Shivaprasad G Bhat <sb...@linux.ibm.com> writes:
> 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
> GPR00: c0000000000ff4cc c0000013aed5fae0 c000000001512700 c0000013aa362138
> GPR04: 0000000000000000 0000000000000000 0000000000000000 0000000119c8afd0
> GPR08: 0000000000000000 c000001284442b00 0000000000000001 0000000000001003
> GPR12: 0000000300000000 c0000018ffff2f00 0000000000000000 0000000000000000
> GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> GPR24: c0000013aed5fc40 0000000000000002 0000000000000000 c000000002757d90
> GPR28: c0000000000ff440 c000000002757cb8 c00000183799c1a0 c0000013aa362b00
> NIP [c0000000000ff4d4] iommu_reconfig_notifier+0x94/0x200
> LR [c0000000000ff4cc] iommu_reconfig_notifier+0x8c/0x200
> Call Trace:
> [c0000013aed5fae0] [c0000000000ff4cc] iommu_reconfig_notifier+0x8c/0x200
> (unreliable)
> [c0000013aed5fb10] [c0000000001a27b0] notifier_call_chain+0xb8/0x19c
> [c0000013aed5fb70] [c0000000001a2a78] blocking_notifier_call_chain+0x64/0x98
> [c0000013aed5fbb0] [c000000000c4a898] of_reconfig_notify+0x44/0xdc
> [c0000013aed5fc20] [c000000000c4add4] of_detach_node+0x78/0xb0
> [c0000013aed5fc70] [c0000000000f96a8] ofdt_write.part.0+0x86c/0xbb8
> [c0000013aed5fce0] [c00000000069b4bc] proc_reg_write+0xf4/0x150
> [c0000013aed5fd10] [c0000000005bfeb4] vfs_write+0xf8/0x488
> [c0000013aed5fdc0] [c0000000005c0570] ksys_write+0x84/0x140
> [c0000013aed5fe10] [c000000000033358] system_call_exception+0x138/0x330
> [c0000013aed5fe50] [c00000000000d05c]
> system_call_vectored_common+0x15c/0x2ec
> --- interrupt: 3000 at 0x20000433acb4
> <snip>
> ---[ end trace 0000000000000000 ]---
>
> The patch makes the iommu_group_get() call only when using it there by
> avoiding the leak.
>
> Fixes: a8ca9fc9134c ("powerpc/iommu: Do not do platform domain attach
> atctions after probe")
> Reported-by: Venkat Rao Bagalkote <venka...@linux.vnet.ibm.com>
> Closes:
> https://lore.kernel.org/all/274e0d2b-b5cc-475e-94e6-8427e88e2...@linux.vnet.ibm.com
> Signed-off-by: Shivaprasad G Bhat <sb...@linux.ibm.com>
> ---
> Changelog:
> v1:
> https://lore.kernel.org/all/170784021983.6249.10039296655906636112.st...@linux.ibm.com/
> - Minor refactor to call the iommu_group_get() only if required.
> - Updated the title, description and signature(Closes/Reported-by).
Sorry I already applied v1.
If you send this as a patch on top of v1 with a new change log I can
merge it as a cleanup/rework.
cheers
