On Thu, Feb 23, 2017 at 11:42 AM, Xiong Zhou <xzhou@xxxxxxxxxx> wrote: > Lower dir comes from another overlayfs dir, then > accessing files in it should work. > > CC: Miklos Szeredi <mszeredi@xxxxxxxxxx> > Signed-off-by: Xiong Zhou <xzhou@xxxxxxxxxx> > --- FYI, this test triggers a false positive lockdep splat. I did not notice it earlier, because I carry a fix patch that Miklos did not pick up yet. The fix patch is here: http://www.spinics.net/lists/linux-unionfs/msg01428.html overlay/029 [08:14:06] ============================================= [ INFO: possible recursive locking detected ] 4.9.0-debug-12264-g60ae0f1 #426 Not tainted --------------------------------------------- cat/3367 is trying to acquire lock: (&sb->s_type->i_mutex_key#15){.+.+.+}, at: [<ffffffff81217858>] lookup_slow+0x81/0x185 but task is already holding lock: (&sb->s_type->i_mutex_key#15){.+.+.+}, at: [<ffffffff8121b955>] do_last+0x179/0x608 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&sb->s_type->i_mutex_key#15); lock(&sb->s_type->i_mutex_key#15); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by cat/3367: #0: (&sb->s_type->i_mutex_key#15){.+.+.+}, at: [<ffffffff8121b955>] do_last+0x179/0x608 stack backtrace: CPU: 0 PID: 3367 Comm: cat Not tainted 4.9.0-debug-12264-g60ae0f1 #426 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0x85/0xbe __lock_acquire+0x1082/0x153f ? mark_held_locks+0x5e/0x74 lock_acquire+0x13b/0x1d6 ? lock_acquire+0x13b/0x1d6 ? lookup_slow+0x81/0x185 down_read+0x43/0x9a ? lookup_slow+0x81/0x185 lookup_slow+0x81/0x185 lookup_one_len_unlocked+0xca/0xdc ovl_lookup_single+0x30/0x2c6 ? ovl_lookup+0x158/0x414 ovl_lookup_layer+0x46/0x137 ovl_lookup+0x1b5/0x414 ? __d_lookup+0x22a/0x23c lookup_open+0x44c/0x622 ? lookup_open+0x44c/0x622 ? rwsem_down_read_failed+0x25/0x164 do_last+0x196/0x608 ? path_init+0x2d9/0x681 path_openat+0x285/0x30c ? __might_fault+0x37/0x84 do_filp_open+0x4d/0xa3 ? sched_clock+0x9/0xd ? __alloc_fd+0x1af/0x1c1 ? _raw_spin_unlock+0x27/0x31 do_sys_open+0x13c/0x1cb ? do_sys_open+0x13c/0x1cb SyS_open+0x1e/0x20 entry_SYSCALL_64_fastpath+0x1f/0xc2 RIP: 0033:0x7f253e9d7960 RSP: 002b:00007fff5caeba48 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007fff5caebca8 RCX: 00007f253e9d7960 RDX: 0000000000020000 RSI: 0000000000000000 RDI: 00007fff5caee235 RBP: 0000000000001000 R08: 0000000000000000 R09: 0000000000000000 R10: 00007fff5caeb810 R11: 0000000000000246 R12: 00000000004025a6 R13: 00007fff5caebca0 R14: 0000000000000000 R15: 0000000000000000 [08:14:07] 1s -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
