Danilo Krummrich raised issue about krealloc+GFP_ZERO [1], and Vlastimil
suggested to add some test case which can sanity test the kmalloc-redzone
and zeroing by utilizing the kmalloc's 'orig_size' debug feature.
It covers the grow and shrink case of krealloc() re-using current kmalloc
object, and the case of re-allocating a new bigger object.
[1]. https://lore.kernel.org/lkml/20240812223707.32049-1-dakr@kernel.org/
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
'modprobe slub_kunit' will have a warning as shown below. The root cause
is that __kmalloc_cache_noprof was directly used, which resulted in no
alloc_tag being allocated. This caused current->alloc_tag to be null,
leading to a warning in alloc_tag_add_check.
Let's add an alloc_hook layer to __kmalloc_cache_noprof specifically
within lib/slub_kunit.c, which is the only user of this internal slub
function outside kmalloc implementation itself.
[58162.947016] WARNING: CPU: 2 PID: 6210 at
./include/linux/alloc_tag.h:125 alloc_tagging_slab_alloc_hook+0x268/0x27c
[58162.957721] Call trace:
[58162.957919] alloc_tagging_slab_alloc_hook+0x268/0x27c
[58162.958286] __kmalloc_cache_noprof+0x14c/0x344
[58162.958615] test_kmalloc_redzone_access+0x50/0x10c [slub_kunit]
[58162.959045] kunit_try_run_case+0x74/0x184 [kunit]
[58162.959401] kunit_generic_run_threadfn_adapter+0x2c/0x4c [kunit]
[58162.959841] kthread+0x10c/0x118
[58162.960093] ret_from_fork+0x10/0x20
[58162.960363] ---[ end trace 0000000000000000 ]---
Signed-off-by: Pei Xiao <xiaopei01@kylinos.cn>
Fixes: a0a44d9175 ("mm, slab: don't wrap internal functions with alloc_hooks()")
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Guenter Roeck reports that the new slub kunit tests added by commit
4e1c44b3db ("kunit, slub: add test_kfree_rcu() and
test_leak_destroy()") cause a lockup on boot on several architectures
when the kunit tests are configured to be built-in and not modules.
The test_kfree_rcu test invokes kfree_rcu() and boot sequence inspection
showed the runner for built-in kunit tests kunit_run_all_tests() is
called before setting system_state to SYSTEM_RUNNING and calling
rcu_end_inkernel_boot(), so this seems like a likely cause. So while I
was unable to reproduce the problem myself, skipping the test when the
slub_kunit module is built-in should avoid the issue.
An alternative fix that was moving the call to kunit_run_all_tests() a
bit later in the boot was tried, but has broken tests with functions
marked as __init due to free_initmem() already being done.
Fixes: 4e1c44b3db ("kunit, slub: add test_kfree_rcu() and test_leak_destroy()")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/all/6fcb1252-7990-4f0d-8027-5e83f0fb9409@roeck-us.net/
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: rcu@vger.kernel.org
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
Cc: linux-kselftest@vger.kernel.org
Cc: kunit-dev@googlegroups.com
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
The test_leak_destroy kunit test intends to test the detection of stray
objects in kmem_cache_destroy(), which normally produces a warning. The
other slab kunit tests suppress the warnings in the kunit test context,
so suppress warnings and related printk output in this test as well.
Automated test running environments then don't need to learn to filter
the warnings.
Also rename the test's kmem_cache, the name was wrongly copy-pasted from
test_kfree_rcu.
Fixes: 4e1c44b3db ("kunit, slub: add test_kfree_rcu() and test_leak_destroy()")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202408251723.42f3d902-oliver.sang@intel.com
Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Closes: https://lore.kernel.org/all/CAB=+i9RHHbfSkmUuLshXGY_ifEZg9vCZi3fqr99+kmmnpDus7Q@mail.gmail.com/
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/all/6fcb1252-7990-4f0d-8027-5e83f0fb9409@roeck-us.net/
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Add a test that will create cache, allocate one object, kfree_rcu() it
and attempt to destroy it. As long as the usage of kvfree_rcu_barrier()
in kmem_cache_destroy() works correctly, there should be no warnings in
dmesg and the test should pass.
Additionally add a test_leak_destroy() test that leaks an object on
purpose and verifies that kmem_cache_destroy() catches it.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
The functions __kmalloc_noprof(), kmalloc_large_noprof(),
kmalloc_trace_noprof() and their _node variants are all internal to the
implementations of kmalloc_noprof() and kmalloc_node_noprof() and are
only declared in the "public" slab.h and exported so that those
implementations can be static inline and distinguish the build-time
constant size variants. The only other users for some of the internal
functions are slub_kunit and fortify_kunit tests which make very
short-lived allocations.
Therefore we can stop wrapping them with the alloc_hooks() macro.
Instead add a __ prefix to all of them and a comment documenting these
as internal. Also rename __kmalloc_trace() to __kmalloc_cache() which is
more descriptive - it is a variant of __kmalloc() where the exact
kmalloc cache has been already determined.
The usage in fortify_kunit can be removed completely, as the internal
functions should be tested already through kmalloc() tests in the
test variant that passes non-constant allocation size.
Reported-by: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: Kent Overstreet <kent.overstreet@linux.dev>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Two failure patterns are seen randomly when running slub_kunit tests with
CONFIG_SLAB_FREELIST_RANDOM and CONFIG_SLAB_FREELIST_HARDENED enabled.
Pattern 1:
# test_clobber_zone: pass:1 fail:0 skip:0 total:1
ok 1 test_clobber_zone
# test_next_pointer: EXPECTATION FAILED at lib/slub_kunit.c:72
Expected 3 == slab_errors, but
slab_errors == 0 (0x0)
# test_next_pointer: EXPECTATION FAILED at lib/slub_kunit.c:84
Expected 2 == slab_errors, but
slab_errors == 0 (0x0)
# test_next_pointer: pass:0 fail:1 skip:0 total:1
not ok 2 test_next_pointer
In this case, test_next_pointer() overwrites p[s->offset], but the data
at p[s->offset] is already 0x12.
Pattern 2:
ok 1 test_clobber_zone
# test_next_pointer: EXPECTATION FAILED at lib/slub_kunit.c:72
Expected 3 == slab_errors, but
slab_errors == 2 (0x2)
# test_next_pointer: pass:0 fail:1 skip:0 total:1
not ok 2 test_next_pointer
In this case, p[s->offset] has a value other than 0x12, but one of the
expected failures is nevertheless missing.
Invert data instead of writing a fixed value to corrupt the cache data
structures to fix the problem.
Fixes: 1f9f78b1b3 ("mm/slub, kunit: add a KUnit test for SLUB debugging functionality")
Cc: Oliver Glitta <glittao@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
CC: Daniel Latypov <dlatypov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
This KUnit next update for Linux 6.2-rc1 consists of several enhancements,
fixes, clean-ups, documentation updates, improvements to logging and KTAP
compliance of KUnit test output:
- log numbers in decimal and hex
- parse KTAP compliant test output
- allow conditionally exposing static symbols to tests
when KUNIT is enabled
- make static symbols visible during kunit testing
- clean-ups to remove unused structure definition
-----BEGIN PGP SIGNATURE-----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=UQNn
-----END PGP SIGNATURE-----
Merge tag 'linux-kselftest-kunit-next-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
Pull KUnit updates from Shuah Khan:
"Several enhancements, fixes, clean-ups, documentation updates,
improvements to logging and KTAP compliance of KUnit test output:
- log numbers in decimal and hex
- parse KTAP compliant test output
- allow conditionally exposing static symbols to tests when KUNIT is
enabled
- make static symbols visible during kunit testing
- clean-ups to remove unused structure definition"
* tag 'linux-kselftest-kunit-next-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (29 commits)
Documentation: dev-tools: Clarify requirements for result description
apparmor: test: make static symbols visible during kunit testing
kunit: add macro to allow conditionally exposing static symbols to tests
kunit: tool: make parser preserve whitespace when printing test log
Documentation: kunit: Fix "How Do I Use This" / "Next Steps" sections
kunit: tool: don't include KTAP headers and the like in the test log
kunit: improve KTAP compliance of KUnit test output
kunit: tool: parse KTAP compliant test output
mm: slub: test: Use the kunit_get_current_test() function
kunit: Use the static key when retrieving the current test
kunit: Provide a static key to check if KUnit is actively running tests
kunit: tool: make --json do nothing if --raw_ouput is set
kunit: tool: tweak error message when no KTAP found
kunit: remove KUNIT_INIT_MEM_ASSERTION macro
Documentation: kunit: Remove redundant 'tips.rst' page
Documentation: KUnit: reword description of assertions
Documentation: KUnit: make usage.rst a superset of tips.rst, remove duplication
kunit: eliminate KUNIT_INIT_*_ASSERT_STRUCT macros
kunit: tool: remove redundant file.close() call in unit test
kunit: tool: unit tests all check parser errors, standardize formatting a bit
...
Use the newly-added function kunit_get_current_test() instead of
accessing current->kunit_test directly. This function uses a static key
to return more quickly when KUnit is enabled, but no tests are actively
running. There should therefore be a negligible performance impact to
enabling the slub KUnit tests.
Other than the performance improvement, this should be a no-op.
Cc: Oliver Glitta <glittao@gmail.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Gow <davidgow@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
kmalloc redzone check for slub has been merged, and it's better to add
a kunit case for it, which is inspired by a real-world case as described
in commit 120ee599b5 ("staging: octeon-usb: prevent memory corruption"):
"
octeon-hcd will crash the kernel when SLOB is used. This usually happens
after the 18-byte control transfer when a device descriptor is read.
The DMA engine is always transferring full 32-bit words and if the
transfer is shorter, some random garbage appears after the buffer.
The problem is not visible with SLUB since it rounds up the allocations
to word boundary, and the extra bytes will go undetected.
"
To avoid interrupting the normal functioning of kmalloc caches, a
kmem_cache mimicing kmalloc cache is created with similar flags, and
kmalloc_trace() is used to really test the orig_size and redzone setup.
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
When kfence is enabled, the buffer allocated from the test case
could be from a kfence pool, and the operation could be also
caught and reported by kfence first, causing the case to fail.
With default kfence setting, this is very difficult to be triggered.
By changing CONFIG_KFENCE_NUM_OBJECTS from 255 to 16383, and
CONFIG_KFENCE_SAMPLE_INTERVAL from 100 to 5, the allocation from
kfence did hit 7 times in different slub_kunit cases out of 900
times of boot test.
To avoid this, initially we tried is_kfence_address() to check this
and repeated allocation till finding a non-kfence address. Vlastimil
Babka suggested SLAB_SKIP_KFENCE flag could be used to achieve this,
and better add a wrapper function for simplifying cache creation.
Signed-off-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
slub_kunit does not expect other debugging flags to be set when running
tests. When SLAB_RED_ZONE flag is set globally, test fails because the
flag affects number of errors reported.
To make slub_kunit unaffected by user specified debugging flags,
introduce SLAB_NO_USER_FLAGS to ignore them. With this flag, only flags
specified in the code are used and others are ignored.
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Link: https://lore.kernel.org/r/Yk0sY9yoJhFEXWOg@hyeyoo
SLUB has resiliency_test() function which is hidden behind #ifdef
SLUB_RESILIENCY_TEST that is not part of Kconfig, so nobody runs it.
KUnit should be a proper replacement for it.
Try changing byte in redzone after allocation and changing pointer to next
free node, first byte, 50th byte and redzone byte. Check if validation
finds errors.
There are several differences from the original resiliency test: Tests
create own caches with known state instead of corrupting shared kmalloc
caches.
The corruption of freepointer uses correct offset, the original resiliency
test got broken with freepointer changes.
Scratch changing random byte test, because it does not have meaning in
this form where we need deterministic results.
Add new option CONFIG_SLUB_KUNIT_TEST in Kconfig. Tests next_pointer,
first_word and clobber_50th_byte do not run with KASAN option on. Because
the test deliberately modifies non-allocated objects.
Use kunit_resource to count errors in cache and silence bug reports.
Count error whenever slab_bug() or slab_fix() is called or when the count
of pages is wrong.
[glittao@gmail.com: remove unused function test_exit(), from SLUB KUnit test]
Link: https://lkml.kernel.org/r/20210512140656.12083-1-glittao@gmail.com
[akpm@linux-foundation.org: export kasan_enable/disable_current to modules]
Link: https://lkml.kernel.org/r/20210511150734.3492-2-glittao@gmail.com
Signed-off-by: Oliver Glitta <glittao@gmail.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Daniel Latypov <dlatypov@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
