| Message ID | 20231025085450.2514906-1-lizhijian@fujitsu.com |
|---|---|
| State | Accepted |
| Commit | 37570686b1a64d988566f638997a49f5e6d43470 |
| Headers | show |
| Series | cxl/region: Fix cxl_region_rwsem lock held when returning to user space | expand |
Li Zhijian wrote: > goto out to release cxl_region_rwsem. Fix below warning: > ================================================ > 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] > > 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> > --- > 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 6d63b8798c29..18da77f8f22b 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -294,7 +294,7 @@ 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); > -- > 2.29.2 >
Li Zhijian wrote: > goto out to release cxl_region_rwsem. Fix below warning: Hi, this change looks good, the changelog would benefit from more detail so that backporters can determine how important this fix is. I will add the following: --- 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. > ================================================ > 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] > > Fixes: d1257d098a5a ("cxl/region: Move cache invalidation before region teardown, and before setup") > Signed-off-by: Li Zhijian <lizhijian@fujitsu.com> > --- > 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 6d63b8798c29..18da77f8f22b 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -294,7 +294,7 @@ 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); > -- > 2.29.2 >
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 6d63b8798c29..18da77f8f22b 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -294,7 +294,7 @@ 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);
goto out to release cxl_region_rwsem. Fix below warning: ================================================ 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] Fixes: d1257d098a5a ("cxl/region: Move cache invalidation before region teardown, and before setup") Signed-off-by: Li Zhijian <lizhijian@fujitsu.com> --- drivers/cxl/core/region.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)