Commit 2b9b305f authored by Song Liu's avatar Song Liu Committed by Alexei Starovoitov
Browse files

bpf: Fix build on architectures with special bpf_user_pt_regs_t 



Architectures like s390, powerpc, arm64, riscv have speical definition of
bpf_user_pt_regs_t. So we need to cast the pointer before passing it to
bpf_get_stack(). This is similar to bpf_get_stack_tp().

Fixes: 03d42fd2d83f ("bpf: Separate bpf_get_[stack|stackid] for perf events BPF")
Reported-by: default avatarkernel test robot <lkp@intel.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200724200503.3629591-1-songliubraving@fb.com
parent dfcdf0e9

kernel/bpf/stackmap.c

+4 −5
Original line number Diff line number Diff line
@@ -678,6 +678,7 @@ const struct bpf_func_proto bpf_get_task_stack_proto = { 
BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx,

	   void *, buf, u32, size, u64, flags)

{

	struct pt_regs *regs = (struct pt_regs *)(ctx->regs);

	struct perf_event *event = ctx->event;

	struct perf_callchain_entry *trace;

	bool kernel, user;
@@ -685,7 +686,7 @@ BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, 
	__u64 nr_kernel;



	if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))

		return __bpf_get_stack(ctx->regs, NULL, NULL, buf, size, flags);

		return __bpf_get_stack(regs, NULL, NULL, buf, size, flags);



	if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |

			       BPF_F_USER_BUILD_ID)))
@@ -705,8 +706,7 @@ BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, 
		__u64 nr = trace->nr;



		trace->nr = nr_kernel;

		err = __bpf_get_stack(ctx->regs, NULL, trace, buf,

				      size, flags);

		err = __bpf_get_stack(regs, NULL, trace, buf, size, flags);



		/* restore nr */

		trace->nr = nr;
@@ -718,8 +718,7 @@ BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, 
			goto clear;



		flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip;

		err = __bpf_get_stack(ctx->regs, NULL, trace, buf,

				      size, flags);

		err = __bpf_get_stack(regs, NULL, trace, buf, size, flags);

	}

	return err;

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