This is a note to let you know that I've just added the patch titled
bpf: Check percpu map value size first
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-check-percpu-map-value-size-first.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5823e06a0c089e3f6f9c487fa3932920793e397f
Author: Tao Chen <chen.dylane@xxxxxxxxx>
Date: Tue Sep 10 22:41:10 2024 +0800
bpf: Check percpu map value size first
[ Upstream commit 1d244784be6b01162b732a5a7d637dfc024c3203 ]
Percpu map is often used, but the map value size limit often ignored,
like issue: https://github.com/iovisor/bcc/issues/2519. Actually,
percpu map value size is bound by PCPU_MIN_UNIT_SIZE, so we
can check the value size whether it exceeds PCPU_MIN_UNIT_SIZE first,
like percpu map of local_storage. Maybe the error message seems clearer
compared with "cannot allocate memory".
Signed-off-by: Jinke Han <jinkehan@xxxxxxxxxxxxxx>
Signed-off-by: Tao Chen <chen.dylane@xxxxxxxxx>
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20240910144111.1464912-2-chen.dylane@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 5102338129d5f..3d92e42c3895a 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -74,6 +74,9 @@ int array_map_alloc_check(union bpf_attr *attr)
* access the elements.
*/
return -E2BIG;
+ /* percpu map value size is bound by PCPU_MIN_UNIT_SIZE */
+ if (percpu && round_up(attr->value_size, 8) > PCPU_MIN_UNIT_SIZE)
+ return -E2BIG;
return 0;
}
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 72bc5f5752543..4c7cab79d90e5 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -404,6 +404,9 @@ static int htab_map_alloc_check(union bpf_attr *attr)
* kmalloc-able later in htab_map_update_elem()
*/
return -E2BIG;
+ /* percpu map value size is bound by PCPU_MIN_UNIT_SIZE */
+ if (percpu && round_up(attr->value_size, 8) > PCPU_MIN_UNIT_SIZE)
+ return -E2BIG;
return 0;
}
