On Fri, Feb 26, 2016 at 10:07:59PM +0000, Al Viro wrote: > On Fri, Feb 26, 2016 at 10:25:21PM +0100, Dmitry Vyukov wrote: > > On Fri, Feb 26, 2016 at 10:21 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > > On Thu, Feb 25, 2016 at 04:39:27PM +0000, Al Viro wrote: > > >> Hrm... OK, seeing that you still seem to trigger those within an hour or > > >> two (and *any* of remaining WARN_ON() are serious bugs - none of the > > >> "mitigation had been triggered" remained, sorry for not making it clear), > > >> let's try this. Again, any WARN_ON triggered means that we'd caught something, > > >> whether it progresses into oops or not. > > > > > > Any news on that one? I'm going to carve fixes for understood bugs out of > > > that one and put those into tonight push, but it would be nice to sort out > > > all remaining crap lurking in that area... > > > > > > Another question: what about the very first trace you'd posted, with apparent > > > GPF at 00000050? Have you seen anything like that afterwards? > > > > No, I did not have time to retest. > > > > GPF at 00000050 was not mine, it was Mickaël's. > > Ah, OK - his is basically a forced nd->stack[] underrun, with passing a > never-assigned nd->link_inode to atime_needs_update(), so we are just > passing a contents of uninitialized stack word there and while it ends > up possible to dereference, it's not an address of struct inode and the > first attempt to follow a pointer in what would've been a struct inode > at that address (accessing inode->i_sb->s_flags) did blow up with GPF at > offsetof(struct super_block, s_flags). > > All right, so we basically have several understood ones with fixes plus > something unknown that leads to lookup_fast() returning 0 with NULL in > *inode in about an hour or two on your setup... BTW, what kind of userland are you using? The thing is, shared-subtree setups differ, and if the crap is anywhere near vfsmount handling, that could have some impact... So far I hadn't been able to trigger any of these WARN_ON(); setup here is debian/testing on 4-way KVM guest with 4Gb memory given to it running on a 6-way host (Phenom II X6 1100T, 3.3GHz, 16Gb RAM total); 4.2 with debian/stable userland on host. What's the setup on your reproducer? -- 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
