Subject: CVE-2024-46680: Bluetooth: btnxpuart: Fix random crash seen while removing driver

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

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

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

Bluetooth: btnxpuart: Fix random crash seen while removing driver

This fixes the random kernel crash seen while removing the driver, when
running the load/unload test over multiple iterations.

1) modprobe btnxpuart
2) hciconfig hci0 reset
3) hciconfig (check hci0 interface up with valid BD address)
4) modprobe -r btnxpuart
Repeat steps 1 to 4

The ps_wakeup() call in btnxpuart_close() schedules the psdata->work(),
which gets scheduled after module is removed, causing a kernel crash.

This hidden issue got highlighted after enabling Power Save by default
in 4183a7be7700 (Bluetooth: btnxpuart: Enable Power Save feature on
startup)

The new ps_cleanup() deasserts UART break immediately while closing
serdev device, cancels any scheduled ps_work and destroys the ps_lock
mutex.

[   85.884604] Unable to handle kernel paging request at virtual address ffffd4a61638f258
[   85.884624] Mem abort info:
[   85.884625]   ESR = 0x0000000086000007
[   85.884628]   EC = 0x21: IABT (current EL), IL = 32 bits
[   85.884633]   SET = 0, FnV = 0
[   85.884636]   EA = 0, S1PTW = 0
[   85.884638]   FSC = 0x07: level 3 translation fault
[   85.884642] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000041dd0000
[   85.884646] [ffffd4a61638f258] pgd=1000000095fff003, p4d=1000000095fff003, pud=100000004823d003, pmd=100000004823e003, pte=0000000000000000
[   85.884662] Internal error: Oops: 0000000086000007 [#1] PREEMPT SMP
[   85.890932] Modules linked in: algif_hash algif_skcipher af_alg overlay fsl_jr_uio caam_jr caamkeyblob_desc caamhash_desc caamalg_desc crypto_engine authenc libdes crct10dif_ce polyval_ce polyval_generic snd_soc_imx_spdif snd_soc_imx_card snd_soc_ak5558 snd_soc_ak4458 caam secvio error snd_soc_fsl_spdif snd_soc_fsl_micfil snd_soc_fsl_sai snd_soc_fsl_utils gpio_ir_recv rc_core fuse [last unloaded: btnxpuart(O)]
[   85.927297] CPU: 1 PID: 67 Comm: kworker/1:3 Tainted: G           O       6.1.36+g937b1be4345a #1
[   85.936176] Hardware name: FSL i.MX8MM EVK board (DT)
[   85.936182] Workqueue: events 0xffffd4a61638f380
[   85.936198] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[   85.952817] pc : 0xffffd4a61638f258
[   85.952823] lr : 0xffffd4a61638f258
[   85.952827] sp : ffff8000084fbd70
[   85.952829] x29: ffff8000084fbd70 x28: 0000000000000000 x27: 0000000000000000
[   85.963112] x26: ffffd4a69133f000 x25: ffff4bf1c8540990 x24: ffff4bf215b87305
[   85.963119] x23: ffff4bf215b87300 x22: ffff4bf1c85409d0 x21: ffff4bf1c8540970
[   85.977382] x20: 0000000000000000 x19: ffff4bf1c8540880 x18: 0000000000000000
[   85.977391] x17: 0000000000000000 x16: 0000000000000133 x15: 0000ffffe2217090
[   85.977399] x14: 0000000000000001 x13: 0000000000000133 x12: 0000000000000139
[   85.977407] x11: 0000000000000001 x10: 0000000000000a60 x9 : ffff8000084fbc50
[   85.977417] x8 : ffff4bf215b7d000 x7 : ffff4bf215b83b40 x6 : 00000000000003e8
[   85.977424] x5 : 00000000410fd030 x4 : 0000000000000000 x3 : 0000000000000000
[   85.977432] x2 : 0000000000000000 x1 : ffff4bf1c4265880 x0 : 0000000000000000
[   85.977443] Call trace:
[   85.977446]  0xffffd4a61638f258
[   85.977451]  0xffffd4a61638f3e8
[   85.977455]  process_one_work+0x1d4/0x330
[   85.977464]  worker_thread+0x6c/0x430
[   85.977471]  kthread+0x108/0x10c
[   85.977476]  ret_from_fork+0x10/0x20
[   85.977488] Code: bad PC value
[   85.977491] ---[ end trace 0000000000000000 ]---

Preset since v6.9.11

The Linux kernel CVE team has assigned CVE-2024-46680 to this issue.

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

	Issue introduced in 6.4 with commit 86d55f124b52 and fixed in 6.6.49 with commit 662a55986b88
	Issue introduced in 6.4 with commit 86d55f124b52 and fixed in 6.10.8 with commit 29a1d9971e38
	Issue introduced in 6.4 with commit 86d55f124b52 and fixed in 6.11 with commit 35237475384a

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-2024-46680
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/bluetooth/btnxpuart.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/662a55986b88807da4d112d838c8aaa05810e938
	https://git.kernel.org/stable/c/29a1d9971e38f92c84b363ff50379dd434ddfe1c
	https://git.kernel.org/stable/c/35237475384ab3622f63c3c09bdf6af6dacfe9c3