From: Varun R Mallya Date: Wed, 1 Apr 2026 19:11:25 +0000 (+0530) Subject: bpf: Reject sleepable kprobe_multi programs at attach time X-Git-Tag: v7.0-rc7~24^2~2 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=eb7024bfcc5f68ed11ed9dd4891a3073c15f04a8;p=thirdparty%2Flinux.git bpf: Reject sleepable kprobe_multi programs at attach time kprobe.multi programs run in atomic/RCU context and cannot sleep. However, bpf_kprobe_multi_link_attach() did not validate whether the program being attached had the sleepable flag set, allowing sleepable helpers such as bpf_copy_from_user() to be invoked from a non-sleepable context. This causes a "sleeping function called from invalid context" splat: BUG: sleeping function called from invalid context at ./include/linux/uaccess.h:169 in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1787, name: sudo preempt_count: 1, expected: 0 RCU nest depth: 2, expected: 0 Fix this by rejecting sleepable programs early in bpf_kprobe_multi_link_attach(), before any further processing. Fixes: 0dcac2725406 ("bpf: Add multi kprobe link") Signed-off-by: Varun R Mallya Acked-by: Kumar Kartikeya Dwivedi Acked-by: Leon Hwang Acked-by: Jiri Olsa Link: https://lore.kernel.org/r/20260401191126.440683-1-varunrmallya@gmail.com Signed-off-by: Alexei Starovoitov --- diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 0b040a417442..af7079aa0f36 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2752,6 +2752,10 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr if (!is_kprobe_multi(prog)) return -EINVAL; + /* kprobe_multi is not allowed to be sleepable. */ + if (prog->sleepable) + return -EINVAL; + /* Writing to context is not allowed for kprobes. */ if (prog->aux->kprobe_write_ctx) return -EINVAL;