From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/uapi/asm-generic/poll.h | 42 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) create mode 100644 include/uapi/asm-generic/poll.h (limited to 'include/uapi/asm-generic/poll.h') diff --git a/include/uapi/asm-generic/poll.h b/include/uapi/asm-generic/poll.h new file mode 100644 index 000000000..f9c520ce4 --- /dev/null +++ b/include/uapi/asm-generic/poll.h @@ -0,0 +1,42 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef __ASM_GENERIC_POLL_H +#define __ASM_GENERIC_POLL_H + +/* These are specified by iBCS2 */ +#define POLLIN 0x0001 +#define POLLPRI 0x0002 +#define POLLOUT 0x0004 +#define POLLERR 0x0008 +#define POLLHUP 0x0010 +#define POLLNVAL 0x0020 + +/* The rest seem to be more-or-less nonstandard. Check them! */ +#define POLLRDNORM 0x0040 +#define POLLRDBAND 0x0080 +#ifndef POLLWRNORM +#define POLLWRNORM 0x0100 +#endif +#ifndef POLLWRBAND +#define POLLWRBAND 0x0200 +#endif +#ifndef POLLMSG +#define POLLMSG 0x0400 +#endif +#ifndef POLLREMOVE +#define POLLREMOVE 0x1000 +#endif +#ifndef POLLRDHUP +#define POLLRDHUP 0x2000 +#endif + +#define POLLFREE (__force __poll_t)0x4000 + +#define POLL_BUSY_LOOP (__force __poll_t)0x8000 + +struct pollfd { + int fd; + short events; + short revents; +}; + +#endif /* __ASM_GENERIC_POLL_H */ -- cgit v1.3.1