Subject: CVE-2024-47696: RDMA/iwcm: Fix WARNING:at_kernel/workqueue.c:#check_flush_dependency

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

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

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

RDMA/iwcm: Fix WARNING:at_kernel/workqueue.c:#check_flush_dependency

In the commit aee2424246f9 ("RDMA/iwcm: Fix a use-after-free related to
destroying CM IDs"), the function flush_workqueue is invoked to flush the
work queue iwcm_wq.

But at that time, the work queue iwcm_wq was created via the function
alloc_ordered_workqueue without the flag WQ_MEM_RECLAIM.

Because the current process is trying to flush the whole iwcm_wq, if
iwcm_wq doesn't have the flag WQ_MEM_RECLAIM, verify that the current
process is not reclaiming memory or running on a workqueue which doesn't
have the flag WQ_MEM_RECLAIM as that can break forward-progress guarantee
leading to a deadlock.

The call trace is as below:

[  125.350876][ T1430] Call Trace:
[  125.356281][ T1430]  <TASK>
[ 125.361285][ T1430] ? __warn (kernel/panic.c:693)
[ 125.367640][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9))
[ 125.375689][ T1430] ? report_bug (lib/bug.c:180 lib/bug.c:219)
[ 125.382505][ T1430] ? handle_bug (arch/x86/kernel/traps.c:239)
[ 125.388987][ T1430] ? exc_invalid_op (arch/x86/kernel/traps.c:260 (discriminator 1))
[ 125.395831][ T1430] ? asm_exc_invalid_op (arch/x86/include/asm/idtentry.h:621)
[ 125.403125][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9))
[ 125.410984][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9))
[ 125.418764][ T1430] __flush_workqueue (kernel/workqueue.c:3970)
[ 125.426021][ T1430] ? __pfx___might_resched (kernel/sched/core.c:10151)
[ 125.433431][ T1430] ? destroy_cm_id (drivers/infiniband/core/iwcm.c:375) iw_cm
[ 125.441209][ T1430] ? __pfx___flush_workqueue (kernel/workqueue.c:3910)
[ 125.473900][ T1430] ? _raw_spin_lock_irqsave (arch/x86/include/asm/atomic.h:107 include/linux/atomic/atomic-arch-fallback.h:2170 include/linux/atomic/atomic-instrumented.h:1302 include/asm-generic/qspinlock.h:111 include/linux/spinlock.h:187 include/linux/spinlock_api_smp.h:111 kernel/locking/spinlock.c:162)
[ 125.473909][ T1430] ? __pfx__raw_spin_lock_irqsave (kernel/locking/spinlock.c:161)
[ 125.482537][ T1430] _destroy_id (drivers/infiniband/core/cma.c:2044) rdma_cm
[ 125.495072][ T1430] nvme_rdma_free_queue (drivers/nvme/host/rdma.c:656 drivers/nvme/host/rdma.c:650) nvme_rdma
[ 125.505827][ T1430] nvme_rdma_reset_ctrl_work (drivers/nvme/host/rdma.c:2180) nvme_rdma
[ 125.505831][ T1430] process_one_work (kernel/workqueue.c:3231)
[ 125.515122][ T1430] worker_thread (kernel/workqueue.c:3306 kernel/workqueue.c:3393)
[ 125.515127][ T1430] ? __pfx_worker_thread (kernel/workqueue.c:3339)
[ 125.531837][ T1430] kthread (kernel/kthread.c:389)
[ 125.539864][ T1430] ? __pfx_kthread (kernel/kthread.c:342)
[ 125.550628][ T1430] ret_from_fork (arch/x86/kernel/process.c:147)
[ 125.558840][ T1430] ? __pfx_kthread (kernel/kthread.c:342)
[ 125.558844][ T1430] ret_from_fork_asm (arch/x86/entry/entry_64.S:257)
[  125.566487][ T1430]  </TASK>
[  125.566488][ T1430] ---[ end trace 0000000000000000 ]---

The Linux kernel CVE team has assigned CVE-2024-47696 to this issue.

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

	Issue introduced in 5.10.224 with commit 94ee7ff99b87 and fixed in 5.10.227 with commit 2efe8da2ddbf
	Issue introduced in 5.15.165 with commit 557d035fe88d and fixed in 5.15.168 with commit da0392698c62
	Issue introduced in 6.1.103 with commit dc8074b8901c and fixed in 6.1.113 with commit a64f30db12bd
	Issue introduced in 6.6.44 with commit ff5bbbdee082 and fixed in 6.6.54 with commit 8b7df76356d0
	Issue introduced in 6.10.3 with commit ee39384ee787 and fixed in 6.10.13 with commit c8b18a75282c
	Issue introduced in 6.11 with commit aee2424246f9 and fixed in 6.11.2 with commit a09dc967b3c5
	Issue introduced in 6.11 with commit aee2424246f9 and fixed in 6.12-rc1 with commit 86dfdd828890
	Issue introduced in 4.19.320 with commit d91d253c87fd
	Issue introduced in 5.4.282 with commit 7f25f296fc9b

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-2024-47696
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:
	drivers/infiniband/core/iwcm.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/2efe8da2ddbf873385b4bc55366d09350b408df6
	https://git.kernel.org/stable/c/da0392698c62397c19deb1b9e9bdf2fbb5a9420e
	https://git.kernel.org/stable/c/a64f30db12bdc937c5108158d98c8eab1925c548
	https://git.kernel.org/stable/c/8b7df76356d098f85f3bd2c7cf6fb43f531893d7
	https://git.kernel.org/stable/c/c8b18a75282cfd27822a8cc3c1f005c1ac8d1a58
	https://git.kernel.org/stable/c/a09dc967b3c58899e259c0aea092f421d22a0b04
	https://git.kernel.org/stable/c/86dfdd8288907f03c18b7fb462e0e232c4f98d89