PCI/pwrctrl: Cancel outstanding rescan work when unregistering

jira LE-3822
cve CVE-2025-38137
Rebuild_History Non-Buildable kernel-6.12.0-55.27.1.el10_0
commit-author Brian Norris <briannorris@google.com>
commit 8b926f2
Empty-Commit: Cherry-Pick Conflicts during history rebuild.
Will be included in final tarball splat. Ref for failed cherry-pick at:
ciq/ciq_backports/kernel-6.12.0-55.27.1.el10_0/8b926f23.failed

It's possible to trigger use-after-free here by:

  (a) forcing rescan_work_func() to take a long time and
  (b) utilizing a pwrctrl driver that may be unloaded for some reason

Cancel outstanding work to ensure it is finished before we allow our data
structures to be cleaned up.

[bhelgaas: tidy commit log]
Fixes: 8f62819 ("PCI/pwrctl: Rescan bus on a separate thread")
	Signed-off-by: Brian Norris <briannorris@google.com>
	Signed-off-by: Brian Norris <briannorris@chromium.org>
	Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
	Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
	Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
	Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
	Cc: Konrad Dybcio <konradybcio@kernel.org>
Link: https://patch.msgid.link/20250409115313.1.Ia319526ed4ef06bec3180378c9a008340cec9658@changeid
(cherry picked from commit 8b926f2)
	Signed-off-by: Jonathan Maple <jmaple@ciq.com>

# Conflicts:
#	drivers/pci/pwrctrl/core.c

Author: PlaidCat

ciq/ciq_backports/kernel-6.12.0-55.27.1.el10_0/8b926f23.failed

@@ -0,0 +1,36 @@
+PCI/pwrctrl: Cancel outstanding rescan work when unregistering
+
+jira LE-3822
+cve CVE-2025-38137
+Rebuild_History Non-Buildable kernel-6.12.0-55.27.1.el10_0
+commit-author Brian Norris <briannorris@google.com>
+commit 8b926f237743f020518162c62b93cb7107a2b5eb
+Empty-Commit: Cherry-Pick Conflicts during history rebuild.
+Will be included in final tarball splat. Ref for failed cherry-pick at:
+ciq/ciq_backports/kernel-6.12.0-55.27.1.el10_0/8b926f23.failed
+
+It's possible to trigger use-after-free here by:
+
+  (a) forcing rescan_work_func() to take a long time and
+  (b) utilizing a pwrctrl driver that may be unloaded for some reason
+
+Cancel outstanding work to ensure it is finished before we allow our data
+structures to be cleaned up.
+
+[bhelgaas: tidy commit log]
+Fixes: 8f62819aaace ("PCI/pwrctl: Rescan bus on a separate thread")
+	Signed-off-by: Brian Norris <briannorris@google.com>
+	Signed-off-by: Brian Norris <briannorris@chromium.org>
+	Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
+	Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
+	Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+	Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
+	Cc: Konrad Dybcio <konradybcio@kernel.org>
+Link: https://patch.msgid.link/20250409115313.1.Ia319526ed4ef06bec3180378c9a008340cec9658@changeid
+(cherry picked from commit 8b926f237743f020518162c62b93cb7107a2b5eb)
+	Signed-off-by: Jonathan Maple <jmaple@ciq.com>
+
+# Conflicts:
+#	drivers/pci/pwrctrl/core.c
+* Unmerged path drivers/pci/pwrctrl/core.c
+* Unmerged path drivers/pci/pwrctrl/core.c