On Sat, Dec 24, 2011 at 04:50:12PM -0500, J. Bruce Fields wrote: > locks: fix null dereference on lease-break failure path > > Commit 778fc546f749c588aa2f6cd50215d2715c374252 "locks: fix tracking of > inprogress lease breaks" introduced a null dereference on failure to > allocate memory. > > This means an open (without O_NONBLOCK set) on a file with a lease > applied (generally only done when Samba or nfsd (with v4) is running) > could crash if a kmalloc() fails. NULL? AFAICS, lease_alloc() returns ERR_PTR() on failure... I really don't like the look of that code, TBH - at the very least it needs to be commented a lot. E.g. the rules for calling or not calling ->lm_break() are really not obvious - AFAICS, we do that if i_have_this_lease || (mode & O_NONBLOCK) is true *or* if allocation has succeeded. The former condition is what'll end up with -EWOULDBLOCK; I can understand not wanting to return that in preference to -ENOMEM, but... Do we want to skip ->lm_break() stuff only in case of allocation failures that won't be overridden by -EWOULDBLOCK? -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
