Matthew Wilcox (Oracle) a16a366927 idr: Fix idr_get_next race with idr_remove ... commit 5c089fd0c7 upstream. If the entry is deleted from the IDR between the call to radix_tree_iter_find() and rcu_dereference_raw(), idr_get_next() will return NULL, which will end the iteration prematurely. We should instead continue to the next entry in the IDR. This only happens if the iteration is protected by the RCU lock. Most IDR users use a spinlock or semaphore to exclude simultaneous modifications. It was noticed once the PID allocator was converted to use the IDR, as it uses the RCU lock, but there may be other users elsewhere in the kernel. We can't use the normal pattern of calling radix_tree_deref_retry() (which catches both a retry entry in a leaf node and a node entry in the root) as the IDR supports storing entries which are unaligned, which will trigger an infinite loop if they are encountered. Instead, we have to explicitly check whether the entry is a retry entry. Fixes: 0a835c4f09 ("Reimplement IDR and IDA using the radix tree") Reported-by: Brendan Gregg <bgregg@netflix.com> Tested-by: Brendan Gregg <bgregg@netflix.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2019-11-24 08:19:11 +01:00
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fault-injection	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
ktest	These commits have either been sitting in my INBOX or have been	2018-04-11 16:42:27 -07:00
nvdimm	libnvdimm/nfit_test: Fix acpi_handle redefinition	2019-10-11 18:21:21 +02:00
radix-tree	idr: Fix idr_get_next race with idr_remove	2019-11-24 08:19:11 +01:00
scatterlist	tools/testing/scatterlist: Test new __sg_alloc_table_from_pages	2017-09-07 10:54:40 +01:00
selftests	selftests/powerpc: Do not fail with reschedule	2019-11-20 18:46:58 +01:00
vsock	VSOCK: add tools/testing/vsock/vsock_diag_test	2017-10-05 18:44:17 -07:00