On Sat, 22 Dec 2018 10:12:44 -0500 Steven Rostedt <rost...@goodmis.org> wrote:
> On Sat, 22 Dec 2018 23:24:11 +0900 > Namhyung Kim <namhy...@kernel.org> wrote: > > > > No, because we don't know the length of str. > > > > > > > > > [ str = "h\0[bad memory]" ] > > > > I don't know what's the bad memory causing memory fault but anyway What I meant by that is if a string is allocated at a end of a page, and the next page is marked as not present. A read into that page will cause a page fault, and since memcmp() does not stop at the '\0' it will read into that not-present memory and trigger a fault, and that read wont be in the exception table, and it will then BUG. > > memcpy() should stop at the NUL character first as it's different, no? > > No, that's the difference between memcpy() and strncpy(), memcpy() > doesn't care about nul characters. It's copying memory not strings. I think we both meant s/cpy/cmp/ ;-) -- Steve
