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If IOMMU domain for device group is not setup properly then we may hit IOMMU page fault. Current page fault handler assumes that domain is always setup and it will hit NULL pointer derefence (see below sample log). Lets check whether domain is setup or not and log appropriate message. Sample log: ---------- amdgpu 0000:00:01.0: amdgpu: SE 1, SH per SE 1, CU per SH 8, active_cu_number 6 BUG: kernel NULL pointer dereference, address: 0000000000000058 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 2 PID: 56 Comm: irq/24-AMD-Vi Not tainted 6.2.0-rc2+ #89 Hardware name: xxx RIP: 0010:report_iommu_fault+0x11/0x90 [...] Call Trace: <TASK> amd_iommu_int_thread+0x60c/0x760 ? __pfx_irq_thread_fn+0x10/0x10 irq_thread_fn+0x1f/0x60 irq_thread+0xea/0x1a0 ? preempt_count_add+0x6a/0xa0 ? __pfx_irq_thread_dtor+0x10/0x10 ? __pfx_irq_thread+0x10/0x10 kthread+0xe9/0x110 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2c/0x50 </TASK> Reported-by: Matt Fagnani <matt.fagnani@bell.net> Suggested-by: Joerg Roedel <joro@8bytes.org> Signed-off-by: Vasant Hegde <vasant.hegde@amd.com> Link: https://bugzilla.kernel.org/show_bug.cgi?id=216865 Link: https://lore.kernel.org/lkml/15d0f9ff-2a56-b3e9-5b45-e6b23300ae3b@leemhuis.info/ Link: https://lore.kernel.org/r/20230215052642.6016-3-vasant.hegde@amd.com Cc: stable@vger.kernel.org [joro: Edit commit message] Signed-off-by: Joerg Roedel <jroedel@suse.de>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.