CVE-2026-64429: gpio: eic-sprd: use raw_spinlock_t in the irq startup path

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

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

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

gpio: eic-sprd: use raw_spinlock_t in the irq startup path

sprd_eic_irq_unmask() enables the GPIO IRQ and then updates controller
state through sprd_eic_update(), which takes sprd_eic->lock with
spin_lock_irqsave().  The callback can be reached from irq_startup()
while setting up a requested IRQ.  That path is not sleepable, but on
PREEMPT_RT a regular spinlock_t becomes a sleeping lock.

This issue was found by our static analysis tool and then manually
reviewed against the current tree.

The grounded PoC kept the request_threaded_irq() -> __setup_irq() ->
irq_startup() -> sprd_eic_irq_unmask() -> sprd_eic_update() carrier and
used the original spin_lock_irqsave(&sprd_eic->lock) edge.  Lockdep

  BUG: sleeping function called from invalid context
  hardirqs last disabled at ... __setup_irq.constprop.0 ... [vuln_msv]
  sprd_rt_spin_lock_irqsave+0x1c/0x30 [vuln_msv]
  sprd_eic_update.constprop.0+0x48/0x90 [vuln_msv]
  sprd_eic_irq_unmask.constprop.0+0x35/0x50 [vuln_msv]
  __setup_irq.constprop.0+0xd/0x30 [vuln_msv]

Convert the Spreadtrum EIC controller lock to raw_spinlock_t.  The
locked section only serializes MMIO register updates and does not contain
sleepable operations, so keeping it non-sleeping is appropriate for the
irqchip callbacks.

The Linux kernel CVE team has assigned CVE-2026-64429 to this issue.


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

	Issue introduced in 4.17 with commit 25518e024e3a6e5715d672f1daa91e1d100f7436 and fixed in 5.10.261 with commit 96612bf2712cd961dbd9b52f3a9b4ab668f57628
	Issue introduced in 4.17 with commit 25518e024e3a6e5715d672f1daa91e1d100f7436 and fixed in 5.15.212 with commit 581ac2ad001ff1128931191f249a7f2074672b7a
	Issue introduced in 4.17 with commit 25518e024e3a6e5715d672f1daa91e1d100f7436 and fixed in 6.1.178 with commit e244cd8b51001ba480f274c44dba9002813a4739
	Issue introduced in 4.17 with commit 25518e024e3a6e5715d672f1daa91e1d100f7436 and fixed in 6.6.145 with commit 19d63fd528719ce7d06d9aeb88d25b7d6478198a
	Issue introduced in 4.17 with commit 25518e024e3a6e5715d672f1daa91e1d100f7436 and fixed in 6.12.96 with commit 6112fba4150039ccd90e29f2d1b788c73ad7b3dd
	Issue introduced in 4.17 with commit 25518e024e3a6e5715d672f1daa91e1d100f7436 and fixed in 6.18.39 with commit 4750909a40da9016185e0ac991510a278cecb1e7
	Issue introduced in 4.17 with commit 25518e024e3a6e5715d672f1daa91e1d100f7436 and fixed in 7.1.4 with commit 5c3c9ec1172a4c3384b8b800b3a8896cc2c1b20e
	Issue introduced in 4.17 with commit 25518e024e3a6e5715d672f1daa91e1d100f7436 and fixed in 7.2-rc1 with commit 90f0109019e6817eb40a486671b7722d1544ae29

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-2026-64429
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/gpio/gpio-eic-sprd.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/96612bf2712cd961dbd9b52f3a9b4ab668f57628
	https://git.kernel.org/stable/c/581ac2ad001ff1128931191f249a7f2074672b7a
	https://git.kernel.org/stable/c/e244cd8b51001ba480f274c44dba9002813a4739
	https://git.kernel.org/stable/c/19d63fd528719ce7d06d9aeb88d25b7d6478198a
	https://git.kernel.org/stable/c/6112fba4150039ccd90e29f2d1b788c73ad7b3dd
	https://git.kernel.org/stable/c/4750909a40da9016185e0ac991510a278cecb1e7
	https://git.kernel.org/stable/c/5c3c9ec1172a4c3384b8b800b3a8896cc2c1b20e
	https://git.kernel.org/stable/c/90f0109019e6817eb40a486671b7722d1544ae29