Date: Fri, 22 May 2020 17:32:37 +0200 From: Paul Floyd <pjfloyd@wanadoo.fr> To: FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: SIGBUS si_code 12 Message-ID: <679A6BE4-E344-49D0-B76D-DB65A41E26FA@wanadoo.fr> In-Reply-To: <068F2B99-24C2-4F38-ACC1-02273C198434@wanadoo.fr> References: <2102917207.11671.1589487524169.JavaMail.www@wwinf1n11> <490544208.11847.1589489181927.JavaMail.www@wwinf1n11> <20200514224347.GB46537@kib.kiev.ua> <9840EA0E-CF11-4332-A5A0-A3CDBA0F0464@wanadoo.fr> <20200521154621.GB85681@raichu> <068F2B99-24C2-4F38-ACC1-02273C198434@wanadoo.fr>
next in thread | previous in thread | raw e-mail | index | archive | help
A bit more on this.
The code in question is in trap.c:
if (signo =3D=3D SIGSEGV) {
ucode =3D SEGV_MAPERR;
} else if (prot_fault_translation =3D=3D 0) {
/*
* Autodetect. This check also covers
* the images without the ABI-tag ELF
* note.
*/
if (SV_CURPROC_ABI() =3D=3D =
SV_ABI_FREEBSD &&
p->p_osrel >=3D P_OSREL_SIGSEGV) {
signo =3D SIGSEGV;
ucode =3D SEGV_ACCERR;
} else {
signo =3D SIGBUS;
ucode =3D T_PAGEFLT;
}
} else if (prot_fault_translation =3D=3D 1) {
/*
* Always compat mode.
*/
signo =3D SIGBUS;
ucode =3D T_PAGEFLT;
} else {
/*
* Always SIGSEGV mode.
*/
signo =3D SIGSEGV;
ucode =3D SEGV_ACCERR;
}
I have machte.prot_fault_translation set to 0 (the default I believe) so =
this enters the first =E2=80=98else if=E2=80=99 branch.
The value of p_osrel looks like it comes from retold.c. I see two =
mechanisms - passed via auxv AT_OSRELDATE (with a backup of using a =
sysctl) and reading the NT_FREEBSD_ABI_TAG note - I=E2=80=99m not sure =
which is used in this case.
The auxv value seems to be sent and I can=E2=80=99t see why either =
should be failing.
A+
Paul
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?679A6BE4-E344-49D0-B76D-DB65A41E26FA>