The commit 5149cbac4235: "locking/rwsem: Add DEBUG_RWSEMS to look for lock/unlock emismatches" (newly added in this merge window) will cause xfstests tests failures in generic/068 for all file systems. This is because the freeze and thaw ioctls, by design, are run in different processes. It looks like the concern for why CONFIG_DEBUG_RWSEMS was added is because read/write semaphores can spin --- which if the case, we need to make sure that (a) the spinlock code path is not used for the freeze/thaw ioctls, and (b) we don't trigger the debug WARN_ON. Cheers, - Ted generic/068 [08:52:46][ 24.807316] run fstests generic/068 at 2018-04-04 08:52:46 [ 25.444734] ------------[ cut here ]------------ [ 25.446991] DEBUG_LOCKS_WARN_ON(sem->owner != get_current()) [ 25.447017] WARNING: CPU: 0 PID: 1302 at /usr/projects/linux/ext4/kernel/locking/rwsem.c:133 up_write+0x113/0x150 [ 25.453885] CPU: 0 PID: 1302 Comm: xfs_io Not tainted 4.16.0-rc7-xfstests-00114-g5149cbac4235 #130 [ 25.457294] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 25.460534] RIP: 0010:up_write+0x113/0x150 [ 25.462096] RSP: 0018:ffff88006504fd30 EFLAGS: 00010282 [ 25.464061] RAX: dffffc0000000008 RBX: ffff880068ab2af8 RCX: ffffffff89a28dde [ 25.466724] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000293 [ 25.469543] RBP: ffff880068ab2b60 R08: fffffbfff179d951 R09: fffffbfff179d951 [ 25.472608] R10: ffff88007ffca010 R11: fffffbfff179d950 R12: ffff880068ab27a0 [ 25.475331] R13: ffff880068ab24f0 R14: ffff880068ab2ca0 R15: ffffffff89cf4d47 [ 25.478000] FS: 0000000001665880(0000) GS:ffff88006d400000(0000) knlGS:0000000000000000 [ 25.481025] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 25.483216] CR2: 000000000166a018 CR3: 00000000696e8000 CR4: 00000000000006f0 [ 25.485900] Call Trace: [ 25.487035] percpu_up_write+0x4c/0x60 [ 25.488532] thaw_super+0x1c4/0x250 [ 25.489904] do_vfs_ioctl+0xe14/0xfb0 [ 25.491296] ? ioctl_preallocate+0x1a0/0x1a0 [ 25.492860] ? _copy_to_user+0x9d/0xc0 [ 25.494179] ? SyS_sysinfo+0x82/0xc0 [ 25.495500] ? SyS_getcpu+0x120/0x120 [ 25.496815] SyS_ioctl+0x43/0x80 [ 25.497944] ? do_vfs_ioctl+0xfb0/0xfb0 [ 25.499268] do_syscall_64+0x1a0/0x640 [ 25.500566] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 25.502038] RIP: 0033:0x45d4c7 [ 25.502901] RSP: 002b:00007ffe95712ff8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 25.505362] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 000000000045d4c7 [ 25.507286] RDX: 00007ffe9571300c RSI: ffffffffc0045878 RDI: 0000000000000003 [ 25.509408] RBP: 0000000001669290 R08: 0000000000000000 R09: 0000000000000000 [ 25.511525] R10: 0000000000434cc0 R11: 0000000000000246 R12: 0000000000000001 [ 25.513404] R13: 0000000001669270 R14: 000000000166a2d0 R15: 0000000001669270 [ 25.515260] Code: 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 48 8b 05 64 84 c2 03 85 c0 75 86 48 c7 c6 20 2a 66 8b 48 c7 c7 e0 29 66 8b e8 ed 07 f2 ff <0f> 0b e9 6c ff ff ff e8 41 74 2d 00 e9 2a ff ff ff 48 89 ef e8 [ 25.520602] ---[ end trace 28e00b42ae928cb1 ]---
