kernel/linux.git/lib/idr.c, branch v6.6.131

idr: fix idr_alloc() returning an ID out of range

2026-01-11T14:22:17+00:00

commit c6e8e595a0798ad67da0f7bebaf69c31ef70dfff upstream. If you use an IDR with a non-zero base, and specify a range that lies entirely below the base, 'max - base' becomes very large and idr_get_free() can return an ID that lies outside of the requested range. Link: https://lkml.kernel.org/r/20251128161853.3200058-1-willy@infradead.org Fixes: 6ce711f27500 ("idr: Make 1-based IDRs more efficient") Signed-off-by: Matthew Wilcox (Oracle) Reported-by: Jan Sokolowski Reported-by: Koen Koning Reported-by: Peter Senna Tschudin Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6449 Reviewed-by: Christian König Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

ida: Fix crash in ida_free when the bitmap is empty

2024-01-20T10:51:46+00:00

[ Upstream commit af73483f4e8b6f5c68c9aa63257bdd929a9c194a ] The IDA usually detects double-frees, but that detection failed to consider the case when there are no nearby IDs allocated and so we have a NULL bitmap rather than simply having a clear bit. Add some tests to the test-suite to be sure we don't inadvertently reintroduce this problem. Unfortunately they're quite noisy so include a message to disregard the warnings. Reported-by: Zhenghan Wang Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

idr: fix param name in idr_alloc_cyclic() doc

2023-09-05T23:01:38+00:00

The relevant parameter is 'start' and not 'nextid' Fixes: 460488c58ca8 ("idr: Remove idr_alloc_ext") Signed-off-by: Ariel Marcovitch Signed-off-by: Matthew Wilcox (Oracle)

ida: don't use BUG_ON() for debugging

2022-07-10T20:55:49+00:00

This is another old BUG_ON() that just shouldn't exist (see also commit a382f8fee42c: "signal handling: don't use BUG_ON() for debugging"). In fact, as Matthew Wilcox points out, this condition shouldn't really even result in a warning, since a negative id allocation result is just a normal allocation failure: "I wonder if we should even warn here -- sure, the caller is trying to free something that wasn't allocated, but we don't warn for kfree(NULL)" and goes on to point out how that current error check is only causing people to unnecessarily do their own index range checking before freeing it. This was noted by Itay Iellin, because the bluetooth HCI socket cookie code does *not* do that range checking, and ends up just freeing the error case too, triggering the BUG_ON(). The HCI code requires CAP_NET_RAW, and seems to just result in an ugly splat, but there really is no reason to BUG_ON() here, and we have generally striven for allocation models where it's always ok to just do free(alloc()); even if the allocation were to fail for some random reason (usually obviously that "random" reason being some resource limit). Fixes: 88eca0207cf1 ("ida: simplified functions for id allocation") Reported-by: Itay Iellin Suggested-by: Matthew Wilcox Signed-off-by: Linus Torvalds

Merge tag 'xarray-5.9' of git://git.infradead.org/users/willy/xarray

2020-10-20T21:39:37+00:00

Pull XArray updates from Matthew Wilcox: - Fix the test suite after introduction of the local_lock - Fix a bug in the IDA spotted by Coverity - Change the API that allows the workingset code to delete a node - Fix xas_reload() when dealing with entries that occupy multiple indices - Add a few more tests to the test suite - Fix an unsigned int being shifted into an unsigned long * tag 'xarray-5.9' of git://git.infradead.org/users/willy/xarray: XArray: Fix xas_create_range for ranges above 4 billion radix-tree: fix the comment of radix_tree_next_slot() XArray: Fix xas_reload for multi-index entries XArray: Add private interface for workingset node deletion XArray: Fix xas_for_each_conflict documentation XArray: Test marked multiorder iterations XArray: Test two more things about xa_cmpxchg ida: Free allocated bitmap in error path radix tree test suite: Fix compilation

lib/idr.c: document calling context for IDA APIs mustn't use locks

2020-10-16T18:11:20+00:00

The documentation for these functions indicates that callers don't need to hold a lock while calling them, but that documentation is only in one place under "IDA Usage". Let's state the same information on each IDA function so that it's clear what the calling context requires. Furthermore, let's document ida_simple_get() with the same information so that callers know how this API works. Signed-off-by: Stephen Boyd Signed-off-by: Andrew Morton Reviewed-by: Greg Kroah-Hartman Cc: Tri Vo Cc: Jonathan Corbet Cc: Matthew Wilcox Link: https://lkml.kernel.org/r/20200910055246.2297797-1-swboyd@chromium.org Signed-off-by: Linus Torvalds

ida: Free allocated bitmap in error path

2020-10-07T13:11:33+00:00

If a bitmap needs to be allocated, and then by the time the thread is scheduled to be run again all the indices which would satisfy the allocation have been allocated then we would leak the allocation. Almost impossible to hit in practice, but a trivial fix. Found by Coverity. Fixes: f32f004cddf8 ("ida: Convert to XArray") Reported-by: coverity-bot Reviewed-by: Kees Cook Signed-off-by: Matthew Wilcox (Oracle)

idr: Fix idr_get_next_ul race with idr_remove

2019-11-02T02:26:34+00:00

Commit 5c089fd0c734 ("idr: Fix idr_get_next race with idr_remove") neglected to fix idr_get_next_ul(). As far as I can tell, nobody's actually using this interface under the RCU read lock, but fix it now before anybody decides to use it. Fixes: 5c089fd0c734 ("idr: Fix idr_get_next race with idr_remove") Signed-off-by: Matthew Wilcox (Oracle)

idr: Fix idr_get_next race with idr_remove

2019-06-03T03:00:24+00:00

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: 0a835c4f090a ("Reimplement IDR and IDA using the radix tree") Reported-by: Brendan Gregg Tested-by: Brendan Gregg Signed-off-by: Matthew Wilcox (Oracle)

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45+00:00

Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman