Subject: CVE-2024-42252: closures: Change BUG_ON() to WARN_ON()

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

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

The Linux kernel CVE team has assigned CVE-2024-42252 to this issue.

Affected and fixed versions
===========================

	Fixed in 6.9.11 with commit 5d85f2ab79d5
	Fixed in 6.10 with commit 339b84ab6b1d

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-42252
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	lib/closure.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/5d85f2ab79d5918a66539ebf046c099f7448db8d
	https://git.kernel.org/stable/c/339b84ab6b1d66900c27bd999271cb2ae40ce812