From 568f196756ad9fe2b49c46bbf6a9de1b190438b4 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 28 Jan 2019 17:21:52 -0800 Subject: bpf: check that BPF programs run with preemption disabled Introduce cant_sleep() macro for annotation of functions that cannot sleep. Use it in BPF_PROG_RUN to catch execution of BPF programs in preemptable context. Suggested-by: Jann Horn Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Alexei Starovoitov Acked-by: Song Liu Signed-off-by: Daniel Borkmann --- include/linux/kernel.h | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 8f0e68e250a7..a8868a32098c 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -245,8 +245,10 @@ extern int _cond_resched(void); #endif #ifdef CONFIG_DEBUG_ATOMIC_SLEEP - void ___might_sleep(const char *file, int line, int preempt_offset); - void __might_sleep(const char *file, int line, int preempt_offset); +extern void ___might_sleep(const char *file, int line, int preempt_offset); +extern void __might_sleep(const char *file, int line, int preempt_offset); +extern void __cant_sleep(const char *file, int line, int preempt_offset); + /** * might_sleep - annotation for functions that can sleep * @@ -259,6 +261,13 @@ extern int _cond_resched(void); */ # define might_sleep() \ do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0) +/** + * cant_sleep - annotation for functions that cannot sleep + * + * this macro will print a stack trace if it is executed with preemption enabled + */ +# define cant_sleep() \ + do { __cant_sleep(__FILE__, __LINE__, 0); } while (0) # define sched_annotate_sleep() (current->task_state_change = 0) #else static inline void ___might_sleep(const char *file, int line, @@ -266,6 +275,7 @@ extern int _cond_resched(void); static inline void __might_sleep(const char *file, int line, int preempt_offset) { } # define might_sleep() do { might_resched(); } while (0) +# define cant_sleep() do { } while (0) # define sched_annotate_sleep() do { } while (0) #endif -- cgit v1.2.3