diff mbox series

[bpf,v2,3/9] bpf: Acquire map uref in .init_seq_private for sock local storage map iterator

Message ID 20220810080538.1845898-4-houtao@huaweicloud.com (mailing list archive)
State Accepted
Commit 3c5f6e698b5c538bbb23cd453b22e1e4922cffd8
Delegated to: BPF
Headers show
Series fixes for bpf map iterator | expand

Checks

Context Check Description
bpf/vmtest-bpf-PR fail PR summary
netdev/tree_selection success Clearly marked for bpf
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 5 this patch: 5
netdev/cc_maintainers warning 4 maintainers not CCed: edumazet@google.com pabeni@redhat.com joannelkoong@gmail.com netdev@vger.kernel.org
netdev/build_clang success Errors and warnings before: 5 this patch: 5
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 5 this patch: 5
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 26 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-VM_Test-1 success Logs for Kernel LATEST on ubuntu-latest with gcc
bpf/vmtest-bpf-VM_Test-2 success Logs for Kernel LATEST on ubuntu-latest with llvm-16
bpf/vmtest-bpf-VM_Test-3 fail Logs for Kernel LATEST on z15 with gcc

Commit Message

Hou Tao Aug. 10, 2022, 8:05 a.m. UTC 
From: Hou Tao <houtao1@huawei.com>

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_sk_storage_map() and
releasing it in bpf_iter_fini_sk_storage_map().

Fixes: 5ce6e77c7edf ("bpf: Implement bpf iterator for sock local storage map")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
---
 net/core/bpf_sk_storage.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

Comments

Martin KaFai Lau Aug. 10, 2022, 4:47 p.m. UTC | #1 
On Wed, Aug 10, 2022 at 04:05:32PM +0800, Hou Tao wrote:
> From: Hou Tao <houtao1@huawei.com>
> 
> 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_sk_storage_map() and
> releasing it in bpf_iter_fini_sk_storage_map().
Acked-by: Martin KaFai Lau <kafai@fb.com>
diff mbox series

Patch

diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index a25ec93729b9..83b89ba824d7 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -875,10 +875,18 @@  static int bpf_iter_init_sk_storage_map(void *priv_data,
 {
 	struct bpf_iter_seq_sk_storage_map_info *seq_info = priv_data;
 
+	bpf_map_inc_with_uref(aux->map);
 	seq_info->map = aux->map;
 	return 0;
 }
 
+static void bpf_iter_fini_sk_storage_map(void *priv_data)
+{
+	struct bpf_iter_seq_sk_storage_map_info *seq_info = priv_data;
+
+	bpf_map_put_with_uref(seq_info->map);
+}
+
 static int bpf_iter_attach_map(struct bpf_prog *prog,
 			       union bpf_iter_link_info *linfo,
 			       struct bpf_iter_aux_info *aux)
@@ -924,7 +932,7 @@  static const struct seq_operations bpf_sk_storage_map_seq_ops = {
 static const struct bpf_iter_seq_info iter_seq_info = {
 	.seq_ops		= &bpf_sk_storage_map_seq_ops,
 	.init_seq_private	= bpf_iter_init_sk_storage_map,
-	.fini_seq_private	= NULL,
+	.fini_seq_private	= bpf_iter_fini_sk_storage_map,
 	.seq_priv_size		= sizeof(struct bpf_iter_seq_sk_storage_map_info),
 };