github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-30 01:53:29 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

rhashtable: Add bucket_table_free_atomic() helper

Browse Source 
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) <urezki@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Uladzislau Rezki (Sony) 2026-04-28 18:14:19 +02:00 committed by Herbert Xu
parent dad0d91cc2
commit d1fa83ecac
1 changed files with 9 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
lib/rhashtable.c
View File

@ -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