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Merge tag 'slab-for-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab updates from Vlastimil Babka:
- Freelist loading optimization (Chengming Zhou)
When the per-cpu slab is depleted and a new one loaded from the cpu
partial list, optimize the loading to avoid an irq enable/disable
cycle. This results in a 3.5% performance improvement on the "perf
bench sched messaging" test.
- Kernel boot parameters cleanup after SLAB removal (Xiongwei Song)
Due to two different main slab implementations we've had boot
parameters prefixed either slab_ and slub_ with some later becoming
an alias as both implementations gained the same functionality (i.e.
slab_nomerge vs slub_nomerge). In order to eventually get rid of the
implementation-specific names, the canonical and documented
parameters are now all prefixed slab_ and the slub_ variants become
deprecated but still working aliases.
- SLAB_ kmem_cache creation flags cleanup (Vlastimil Babka)
The flags had hardcoded #define values which became tedious and
error-prone when adding new ones. Assign the values via an enum that
takes care of providing unique bit numbers. Also deprecate
SLAB_MEM_SPREAD which was only used by SLAB, so it's a no-op since
SLAB removal. Assign it an explicit zero value. The removals of the
flag usage are handled independently in the respective subsystems,
with a final removal of any leftover usage planned for the next
release.
- Misc cleanups and fixes (Chengming Zhou, Xiaolei Wang, Zheng Yejian)
Includes removal of unused code or function parameters and a fix of a
memleak.
* tag 'slab-for-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
slab: remove PARTIAL_NODE slab_state
mm, slab: remove memcg_from_slab_obj()
mm, slab: remove the corner case of inc_slabs_node()
mm/slab: Fix a kmemleak in kmem_cache_destroy()
mm, slab, kasan: replace kasan_never_merge() with SLAB_NO_MERGE
mm, slab: use an enum to define SLAB_ cache creation flags
mm, slab: deprecate SLAB_MEM_SPREAD flag
mm, slab: fix the comment of cpu partial list
mm, slab: remove unused object_size parameter in kmem_cache_flags()
mm/slub: remove parameter 'flags' in create_kmalloc_caches()
mm/slub: remove unused parameter in next_freelist_entry()
mm/slub: remove full list manipulation for non-debug slab
mm/slub: directly load freelist from cpu partial slab in the likely case
mm/slub: make the description of slab_min_objects helpful in doc
mm/slub: replace slub_$params with slab_$params in slub.rst
mm/slub: unify all sl[au]b parameters with "slab_$param"
Documentation: kernel-parameters: remove noaliencache
The SLAB_KASAN flag prevents merging of caches in some configurations,
which is handled in a rather complicated way via kasan_never_merge().
Since we now have a generic SLAB_NO_MERGE flag, we can instead use it
for KASAN caches in addition to SLAB_KASAN in those configurations,
and simplify the SLAB_NEVER_MERGE handling.
Tested-by: Xiongwei Song <xiongwei.song@windriver.com>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Tested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
This partially reverts commits cc478e0b6b, 63b85ac56a, 08d7c94d96,
a414d4286f, and 773688a6cb to make use of variable-sized stack depot
records, since eviction of stack entries from stack depot forces fixed-
sized stack records. Care was taken to retain the code cleanups by the
above commits.
Eviction was added to generic KASAN as a response to alleviating the
additional memory usage from fixed-sized stack records, but this still
uses more memory than previously.
With the re-introduction of variable-sized records for stack depot, we can
just switch back to non-evictable stack records again, and return back to
the previous performance and memory usage baseline.
Before (observed after a KASAN kernel boot):
pools: 597
refcounted_allocations: 17547
refcounted_frees: 6477
refcounted_in_use: 11070
freelist_size: 3497
persistent_count: 12163
persistent_bytes: 1717008
After:
pools: 319
refcounted_allocations: 0
refcounted_frees: 0
refcounted_in_use: 0
freelist_size: 0
persistent_count: 29397
persistent_bytes: 5183536
As can be seen from the counters, with a generic KASAN config, refcounted
allocations and evictions are no longer used. Due to using variable-sized
records, I observe a reduction of 278 stack depot pools (saving 4448 KiB)
with my test setup.
Link: https://lkml.kernel.org/r/20240129100708.39460-2-elver@google.com
Fixes: cc478e0b6b ("kasan: avoid resetting aux_lock")
Fixes: 63b85ac56a ("kasan: stop leaking stack trace handles")
Fixes: 08d7c94d96 ("kasan: memset free track in qlink_free")
Fixes: a414d4286f ("kasan: handle concurrent kasan_record_aux_stack calls")
Fixes: 773688a6cb ("kasan: use stack_depot_put for Generic mode")
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
release_free_meta() accesses the shadow directly through the path
kasan_slab_free
__kasan_slab_free
kasan_release_object_meta
release_free_meta
kasan_mem_to_shadow
There are no kasan_arch_is_ready() guards here, allowing an oops when the
shadow is not initialized. The oops can be seen on a Power8 KVM guest.
This patch adds the guard to release_free_meta(), as it's the first level
that specifically requires the shadow.
It is safe to put the guard at the start of this function, before the
stack put: only kasan_save_free_info() can initialize the saved stack,
which itself is guarded with kasan_arch_is_ready() by its caller
poison_slab_object(). If the arch becomes ready before
release_free_meta() then we will not observe KASAN_SLAB_FREE_META in the
object's shadow, so we will not put an uninitialized stack either.
Link: https://lkml.kernel.org/r/20240213033958.139383-1-bgray@linux.ibm.com
Fixes: 63b85ac56a ("kasan: stop leaking stack trace handles")
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
With commit 63b85ac56a ("kasan: stop leaking stack trace handles"),
KASAN zeroes out alloc meta when an object is freed. The zeroed out data
purposefully includes alloc and auxiliary stack traces but also
accidentally includes aux_lock.
As aux_lock is only initialized for each object slot during slab creation,
when the freed slot is reallocated, saving auxiliary stack traces for the
new object leads to lockdep reports when taking the zeroed out aux_lock.
Arguably, we could reinitialize aux_lock when the object is reallocated,
but a simpler solution is to avoid zeroing out aux_lock when an object
gets freed.
Link: https://lkml.kernel.org/r/20240109221234.90929-1-andrey.konovalov@linux.dev
Fixes: 63b85ac56a ("kasan: stop leaking stack trace handles")
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Closes: https://lore.kernel.org/linux-next/5cc0f83c-e1d6-45c5-be89-9b86746fe731@paulmck-laptop/
Reviewed-by: Marco Elver <elver@google.com>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 773688a6cb ("kasan: use stack_depot_put for Generic mode") added
support for stack trace eviction for Generic KASAN.
However, that commit didn't evict stack traces when the object is not put
into quarantine. As a result, some stack traces are never evicted from
the stack depot.
In addition, with the "kasan: save mempool stack traces" series, the free
stack traces for mempool objects are also not properly evicted from the
stack depot.
Fix both issues by:
1. Evicting all stack traces when an object if freed if it was not put
into quarantine;
2. Always evicting an existing free stack trace when a new one is saved.
Also do a few related clean-ups:
- Do not zero out free track when initializing/invalidating free meta:
set a value in shadow memory instead;
- Rename KASAN_SLAB_FREETRACK to KASAN_SLAB_FREE_META;
- Drop the kasan_init_cache_meta function as it's not used by KASAN;
- Add comments for the kasan_alloc_meta and kasan_free_meta structs.
[akpm@linux-foundation.org: make release_free_meta() and release_alloc_meta() static]
Link: https://lkml.kernel.org/r/20231226225121.235865-1-andrey.konovalov@linux.dev
Fixes: 773688a6cb ("kasan: use stack_depot_put for Generic mode")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Avoid duplicating code for saving extra info into tracks: reuse the common
function for this.
Link: https://lkml.kernel.org/r/20231221183540.168428-3-andrey.konovalov@linux.dev
Fixes: 5d4c6ac946 ("kasan: record and report more information")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Juntong Deng <juntong.deng@outlook.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reorganize the code to avoid nested if/else checks to improve the
readability.
Also drop the confusing comments about KMALLOC_MAX_SIZE checks: they are
relevant for both SLUB and SLAB (originally, the comments likely confused
KMALLOC_MAX_SIZE with KMALLOC_MAX_CACHE_SIZE).
Link: https://lkml.kernel.org/r/20231221183540.168428-1-andrey.konovalov@linux.dev
Fixes: a5989d4ed4 ("kasan: improve free meta storage in Generic KASAN")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Juntong Deng <juntong.deng@outlook.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
kasan_record_aux_stack can be called concurrently on the same object.
This might lead to a race condition when rotating the saved aux stack
trace handles, which in turns leads to incorrect accounting of stack depot
handles and refcount underflows in the stack depot code.
Fix by introducing a raw spinlock to protect the aux stack trace handles
in kasan_record_aux_stack.
Link: https://lkml.kernel.org/r/1606b960e2f746862d1f459515972f9695bf448a.1703020707.git.andreyknvl@google.com
Fixes: 773688a6cb ("kasan: use stack_depot_put for Generic mode")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Reported-by: syzbot+186b55175d8360728234@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/000000000000784b1c060b0074a2@google.com/
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently free meta can only be stored in object if the object is not
smaller than free meta.
After the improvement, when the object is smaller than free meta and SLUB
DEBUG is not enabled, it is possible to store part of the free meta in the
object, reducing the increased size of the red zone.
Example:
free meta size: 16 bytes
alloc meta size: 16 bytes
object size: 8 bytes
optimal redzone size (object_size <= 64): 16 bytes
Before improvement:
actual redzone size = alloc meta size + free meta size = 32 bytes
After improvement:
actual redzone size = alloc meta size + (free meta size - object size)
= 24 bytes
[juntong.deng@outlook.com: make kasan_metadata_size() adapt to the improved free meta storage]
Link: https://lkml.kernel.org/r/VI1P193MB0752675D6E0A2D16CE656F8299BAA@VI1P193MB0752.EURP193.PROD.OUTLOOK.COM
Link: https://lkml.kernel.org/r/VI1P193MB0752DE2CCD9046B5FED0AA8E99B5A@VI1P193MB0752.EURP193.PROD.OUTLOOK.COM
Signed-off-by: Juntong Deng <juntong.deng@outlook.com>
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Evict alloc/free stack traces from the stack depot for Generic KASAN once
they are evicted from the quaratine.
For auxiliary stack traces, evict the oldest stack trace once a new one is
saved (KASAN only keeps references to the last two).
Also evict all saved stack traces on krealloc.
To avoid double-evicting and mis-evicting stack traces (in case KASAN's
metadata was corrupted), reset KASAN's per-object metadata that stores
stack depot handles when the object is initialized and when it's evicted
from the quarantine.
Note that stack_depot_put is no-op if the handle is 0.
Link: https://lkml.kernel.org/r/5cef104d9b842899489b4054fe8d1339a71acee0.1700502145.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Change the bool can_alloc argument of __stack_depot_save to a u32
argument that accepts a set of flags.
The following patch will add another flag to stack_depot_save_flags
besides the existing STACK_DEPOT_FLAG_CAN_ALLOC.
Also rename the function to stack_depot_save_flags, as
__stack_depot_save is a cryptic name,
Link: https://lkml.kernel.org/r/645fa15239621eebbd3a10331e5864b718839512.1700502145.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit bb6e04a173 ("kasan: use internal prototypes matching gcc-13
builtins") introduced a bug into the memory_is_poisoned_n implementation:
it effectively removed the cast to a signed integer type after applying
KASAN_GRANULE_MASK.
As a result, KASAN started failing to properly check memset, memcpy, and
other similar functions.
Fix the bug by adding the cast back (through an additional signed integer
variable to make the code more readable).
Link: https://lkml.kernel.org/r/8c9e0251c2b8b81016255709d4ec42942dcaf018.1688431866.git.andreyknvl@google.com
Fixes: bb6e04a173 ("kasan: use internal prototypes matching gcc-13 builtins")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
syzbot is reporting lockdep warning in __stack_depot_save(), for
the caller of __stack_depot_save() (i.e. __kasan_record_aux_stack() in
this report) is responsible for masking __GFP_KSWAPD_RECLAIM flag in
order not to wake kswapd which in turn wakes kcompactd.
Since kasan/kmsan functions might be called with arbitrary locks held,
mask __GFP_KSWAPD_RECLAIM flag from all GFP_NOWAIT/GFP_ATOMIC allocations
in kasan/kmsan.
Note that kmsan_save_stack_with_flags() is changed to mask both
__GFP_DIRECT_RECLAIM flag and __GFP_KSWAPD_RECLAIM flag, for
wakeup_kswapd() from wake_all_kswapds() from __alloc_pages_slowpath()
calls wakeup_kcompactd() if __GFP_KSWAPD_RECLAIM flag is set and
__GFP_DIRECT_RECLAIM flag is not set.
Link: https://lkml.kernel.org/r/656cb4f5-998b-c8d7-3c61-c2d37aa90f9a@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+ece2915262061d6e0ac1@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=ece2915262061d6e0ac1
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
gcc-13 warns about function definitions for builtin interfaces that have a
different prototype, e.g.:
In file included from kasan_test.c:31:
kasan.h:574:6: error: conflicting types for built-in function '__asan_register_globals'; expected 'void(void *, long int)' [-Werror=builtin-declaration-mismatch]
574 | void __asan_register_globals(struct kasan_global *globals, size_t size);
kasan.h:577:6: error: conflicting types for built-in function '__asan_alloca_poison'; expected 'void(void *, long int)' [-Werror=builtin-declaration-mismatch]
577 | void __asan_alloca_poison(unsigned long addr, size_t size);
kasan.h:580:6: error: conflicting types for built-in function '__asan_load1'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
580 | void __asan_load1(unsigned long addr);
kasan.h:581:6: error: conflicting types for built-in function '__asan_store1'; expected 'void(void *)' [-Werror=builtin-declaration-mismatch]
581 | void __asan_store1(unsigned long addr);
kasan.h:643:6: error: conflicting types for built-in function '__hwasan_tag_memory'; expected 'void(void *, unsigned char, long int)' [-Werror=builtin-declaration-mismatch]
643 | void __hwasan_tag_memory(unsigned long addr, u8 tag, unsigned long size);
The two problems are:
- Addresses are passes as 'unsigned long' in the kernel, but gcc-13
expects a 'void *'.
- sizes meant to use a signed ssize_t rather than size_t.
Change all the prototypes to match these. Using 'void *' consistently for
addresses gets rid of a couple of type casts, so push that down to the
leaf functions where possible.
This now passes all randconfig builds on arm, arm64 and x86, but I have
not tested it on the other architectures that support kasan, since they
tend to fail randconfig builds in other ways. This might fail if any of
the 32-bit architectures expect a 'long' instead of 'int' for the size
argument.
The __asan_allocas_unpoison() function prototype is somewhat weird, since
it uses a pointer for 'stack_top' and an size_t for 'stack_bottom'. This
looks like it is meant to be 'addr' and 'size' like the others, but the
implementation clearly treats them as 'top' and 'bottom'.
Link: https://lkml.kernel.org/r/20230509145735.9263-2-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Make KASAN scan metadata to infer the requested allocation size instead of
printing cache->object_size.
This patch fixes confusing slab-out-of-bounds reports as reported in:
https://bugzilla.kernel.org/show_bug.cgi?id=216457
As an example of the confusing behavior, the report below hints that the
allocation size was 192, while the kernel actually called kmalloc(184):
==================================================================
BUG: KASAN: slab-out-of-bounds in _find_next_bit+0x143/0x160 lib/find_bit.c:109
Read of size 8 at addr ffff8880175766b8 by task kworker/1:1/26
...
The buggy address belongs to the object at ffff888017576600
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 184 bytes inside of
192-byte region [ffff888017576600, ffff8880175766c0)
...
Memory state around the buggy address:
ffff888017576580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff888017576600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888017576680: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
^
ffff888017576700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888017576780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
With this patch, the report shows:
==================================================================
...
The buggy address belongs to the object at ffff888017576600
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 0 bytes to the right of
allocated 184-byte region [ffff888017576600, ffff8880175766b8)
...
==================================================================
Also report slab use-after-free bugs as "slab-use-after-free" and print
"freed" instead of "allocated" in the report when describing the accessed
memory region.
Also improve the metadata-related comment in kasan_find_first_bad_addr
and use addr_has_metadata across KASAN code instead of open-coding
KASAN_SHADOW_START checks.
[akpm@linux-foundation.org: fix printk warning]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216457
Link: https://lkml.kernel.org/r/20230129021437.18812-1-Kuan-Ying.Lee@mediatek.com
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Co-developed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Qun-Wei Lin <qun-wei.lin@mediatek.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When kasan is enabled for slab/slub, it may save kasan' free_meta
data in the former part of slab object data area in slab object's
free path, which works fine.
There is ongoing effort to extend slub's debug function which will
redzone the latter part of kmalloc object area, and when both of
the debug are enabled, there is possible conflict, especially when
the kmalloc object has small size, as caught by 0Day bot [1].
To solve it, slub code needs to know the in-object kasan's meta
data size. Currently, there is existing kasan_metadata_size()
which returns the kasan's metadata size inside slub's metadata
area, so extend it to also cover the in-object meta size by
adding a boolean flag 'in_object'.
There is no functional change to existing code logic.
[1]. https://lore.kernel.org/lkml/YuYm3dWwpZwH58Hu@xsang-OptiPlex-9020/
Reported-by: kernel test robot <oliver.sang@intel.com>
Suggested-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Move the definitions of kasan_get_alloc/free_track() to report_*.c, as
they belong with other the reporting code.
Link: https://lkml.kernel.org/r/0cb15423956889b3905a0174b58782633bbbd72e.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pass tagged pointers to kasan_save_alloc/free_info().
This is a preparatory patch to simplify other changes in the series.
Link: https://lkml.kernel.org/r/d5bc48cfcf0dca8269dc3ed863047e4d4d2030f1.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Right now, kasan_cache_create() assigns SLAB_KASAN for all KASAN modes and
then sets up metadata-related cache parameters for the Generic mode.
SLAB_KASAN is used in two places:
1. In slab_ksize() to account for per-object metadata when
calculating the size of the accessible memory within the object.
2. In slab_common.c via kasan_never_merge() to prevent merging of
caches with per-object metadata.
Both cases are only relevant when per-object metadata is present, which is
only the case with the Generic mode.
Thus, assign SLAB_KASAN and define kasan_cache_create() only for the
Generic mode.
Also update the SLAB_KASAN-related comment.
Link: https://lkml.kernel.org/r/61faa2aa1906e2d02c97d00ddf99ce8911dda095.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
KASAN prevents merging of slab caches whose objects have per-object
metadata stored in redzones.
As now only the Generic mode uses per-object metadata, define
kasan_never_merge() only for this mode.
Link: https://lkml.kernel.org/r/81ed01f29ff3443580b7e2fe362a8b47b1e8006d.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
KASAN provides a helper for calculating the size of per-object metadata
stored in the redzone.
As now only the Generic mode uses per-object metadata, only define
kasan_metadata_size() for this mode.
Link: https://lkml.kernel.org/r/8f81d4938b80446bc72538a08217009f328a3e23.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
As kasan_init_cache_meta() is only defined for the Generic mode, it does
not require the CONFIG_KASAN_GENERIC check.
Link: https://lkml.kernel.org/r/211f8f2b213aa91e9148ca63342990b491c4917a.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add a kasan_init_cache_meta() helper that initializes metadata-related
cache parameters and use this helper in the common KASAN code.
Put the implementation of this new helper into generic.c, as only the
Generic mode uses per-object metadata.
Link: https://lkml.kernel.org/r/a6d7ea01876eb36472c9879f7b23f1b24766276e.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Move the implementations of kasan_get_alloc/free_meta() to generic.c, as
the common KASAN code does not use these functions anymore.
Also drop kasan_reset_tag() from the implementation, as the Generic mode
does not tag pointers.
Link: https://lkml.kernel.org/r/ffcfc0ad654d78a2ef4ca054c943ddb4e5ca477b.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add a kasan_init_object_meta() helper that initializes metadata for a slab
object and use it in the common code.
For now, the implementations of this helper are the same for the Generic
and tag-based modes, but they will diverge later in the series.
This change hides references to alloc_meta from the common code. This is
desired as only the Generic mode will be using per-object metadata after
this series.
Link: https://lkml.kernel.org/r/47c12938fc7f8105e7aaa592527c0e9d3c81fc37.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add a kasan_get_alloc_track() helper that fetches alloc_track for a slab
object and use this helper in the common reporting code.
For now, the implementations of this helper are the same for the Generic
and tag-based modes, but they will diverge later in the series.
This change hides references to alloc_meta from the common reporting code.
This is desired as only the Generic mode will be using per-object
metadata after this series.
Link: https://lkml.kernel.org/r/0c365a35f4a833fff46f9d42c3212b32f7166556.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Provide standalone implementations of save_alloc_info() for the Generic
and tag-based modes.
For now, the implementations are the same, but they will diverge later in
the series.
Link: https://lkml.kernel.org/r/77f1a078489c1e859aedb5403f772e5e1f7410a0.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rename set_alloc_info() and kasan_set_free_info() to save_alloc_info() and
kasan_save_free_info(). The new names make more sense.
Link: https://lkml.kernel.org/r/9f04777a15cb9d96bf00331da98e021d732fe1c9.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rename KASAN_KMALLOC_* shadow values to KASAN_SLAB_*, as they are used for
all slab allocations, not only for kmalloc.
Also rename KASAN_FREE_PAGE to KASAN_PAGE_FREE to be consistent with
KASAN_PAGE_REDZONE and KASAN_SLAB_FREE.
Link: https://lkml.kernel.org/r/bebcaf4eafdb0cabae0401a69c0af956aa87fcaa.1652111464.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
KASAN accesses some slab related struct page fields so we need to
convert it to struct slab. Some places are a bit simplified thanks to
kasan_addr_to_slab() encapsulating the PageSlab flag check through
virt_to_slab(). When resolving object address to either a real slab or
a large kmalloc, use struct folio as the intermediate type for testing
the slab flag to avoid unnecessary implicit compound_head().
[ vbabka@suse.cz: use struct folio, adjust to differences in previous
patches ]
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Tested-by: Hyeongogn Yoo <42.hyeyoo@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <kasan-dev@googlegroups.com>
Introduce a variant of kasan_record_aux_stack() that does not do any
memory allocation through stackdepot. This will permit using it in
contexts that cannot allocate any memory.
Link: https://lkml.kernel.org/r/20210913112609.2651084-6-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Tested-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Taras Madan <tarasmadan@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: Walter Wu <walter-zh.wu@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow architectures to define a kasan_arch_is_ready() hook that bails out
of any function that's about to touch the shadow unless the arch says that
it is ready for the memory to be accessed. This is fairly uninvasive and
should have a negligible performance penalty.
This will only work in outline mode, so an arch must specify
ARCH_DISABLE_KASAN_INLINE if it requires this.
Link: https://lkml.kernel.org/r/20210624034050.511391-3-dja@axtens.net
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Marco Elver <elver@google.com>
Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change adds an argument to kasan_poison() and kasan_unpoison() that
allows initializing memory along with setting the tags for HW_TAGS.
Combining setting allocation tags with memory initialization will improve
HW_TAGS KASAN performance when init_on_alloc/free is enabled.
This change doesn't integrate memory initialization with KASAN, this is
done is subsequent patches in this series.
Link: https://lkml.kernel.org/r/3054314039fa64510947e674180d675cab1b4c41.1615296150.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make KFENCE compatible with KASAN. Currently this helps test KFENCE
itself, where KASAN can catch potential corruptions to KFENCE state, or
other corruptions that may be a result of freepointer corruptions in the
main allocators.
[akpm@linux-foundation.org: merge fixup]
[andreyknvl@google.com: untag addresses for KFENCE]
Link: https://lkml.kernel.org/r/9dc196006921b191d25d10f6e611316db7da2efc.1611946152.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/20201103175841.3495947-7-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Jann Horn <jannh@google.com>
Co-developed-by: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joern Engel <joern@purestorage.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: SeongJae Park <sjpark@amazon.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The currently existing kasan_check_read/write() annotations are intended
to be used for kernel modules that have KASAN compiler instrumentation
disabled. Thus, they are only relevant for the software KASAN modes that
rely on compiler instrumentation.
However there's another use case for these annotations: ksize() checks
that the object passed to it is indeed accessible before unpoisoning the
whole object. This is currently done via __kasan_check_read(), which is
compiled away for the hardware tag-based mode that doesn't rely on
compiler instrumentation. This leads to KASAN missing detecting some
memory corruptions.
Provide another annotation called kasan_check_byte() that is available
for all KASAN modes. As the implementation rename and reuse
kasan_check_invalid_free(). Use this new annotation in ksize().
To avoid having ksize() as the top frame in the reported stack trace
pass _RET_IP_ to __kasan_check_byte().
Also add a new ksize_uaf() test that checks that a use-after-free is
detected via ksize() itself, and via plain accesses that happen later.
Link: https://linux-review.googlesource.com/id/Iaabf771881d0f9ce1b969f2a62938e99d3308ec5
Link: https://lkml.kernel.org/r/f32ad74a60b28d8402482a38476f02bb7600f620.1610733117.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "kasan: HW_TAGS tests support and fixes", v4.
This patchset adds support for running KASAN-KUnit tests with the
hardware tag-based mode and also contains a few fixes.
This patch (of 15):
There's a number of internal KASAN functions that are used across multiple
source code files and therefore aren't marked as static inline. To avoid
littering the kernel function names list with generic function names,
prefix all such KASAN functions with kasan_.
As a part of this change:
- Rename internal (un)poison_range() to kasan_(un)poison() (no _range)
to avoid name collision with a public kasan_unpoison_range().
- Rename check_memory_region() to kasan_check_range(), as it's a more
fitting name.
Link: https://lkml.kernel.org/r/cover.1610733117.git.andreyknvl@google.com
Link: https://linux-review.googlesource.com/id/I719cc93483d4ba288a634dba80ee6b7f2809cd26
Link: https://lkml.kernel.org/r/13777aedf8d3ebbf35891136e1f2287e2f34aaba.1610733117.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Suggested-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
KASAN marks caches that are sanitized with the SLAB_KASAN cache flag.
Currently if the metadata that is appended after the object (stores e.g.
stack trace ids) doesn't fit into KMALLOC_MAX_SIZE (can only happen with
SLAB, see the comment in the patch), KASAN turns off sanitization
completely.
With this change sanitization of the object data is always enabled.
However the metadata is only stored when it fits. Instead of checking for
SLAB_KASAN flag accross the code to find out whether the metadata is
there, use cache->kasan_info.alloc/free_meta_offset. As 0 can be a valid
value for free_meta_offset, introduce KASAN_NO_FREE_META as an indicator
that the free metadata is missing.
Without this change all sanitized KASAN objects would be put into
quarantine with generic KASAN. With this change, only the objects that
have metadata (i.e. when it fits) are put into quarantine, the rest is
freed right away.
Along the way rework __kasan_cache_create() and add claryfying comments.
Link: https://lkml.kernel.org/r/aee34b87a5e4afe586c2ac6a0b32db8dc4dcc2dc.1606162397.git.andreyknvl@google.com
Link: https://linux-review.googlesource.com/id/Icd947e2bea054cb5cfbdc6cf6652227d97032dcb
Co-developed-by: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Signed-off-by: Vincenzo Frascino <Vincenzo.Frascino@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Software tag-based KASAN mode is fully initialized with kasan_init_tags(),
while the generic mode only requires kasan_init(). Move the
initialization message for tag-based mode into kasan_init_tags().
Also fix pr_fmt() usage for KASAN code: generic.c doesn't need it as it
doesn't use any printing functions; tag-based mode should use "kasan:"
instead of KBUILD_MODNAME (which stands for file name).
Link: https://lkml.kernel.org/r/29a30ea4e1750450dd1f693d25b7b6cb05913ecf.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
For software KASAN modes the check is based on the value in the shadow
memory. Hardware tag-based KASAN won't be using shadow, so hide the
implementation of the check in check_invalid_free().
Also simplify the code for software tag-based mode.
No functional changes for software modes.
Link: https://lkml.kernel.org/r/d01534a4b977f97d87515dc590e6348e1406de81.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
The new mode won't be using shadow memory, but will still use the concept
of memory granules. Each memory granule maps to a single metadata entry:
8 bytes per one shadow byte for generic mode, 16 bytes per one shadow byte
for software tag-based mode, and 16 bytes per one allocation tag for
hardware tag-based mode.
Rename KASAN_SHADOW_SCALE_SIZE to KASAN_GRANULE_SIZE, and
KASAN_SHADOW_MASK to KASAN_GRANULE_MASK.
Also use MASK when used as a mask, otherwise use SIZE.
No functional changes.
Link: https://lkml.kernel.org/r/939b5754e47f528a6e6a6f28ffc5815d8d128033.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "kasan: add hardware tag-based mode for arm64", v11.
This patchset adds a new hardware tag-based mode to KASAN [1]. The new
mode is similar to the existing software tag-based KASAN, but relies on
arm64 Memory Tagging Extension (MTE) [2] to perform memory and pointer
tagging (instead of shadow memory and compiler instrumentation).
This patchset is co-developed and tested by
Vincenzo Frascino <vincenzo.frascino@arm.com>.
This patchset is available here:
https://github.com/xairy/linux/tree/up-kasan-mte-v11
For testing in QEMU hardware tag-based KASAN requires:
1. QEMU built from master [4] (use "-machine virt,mte=on -cpu max" arguments
to run).
2. GCC version 10.
[1] https://www.kernel.org/doc/html/latest/dev-tools/kasan.html
[2] https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/enhancing-memory-safety
[3] git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux for-next/mte
[4] https://github.com/qemu/qemu
====== Overview
The underlying ideas of the approach used by hardware tag-based KASAN are:
1. By relying on the Top Byte Ignore (TBI) arm64 CPU feature, pointer tags
are stored in the top byte of each kernel pointer.
2. With the Memory Tagging Extension (MTE) arm64 CPU feature, memory tags
for kernel memory allocations are stored in a dedicated memory not
accessible via normal instuctions.
3. On each memory allocation, a random tag is generated, embedded it into
the returned pointer, and the corresponding memory is tagged with the
same tag value.
4. With MTE the CPU performs a check on each memory access to make sure
that the pointer tag matches the memory tag.
5. On a tag mismatch the CPU generates a tag fault, and a KASAN report is
printed.
Same as other KASAN modes, hardware tag-based KASAN is intended as a
debugging feature at this point.
====== Rationale
There are two main reasons for this new hardware tag-based mode:
1. Previously implemented software tag-based KASAN is being successfully
used on dogfood testing devices due to its low memory overhead (as
initially planned). The new hardware mode keeps the same low memory
overhead, and is expected to have significantly lower performance
impact, due to the tag checks being performed by the hardware.
Therefore the new mode can be used as a better alternative in dogfood
testing for hardware that supports MTE.
2. The new mode lays the groundwork for the planned in-kernel MTE-based
memory corruption mitigation to be used in production.
====== Technical details
Considering the implementation perspective, hardware tag-based KASAN is
almost identical to the software mode. The key difference is using MTE
for assigning and checking tags.
Compared to the software mode, the hardware mode uses 4 bits per tag, as
dictated by MTE. Pointer tags are stored in bits [56:60), the top 4 bits
have the normal value 0xF. Having less distict tags increases the
probablity of false negatives (from ~1/256 to ~1/16) in certain cases.
Only synchronous exceptions are set up and used by hardware tag-based KASAN.
====== Benchmarks
Note: all measurements have been performed with software emulation of Memory
Tagging Extension, performance numbers for hardware tag-based KASAN on the
actual hardware are expected to be better.
Boot time [1]:
* 2.8 sec for clean kernel
* 5.7 sec for hardware tag-based KASAN
* 11.8 sec for software tag-based KASAN
* 11.6 sec for generic KASAN
Slab memory usage after boot [2]:
* 7.0 kb for clean kernel
* 9.7 kb for hardware tag-based KASAN
* 9.7 kb for software tag-based KASAN
* 41.3 kb for generic KASAN
Measurements have been performed with:
* defconfig-based configs
* Manually built QEMU master
* QEMU arguments: -machine virt,mte=on -cpu max
* CONFIG_KASAN_STACK_ENABLE disabled
* CONFIG_KASAN_INLINE enabled
* clang-10 as the compiler and gcc-10 as the assembler
[1] Time before the ext4 driver is initialized.
[2] Measured as `cat /proc/meminfo | grep Slab`.
====== Notes
The cover letter for software tag-based KASAN patchset can be found here:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0116523cfffa62aeb5aa3b85ce7419f3dae0c1b8
===== Tags
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
This patch (of 41):
Don't mention "GNU General Public License version 2" text explicitly, as
it's already covered by the SPDX-License-Identifier.
Link: https://lkml.kernel.org/r/cover.1606161801.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/6ea9f5f4aa9dbbffa0d0c0a780b37699a4531034.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The aux_stack[2] is reused to record the call_rcu() call stack and
enqueuing work call stacks. So that we need to change the auxiliary stack
title for common title, print them in KASAN report.
Link: https://lkml.kernel.org/r/20201203022715.30635-1-walter-zh.wu@mediatek.com
Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
Suggested-by: Marco Elver <elver@google.com>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
