(2014/11/18 5:49), Dave Hansen wrote: > On 11/13/2014 06:49 AM, Masami Hiramatsu wrote: >> (2014/11/13 7:53), Dave Hansen wrote: >>> The kprobes code probably needs to be looked at here a bit more >>> carefully. This patch still respects the MAX_INSN_SIZE limit >>> there but the kprobes code does look like it might be able to >>> be a bit more strict than it currently is. >> >> Would you mean kprobes can copy shorter? Maybe, but I think current >> one is enough because it is on a cold path. >> OK, at least this looks good to me. > > As it stands now, if you happened to be decoding an instruction which is > short and it was *JUST* before a memory hole, I think it could oops the > kernel. > > This doesn't look like it is very common (or maybe even possible) in > practice.
OK, then I'll add a check whether the end address is also in kernel_text. (we've done it for the start address) > >>> Note: the v10 version of the MPX patches I just posted depends >>> on this patch. >> >> BTW, current insn decoder doesn't support MPX... That should be >> updated (add bnd* to x86-insn-map.txt) > > I think they're in there already: > >> grep -i bnd arch/x86/lib/x86-opcode-map.txt > 1a: BNDCL Ev,Gv | BNDCU Ev,Gv | BNDMOV Gv,Ev | BNDLDX Gv,Ev,Gv > 1b: BNDCN Ev,Gv | BNDMOV Ev,Gv | BNDMK Gv,Ev | BNDSTX Ev,GV,Gv > > Or were there others you were thinking of? Ah, I misunderstood that AVX512 etc... Thank you, -- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Research Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: [email protected] -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
