From: Uladzislau Rezki (Sony) Date: Tue, 28 Apr 2026 16:14:19 +0000 (+0200) Subject: rhashtable: Add bucket_table_free_atomic() helper X-Git-Tag: v7.1-rc4~27^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d1fa83ecac31093a550534a79a33bc7f4ba8fc10;p=thirdparty%2Flinux.git rhashtable: Add bucket_table_free_atomic() helper rhashtable_insert_rehash() allocates a new bucket table with GFP_ATOMIC, as it is called from an RCU read-side critical section. If rhashtable_rehash_attach() then fails, the new table is freed via kvfree(). This is unsafe, since kvfree() may fall back to vfree() for vmalloc-backed allocations, which can sleep and trigger: BUG: sleeping function called from invalid context Add bucket_table_free_atomic(), which uses kvfree_atomic() so the table can be freed safely from non-sleeping context. Signed-off-by: Uladzislau Rezki (Sony) Signed-off-by: Herbert Xu --- diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 426d4e381f13..04b3a808fca9 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -114,6 +114,14 @@ static void bucket_table_free(const struct bucket_table *tbl) kvfree(tbl); } +static void bucket_table_free_atomic(const struct bucket_table *tbl) +{ + if (tbl->nest) + nested_bucket_table_free(tbl); + + kvfree_atomic(tbl); +} + static void bucket_table_free_rcu(struct rcu_head *head) { bucket_table_free(container_of(head, struct bucket_table, rcu)); @@ -496,7 +504,7 @@ static int rhashtable_insert_rehash(struct rhashtable *ht, err = rhashtable_rehash_attach(ht, tbl, new_tbl); if (err) { - bucket_table_free(new_tbl); + bucket_table_free_atomic(new_tbl); if (err == -EEXIST) err = 0; } else