On Fri, 2009-03-06 at 21:08 +0530, Balbir Singh wrote: > * Nick Piggin <npiggin@xxxxxxx> [2009-03-05 08:00:45]: > > > On Wed, Mar 04, 2009 at 06:41:15PM +0100, Ingo Molnar wrote: > > > > > > * Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > > > > > > On Wed, 2009-03-04 at 18:27 +0530, Balbir Singh wrote: > > > > > I see the following on my machine. My understanding is that the > > > > > lockdep warning is complaining about a potential deadlock while > > > > > reclaiming, where we could end up waiting on holding inotify_mutex, > > > > > and we could end up calling reclaim with inotify_mutex held. > > > > > > > > > > The race seems rare, since one path shows a new inode being created > > > > > and the other one being deleted. It seems like a false positive unless > > > > > the inode's in question turn out to be potentially the same. > > > > > > > > Its not a false positive until you can guarantee the inodes will _never_ > > > > be the same. > > > > > > > > This thing has been reported numerous times, Ingo even posted > > > > a potential fix for it, Nick poked the inotify people to speak > > > > up, but they have so far been silent on the issue :-( > > > > > > that particular fix is upstream, via: > > > > > > 3023a3e: inotify: fix GFP_KERNEL related deadlock > > > > > > so does this reproduce with latest .29-rc7-ish kernels too - or > > > do we have some other problem in this area too? > > > > Well as I said, I think it is just a bandaid to shut up lockdep, > > because I think inotify always is guaranteed to have a ref on > > the inode at this point so it should not be subject to reclaim. > > I got dropped from the cc and thus could not respond earlier. The > problem can be seen even in 2.6.29-rc7-mm1. Ok, I'll take a look at it this afternoon. Sadly I know those allocations and object lifetimes all to well now. -Eric -- 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
