6.6-stable review patch. If anyone has any objections, please let me know.
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From: Li Zhijian lizhijian@fujitsu.com
[ Upstream commit 3531b27f1f04a6bc9c95cf00d40efe618d57aa93 ]
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: d1257d098a5a ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/cxl/core/region.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 644032cd680e4..d1f513800c10d 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -288,7 +288,7 @@ static ssize_t commit_store(struct device *dev, struct device_attribute *attr, */ rc = cxl_region_invalidate_memregion(cxlr); if (rc) - return rc; + goto out;
if (commit) { rc = cxl_region_decode_commit(cxlr);