On Tue, 4 Sep 2012 17:23:00 +0800 Wanlong Gao <gaowanlong@xxxxxxxxxxxxxx> wrote: > POSIX said that if the file is a regular file and the value of "off" > plus "len" exceeds the offset maximum established in the open file > description associated with fildes, mmap should return EOVERFLOW. That's what POSIX says, but what does Linux do? It is important that we precisely describe and understand the behaviour change, as there is potential here to break existing applications. I'm assuming that Linux presently permits the mmap() and then generates SIGBUS if an access is attempted beyond the max file size? > /* offset overflow? */ > - if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) > - return -EOVERFLOW; > + if (off + len < off) > + return -EOVERFLOW; Well, this treats sizeof(off_t) as the "offset maximum established in the open file". But from my reading of the above excerpt, we should in fact be checking against the underlying fs's s_maxbytes? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>