diff options
| author | Harry Yoo <harry.yoo@oracle.com> | 2026-02-10 13:46:41 +0900 |
|---|---|---|
| committer | Vlastimil Babka <vbabka@suse.cz> | 2026-02-10 11:39:30 +0100 |
| commit | c4d6d7829817f762dfdce829ffd0c14ea3bad7fe (patch) | |
| tree | cdd24f838ce215529cebdc1f77716a1c9989bdc2 /include | |
| parent | a1e244a9f177894969c6cd5ebbc6d72c19fc4a7a (diff) | |
mm/slab: allow freeing kmalloc_nolock()'d objects using kfree[_rcu]()
Slab objects that are allocated with kmalloc_nolock() must be freed
using kfree_nolock() because only a subset of alloc hooks are called,
since kmalloc_nolock() can't spin on a lock during allocation.
This imposes a limitation: such objects cannot be freed with kfree_rcu(),
forcing users to work around this limitation by calling call_rcu()
with a callback that frees the object using kfree_nolock().
Remove this limitation by teaching kmemleak to gracefully ignore cases
when kmemleak_free() or kmemleak_ignore() is called without a prior
kmemleak_alloc().
Unlike kmemleak, kfence already handles this case, because,
due to its design, only a subset of allocations are served from kfence.
With this change, kfree() and kfree_rcu() can be used to free objects
that are allocated using kmalloc_nolock().
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Harry Yoo <harry.yoo@oracle.com>
Link: https://patch.msgid.link/20260210044642.139482-2-harry.yoo@oracle.com
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/rcupdate.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index c5b30054cd01..72ba681360ad 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -1076,8 +1076,8 @@ static inline void rcu_read_unlock_migrate(void) * either fall back to use of call_rcu() or rearrange the structure to * position the rcu_head structure into the first 4096 bytes. * - * The object to be freed can be allocated either by kmalloc() or - * kmem_cache_alloc(). + * The object to be freed can be allocated either by kmalloc(), + * kmalloc_nolock(), or kmem_cache_alloc(). * * Note that the allowable offset might decrease in the future. * |