This is a note to let you know that I've just added the patch titled
bpf: Acquire map uref in .init_seq_private for hash map iterator
to the 5.19-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-acquire-map-uref-in-.init_seq_private-for-hash-map-iterator.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ef1e93d2eeb58a1f08c37b22a2314b94bc045f15 Mon Sep 17 00:00:00 2001
From: Hou Tao <houtao1@xxxxxxxxxx>
Date: Wed, 10 Aug 2022 16:05:31 +0800
Subject: bpf: Acquire map uref in .init_seq_private for hash map iterator
From: Hou Tao <houtao1@xxxxxxxxxx>
commit ef1e93d2eeb58a1f08c37b22a2314b94bc045f15 upstream.
bpf_iter_attach_map() acquires a map uref, and the uref may be released
before or in the middle of iterating map elements. For example, the uref
could be released in bpf_iter_detach_map() as part of
bpf_link_release(), or could be released in bpf_map_put_with_uref() as
part of bpf_map_release().
So acquiring an extra map uref in bpf_iter_init_hash_map() and
releasing it in bpf_iter_fini_hash_map().
Fixes: d6c4503cc296 ("bpf: Implement bpf iterator for hash maps")
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
Acked-by: Yonghong Song <yhs@xxxxxx>
Link: https://lore.kernel.org/r/20220810080538.1845898-3-houtao@xxxxxxxxxxxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/bpf/hashtab.c | 2 ++
1 file changed, 2 insertions(+)
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -2060,6 +2060,7 @@ static int bpf_iter_init_hash_map(void *
seq_info->percpu_value_buf = value_buf;
}
+ bpf_map_inc_with_uref(map);
seq_info->map = map;
seq_info->htab = container_of(map, struct bpf_htab, map);
return 0;
@@ -2069,6 +2070,7 @@ static void bpf_iter_fini_hash_map(void
{
struct bpf_iter_seq_hash_map_info *seq_info = priv_data;
+ bpf_map_put_with_uref(seq_info->map);
kfree(seq_info->percpu_value_buf);
}
Patches currently in stable-queue which might be from houtao1@xxxxxxxxxx are
queue-5.19/bpf-acquire-map-uref-in-.init_seq_private-for-array-map-iterator.patch
queue-5.19/bpf-acquire-map-uref-in-.init_seq_private-for-sock-map-hash-iterator.patch
queue-5.19/bpf-acquire-map-uref-in-.init_seq_private-for-hash-map-iterator.patch
queue-5.19/bpf-acquire-map-uref-in-.init_seq_private-for-sock-local-storage-map-iterator.patch
queue-5.19/bpf-check-the-validity-of-max_rdwr_access-for-sock-local-storage-map-iterator.patch
