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Tue, 10 Mar 2026 08:21:37 +0000 (GMT) From: Nilay Shroff To: iommu@lists.linux.dev, linuxppc-dev@lists.ozlabs.org Cc: nicolinc@nvidia.com, joerg.roedel@amd.com, jgg@nvidia.com, baolu.lu@linux.intel.com, kevin.tian@intel.com, maddy@linux.ibm.com, sbhat@linux.ibm.com, Nilay Shroff , stable@vger.kernel.org Subject: [PATCH] powerpc/iommu: fix lockdep warning during PCI enumeration Date: Tue, 10 Mar 2026 13:51:24 +0530 Message-ID: <20260310082129.3630996-1-nilay@linux.ibm.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzEwMDA2NyBTYWx0ZWRfX9zIN52HLKd+M FDuF9gD3N8l9EulZyXFz7g59ci4YfCL5D06JSIKpCG9Sdm6aQzNnh2GoPjD3fQL2IH0g3BtFd3q Y0iwYUAqwVQns+ZUWaVY7DvPCPgQYrhZkB+s5ChGIaiIgTqdzwGxnM8Ig1vQN2zjB8FglMXhYXB iWt8QS6XmpnvGOpL/rlZgiGX9PLmzlrnoyXsFQyP6ln8jiHOtcL/oBiRwl+4u2jb0+enplbZ+VN s0iqL6W28cqy3MH4Tle4VWfdxGKG9yaQImbFM3FQgXGrW1umHzLiA/AdSNoVJL7JZK19kACJ2q5 Mgays45JNmPYNepC8qYMeyLB/4/vCkSylVzE6uqlgbw1K/SUW9n92WshPEFD1Q5MJFpEfdRj9qf U0718joUHo7gmgBXHCQzIuxzDtPpSIXFbS8wMuLfeSSyxH1VY/Kfuu0S+3QaN6kcxPJoMT/jCRs fSI63QfOu62WLpRZxSw== X-Authority-Analysis: v=2.4 cv=QaVrf8bv c=1 sm=1 tr=0 ts=69afd49b cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=Yq5XynenixoA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=ekpCZll6AK0GQq_nEskA:9 X-Proofpoint-GUID: 2Elq3pM91g6BGRAPrlWp0DnOX4jzOR_A X-Proofpoint-ORIG-GUID: 2Elq3pM91g6BGRAPrlWp0DnOX4jzOR_A X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-10_01,2026-03-09_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 spamscore=0 impostorscore=0 clxscore=1015 adultscore=0 bulkscore=0 lowpriorityscore=0 priorityscore=1501 suspectscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2602130000 definitions=main-2603100067 Commit a75b2be249d6 ("iommu: Add iommu_driver_get_domain_for_dev() helper") introduced iommu_driver_get_domain_for_dev() for driver code paths that hold iommu_group->mutex while attaching a device to an IOMMU domain. The same commit also added a lockdep assertion in iommu_get_domain_for_dev() to ensure that callers do not hold iommu_group->mutex when invoking it. On powerpc platforms, when PCI device ownership is switched from BLOCKED to the PLATFORM domain, the attach callback spapr_tce_platform_iommu_attach_dev() still calls iommu_get_domain_for_dev(). This happens while iommu_group->mutex is held during domain switching, which triggers the lockdep warning below during PCI enumeration: WARNING: drivers/iommu/iommu.c:2252 at iommu_get_domain_for_dev+0x38/0x80, CPU#2: swapper/0/1 Modules linked in: CPU: 2 UID: 0 PID: 1 Comm: swapper/0 Not tainted 7.0.0-rc2+ #35 PREEMPT Hardware name: IBM,9105-22A Power11 (architected) 0x820200 0xf000007 of:IBM,FW1120.00 (RB1120_115) hv:phyp pSeries NIP: c000000000c244c4 LR: c00000000005b5a4 CTR: c00000000005b578 REGS: c00000000a7bf280 TRAP: 0700 Not tainted (7.0.0-rc2+) MSR: 8000000002029033 CR: 22004422 XER: 0000000a CFAR: c000000000c24508 IRQMASK: 0 GPR00: c00000000005b5a4 c00000000a7bf520 c000000001dc8100 0000000000000001 GPR04: c00000000f972f10 0000000000000000 0000000000000000 0000000000000001 GPR08: 0000001ffbc60000 0000000000000001 0000000000000000 0000000000000000 GPR12: c00000000005b578 c000001fffffe480 c000000000011618 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: ffffffffffffefff 0000000000000000 c000000002d30eb0 0000000000000001 GPR24: c0000000017881f8 0000000000000000 0000000000000001 c00000000f972e00 GPR28: c00000000bbba0d0 0000000000000000 c00000000bbba0d0 c00000000f972e00 NIP [c000000000c244c4] iommu_get_domain_for_dev+0x38/0x80 LR [c00000000005b5a4] spapr_tce_platform_iommu_attach_dev+0x2c/0x98 Call Trace: iommu_get_domain_for_dev+0x68/0x80 (unreliable) spapr_tce_platform_iommu_attach_dev+0x2c/0x98 __iommu_attach_device+0x44/0x220 __iommu_device_set_domain+0xf4/0x194 __iommu_group_set_domain_internal+0xec/0x228 iommu_setup_default_domain+0x5f4/0x6a4 __iommu_probe_device+0x674/0x724 iommu_probe_device+0x50/0xb4 iommu_add_device+0x48/0x198 pci_dma_dev_setup_pSeriesLP+0x198/0x4f0 pcibios_bus_add_device+0x80/0x464 pci_bus_add_device+0x40/0x100 pci_bus_add_devices+0x54/0xb0 pcibios_init+0xd8/0x140 do_one_initcall+0x8c/0x598 kernel_init_freeable+0x3ec/0x850 kernel_init+0x34/0x270 ret_from_kernel_user_thread+0x14/0x1c Fix this by using iommu_driver_get_domain_for_dev() instead of iommu_get_domain_for_dev() in spapr_tce_platform_iommu_attach_dev(), which is the appropriate helper for callers holding the group mutex. Cc: stable@vger.kernel.org Fixes: a75b2be249d6 ("iommu: Add iommu_driver_get_domain_for_dev() helper") Signed-off-by: Nilay Shroff --- arch/powerpc/kernel/iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index 0ce71310b7d9..d122e8447831 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -1159,7 +1159,7 @@ spapr_tce_platform_iommu_attach_dev(struct iommu_domain *platform_domain, struct device *dev, struct iommu_domain *old) { - struct iommu_domain *domain = iommu_get_domain_for_dev(dev); + struct iommu_domain *domain = iommu_driver_get_domain_for_dev(dev); struct iommu_table_group *table_group; struct iommu_group *grp; -- 2.53.0