6.7-stable review patch. If anyone has any objections, please let me know.
------------------
From: Shivaprasad G Bhat sbhat@linux.ibm.com
[ Upstream commit 0846dd77c8349ec92ca0079c9c71d130f34cb192 ]
The function spapr_tce_platform_iommu_attach_dev() is missing to call iommu_group_put() when the domain is already set. This refcount leak shows up with BUG_ON() during DLPAR remove operation as:
KernelBug: Kernel bug in state 'None': kernel BUG at arch/powerpc/platforms/pseries/iommu.c:100! Oops: Exception in kernel mode, sig: 5 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=8192 NUMA pSeries <snip> Hardware name: IBM,9080-HEX POWER10 (raw) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_016) hv:phyp pSeries NIP: c0000000000ff4d4 LR: c0000000000ff4cc CTR: 0000000000000000 REGS: c0000013aed5f840 TRAP: 0700 Tainted: G I (6.8.0-rc3-autotest-g99bd3cb0d12e) MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 44002402 XER: 20040000 CFAR: c000000000a0d170 IRQMASK: 0 ... NIP iommu_reconfig_notifier+0x94/0x200 LR iommu_reconfig_notifier+0x8c/0x200 Call Trace: iommu_reconfig_notifier+0x8c/0x200 (unreliable) notifier_call_chain+0xb8/0x19c blocking_notifier_call_chain+0x64/0x98 of_reconfig_notify+0x44/0xdc of_detach_node+0x78/0xb0 ofdt_write.part.0+0x86c/0xbb8 proc_reg_write+0xf4/0x150 vfs_write+0xf8/0x488 ksys_write+0x84/0x140 system_call_exception+0x138/0x330 system_call_vectored_common+0x15c/0x2ec
The patch adds the missing iommu_group_put() call.
Fixes: a8ca9fc9134c ("powerpc/iommu: Do not do platform domain attach atctions after probe") Reported-by: Venkat Rao Bagalkote venkat88@linux.vnet.ibm.com Closes: https://lore.kernel.org/all/274e0d2b-b5cc-475e-94e6-8427e88e271d@linux.vnet.... Signed-off-by: Shivaprasad G Bhat sbhat@linux.ibm.com Tested-by: Venkat Rao Bagalkote venkat88@linux.vnet.ibm.com Reviewed-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://msgid.link/170784021983.6249.10039296655906636112.stgit@linux.ibm.co... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kernel/iommu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index c6f62e130d55..4393d447cb56 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -1290,8 +1290,10 @@ spapr_tce_platform_iommu_attach_dev(struct iommu_domain *platform_domain, int ret = -EINVAL;
/* At first attach the ownership is already set */ - if (!domain) + if (!domain) { + iommu_group_put(grp); return 0; + }
if (!grp) return -ENODEV;