CVS commit: [netbsd-7-0] src/sys/arch

["Soren Jacobsen" <snj%netbsd.org@localhost>]

Module Name:    src
Committed By:   snj
Date:           Sat Mar 25 16:59:01 UTC 2017

Modified Files:
        src/sys/arch/amd64/amd64 [netbsd-7-0]: trap.c
        src/sys/arch/i386/i386 [netbsd-7-0]: trap.c

Log Message:
Pull up following revision(s) (requested by maxv in ticket #1391):
        sys/arch/amd64/amd64/trap.c: revision 1.94
        sys/arch/i386/i386/trap.c: revision 1.287
Mmh, allow iret to be handled when an #SS fault (T_STKFLT) happens. Even
if the sdm is far from being clear, it appears that iret can trigger an #SS
fault if %ss points to a writable but non-present segment; in which case
the kernel would panic, thinking the fault was internal to it.
In particular, userland can create a broken segment in the ldt with
USER_LDT, update its %ss with setcontext and trigger the panic. I don't
think amd64 is affected since USER_LDT does not exist there, and the
changes on tf_ss seem correct - but I'm still adding T_STKFLT for safety.


To generate a diff of this commit:
cvs rdiff -u -r1.78 -r1.78.6.1 src/sys/arch/amd64/amd64/trap.c
cvs rdiff -u -r1.272 -r1.272.6.1 src/sys/arch/i386/i386/trap.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.