io_uring/bpf_filters: retain COW'ed settings on parse failures

aa35dd6b · Jens Axboe <[email protected]> · 2026-03-31 08:16:58 -06:00

If io_parse_restrictions() fails, it ends up clearing any restrictions
currently set. The intent is only to clear whatever it already applied,
but it ends up clearing everything, including whatever settings may have
been applied in a copy-on-write fashion already. Ensure that those are
retained.

Link: https://lore.kernel.org/io-uring/CAK8a0jzF-zaO5ZmdOrmfuxrhXuKg5m5+RDuO7tNvtj=kUYbW7Q@mail.gmail.com/
Reported-by: antonius <[email protected]>
Fixes: ed82f35b926b ("io_uring: allow registration of per-task restrictions")
Signed-off-by: Jens Axboe <[email protected]>

Commit: aa35dd6bdd033dea8aa3e20cbbbe10e06b2d044f
Parents: 61a11cf4

Changes

1 files changed · +9 −1

File	Status	Add	Del	Content
io_uring/register.c	modified	+9	−1	View file

io_uring/register.c

View file

diff --git a/io_uring/register.c b/io_uring/register.c
index 5f3eb01..837324b 100644
--- a/io_uring/register.c
+++ b/io_uring/register.c
@@ -178,9 +178,17 @@ static __cold int io_register_restrictions(struct io_ring_ctx *ctx,
 		return -EBUSY;
 
 	ret = io_parse_restrictions(arg, nr_args, &ctx->restrictions);
-	/* Reset all restrictions if an error happened */
+	/*
+	 * Reset all restrictions if an error happened, but retain any COW'ed
+	 * settings.
+	 */
 	if (ret < 0) {
+		struct io_bpf_filters *bpf = ctx->restrictions.bpf_filters;
+		bool cowed = ctx->restrictions.bpf_filters_cow;
+
 		memset(&ctx->restrictions, 0, sizeof(ctx->restrictions));
+		ctx->restrictions.bpf_filters = bpf;
+		ctx->restrictions.bpf_filters_cow = cowed;
 		return ret;
 	}
 	if (ctx->restrictions.op_registered)