The patch titled
Subject: idr: explain WARN_ON_ONCE() on negative IDs out-of-range ID
has been added to the -mm tree. Its filename is
idr-explain-warn_on_once-on-negative-ids-out-of-range-id.patch
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From: Tejun Heo <tj@xxxxxxxxxx>
Subject: idr: explain WARN_ON_ONCE() on negative IDs out-of-range ID
Until recently, when an negative ID is specified, idr functions used to
ignore the sign bit and proceeded with the operation with the rest of
bits, which is bizarre and error-prone. The behavior recently got changed
so that negative IDs are treated as invalid but we're triggering
WARN_ON_ONCE() on negative IDs just in case somebody was depending on the
sign bit being ignored, so that those can be detected and fixed easily.
We only need this for a while. Explain why WARN_ON_ONCE()s are there and
that they can be removed later.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/idr.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff -puN lib/idr.c~idr-explain-warn_on_once-on-negative-ids-out-of-range-id lib/idr.c
--- a/lib/idr.c~idr-explain-warn_on_once-on-negative-ids-out-of-range-id
+++ a/lib/idr.c
@@ -569,6 +569,7 @@ void idr_remove(struct idr *idp, int id)
struct idr_layer *p;
struct idr_layer *to_free;
+ /* see comment in idr_find_slowpath() */
if (WARN_ON_ONCE(id < 0))
return;
@@ -666,6 +667,14 @@ void *idr_find_slowpath(struct idr *idp,
int n;
struct idr_layer *p;
+ /*
+ * If @id is negative, idr_find() used to ignore the sign bit and
+ * performed lookup with the rest of bits, which is weird and can
+ * lead to very obscure bugs. We're now returning NULL for all
+ * negative IDs but just in case somebody was depending on the sign
+ * bit being ignored, let's trigger WARN_ON_ONCE() so that they can
+ * be detected and fixed. WARN_ON_ONCE() can later be removed.
+ */
if (WARN_ON_ONCE(id < 0))
return NULL;
@@ -815,6 +824,7 @@ void *idr_replace(struct idr *idp, void
int n;
struct idr_layer *p, *old_p;
+ /* see comment in idr_find_slowpath() */
if (WARN_ON_ONCE(id < 0))
return ERR_PTR(-EINVAL);
_
Patches currently in -mm which might be from tj@xxxxxxxxxx are
origin.patch
device_cgroup-dont-grab-mutex-in-rcu-callback.patch
linux-next.patch
cfq-fix-lock-imbalance-with-failed-allocations.patch
block-restore-proc-partitions-to-not-display-non-partitionable-removable-devices.patch
memcg-do-not-create-memsw-files-if-swap-accounting-is-disabled.patch
memcg-clean-up-swap-accounting-initialization-code.patch
memcg-prevent-changes-to-move_charge_at_immigrate-during-task-attach.patch
memcg-split-part-of-memcg-creation-to-css_online.patch
memcg-fast-hierarchy-aware-child-test.patch
memcg-fast-hierarchy-aware-child-test-fix.patch
memcg-fast-hierarchy-aware-child-test-fix-fix.patch
memcg-replace-cgroup_lock-with-memcg-specific-memcg_lock.patch
memcg-replace-cgroup_lock-with-memcg-specific-memcg_lock-fix.patch
memcg-increment-static-branch-right-after-limit-set.patch
memcg-avoid-dangling-reference-count-in-creation-failure.patch
lib-scatterlist-add-simple-page-iterator.patch
lib-scatterlist-use-page-iterator-in-the-mapping-iterator.patch
coredump-only-sigkill-should-interrupt-the-coredumping-task.patch
coredump-ensure-that-sigkill-always-kills-the-dumping-thread.patch
coredump-sanitize-the-setting-of-signal-group_exit_code.patch
vfork-dont-freezer_count-for-in-kernel-users-of-clone_vfork.patch
lockdep-check-that-no-locks-held-at-freeze-time.patch
lockdep-check-that-no-locks-held-at-freeze-time-fix.patch
coredump-cleanup-the-waiting-for-coredump_finish-code.patch
coredump-use-a-freezable_schedule-for-the-coredump_finish-wait.patch
coredump-abort-core-dump-piping-only-due-to-a-fatal-signal.patch
idr-fix-a-subtle-bug-in-idr_get_next.patch
idr-make-idr_destroy-imply-idr_remove_all.patch
atm-nicstar-dont-use-idr_remove_all.patch
block-loop-dont-use-idr_remove_all.patch
firewire-dont-use-idr_remove_all.patch
drm-dont-use-idr_remove_all.patch
dm-dont-use-idr_remove_all.patch
remoteproc-dont-use-idr_remove_all.patch
rpmsg-dont-use-idr_remove_all.patch
dlm-use-idr_for_each_entry-in-recover_idr_clear-error-path.patch
dlm-dont-use-idr_remove_all.patch
nfs-idr_destroy-no-longer-needs-idr_remove_all.patch
inotify-dont-use-idr_remove_all.patch
cgroup-dont-use-idr_remove_all.patch
nfsd-idr_destroy-no-longer-needs-idr_remove_all.patch
idr-deprecate-idr_remove_all.patch
idr-cosmetic-updates-to-struct-initializer-definitions.patch
idr-relocate-idr_for_each_entry-and-reorganize-id_get_new.patch
idr-remove-_idr_rc_to_errno-hack.patch
idr-refactor-idr_get_new_above.patch
idr-implement-idr_preload-and-idr_alloc.patch
idr-implement-idr_preload-and-idr_alloc-fix.patch
block-fix-synchronization-and-limit-check-in-blk_alloc_devt.patch
block-convert-to-idr_alloc.patch
block-loop-convert-to-idr_alloc.patch
atm-nicstar-convert-to-idr_alloc.patch
drbd-convert-to-idr_alloc.patch
dca-convert-to-idr_alloc.patch
dmaengine-convert-to-idr_alloc.patch
firewire-add-minor-number-range-check-to-fw_device_init.patch
firewire-convert-to-idr_alloc.patch
firewire-convert-to-idr_alloc-fix.patch
gpio-convert-to-idr_alloc.patch
drm-convert-to-idr_alloc.patch
drm-convert-to-idr_alloc-fix.patch
drm-convert-to-idr_alloc-fix-fix.patch
drm-exynos-convert-to-idr_alloc.patch
drm-i915-convert-to-idr_alloc.patch
drm-sis-convert-to-idr_alloc.patch
drm-via-convert-to-idr_alloc.patch
drm-vmwgfx-convert-to-idr_alloc.patch
i2c-convert-to-idr_alloc.patch
i2c-convert-to-idr_alloc-fix.patch
i2c-convert-to-idr_alloc-fix-fix.patch
ib-core-convert-to-idr_alloc.patch
ib-amso1100-convert-to-idr_alloc.patch
ib-cxgb3-convert-to-idr_alloc.patch
ib-cxgb4-convert-to-idr_alloc.patch
ib-ehca-convert-to-idr_alloc.patch
ib-ipath-convert-to-idr_alloc.patch
ib-mlx4-convert-to-idr_alloc.patch
ib-ocrdma-convert-to-idr_alloc.patch
ib-qib-convert-to-idr_alloc.patch
dm-convert-to-idr_alloc.patch
memstick-convert-to-idr_alloc.patch
mfd-convert-to-idr_alloc.patch
misc-c2port-convert-to-idr_alloc.patch
misc-tifm_core-convert-to-idr_alloc.patch
mmc-convert-to-idr_alloc.patch
mtd-convert-to-idr_alloc.patch
macvtap-convert-to-idr_alloc.patch
ppp-convert-to-idr_alloc.patch
power-convert-to-idr_alloc.patch
pps-convert-to-idr_alloc.patch
remoteproc-convert-to-idr_alloc.patch
rpmsg-convert-to-idr_alloc.patch
scsi-bfa-convert-to-idr_alloc.patch
scsi-convert-to-idr_alloc.patch
target-iscsi-convert-to-idr_alloc.patch
scsi-lpfc-convert-to-idr_alloc.patch
thermal-convert-to-idr_alloc.patch
uio-convert-to-idr_alloc.patch
vfio-convert-to-idr_alloc.patch
dlm-convert-to-idr_alloc.patch
inotify-convert-to-idr_alloc.patch
ocfs2-convert-to-idr_alloc.patch
ipc-convert-to-idr_alloc.patch
ipc-convert-to-idr_alloc-fix.patch
cgroup-convert-to-idr_alloc.patch
events-convert-to-idr_alloc.patch
posix-timer-dont-call-idr_find-w-out-of-range-id.patch
posix-timers-convert-to-idr_alloc.patch
net-9p-convert-to-idr_alloc.patch
mac80211-convert-to-idr_alloc.patch
sctp-convert-to-idr_alloc.patch
nfs4client-convert-to-idr_alloc.patch
idr-fix-top-layer-handling.patch
idr-remove-max_idr_mask-and-move-left-max_idr_-into-idrc.patch
idr-remove-length-restriction-from-idr_layer-bitmap.patch
idr-remove-length-restriction-from-idr_layer-bitmap-checkpatch-fixes.patch
idr-make-idr_layer-larger.patch
idr-add-idr_layer-prefix.patch
idr-implement-lookup-hint.patch
idr-implement-lookup-hint-always-do-slow-path-when-hint-is-uninitialized.patch
idr-explain-warn_on_once-on-negative-ids-out-of-range-id.patch
hlist-drop-the-node-parameter-from-iterators-fix-fix-fix-fix.patch
hlist-drop-the-node-parameter-from-iterators-fix-fix-fix.patch
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