b6a1695>