Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2024-04-04

We've added 7 non-merge commits during the last 5 day(s) which contain
a total of 9 files changed, 75 insertions(+), 24 deletions(-).

The main changes are:

1) Fix x86 BPF JIT under retbleed=stuff which causes kernel panics due to
   incorrect destination IP calculation and incorrect IP for relocations,
   from Uros Bizjak and Joan Bruguera Micó.

2) Fix BPF arena file descriptor leaks in the verifier,
   from Anton Protopopov.

3) Defer bpf_link deallocation to after RCU grace period as currently
   running multi-{kprobes,uprobes} programs might still access cookie
   information from the link, from Andrii Nakryiko.

4) Fix a BPF sockmap lock inversion deadlock in map_delete_elem reported
   by syzkaller, from Jakub Sitnicki.

5) Fix resolve_btfids build with musl libc due to missing linux/types.h
   include, from Natanael Copa.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf, sockmap: Prevent lock inversion deadlock in map delete elem
  x86/bpf: Fix IP for relocating call depth accounting
  x86/bpf: Fix IP after emitting call depth accounting
  bpf: fix possible file descriptor leaks in verifier
  tools/resolve_btfids: fix build with musl libc
  bpf: support deferring bpf_link dealloc to after RCU grace period
  bpf: put uprobe link's path and task in release callback
====================

Link: https://lore.kernel.org/r/20240404183258.4401-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 15 insertions, 1 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 4f20f62f9d63..890e152d553e 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1574,12 +1574,26 @@ struct bpf_link {
 	enum bpf_link_type type;
 	const struct bpf_link_ops *ops;
 	struct bpf_prog *prog;
-	struct work_struct work;
+	/* rcu is used before freeing, work can be used to schedule that
+	 * RCU-based freeing before that, so they never overlap
+	 */
+	union {
+		struct rcu_head rcu;
+		struct work_struct work;
+	};
 };
 
 struct bpf_link_ops {
 	void (*release)(struct bpf_link *link);
+	/* deallocate link resources callback, called without RCU grace period
+	 * waiting
+	 */
 	void (*dealloc)(struct bpf_link *link);
+	/* deallocate link resources callback, called after RCU grace period;
+	 * if underlying BPF program is sleepable we go through tasks trace
+	 * RCU GP and then "classic" RCU GP
+	 */
+	void (*dealloc_deferred)(struct bpf_link *link);
 	int (*detach)(struct bpf_link *link);
 	int (*update_prog)(struct bpf_link *link, struct bpf_prog *new_prog,
 			   struct bpf_prog *old_prog);