linux/drivers/cxl
Li Zhijian 3531b27f1f cxl/region: Fix cxl_region_rwsem lock held when returning to user space
Fix a missed "goto out" to unlock on error to cleanup this splat:

    WARNING: lock held when returning to user space!
    6.6.0-rc3-lizhijian+ #213 Not tainted
    ------------------------------------------------
    cxl/673 is leaving the kernel with locks still held!
    1 lock held by cxl/673:
     #0: ffffffffa013b9d0 (cxl_region_rwsem){++++}-{3:3}, at: commit_store+0x7d/0x3e0 [cxl_core]

In terms of user visible impact of this bug for backports:

cxl_region_invalidate_memregion() on x86 invokes wbinvd which is a
problematic instruction for virtualized environments. So, on virtualized
x86, cxl_region_invalidate_memregion() returns an error. This failure
case got missed because CXL memory-expander device passthrough is not a
production use case, and emulation of CXL devices is typically limited
to kernel development builds with CONFIG_CXL_REGION_INVALIDATION_TEST=y,
that makes cxl_region_invalidate_memregion() succeed.

In other words, the expected exposure of this bug is limited to CXL
subsystem development environments using QEMU that neglected
CONFIG_CXL_REGION_INVALIDATION_TEST=y.

Fixes: d1257d098a ("cxl/region: Move cache invalidation before region teardown, and before setup")
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20231025085450.2514906-1-lizhijian@fujitsu.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2023-10-27 13:04:51 -07:00
..
core cxl/region: Fix cxl_region_rwsem lock held when returning to user space 2023-10-27 13:04:51 -07:00
acpi.c cxl/acpi: Annotate struct cxl_cxims_data with __counted_by 2023-09-22 14:31:04 -07:00
cxl.h Merge branch 'for-6.5/cxl-rch-eh' into for-6.5/cxl 2023-06-25 18:56:13 -07:00
cxlmem.h cxl/memdev: Fix sanitize vs decoder setup locking 2023-10-06 00:12:45 -07:00
cxlpci.h cxl/pci: Find and register CXL PMU devices 2023-05-30 11:20:35 -07:00
Kconfig cxl: fix CONFIG_FW_LOADER dependency 2023-07-14 14:32:22 -06:00
Makefile cxl/pmem: Introduce nvdimm_security_ops with ->get_flags() operation 2022-11-30 16:30:47 -08:00
mem.c Merge branch 'for-6.5/cxl-rch-eh' into for-6.5/cxl 2023-06-25 18:56:13 -07:00
pci.c cxl/memdev: Fix sanitize vs decoder setup locking 2023-10-06 00:12:45 -07:00
pmem.c cxl/mbox: Move mailbox related driver state to its own data structure 2023-06-25 14:31:08 -07:00
pmu.h cxl/pci: Find and register CXL PMU devices 2023-05-30 11:20:35 -07:00
port.c Merge branch 'for-6.5/cxl-rch-eh' into for-6.5/cxl 2023-06-25 18:56:13 -07:00
security.c Merge branch 'for-6.5/cxl-type-2' into for-6.5/cxl 2023-06-25 17:16:51 -07:00