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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-05-03 08:19:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-05-03 08:19:57 -0700 |
| commit | 811129272de4f91da34f869ae1a1dd1fe608f64f (patch) | |
| tree | ce815cc9a53454a0ab4b6ac756bb348c07d8ab91 | |
| parent | cffcf520fd69fe5a93b519cf0c7ccc5e467fcb1c (diff) | |
| parent | 5b31044e649e3e54c2caef135c09b371c2fbcd08 (diff) | |
Merge tag 'slab-for-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab
Pull slab fixes from Vlastimil Babka:
- Stable fixes for CONFIG_SMP=n where _nolock() allocations in NMI both
at kmalloc and page allocator levels are not properly protected by
the spin_trylock() semantics on !SMP (Harry Yoo)
* tag 'slab-for-7.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
mm/slab: return NULL early from kmalloc_nolock() in NMI on UP
mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP
| -rw-r--r-- | mm/page_alloc.c | 5 | ||||
| -rw-r--r-- | mm/slub.c | 4 |
2 files changed, 9 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 65e205111553..227d58dc3de6 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7737,6 +7737,11 @@ struct page *alloc_frozen_pages_nolock_noprof(gfp_t gfp_flags, int nid, unsigned */ if (IS_ENABLED(CONFIG_PREEMPT_RT) && (in_nmi() || in_hardirq())) return NULL; + + /* On UP, spin_trylock() always succeeds even when it is locked */ + if (!IS_ENABLED(CONFIG_SMP) && in_nmi()) + return NULL; + if (!pcp_allowed_order(order)) return NULL; diff --git a/mm/slub.c b/mm/slub.c index 161079ac5ba1..0baa906f39ab 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5339,6 +5339,10 @@ void *kmalloc_nolock_noprof(size_t size, gfp_t gfp_flags, int node) if (IS_ENABLED(CONFIG_PREEMPT_RT) && (in_nmi() || in_hardirq())) return NULL; + /* On UP, spin_trylock() always succeeds even when it is locked */ + if (!IS_ENABLED(CONFIG_SMP) && in_nmi()) + return NULL; + retry: if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) return NULL; |