Instead of just reporting an assertion failure, report enough information
that we can start diagnosing exactly went wrong.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
The throbber could race with creation of the anchor entry and cause the
IDR to have zero entries in it, which would cause the test to fail.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
When run on a single CPU, this test would frequently access already-freed
memory. Due to timing, this bug never showed up on multi-CPU tests.
Reported-by: Chris von Recklinghausen <crecklin@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Several test runners register individual worker threads with the
RCU library, but neglect to register the main thread, which can lead
to objects being freed while the main thread is in what appears to be
an RCU critical section.
Reported-by: Chris von Recklinghausen <crecklin@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Commit 4bba4c4bb0 added tools/include/linux/compiler_types.h which
includes linux/compiler-gcc.h. Unfortunately, we had our own (empty)
compiler_types.h which overrode the one added by that commit, and
so we lost the definition of __must_be_array(). Removing our empty
compiler_types.h fixes the problem and reduces our divergence from the
rest of the tools.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
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: f32f004cdd ("ida: Convert to XArray")
Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Here are 3 SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your current
tree, that should be trivial to handle (one file modified by two things,
one file deleted.)
All 3 of these have been in linux-next for a while, with no reported
issues other than the merge conflict.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx
Pull SPDX updates from Greg KH:
"Here are three SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your
current tree, that should be trivial to handle (one file modified by
two things, one file deleted.)
All three of these have been in linux-next for a while, with no
reported issues other than the merge conflict"
* tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx:
ASoC: MT6660: make spdxcheck.py happy
.gitignore: add SPDX License Identifier
.gitignore: remove too obvious comments
xas_for_each_marked() is using entry == NULL as a termination condition
of the iteration. When xas_for_each_marked() is used protected only by
RCU, this can however race with xas_store(xas, NULL) in the following
way:
TASK1 TASK2
page_cache_delete() find_get_pages_range_tag()
xas_for_each_marked()
xas_find_marked()
off = xas_find_chunk()
xas_store(&xas, NULL)
xas_init_marks(&xas);
...
rcu_assign_pointer(*slot, NULL);
entry = xa_entry(off);
And thus xas_for_each_marked() terminates prematurely possibly leading
to missed entries in the iteration (translating to missing writeback of
some pages or a similar problem).
If we find a NULL entry that has been marked, skip it (unless we're trying
to allocate an entry).
Reported-by: Jan Kara <jack@suse.cz>
CC: stable@vger.kernel.org
Fixes: ef8e5717db ("page cache: Convert delete_batch to XArray")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
The radix tree doesn't use alignment, so the argument was ignored.
The maple tree needs its nodes to be aligned, so we need to pay attention
to the alignment argument. Also change the types of 'size' and 'align'
to unsigned int to match commit f4957d5bd0.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Pull RCU updates from Ingo Molnar:
"The changes in this cycle are:
- RCU flavor consolidation cleanups and optmizations
- Documentation updates
- Miscellaneous fixes
- SRCU updates
- RCU-sync flavor consolidation
- Torture-test updates
- Linux-kernel memory-consistency-model updates, most notably the
addition of plain C-language accesses"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits)
tools/memory-model: Improve data-race detection
tools/memory-model: Change definition of rcu-fence
tools/memory-model: Expand definition of barrier
tools/memory-model: Do not use "herd" to refer to "herd7"
tools/memory-model: Fix comment in MP+poonceonces.litmus
Documentation: atomic_t.txt: Explain ordering provided by smp_mb__{before,after}_atomic()
rcu: Don't return a value from rcu_assign_pointer()
rcu: Force inlining of rcu_read_lock()
rcu: Fix irritating whitespace error in rcu_assign_pointer()
rcu: Upgrade sync_exp_work_done() to smp_mb()
rcutorture: Upper case solves the case of the vanishing NULL pointer
torture: Suppress propagating trace_printk() warning
rcutorture: Dump trace buffer for callback pipe drain failures
torture: Add --trust-make to suppress "make clean"
torture: Make --cpus override idleness calculations
torture: Run kernel build in source directory
torture: Add function graph-tracing cheat sheet
torture: Capture qemu output
rcutorture: Tweak kvm options
rcutorture: Add trivial RCU implementation
...
Account XArray nodes for the page cache to the appropriate cgroup
(Johannes Weiner)
Fix idr_get_next() when called under the RCU lock (Matthew Wilcox)
Add a test for xa_insert() (Matthew Wilcox)
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Merge tag 'xarray-5.2-rc6' of git://git.infradead.org/users/willy/linux-dax
Pull XArray fixes from Matthew Wilcox:
- Account XArray nodes for the page cache to the appropriate cgroup
(Johannes Weiner)
- Fix idr_get_next() when called under the RCU lock (Matthew Wilcox)
- Add a test for xa_insert() (Matthew Wilcox)
* tag 'xarray-5.2-rc6' of git://git.infradead.org/users/willy/linux-dax:
XArray tests: Add check_insert
idr: Fix idr_get_next race with idr_remove
mm: fix page cache convergence regression
Quoting Paul [1]:
"Given that a quick (and perhaps error-prone) search of the uses
of rcu_assign_pointer() in v5.1 didn't find a single use of the
return value, let's please instead change the documentation and
implementation to eliminate the return value."
[1] https://lkml.kernel.org/r/20190523135013.GL28207@linux.ibm.com
Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Cc: "Paul E. McKenney" <paulmck@linux.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: rcu@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms and conditions of the gnu general public license
version 2 as published by the free software foundation this program
is distributed in the hope it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 263 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.208660670@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
Commit 66ee620f06 ("idr: Permit any valid kernel pointer to be stored")
changed the radix tree lookup so that it stops when reaching the bottom
of the tree. However, the condition was added in the wrong place,
making it possible to return retry entries to the caller. Reorder the
tests to check for the retry entry before checking whether we're at the
bottom of the tree. The retry entry should never be found in the tree
root, so it's safe to defer the check until the end of the loop.
Add a regression test to the test-suite to be sure this doesn't come
back.
Fixes: 66ee620f06 ("idr: Permit any valid kernel pointer to be stored")
Reported-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
All users have now been converted to the XArray. Removing the support
reduces code size and ensures new users will use the XArray instead.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
This is the last remaining user of the multiorder functionality of the
radix tree. Test the XArray instead.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
In preparation for the removal of the multiorder radix tree code,
convert item_delete_rcu() to use the XArray so it can still be called
for XArrays containing multi-index entries.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
In preparation for the removal of the multiorder radix tree code,
convert item_kill_tree() to use the XArray so it can still be called
for XArrays containing multi-index entries.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
The remaining tests are not suitable for moving in-kernel, so move
item_insert_order() into multiorder.c, make it static and make it use
the XArray.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
This version is a little less thorough in order to be a little quicker,
but tests the important edge cases. Also test adding a multiorder entry
at a non-canonical index, and erasing it.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Test this functionality inside the kernel as well as in userspace.
Also remove insert_bug() as there's no comparable thing to test
in the XArray code.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
With no code left in the kernel using the multiorder radix tree, convert
the iteration test from the radix tree to the XArray. It's unlikely to
suffer the same bug as the radix tree, but this test will prevent that
bug from ever creeping into the XArray implementation.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
The tag_tagged_items() function is supposed to test the page-writeback
tagging code. Since that has been converted to the XArray, there's
not much point in testing the radix tree's tagging code. This requires
using the pthread mutex embedded in the xarray instead of an external
lock, so remove the pthread mutexes which protect xarrays/radix trees.
Also remove radix_tree_iter_tag_set() as this was the last user.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
The page cache was the only user of this interface and it has now
been converted to the XArray. Transform the test into a test of
xas_init_marks().
Signed-off-by: Matthew Wilcox <willy@infradead.org>
radix_tree_split and radix_tree_join were never used upstream. Remove
them; if they're needed in future they will be replaced by XArray
equivalents.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
The only user of this functionality was the workingset code, and it's
now been converted to the XArray. Remove __radix_tree_delete_node()
entirely as it was also only used by the workingset code.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
This is a 1:1 conversion. The major part of this patch is converting
the test framework from userspace to kernel space and mirroring the
algorithm now used in find_swap_entry().
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Now the page cache lookup is using the XArray, let's convert this
regression test from the radix tree API to the XArray so it's testing
roughly the same thing it was testing before.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
There's no direct replacement for radix_tree_for_each_contig()
in the XArray API as it's an unusual thing to do. Instead,
open-code a loop using xas_next(). This removes the only user of
radix_tree_for_each_contig() so delete the iterator from the API and
the test suite code for it.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Use the XA_TRACK_FREE ability to track which entries have a free bit,
similarly to how it uses the radix tree's IDR_FREE tag. This eliminates
the per-cpu ida_bitmap preload, and fixes the memory consumption
regression I introduced when making the IDR able to store any pointer.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
xa_store() differs from radix_tree_insert() in that it will overwrite an
existing element in the array rather than returning an error. This is
the behaviour which most users want, and those that want more complex
behaviour generally want to use the xas family of routines anyway.
For memory allocation, xa_store() will first attempt to request memory
from the slab allocator; if memory is not immediately available, it will
drop the xa_lock and allocate memory, keeping a pointer in the xa_state.
It does not use the per-CPU cache, although those will continue to exist
until all radix tree users are converted to the xarray.
This patch also includes xa_erase() and __xa_erase() for a streamlined
way to store NULL. Since there is no need to allocate memory in order
to store a NULL in the XArray, we do not need to trouble the user with
deciding what memory allocation flags to use.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
The xa_load function brings with it a lot of infrastructure; xa_empty(),
xa_is_err(), and large chunks of the XArray advanced API that are used
to implement xa_load.
As the test-suite demonstrates, it is possible to use the XArray functions
on a radix tree. The radix tree functions depend on the GFP flags being
stored in the root of the tree, so it's not possible to use the radix
tree functions on an XArray.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
This is a direct replacement for struct radix_tree_node. A couple of
struct members have changed name, so convert those. Use a #define so
that radix tree users continue to work without change.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
This is a direct replacement for struct radix_tree_root. Some of the
struct members have changed name; convert those, and use a #define so
that radix_tree users continue to work without change.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Instead of storing a pointer to the slot containing the canonical entry,
store the offset of the slot. Produces slightly more efficient code
(~300 bytes) and simplifies the implementation.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Introduce xarray value entries and tagged pointers to replace radix
tree exceptional entries. This is a slight change in encoding to allow
the use of an extra bit (we can now store BITS_PER_LONG - 1 bits in a
value entry). It is also a change in emphasis; exceptional entries are
intimidating and different. As the comment explains, you can choose
to store values or pointers in the xarray and they are both first-class
citizens.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
An upcoming change to the encoding of internal entries will set the bottom
two bits to 0b10. Unfortunately, m68k only aligns some data structures
to 2 bytes, so the IDR will interpret them as internal entries and things
will go badly wrong.
Change the radix tree so that it stops either when the node indicates
that it's the bottom of the tree (shift == 0) or when the entry is not an
internal entry. This means we cannot insert an arbitrary kernel pointer
as a multiorder entry, but the IDR does not permit multiorder entries.
Annoyingly, this means the IDR can no longer take advantage of the radix
tree's ability to store a single entry at offset 0 without allocating
memory. A pointer which is 2-byte aligned cannot be stored directly in
the root as it would be indistinguishable from a node, so we must allocate
a node in order to store a 2-byte pointer at index 0. The idr_replace()
function does not take a GFP flags argument, so cannot allocate memory.
If a user inserts a 4-byte aligned pointer at index 0 and then replaces
it with a 2-byte aligned pointer, we must be able to store it.
Arbitrary pointer values are still not permitted; pointers of the
form 2 + (i * 4) for values of i between 0 and 1023 are reserved for
the implementation. These are not valid kernel pointers as they would
point into the zero page.
This change does cause a runtime memory consumption regression for
the IDA. I will recover that later.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Move these tests from the userspace test-suite to the kernel test-suite.
Also convert check_ida_random to the new API.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Move as much as possible to kernel space; leave the parts in user space
that rely on checking memory allocation failures to detect the
transition between an exceptional entry and a bitmap.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Convert to new API and move to kernel space. Take the opportunity to
test the situation a little more thoroughly (ie at different offsets).
Signed-off-by: Matthew Wilcox <willy@infradead.org>
We can't move this test to kernel space because there's no way to
force kmalloc to fail. But we can use the new API and check this
works when the test is in userspace.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
