mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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0da170b9e600da6930cfb8352e4cc036db3b6159
1250 Commits
| Author | SHA1 | Message | Date | |
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b6e5cef4d6 |
mm/slab: use unsigned long for orig_size to ensure proper metadata align
[ Upstream commit |
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b8bc72587c |
mm/slab: Add alloc_tagging_slab_free_hook for memcg_alloc_abort_single
commit |
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fc6acd4cdd |
codetag: debug: handle existing CODETAG_EMPTY in mark_objexts_empty for slabobj_ext
commit |
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f3886f075c |
slab: Fix obj_ext mistakenly considered NULL due to race condition
commit |
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c7af5300d7 |
slab: Avoid race on slab->obj_exts in alloc_slab_obj_exts
commit |
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4772e7f18a |
slab: reset slab->obj_ext when freeing and it is OBJEXTS_ALLOC_FAIL
commit |
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715b6a5b41 |
slab: mark slab->obj_exts allocation failures unconditionally
commit |
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dda6ec365a |
mm/slub: avoid accessing metadata when pointer is invalid in object_err()
[ Upstream commit |
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9cd3206f01 |
mm, slab: cleanup slab_bug() parameters
[ Upstream commit |
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d06b739f41 |
mm: slub: call WARN() when detecting a slab corruption
[ Upstream commit |
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20a54a8db4 |
mm: slub: Print the broken data before restoring them
[ Upstream commit |
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243b705a90 |
mm: slub: avoid wake up kswapd in set_track_prepare
commit |
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769682164d |
mm, slab: restore NUMA policy support for large kmalloc
commit |
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dab2a13059 |
mm, slab: clean up slab->obj_exts always
commit |
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8baa747193 |
slab: ensure slab->obj_exts is clear in a newly allocated slab page
commit |
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825bccd943 |
memcg: slub: fix SUnreclaim for post charged objects
commit |
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943c0f601c |
mm/slub: Avoid list corruption when removing a slab from the full list
commit |
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3f1dd33f99 |
mm, slab: suppress warnings in test_leak_destroy kunit test
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:
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bdf56c7580 |
Merge tag 'slab-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab updates from Vlastimil Babka:
"This time it's mostly refactoring and improving APIs for slab users in
the kernel, along with some debugging improvements.
- kmem_cache_create() refactoring (Christian Brauner)
Over the years have been growing new parameters to
kmem_cache_create() where most of them are needed only for a small
number of caches - most recently the rcu_freeptr_offset parameter.
To avoid adding new parameters to kmem_cache_create() and adjusting
all its callers, or creating new wrappers such as
kmem_cache_create_rcu(), we can now pass extra parameters using the
new struct kmem_cache_args. Not explicitly initialized fields
default to values interpreted as unused.
kmem_cache_create() is for now a wrapper that works both with the
new form: kmem_cache_create(name, object_size, args, flags) and the
legacy form: kmem_cache_create(name, object_size, align, flags,
ctor)
- kmem_cache_destroy() waits for kfree_rcu()'s in flight (Vlastimil
Babka, Uladislau Rezki)
Since SLOB removal, kfree() is allowed for freeing objects
allocated by kmem_cache_create(). By extension kfree_rcu() as
allowed as well, which can allow converting simple call_rcu()
callbacks that only do kmem_cache_free(), as there was never a
kmem_cache_free_rcu() variant. However, for caches that can be
destroyed e.g. on module removal, the cache owners knew to issue
rcu_barrier() first to wait for the pending call_rcu()'s, and this
is not sufficient for pending kfree_rcu()'s due to its internal
batching optimizations. Ulad has provided a new
kvfree_rcu_barrier() and to make the usage less error-prone,
kmem_cache_destroy() calls it. Additionally, destroying
SLAB_TYPESAFE_BY_RCU caches now again issues rcu_barrier()
synchronously instead of using an async work, because the past
motivation for async work no longer applies. Users of custom
call_rcu() callbacks should however keep calling rcu_barrier()
before cache destruction.
- Debugging use-after-free in SLAB_TYPESAFE_BY_RCU caches (Jann Horn)
Currently, KASAN cannot catch UAFs in such caches as it is legal to
access them within a grace period, and we only track the grace
period when trying to free the underlying slab page. The new
CONFIG_SLUB_RCU_DEBUG option changes the freeing of individual
object to be RCU-delayed, after which KASAN can poison them.
- Delayed memcg charging (Shakeel Butt)
In some cases, the memcg is uknown at allocation time, such as
receiving network packets in softirq context. With
kmem_cache_charge() these may be now charged later when the user
and its memcg is known.
- Misc fixes and improvements (Pedro Falcato, Axel Rasmussen,
Christoph Lameter, Yan Zhen, Peng Fan, Xavier)"
* tag 'slab-for-6.12' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (34 commits)
mm, slab: restore kerneldoc for kmem_cache_create()
io_uring: port to struct kmem_cache_args
slab: make __kmem_cache_create() static inline
slab: make kmem_cache_create_usercopy() static inline
slab: remove kmem_cache_create_rcu()
file: port to struct kmem_cache_args
slab: create kmem_cache_create() compatibility layer
slab: port KMEM_CACHE_USERCOPY() to struct kmem_cache_args
slab: port KMEM_CACHE() to struct kmem_cache_args
slab: remove rcu_freeptr_offset from struct kmem_cache
slab: pass struct kmem_cache_args to do_kmem_cache_create()
slab: pull kmem_cache_open() into do_kmem_cache_create()
slab: pass struct kmem_cache_args to create_cache()
slab: port kmem_cache_create_usercopy() to struct kmem_cache_args
slab: port kmem_cache_create_rcu() to struct kmem_cache_args
slab: port kmem_cache_create() to struct kmem_cache_args
slab: add struct kmem_cache_args
slab: s/__kmem_cache_create/do_kmem_cache_create/g
memcg: add charging of already allocated slab objects
mm/slab: Optimize the code logic in find_mergeable()
...
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3352633ce6 |
Merge tag 'vfs-6.12.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs file updates from Christian Brauner:
"This is the work to cleanup and shrink struct file significantly.
Right now, (focusing on x86) struct file is 232 bytes. After this
series struct file will be 184 bytes aka 3 cacheline and a spare 8
bytes for future extensions at the end of the struct.
With struct file being as ubiquitous as it is this should make a
difference for file heavy workloads and allow further optimizations in
the future.
- struct fown_struct was embedded into struct file letting it take up
32 bytes in total when really it shouldn't even be embedded in
struct file in the first place. Instead, actual users of struct
fown_struct now allocate the struct on demand. This frees up 24
bytes.
- Move struct file_ra_state into the union containg the cleanup hooks
and move f_iocb_flags out of the union. This closes a 4 byte hole
we created earlier and brings struct file to 192 bytes. Which means
struct file is 3 cachelines and we managed to shrink it by 40
bytes.
- Reorder struct file so that nothing crosses a cacheline.
I suspect that in the future we will end up reordering some members
to mitigate false sharing issues or just because someone does
actually provide really good perf data.
- Shrinking struct file to 192 bytes is only part of the work.
Files use a slab that is SLAB_TYPESAFE_BY_RCU and when a kmem cache
is created with SLAB_TYPESAFE_BY_RCU the free pointer must be
located outside of the object because the cache doesn't know what
part of the memory can safely be overwritten as it may be needed to
prevent object recycling.
That has the consequence that SLAB_TYPESAFE_BY_RCU may end up
adding a new cacheline.
So this also contains work to add a new kmem_cache_create_rcu()
function that allows the caller to specify an offset where the
freelist pointer is supposed to be placed. Thus avoiding the
implicit addition of a fourth cacheline.
- And finally this removes the f_version member in struct file.
The f_version member isn't particularly well-defined. It is mainly
used as a cookie to detect concurrent seeks when iterating
directories. But it is also abused by some subsystems for
completely unrelated things.
It is mostly a directory and filesystem specific thing that doesn't
really need to live in struct file and with its wonky semantics it
really lacks a specific function.
For pipes, f_version is (ab)used to defer poll notifications until
a write has happened. And struct pipe_inode_info is used by
multiple struct files in their ->private_data so there's no chance
of pushing that down into file->private_data without introducing
another pointer indirection.
But pipes don't rely on f_pos_lock so this adds a union into struct
file encompassing f_pos_lock and a pipe specific f_pipe member that
pipes can use. This union of course can be extended to other file
types and is similar to what we do in struct inode already"
* tag 'vfs-6.12.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
fs: remove f_version
pipe: use f_pipe
fs: add f_pipe
ubifs: store cookie in private data
ufs: store cookie in private data
udf: store cookie in private data
proc: store cookie in private data
ocfs2: store cookie in private data
input: remove f_version abuse
ext4: store cookie in private data
ext2: store cookie in private data
affs: store cookie in private data
fs: add generic_llseek_cookie()
fs: use must_set_pos()
fs: add must_set_pos()
fs: add vfs_setpos_cookie()
s390: remove unused f_version
ceph: remove unused f_version
adi: remove unused f_version
mm: Removed @freeptr_offset to prevent doc warning
...
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ecc4d6af97 |
Merge branch 'slab/for-6.12/kmem_cache_args' into slab/for-next
Merge kmem_cache_create() refactoring by Christian Brauner. Note this includes a merge of the vfs.file tree that contains the prerequisity kmem_cache_create_rcu() work. |
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a715e94dbd |
Merge branch 'slab/for-6.12/rcu_barriers' into slab/for-next
Merge most of SLUB feature work for 6.12: - Barrier for pending kfree_rcu() in kmem_cache_destroy() and associated refactoring of the destroy path (Vlastimil Babka) - CONFIG_SLUB_RCU_DEBUG to allow KASAN catching UAF bugs in SLAB_TYPESAFE_BY_RCU caches (Jann Horn) - kmem_cache_charge() for delayed kmemcg charging (Shakeel Butt) |
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dacf472bcd |
slab: remove rcu_freeptr_offset from struct kmem_cache
Pass down struct kmem_cache_args to calculate_sizes() so we can use
args->{use}_freeptr_offset directly. This allows us to remove
->rcu_freeptr_offset from struct kmem_cache.
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
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3dbe2bad57 |
slab: pass struct kmem_cache_args to do_kmem_cache_create()
and initialize most things in do_kmem_cache_create(). In a follow-up patch we'll remove rcu_freeptr_offset from struct kmem_cache. Reviewed-by: Kees Cook <kees@kernel.org> Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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fc0eac57d0 |
slab: pull kmem_cache_open() into do_kmem_cache_create()
do_kmem_cache_create() is the only caller and we're going to pass down struct kmem_cache_args in a follow-up patch. Reviewed-by: Kees Cook <kees@kernel.org> Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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53d3d21086 |
slab: s/__kmem_cache_create/do_kmem_cache_create/g
Free up reusing the double-underscore variant for follow-up patches. Reviewed-by: Kees Cook <kees@kernel.org> Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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9028cdeb38 |
memcg: add charging of already allocated slab objects
At the moment, the slab objects are charged to the memcg at the
allocation time. However there are cases where slab objects are
allocated at the time where the right target memcg to charge it to is
not known. One such case is the network sockets for the incoming
connection which are allocated in the softirq context.
Couple hundred thousand connections are very normal on large loaded
server and almost all of those sockets underlying those connections get
allocated in the softirq context and thus not charged to any memcg.
However later at the accept() time we know the right target memcg to
charge. Let's add new API to charge already allocated objects, so we can
have better accounting of the memory usage.
To measure the performance impact of this change, tcp_crr is used from
the neper [1] performance suite. Basically it is a network ping pong
test with new connection for each ping pong.
The server and the client are run inside 3 level of cgroup hierarchy
using the following commands:
Server:
$ tcp_crr -6
Client:
$ tcp_crr -6 -c -H ${server_ip}
If the client and server run on different machines with 50 GBPS NIC,
there is no visible impact of the change.
For the same machine experiment with v6.11-rc5 as base.
base (throughput) with-patch
tcp_crr 14545 (+- 80) 14463 (+- 56)
It seems like the performance impact is within the noise.
Link: https://github.com/google/neper [1]
Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Paolo Abeni <pabeni@redhat.com> # net
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
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59090e479a |
mm, slub: avoid zeroing kmalloc redzone
Since commit |
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ab7ca09520 |
mm/slub: add check for s->flags in the alloc_tagging_slab_free_hook
When enable CONFIG_MEMCG & CONFIG_KFENCE & CONFIG_KMEMLEAK, the following
warning always occurs,This is because the following call stack occurred:
mem_pool_alloc
kmem_cache_alloc_noprof
slab_alloc_node
kfence_alloc
Once the kfence allocation is successful,slab->obj_exts will not be empty,
because it has already been assigned a value in kfence_init_pool.
Since in the prepare_slab_obj_exts_hook function,we perform a check for
s->flags & (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE),the alloc_tag_add function
will not be called as a result.Therefore,ref->ct remains NULL.
However,when we call mem_pool_free,since obj_ext is not empty, it
eventually leads to the alloc_tag_sub scenario being invoked. This is
where the warning occurs.
So we should add corresponding checks in the alloc_tagging_slab_free_hook.
For __GFP_NO_OBJ_EXT case,I didn't see the specific case where it's using
kfence,so I won't add the corresponding check in
alloc_tagging_slab_free_hook for now.
[ 3.734349] ------------[ cut here ]------------
[ 3.734807] alloc_tag was not set
[ 3.735129] WARNING: CPU: 4 PID: 40 at ./include/linux/alloc_tag.h:130 kmem_cache_free+0x444/0x574
[ 3.735866] Modules linked in: autofs4
[ 3.736211] CPU: 4 UID: 0 PID: 40 Comm: ksoftirqd/4 Tainted: G W 6.11.0-rc3-dirty #1
[ 3.736969] Tainted: [W]=WARN
[ 3.737258] Hardware name: QEMU KVM Virtual Machine, BIOS unknown 2/2/2022
[ 3.737875] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 3.738501] pc : kmem_cache_free+0x444/0x574
[ 3.738951] lr : kmem_cache_free+0x444/0x574
[ 3.739361] sp : ffff80008357bb60
[ 3.739693] x29: ffff80008357bb70 x28: 0000000000000000 x27: 0000000000000000
[ 3.740338] x26: ffff80008207f000 x25: ffff000b2eb2fd60 x24: ffff0000c0005700
[ 3.740982] x23: ffff8000804229e4 x22: ffff800082080000 x21: ffff800081756000
[ 3.741630] x20: fffffd7ff8253360 x19: 00000000000000a8 x18: ffffffffffffffff
[ 3.742274] x17: ffff800ab327f000 x16: ffff800083398000 x15: ffff800081756df0
[ 3.742919] x14: 0000000000000000 x13: 205d344320202020 x12: 5b5d373038343337
[ 3.743560] x11: ffff80008357b650 x10: 000000000000005d x9 : 00000000ffffffd0
[ 3.744231] x8 : 7f7f7f7f7f7f7f7f x7 : ffff80008237bad0 x6 : c0000000ffff7fff
[ 3.744907] x5 : ffff80008237ba78 x4 : ffff8000820bbad0 x3 : 0000000000000001
[ 3.745580] x2 : 68d66547c09f7800 x1 : 68d66547c09f7800 x0 : 0000000000000000
[ 3.746255] Call trace:
[ 3.746530] kmem_cache_free+0x444/0x574
[ 3.746931] mem_pool_free+0x44/0xf4
[ 3.747306] free_object_rcu+0xc8/0xdc
[ 3.747693] rcu_do_batch+0x234/0x8a4
[ 3.748075] rcu_core+0x230/0x3e4
[ 3.748424] rcu_core_si+0x14/0x1c
[ 3.748780] handle_softirqs+0x134/0x378
[ 3.749189] run_ksoftirqd+0x70/0x9c
[ 3.749560] smpboot_thread_fn+0x148/0x22c
[ 3.749978] kthread+0x10c/0x118
[ 3.750323] ret_from_fork+0x10/0x20
[ 3.750696] ---[ end trace 0000000000000000 ]---
Link: https://lkml.kernel.org/r/20240816013336.17505-1-hao.ge@linux.dev
Fixes:
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d345bd2e98 |
mm: add kmem_cache_create_rcu()
When a kmem cache is created with SLAB_TYPESAFE_BY_RCU the free pointer must be located outside of the object because we don't know what part of the memory can safely be overwritten as it may be needed to prevent object recycling. That has the consequence that SLAB_TYPESAFE_BY_RCU may end up adding a new cacheline. This is the case for e.g., struct file. After having it shrunk down by 40 bytes and having it fit in three cachelines we still have SLAB_TYPESAFE_BY_RCU adding a fourth cacheline because it needs to accommodate the free pointer. Add a new kmem_cache_create_rcu() function that allows the caller to specify an offset where the free pointer is supposed to be placed. Link: https://lore.kernel.org/r/20240828-work-kmem_cache-rcu-v3-2-5460bc1f09f6@kernel.org Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Christian Brauner <brauner@kernel.org> |
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b8c8ba73c6 |
slub: Introduce CONFIG_SLUB_RCU_DEBUG
Currently, KASAN is unable to catch use-after-free in SLAB_TYPESAFE_BY_RCU slabs because use-after-free is allowed within the RCU grace period by design. Add a SLUB debugging feature which RCU-delays every individual kmem_cache_free() before either actually freeing the object or handing it off to KASAN, and change KASAN to poison freed objects as normal when this option is enabled. For now I've configured Kconfig.debug to default-enable this feature in the KASAN GENERIC and SW_TAGS modes; I'm not enabling it by default in HW_TAGS mode because I'm not sure if it might have unwanted performance degradation effects there. Note that this is mostly useful with KASAN in the quarantine-based GENERIC mode; SLAB_TYPESAFE_BY_RCU slabs are basically always also slabs with a ->ctor, and KASAN's assign_tag() currently has to assign fixed tags for those, reducing the effectiveness of SW_TAGS/HW_TAGS mode. (A possible future extension of this work would be to also let SLUB call the ->ctor() on every allocation instead of only when the slab page is allocated; then tag-based modes would be able to assign new tags on every reallocation.) Tested-by: syzbot+263726e59eab6b442723@syzkaller.appspotmail.com Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Acked-by: Marco Elver <elver@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> #slab Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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b3c3424575 |
kasan: catch invalid free before SLUB reinitializes the object
Currently, when KASAN is combined with init-on-free behavior, the initialization happens before KASAN's "invalid free" checks. More importantly, a subsequent commit will want to RCU-delay the actual SLUB freeing of an object, and we'd like KASAN to still validate synchronously that freeing the object is permitted. (Otherwise this change will make the existing testcase kmem_cache_invalid_free fail.) So add a new KASAN hook that allows KASAN to pre-validate a kmem_cache_free() operation before SLUB actually starts modifying the object or its metadata. Inside KASAN, this: - moves checks from poison_slab_object() into check_slab_allocation() - moves kasan_arch_is_ready() up into callers of poison_slab_object() - removes "ip" argument of poison_slab_object() and __kasan_slab_free() (since those functions no longer do any reporting) Acked-by: Vlastimil Babka <vbabka@suse.cz> #slub Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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1941b31482 |
Reenable NUMA policy support in the slab allocator
Revert commit |
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bf6b9e9ba0 |
mm, slub: print CPU id (and its node) on slab OOM
Depending on how remote_node_defrag_ratio is configured, allocations can end up in this path as a result of the local node being OOM, despite the allocation overall being unconstrained (node == -1). When we print a warning, printing the current CPU makes that situation more clear (i.e., you can immediately see which node's OOM status matters for the allocation at hand). Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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a371d558e6 |
mm, slub: do not call do_slab_free for kfence object
In |
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fbc90c042c |
Merge tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- In the series "mm: Avoid possible overflows in dirty throttling" Jan
Kara addresses a couple of issues in the writeback throttling code.
These fixes are also targetted at -stable kernels.
- Ryusuke Konishi's series "nilfs2: fix potential issues related to
reserved inodes" does that. This should actually be in the
mm-nonmm-stable tree, along with the many other nilfs2 patches. My
bad.
- More folio conversions from Kefeng Wang in the series "mm: convert to
folio_alloc_mpol()"
- Kemeng Shi has sent some cleanups to the writeback code in the series
"Add helper functions to remove repeated code and improve readability
of cgroup writeback"
- Kairui Song has made the swap code a little smaller and a little
faster in the series "mm/swap: clean up and optimize swap cache
index".
- In the series "mm/memory: cleanly support zeropage in
vm_insert_page*(), vm_map_pages*() and vmf_insert_mixed()" David
Hildenbrand has reworked the rather sketchy handling of the use of
the zeropage in MAP_SHARED mappings. I don't see any runtime effects
here - more a cleanup/understandability/maintainablity thing.
- Dev Jain has improved selftests/mm/va_high_addr_switch.c's handling
of higher addresses, for aarch64. The (poorly named) series is
"Restructure va_high_addr_switch".
- The core TLB handling code gets some cleanups and possible slight
optimizations in Bang Li's series "Add update_mmu_tlb_range() to
simplify code".
- Jane Chu has improved the handling of our
fake-an-unrecoverable-memory-error testing feature MADV_HWPOISON in
the series "Enhance soft hwpoison handling and injection".
- Jeff Johnson has sent a billion patches everywhere to add
MODULE_DESCRIPTION() to everything. Some landed in this pull.
- In the series "mm: cleanup MIGRATE_SYNC_NO_COPY mode", Kefeng Wang
has simplified migration's use of hardware-offload memory copying.
- Yosry Ahmed performs more folio API conversions in his series "mm:
zswap: trivial folio conversions".
- In the series "large folios swap-in: handle refault cases first",
Chuanhua Han inches us forward in the handling of large pages in the
swap code. This is a cleanup and optimization, working toward the end
objective of full support of large folio swapin/out.
- In the series "mm,swap: cleanup VMA based swap readahead window
calculation", Huang Ying has contributed some cleanups and a possible
fixlet to his VMA based swap readahead code.
- In the series "add mTHP support for anonymous shmem" Baolin Wang has
taught anonymous shmem mappings to use multisize THP. By default this
is a no-op - users must opt in vis sysfs controls. Dramatic
improvements in pagefault latency are realized.
- David Hildenbrand has some cleanups to our remaining use of
page_mapcount() in the series "fs/proc: move page_mapcount() to
fs/proc/internal.h".
- David also has some highmem accounting cleanups in the series
"mm/highmem: don't track highmem pages manually".
- Build-time fixes and cleanups from John Hubbard in the series
"cleanups, fixes, and progress towards avoiding "make headers"".
- Cleanups and consolidation of the core pagemap handling from Barry
Song in the series "mm: introduce pmd|pte_needs_soft_dirty_wp helpers
and utilize them".
- Lance Yang's series "Reclaim lazyfree THP without splitting" has
reduced the latency of the reclaim of pmd-mapped THPs under fairly
common circumstances. A 10x speedup is seen in a microbenchmark.
It does this by punting to aother CPU but I guess that's a win unless
all CPUs are pegged.
- hugetlb_cgroup cleanups from Xiu Jianfeng in the series
"mm/hugetlb_cgroup: rework on cftypes".
- Miaohe Lin's series "Some cleanups for memory-failure" does just that
thing.
- Someone other than SeongJae has developed a DAMON feature in Honggyu
Kim's series "DAMON based tiered memory management for CXL memory".
This adds DAMON features which may be used to help determine the
efficiency of our placement of CXL/PCIe attached DRAM.
- DAMON user API centralization and simplificatio work in SeongJae
Park's series "mm/damon: introduce DAMON parameters online commit
function".
- In the series "mm: page_type, zsmalloc and page_mapcount_reset()"
David Hildenbrand does some maintenance work on zsmalloc - partially
modernizing its use of pageframe fields.
- Kefeng Wang provides more folio conversions in the series "mm: remove
page_maybe_dma_pinned() and page_mkclean()".
- More cleanup from David Hildenbrand, this time in the series
"mm/memory_hotplug: use PageOffline() instead of PageReserved() for
!ZONE_DEVICE". It "enlightens memory hotplug more about PageOffline()
pages" and permits the removal of some virtio-mem hacks.
- Barry Song's series "mm: clarify folio_add_new_anon_rmap() and
__folio_add_anon_rmap()" is a cleanup to the anon folio handling in
preparation for mTHP (multisize THP) swapin.
- Kefeng Wang's series "mm: improve clear and copy user folio"
implements more folio conversions, this time in the area of large
folio userspace copying.
- The series "Docs/mm/damon/maintaier-profile: document a mailing tool
and community meetup series" tells people how to get better involved
with other DAMON developers. From SeongJae Park.
- A large series ("kmsan: Enable on s390") from Ilya Leoshkevich does
that.
- David Hildenbrand sends along more cleanups, this time against the
migration code. The series is "mm/migrate: move NUMA hinting fault
folio isolation + checks under PTL".
- Jan Kara has found quite a lot of strangenesses and minor errors in
the readahead code. He addresses this in the series "mm: Fix various
readahead quirks".
- SeongJae Park's series "selftests/damon: test DAMOS tried regions and
{min,max}_nr_regions" adds features and addresses errors in DAMON's
self testing code.
- Gavin Shan has found a userspace-triggerable WARN in the pagecache
code. The series "mm/filemap: Limit page cache size to that supported
by xarray" addresses this. The series is marked cc:stable.
- Chengming Zhou's series "mm/ksm: cmp_and_merge_page() optimizations
and cleanup" cleans up and slightly optimizes KSM.
- Roman Gushchin has separated the memcg-v1 and memcg-v2 code - lots of
code motion. The series (which also makes the memcg-v1 code
Kconfigurable) are "mm: memcg: separate legacy cgroup v1 code and put
under config option" and "mm: memcg: put cgroup v1-specific memcg
data under CONFIG_MEMCG_V1"
- Dan Schatzberg's series "Add swappiness argument to memory.reclaim"
adds an additional feature to this cgroup-v2 control file.
- The series "Userspace controls soft-offline pages" from Jiaqi Yan
permits userspace to stop the kernel's automatic treatment of
excessive correctable memory errors. In order to permit userspace to
monitor and handle this situation.
- Kefeng Wang's series "mm: migrate: support poison recover from
migrate folio" teaches the kernel to appropriately handle migration
from poisoned source folios rather than simply panicing.
- SeongJae Park's series "Docs/damon: minor fixups and improvements"
does those things.
- In the series "mm/zsmalloc: change back to per-size_class lock"
Chengming Zhou improves zsmalloc's scalability and memory
utilization.
- Vivek Kasireddy's series "mm/gup: Introduce memfd_pin_folios() for
pinning memfd folios" makes the GUP code use FOLL_PIN rather than
bare refcount increments. So these paes can first be moved aside if
they reside in the movable zone or a CMA block.
- Andrii Nakryiko has added a binary ioctl()-based API to
/proc/pid/maps for much faster reading of vma information. The series
is "query VMAs from /proc/<pid>/maps".
- In the series "mm: introduce per-order mTHP split counters" Lance
Yang improves the kernel's presentation of developer information
related to multisize THP splitting.
- Michael Ellerman has developed the series "Reimplement huge pages
without hugepd on powerpc (8xx, e500, book3s/64)". This permits
userspace to use all available huge page sizes.
- In the series "revert unconditional slab and page allocator fault
injection calls" Vlastimil Babka removes a performance-affecting and
not very useful feature from slab fault injection.
* tag 'mm-stable-2024-07-21-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (411 commits)
mm/mglru: fix ineffective protection calculation
mm/zswap: fix a white space issue
mm/hugetlb: fix kernel NULL pointer dereference when migrating hugetlb folio
mm/hugetlb: fix possible recursive locking detected warning
mm/gup: clear the LRU flag of a page before adding to LRU batch
mm/numa_balancing: teach mpol_to_str about the balancing mode
mm: memcg1: convert charge move flags to unsigned long long
alloc_tag: fix page_ext_get/page_ext_put sequence during page splitting
lib: reuse page_ext_data() to obtain codetag_ref
lib: add missing newline character in the warning message
mm/mglru: fix overshooting shrinker memory
mm/mglru: fix div-by-zero in vmpressure_calc_level()
mm/kmemleak: replace strncpy() with strscpy()
mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC
mm, slab: put should_failslab() back behind CONFIG_SHOULD_FAILSLAB
mm: ignore data-race in __swap_writepage
hugetlbfs: ensure generic_hugetlb_get_unmapped_area() returns higher address than mmap_min_addr
mm: shmem: rename mTHP shmem counters
mm: swap_state: use folio_alloc_mpol() in __read_swap_cache_async()
mm/migrate: putback split folios when numa hint migration fails
...
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a7526fe8b9 |
mm, slab: put should_failslab() back behind CONFIG_SHOULD_FAILSLAB
Patch series "revert unconditional slab and page allocator fault injection calls". These two patches largely revert commits that added function call overhead into slab and page allocation hotpaths and that cannot be currently disabled even though related CONFIG_ options do exist. A much more involved solution that can keep the callsites always existing but hidden behind a static key if unused, is possible [1] and can be pursued by anyone who believes it's necessary. Meanwhile the fact the should_failslab() error injection is already not functional on kernels built with current gcc without anyone noticing [2], and lukewarm response to [1] suggests the need is not there. I believe it will be more fair to have the state after this series as a baseline for possible further optimisation, instead of the unconditional overhead. For example a possible compromise for anyone who's fine with an empty function call overhead but not the full CONFIG_FAILSLAB / CONFIG_FAIL_PAGE_ALLOC overhead is to reuse patch 1 from [1] but insert a static key check only inside should_failslab() and should_fail_alloc_page() before performing the more expensive checks. [1] https://lore.kernel.org/all/20240620-fault-injection-statickeys-v2-0-e23947d3d84b@suse.cz/#t [2] https://github.com/bpftrace/bpftrace/issues/3258 This patch (of 2): This mostly reverts commit |
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436381eaf2 |
Merge branch 'slab/for-6.11/buckets' into slab/for-next
Merge all the slab patches previously collected on top of v6.10-rc1, over cleanups/fixes that had to be based on rc6. |
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7b1fdf2ba4 |
mm, slab: move prepare_slab_obj_exts_hook under CONFIG_MEM_ALLOC_PROFILING
The only place prepare_slab_obj_exts_hook() is currently being used is from alloc_tagging_slab_alloc_hook() when CONFIG_MEM_ALLOC_PROFILING=y. Move its definition under CONFIG_MEM_ALLOC_PROFILING to prevent unused function warning for CONFIG_SLAB_OBJ_EXT=n case. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202407050845.zNONqauD-lkp@intel.com/ Signed-off-by: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Xiongwei Song <xiongwei.song@linux.dev> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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3a3b7fec39 |
mm: remove CONFIG_MEMCG_KMEM
CONFIG_MEMCG_KMEM used to be a user-visible option for whether slab tracking is enabled. It has been default-enabled and equivalent to CONFIG_MEMCG for almost a decade. We've only grown more kernel memory accounting sites since, and there is no imaginable cgroup usecase going forward that wants to track user pages but not the multitude of user-drivable kernel allocations. Link: https://lkml.kernel.org/r/20240701153148.452230-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: David Hildenbrand <david@redhat.com> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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302a3ea38a |
mm, slab: move allocation tagging code in the alloc path into a hook
Move allocation tagging specific code in the allocation path into alloc_tagging_slab_alloc_hook, similar to how freeing path uses alloc_tagging_slab_free_hook. No functional changes, just code cleanup. Suggested-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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adea987618 |
mm: slub: disable KMSAN when checking the padding bytes
Even though the KMSAN warnings generated by memchr_inv() are suppressed by metadata_access_enable(), its return value may still be poisoned. The reason is that the last iteration of memchr_inv() returns `*start != value ? start : NULL`, where *start is poisoned. Because of this, somewhat counterintuitively, the shadow value computed by visitSelectInst() is equal to `(uintptr_t)start`. One possibility to fix this, since the intention behind guarding memchr_inv() behind metadata_access_enable() is to touch poisoned metadata without triggering KMSAN, is to unpoison its return value. However, this approach is too fragile. So simply disable the KMSAN checks in the respective functions. Link: https://lkml.kernel.org/r/20240621113706.315500-19-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <kasan-dev@googlegroups.com> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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0e9a8550f3 |
mm: slub: let KMSAN access metadata
Building the kernel with CONFIG_SLUB_DEBUG and CONFIG_KMSAN causes KMSAN to complain about touching redzones in kfree(). Fix by extending the existing KASAN-related metadata_access_enable() and metadata_access_disable() functions to KMSAN. Link: https://lkml.kernel.org/r/20240621113706.315500-18-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <kasan-dev@googlegroups.com> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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f416817197 |
kmsan: support SLAB_POISON
Avoid false KMSAN negatives with SLUB_DEBUG by allowing kmsan_slab_free() to poison the freed memory, and by preventing init_object() from unpoisoning new allocations by using __memset(). There are two alternatives to this approach. First, init_object() can be marked with __no_sanitize_memory. This annotation should be used with great care, because it drops all instrumentation from the function, and any shadow writes will be lost. Even though this is not a concern with the current init_object() implementation, this may change in the future. Second, kmsan_poison_memory() calls may be added after memset() calls. The downside is that init_object() is called from free_debug_processing(), in which case poisoning will erase the distinction between simply uninitialized memory and UAF. Link: https://lkml.kernel.org/r/20240621113706.315500-14-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <kasan-dev@googlegroups.com> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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67f2df3b82 |
mm/slab: Plumb kmem_buckets into __do_kmalloc_node()
Introduce CONFIG_SLAB_BUCKETS which provides the infrastructure to support separated kmalloc buckets (in the following kmem_buckets_create() patches and future codetag-based separation). Since this will provide a mitigation for a very common case of exploits, it is recommended to enable this feature for general purpose distros. By default, the new Kconfig will be enabled if CONFIG_SLAB_FREELIST_HARDENED is enabled (and it is added to the hardening.config Kconfig fragment). To be able to choose which buckets to allocate from, make the buckets available to the internal kmalloc interfaces by adding them as the second argument, rather than depending on the buckets being chosen from the fixed set of global buckets. Where the bucket is not available, pass NULL, which means "use the default system kmalloc bucket set" (the prior existing behavior), as implemented in kmalloc_slab(). To avoid adding the extra argument when !CONFIG_SLAB_BUCKETS, only the top-level macros and static inlines use the buckets argument (where they are stripped out and compiled out respectively). The actual extern functions can then be built without the argument, and the internals fall back to the global kmalloc buckets unconditionally. Co-developed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Kees Cook <kees@kernel.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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b4601d096a |
mm/slab: fix 'variable obj_exts set but not used' warning
slab_post_alloc_hook() uses prepare_slab_obj_exts_hook() to obtain
slabobj_ext object. Currently the only user of slabobj_ext object in this
path is memory allocation profiling, therefore when it's not enabled this
object is not needed. This also generates a warning when compiling with
CONFIG_MEM_ALLOC_PROFILING=n. Move the code under this configuration to
fix the warning. If more slabobj_ext users appear in the future, the code
will have to be changed back to call prepare_slab_obj_exts_hook().
Link: https://lkml.kernel.org/r/20240614225951.3845577-1-surenb@google.com
Fixes:
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4a24bbabc8 |
slab: delete useless RED_INACTIVE and RED_ACTIVE
These seem useless since we use the SLUB_RED_INACTIVE and SLUB_RED_ACTIVE, so just delete them, no functional change. Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev> Reviewed-by: Christoph Lameter (Ampere) <cl@linux.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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adef2aeaa2 |
slab: don't put freepointer outside of object if only orig_size
The commit
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47d911b02c |
slab: make check_object() more consistent
Now check_object() calls check_bytes_and_report() multiple times to check every section of the object it cares about, like left and right redzones, object poison, paddings poison and freepointer. It will abort the checking process and return 0 once it finds an error. There are two inconsistencies in check_object(), which are alignment padding checking and object padding checking. We only print the error messages but don't return 0 to tell callers that something is wrong and needs to be handled. Please see alloc_debug_processing() and free_debug_processing() for details. We want to do all checks without skipping, so use a local variable "ret" to save each check result and change check_bytes_and_report() to only report specific error findings. Then at end of check_object(), print the trailer once if any found an error. Suggested-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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3f0c44c8c2 |
codetag: avoid race at alloc_slab_obj_exts
When CONFIG_MEM_ALLOC_PROFILING_DEBUG is enabled, the following warning
may be noticed:
[ 48.299584] ------------[ cut here ]------------
[ 48.300092] alloc_tag was not set
[ 48.300528] WARNING: CPU: 2 PID: 1361 at include/linux/alloc_tag.h:130 alloc_tagging_slab_free_hook+0x84/0xc7
[ 48.301305] Modules linked in:
[ 48.301553] CPU: 2 PID: 1361 Comm: systemd-udevd Not tainted 6.10.0-rc1-00003-gac8755535862 #176
[ 48.302196] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
[ 48.302752] RIP: 0010:alloc_tagging_slab_free_hook+0x84/0xc7
[ 48.303169] Code: 8d 1c c4 48 85 db 74 4d 48 83 3b 00 75 1e 80 3d 65 02 86 04 00 75 15 48 c7 c7 11 48 1d 85 c6 05 55 02 86 04 01 e8 64 44 a5 ff <0f> 0b 48 8b 03 48 85 c0 74 21 48 83 f8 01 74 14 48 8b 50 20 48 f7
[ 48.304411] RSP: 0018:ffff8880111b7d40 EFLAGS: 00010282
[ 48.304916] RAX: 0000000000000000 RBX: ffff88800fcc9008 RCX: 0000000000000000
[ 48.305455] RDX: 0000000080000000 RSI: ffff888014060000 RDI: ffffed1002236f97
[ 48.305979] RBP: 0000000000001100 R08: fffffbfff0aa73a1 R09: 0000000000000000
[ 48.306473] R10: ffffffff814515e5 R11: 0000000000000003 R12: ffff88800fcc9000
[ 48.306943] R13: ffff88800b2e5cc0 R14: ffff8880111b7d90 R15: 0000000000000000
[ 48.307529] FS: 00007faf5d1908c0(0000) GS:ffff88806cf00000(0000) knlGS:0000000000000000
[ 48.308223] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 48.308710] CR2: 000058fb220c9118 CR3: 00000000110cc000 CR4: 0000000000750ef0
[ 48.309274] PKRU: 55555554
[ 48.309804] Call Trace:
[ 48.310029] <TASK>
[ 48.310290] ? show_regs+0x84/0x8d
[ 48.310722] ? alloc_tagging_slab_free_hook+0x84/0xc7
[ 48.311298] ? __warn+0x13b/0x2ff
[ 48.311580] ? alloc_tagging_slab_free_hook+0x84/0xc7
[ 48.311987] ? report_bug+0x2ce/0x3ab
[ 48.312292] ? handle_bug+0x8c/0x107
[ 48.312563] ? exc_invalid_op+0x34/0x6f
[ 48.312842] ? asm_exc_invalid_op+0x1a/0x20
[ 48.313173] ? this_cpu_in_panic+0x1c/0x72
[ 48.313503] ? alloc_tagging_slab_free_hook+0x84/0xc7
[ 48.313880] ? putname+0x143/0x14e
[ 48.314152] kmem_cache_free+0xe9/0x214
[ 48.314454] putname+0x143/0x14e
[ 48.314712] do_unlinkat+0x413/0x45e
[ 48.315001] ? __pfx_do_unlinkat+0x10/0x10
[ 48.315388] ? __check_object_size+0x4d7/0x525
[ 48.315744] ? __sanitizer_cov_trace_pc+0x20/0x4a
[ 48.316167] ? __sanitizer_cov_trace_pc+0x20/0x4a
[ 48.316757] ? getname_flags+0x4ed/0x500
[ 48.317261] __x64_sys_unlink+0x42/0x4a
[ 48.317741] do_syscall_64+0xe2/0x149
[ 48.318171] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 48.318602] RIP: 0033:0x7faf5d8850ab
[ 48.318891] Code: fd ff ff e8 27 dd 01 00 0f 1f 80 00 00 00 00 f3 0f 1e fa b8 5f 00 00 00 0f 05 c3 0f 1f 40 00 f3 0f 1e fa b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15 41 2d 0e 00 f7 d8
[ 48.320649] RSP: 002b:00007ffc44982b38 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
[ 48.321182] RAX: ffffffffffffffda RBX: 00005ba344a44680 RCX: 00007faf5d8850ab
[ 48.321667] RDX: 0000000000000000 RSI: 00005ba344a44430 RDI: 00007ffc44982b40
[ 48.322139] RBP: 00007ffc44982c00 R08: 0000000000000000 R09: 0000000000000007
[ 48.322598] R10: 00005ba344a44430 R11: 0000000000000246 R12: 0000000000000000
[ 48.323071] R13: 00007ffc44982b40 R14: 0000000000000000 R15: 0000000000000000
[ 48.323596] </TASK>
This is due to a race when two objects are allocated from the same slab,
which did not have an obj_exts allocated for.
In such a case, the two threads will notice the NULL obj_exts and after
one assigns slab->obj_exts, the second one will happily do the exchange if
it reads this new assigned value.
In order to avoid that, verify that the read obj_exts does not point to an
allocated obj_exts before doing the exchange.
Link: https://lkml.kernel.org/r/20240527183007.1595037-1-cascardo@igalia.com
Fixes:
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