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authorPeter Zijlstra <peterz@infradead.org>2019-01-28 17:21:52 -0800
committerDaniel Borkmann <daniel@iogearbox.net>2019-02-19 21:53:07 +0100
commit568f196756ad9fe2b49c46bbf6a9de1b190438b4 (patch)
treea8c84a1e56786296cd005d6c7ca7ad741c2367ea /kernel/sched
parenta5d9265e017f081f0dc133c0e2f45103d027b874 (diff)
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 <jannh@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/core.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d8d76a65cfdd..7cbb5658be80 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6162,6 +6162,34 @@ void ___might_sleep(const char *file, int line, int preempt_offset)
add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
}
EXPORT_SYMBOL(___might_sleep);
+
+void __cant_sleep(const char *file, int line, int preempt_offset)
+{
+ static unsigned long prev_jiffy;
+
+ if (irqs_disabled())
+ return;
+
+ if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
+ return;
+
+ if (preempt_count() > preempt_offset)
+ return;
+
+ if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+ return;
+ prev_jiffy = jiffies;
+
+ printk(KERN_ERR "BUG: assuming atomic context at %s:%d\n", file, line);
+ printk(KERN_ERR "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
+ in_atomic(), irqs_disabled(),
+ current->pid, current->comm);
+
+ debug_show_held_locks(current);
+ dump_stack();
+ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+EXPORT_SYMBOL_GPL(__cant_sleep);
#endif
#ifdef CONFIG_MAGIC_SYSRQ