linux-kernel - [BUG] vmlinux.o: warning: objtool: iommu_dma_sw_msi() falls through to next function alloc_io_pgtable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <5dd1f35e-8ece-43b7-ad6d-86d02d2718f6@paulmck-laptop>
Date: Wed, 26 Mar 2025 16:18:51 -0700
From: "Paul E. McKenney" <paulmck@...nel.org>
To: Josh Poimboeuf <jpoimboe@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>
Cc: linux-kernel@...r.kernel.org, Robin Murphy <robin.murphy@....com>,
	iommu@...ts.linux.dev
Subject: [BUG] vmlinux.o: warning: objtool: iommu_dma_sw_msi() falls through
 to next function alloc_io_pgtable_ops()

Hello!

Building next-20250326 using clang version 19.1.7 (CentOS 19.1.7-1.el9)
gets me the following warning:

vmlinux.o: warning: objtool: iommu_dma_sw_msi() falls through to next function alloc_io_pgtable_ops()

This surprised me for a couple of reasons.  First, from what I
can see, iommu_dma_sw_msi() does not fall through.  Second, it
is in drivers/iommu/dma-iommu.c while alloc_io_pgtable_ops() is in
drivers/iommu/io-pgtable.c, though maybe the compiler and/or linker saw
fit to rearrange these functions' object code.

Please let me know of any debug patches or fixes that I could apply,
or any additional information that you might need.

						Thanx, Paul

Note to self: Run 2025.03.26-14.37.10-remote on first test system.  ;-)

------------------------------------------------------------------------

int iommu_dma_sw_msi(struct iommu_domain *domain, struct msi_desc *desc,
		     phys_addr_t msi_addr)
{
	struct device *dev = msi_desc_to_dev(desc);
	const struct iommu_dma_msi_page *msi_page;

	if (!has_msi_cookie(domain)) {
		msi_desc_set_iommu_msi_iova(desc, 0, 0);
		return 0;
	}

	iommu_group_mutex_assert(dev);
	msi_page = iommu_dma_get_msi_page(dev, msi_addr, domain);
	if (!msi_page)
		return -ENOMEM;

	msi_desc_set_iommu_msi_iova(desc, msi_page->iova,
				    ilog2(cookie_msi_granule(domain)));
	return 0;
}