On Thu, 22 Oct 2015 17:19:28 -0400 "J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote: > Looks like there's a leak--is this something you've seen already? > > This is on my current nfsd-next, which has some other stuff too. > > --b. > > [ 819.980697] kmem_cache_destroy nfsd_file_mark: Slab cache still has objects > [ 819.981326] CPU: 0 PID: 4360 Comm: nfsd Not tainted 4.3.0-rc3-00040-ga6bca98 #360 > [ 819.981969] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140709_153950- 04/01/2014 > [ 819.982805] ffff8800738d7d30 ffff8800738d7d20 ffffffff816053ac ffff880051ee5540 > [ 819.983803] ffff8800738d7d58 ffffffff811813df ffff8800738d7d30 ffff8800738d7d30 > [ 819.984782] ffff880074fd5e00 ffffffff822f9c80 ffff88007c64cf80 ffff8800738d7d68 > [ 819.985751] Call Trace: > [ 819.985940] [<ffffffff816053ac>] dump_stack+0x4e/0x82 > [ 819.986369] [<ffffffff811813df>] kmem_cache_destroy+0xef/0x100 > [ 819.986899] [<ffffffffa00c2198>] nfsd_file_cache_shutdown+0x78/0xa0 [nfsd] > [ 819.987513] [<ffffffffa00b2c4d>] nfsd_shutdown_generic+0x1d/0x20 [nfsd] > [ 819.988100] [<ffffffffa00b2d2d>] nfsd_shutdown_net+0xdd/0x180 [nfsd] > [ 819.988656] [<ffffffffa00b2c55>] ? nfsd_shutdown_net+0x5/0x180 [nfsd] > [ 819.989218] [<ffffffffa00b2f34>] nfsd_last_thread+0x164/0x190 [nfsd] > [ 819.989770] [<ffffffffa00b2dd5>] ? nfsd_last_thread+0x5/0x190 [nfsd] > [ 819.990328] [<ffffffffa001463e>] svc_shutdown_net+0x2e/0x40 [sunrpc] > [ 819.990996] [<ffffffffa00b3936>] nfsd_destroy+0xd6/0x190 [nfsd] > [ 819.991719] [<ffffffffa00b3865>] ? nfsd_destroy+0x5/0x190 [nfsd] > [ 819.992373] [<ffffffffa00b3bb1>] nfsd+0x1c1/0x280 [nfsd] > [ 819.992960] [<ffffffffa00b39f5>] ? nfsd+0x5/0x280 [nfsd] > [ 819.993537] [<ffffffffa00b39f0>] ? nfsd_destroy+0x190/0x190 [nfsd] > [ 819.994195] [<ffffffff81098d6f>] kthread+0xef/0x110 > [ 819.994734] [<ffffffff81a7677c>] ? _raw_spin_unlock_irq+0x2c/0x50 > [ 819.995439] [<ffffffff81098c80>] ? kthread_create_on_node+0x200/0x200 > [ 819.996129] [<ffffffff81a7744f>] ret_from_fork+0x3f/0x70 > [ 819.996706] [<ffffffff81098c80>] ? kthread_create_on_node+0x200/0x200 > [ 819.998854] nfsd: last server has exited, flushing export cache > [ 820.195957] NFSD: starting 20-second grace period (net ffffffff822f9c80) > Thanks...interesting. I'll go over the refcounting again to be sure but I suspect that this might be a race between tearing down the cache and destruction of the fsnotify marks. fsnotify marks are destroyed by a dedicated thread that cleans them up after the srcu grace period settles. That's a bit of a flimsy guarantee unfortunately. We can use srcu_barrier(), but if the thread hasn't picked up the list and started destroying yet then that may not help. I'll look over that code -- maybe it's possible to use call_srcu instead, which would allow us to use srcu_barrier to wait for them all to complete. Thanks! -- Jeff Layton <jlayton@xxxxxxxxxxxxxxx> -- 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
