From: Sebastian Andrzej Siewior Date: Wed, 30 Aug 2023 08:04:04 +0000 (+0200) Subject: bpf: Invoke __bpf_prog_exit_sleepable_recur() on recursion in kern_sys_bpf(). X-Git-Tag: v6.6.7~1946^2~5^2~5 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7645629f7dc88cd777f98970134bf1a54c8d77e3;p=platform%2Fkernel%2Flinux-starfive.git bpf: Invoke __bpf_prog_exit_sleepable_recur() on recursion in kern_sys_bpf(). If __bpf_prog_enter_sleepable_recur() detects recursion then it returns 0 without undoing rcu_read_lock_trace(), migrate_disable() or decrementing the recursion counter. This is fine in the JIT case because the JIT code will jump in the 0 case to the end and invoke the matching exit trampoline (__bpf_prog_exit_sleepable_recur()). This is not the case in kern_sys_bpf() which returns directly to the caller with an error code. Add __bpf_prog_exit_sleepable_recur() as clean up in the recursion case. Fixes: b1d18a7574d0d ("bpf: Extend sys_bpf commands for bpf_syscall programs.") Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Daniel Borkmann Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/20230830080405.251926-2-bigeasy@linutronix.de --- diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index ebeb069..53a0b62 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -5505,6 +5505,7 @@ int kern_sys_bpf(int cmd, union bpf_attr *attr, unsigned int size) run_ctx.saved_run_ctx = NULL; if (!__bpf_prog_enter_sleepable_recur(prog, &run_ctx)) { /* recursion detected */ + __bpf_prog_exit_sleepable_recur(prog, 0, &run_ctx); bpf_prog_put(prog); return -EBUSY; }