From: Dan Carpenter <error27@gmail.com>
To: Antti Laakso <antti.laakso@linux.intel.com>
Cc: linux-media@vger.kernel.org
Subject: [bug report] media: ipu6: Move isys fw mapping to pci_probe
Date: Tue, 15 Sep 2026 17:32:33 +0300 [thread overview]
Message-ID: <aqlXAXcXvMM3HWtJ@stanley.mountain> (raw)
Hello Antti Laakso,
Commit 69ebb1bfc865 ("media: ipu6: Move isys fw mapping to
pci_probe") from Aug 27, 2026 (linux-next), leads to the following
Smatch static checker warning:
drivers/media/pci/intel/ipu6/ipu6.c:865 ipu6_pci_remove()
warn: variable dereferenced before check 'isp->psys' (see line 844)
drivers/media/pci/intel/ipu6/ipu6.c
836 static void ipu6_pci_remove(struct pci_dev *pdev)
837 {
838 struct ipu6_device *isp = pci_get_drvdata(pdev);
839 unsigned long dir;
840
841 devm_free_irq(&pdev->dev, pdev->irq, isp);
842
843 dir = IS_IPU7(isp) ? DMA_BIDIRECTIONAL : DMA_TO_DEVICE;
844 ipu6_cpd_free_pkg_dir(isp->psys);
ipu6_cpd_free_pkg_dir() dereferences isp->psys so
845 ipu6_unmap_fw_region(isp->psys, dir);
846
847 if (isp->isys) {
is too late. Fortunately, it's also unnecessary. Just delete it.
848 ipu6_cpd_free_pkg_dir(isp->isys);
849 if (isp->isys->fw_sgt.nents)
850 ipu6_unmap_fw_region(isp->isys, dir);
851 }
852
853 vfree(isp->fw_code_region);
854 isp->fw_code_region = NULL;
855
856 ipu6_buttress_exit(isp);
857
858 ipu6_bus_del_devices(pdev);
I'm using ChatGPT to review Smatch warnings these days and it
gives a bonus bug that ipu6_bus_del_devices() frees isp->psys.
"ipu6_bus_del_devices() calls:
auxiliary_device_delete(&adev->auxdev);
auxiliary_device_uninit(&adev->auxdev);
The uninit drops the device reference, and ipu6_bus_release() frees
the containing ipu6_bus_device. Consequently, accessing isp->psys->mmu
or isp->isys->mmu afterward can use freed memory."
859
860 pm_runtime_forbid(&pdev->dev);
861 pm_runtime_get_noresume(&pdev->dev);
862
863 release_firmware(isp->cpd_fw);
864
--> 865 if (isp->psys)
866 ipu6_mmu_cleanup(isp->psys->mmu);
^^^^^^^^^
867 if (isp->isys)
868 ipu6_mmu_cleanup(isp->isys->mmu);
^^^^^^^^^
So these dereferences are a use after free. Originally, this code saved
the pointer the mmus before calling ipu6_bus_del_devices().
869 }
This email is a free service from the Smatch-CI project [smatch.sf.net].
regards,
dan carpenter
reply other threads:[~2026-09-15 14:32 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=aqlXAXcXvMM3HWtJ@stanley.mountain \
--to=error27@gmail.com \
--cc=antti.laakso@linux.intel.com \
--cc=linux-media@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.