aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorArnd Bergmann <arnd@arndb.de>2018-05-25 23:33:20 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2018-05-28 17:40:59 +0200
commitdc3b8ae9d271897e09b27fa4e4e0000de98590d1 (patch)
treed801db41bd5c8ced70e67a853d85e09022a75bb6
parentbpf: btf: avoid -Wreturn-type warning (diff)
downloadlinux-dev-dc3b8ae9d271897e09b27fa4e4e0000de98590d1.tar.xz
linux-dev-dc3b8ae9d271897e09b27fa4e4e0000de98590d1.zip
bpf: avoid -Wmaybe-uninitialized warning
The stack_map_get_build_id_offset() function is too long for gcc to track whether 'work' may or may not be initialized at the end of it, leading to a false-positive warning: kernel/bpf/stackmap.c: In function 'stack_map_get_build_id_offset': kernel/bpf/stackmap.c:334:13: error: 'work' may be used uninitialized in this function [-Werror=maybe-uninitialized] This removes the 'in_nmi_ctx' flag and uses the state of that variable itself to see if it got initialized. Fixes: bae77c5eb5b2 ("bpf: enable stackmap with build_id in nmi context") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
-rw-r--r--kernel/bpf/stackmap.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index b59ace0f0f09..b675a3f3d141 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -285,11 +285,10 @@ static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
{
int i;
struct vm_area_struct *vma;
- bool in_nmi_ctx = in_nmi();
bool irq_work_busy = false;
- struct stack_map_irq_work *work;
+ struct stack_map_irq_work *work = NULL;
- if (in_nmi_ctx) {
+ if (in_nmi()) {
work = this_cpu_ptr(&up_read_work);
if (work->irq_work.flags & IRQ_WORK_BUSY)
/* cannot queue more up_read, fallback */
@@ -328,7 +327,7 @@ static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
id_offs[i].status = BPF_STACK_BUILD_ID_VALID;
}
- if (!in_nmi_ctx) {
+ if (!work) {
up_read(&current->mm->mmap_sem);
} else {
work->sem = &current->mm->mmap_sem;