closures: Change BUG_ON() to WARN_ON()

In the Linux kernel, the following vulnerability has been resolved:

closures: Change BUG_ON() to WARN_ON()

If a BUG_ON() can be hit in the wild, it shouldn't be a BUG_ON()

For reference, this has popped up once in the CI, and we'll need more

info to debug it:

03240 ------------[ cut here ]------------

03240 kernel BUG at lib/closure.c:21!

03240 kernel BUG at lib/closure.c:21!

03240 Internal error: Oops - BUG: 00000000f2000800 [#1] SMP

03240 Modules linked in:

03240 CPU: 15 PID: 40534 Comm: kworker/u80:1 Not tainted 6.10.0-rc4-ktest-ga56da69799bd #25570

03240 Hardware name: linux,dummy-virt (DT)

03240 Workqueue: btree_update btree_interior_update_work

03240 pstate: 00001005 (nzcv daif -PAN -UAO -TCO -DIT +SSBS BTYPE=--)

03240 pc : closure_put+0x224/0x2a0

03240 lr : closure_put+0x24/0x2a0

03240 sp : ffff0000d12071c0

03240 x29: ffff0000d12071c0 x28: dfff800000000000 x27: ffff0000d1207360

03240 x26: 0000000000000040 x25: 0000000000000040 x24: 0000000000000040

03240 x23: ffff0000c1f20180 x22: 0000000000000000 x21: ffff0000c1f20168

03240 x20: 0000000040000000 x19: ffff0000c1f20140 x18: 0000000000000001

03240 x17: 0000000000003aa0 x16: 0000000000003ad0 x15: 1fffe0001c326974

03240 x14: 0000000000000a1e x13: 0000000000000000 x12: 1fffe000183e402d

03240 x11: ffff6000183e402d x10: dfff800000000000 x9 : ffff6000183e402e

03240 x8 : 0000000000000001 x7 : 00009fffe7c1bfd3 x6 : ffff0000c1f2016b

03240 x5 : ffff0000c1f20168 x4 : ffff6000183e402e x3 : ffff800081391954

03240 x2 : 0000000000000001 x1 : 0000000000000000 x0 : 00000000a8000000

03240 Call trace:

03240 closure_put+0x224/0x2a0

03240 bch2_check_for_deadlock+0x910/0x1028

03240 bch2_six_check_for_deadlock+0x1c/0x30

03240 six_lock_slowpath.isra.0+0x29c/0xed0

03240 six_lock_ip_waiter+0xa8/0xf8

03240 __bch2_btree_node_lock_write+0x14c/0x298

03240 bch2_trans_lock_write+0x6d4/0xb10

03240 __bch2_trans_commit+0x135c/0x5520

03240 btree_interior_update_work+0x1248/0x1c10

03240 process_scheduled_works+0x53c/0xd90

03240 worker_thread+0x370/0x8c8

03240 kthread+0x258/0x2e8

03240 ret_from_fork+0x10/0x20

03240 Code: aa1303e0 d63f0020 a94363f7 17ffff8c (d4210000)

03240 ---[ end trace 0000000000000000 ]---

03240 Kernel panic - not syncing: Oops - BUG: Fatal exception

03240 SMP: stopping secondary CPUs

03241 SMP: failed to stop secondary CPUs 13,15

03241 Kernel Offset: disabled

03241 CPU features: 0x00,00000003,80000008,4240500b

03241 Memory Limit: none

03241 ---[ end Kernel panic - not syncing: Oops - BUG: Fatal exception ]---

03246 ========= FAILED TIMEOUT copygc_torture_no_checksum in 7200s