Merge branch 'introduce bpf_find_vma'

Song Liu says:

====================

Changes v4 => v5:
1. Clean up and style change in 2/2. (Andrii)

Changes v3 => v4:
1. Move mmap_unlock_work to task_iter.c to fix build for .config without
   !CONFIG_PERF_EVENTS. (kernel test robot <[email protected]>)

Changes v2 => v3:
1. Avoid using x86 only function in selftests. (Yonghong)
2. Add struct file and struct vm_area_struct to btf_task_struct_ids, and
   use it in bpf_find_vma and stackmap.c. (Yonghong)
3. Fix inaccurate comments. (Yonghong)

Changes v1 => v2:
1. Share irq_work with stackmap.c. (Daniel)
2. Add tests for illegal writes to task/vma from the callback function.
   (Daniel)
3. Other small fixes.

Add helper bpf_find_vma. This can be used in some profiling use cases. It
might also be useful for LSM.
====================

Signed-off-by: Alexei Starovoitov <[email protected]>

2 files changed, 21 insertions, 0 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 2be6dfd68df9..df3410bff4b0 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2157,6 +2157,7 @@ extern const struct bpf_func_proto bpf_btf_find_by_name_kind_proto;
 extern const struct bpf_func_proto bpf_sk_setsockopt_proto;
 extern const struct bpf_func_proto bpf_sk_getsockopt_proto;
 extern const struct bpf_func_proto bpf_kallsyms_lookup_name_proto;
+extern const struct bpf_func_proto bpf_find_vma_proto;
 
 const struct bpf_func_proto *tracing_prog_func_proto(
   enum bpf_func_id func_id, const struct bpf_prog *prog);
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index ba5af15e25f5..509eee5f0393 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4938,6 +4938,25 @@ union bpf_attr {
  *		**-ENOENT** if symbol is not found.
  *
  *		**-EPERM** if caller does not have permission to obtain kernel address.
+ *
+ * long bpf_find_vma(struct task_struct *task, u64 addr, void *callback_fn, void *callback_ctx, u64 flags)
+ *	Description
+ *		Find vma of *task* that contains *addr*, call *callback_fn*
+ *		function with *task*, *vma*, and *callback_ctx*.
+ *		The *callback_fn* should be a static function and
+ *		the *callback_ctx* should be a pointer to the stack.
+ *		The *flags* is used to control certain aspects of the helper.
+ *		Currently, the *flags* must be 0.
+ *
+ *		The expected callback signature is
+ *
+ *		long (\*callback_fn)(struct task_struct \*task, struct vm_area_struct \*vma, void \*callback_ctx);
+ *
+ *	Return
+ *		0 on success.
+ *		**-ENOENT** if *task->mm* is NULL, or no vma contains *addr*.
+ *		**-EBUSY** if failed to try lock mmap_lock.
+ *		**-EINVAL** for invalid **flags**.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -5120,6 +5139,7 @@ union bpf_attr {
 	FN(trace_vprintk),		\
 	FN(skc_to_unix_sock),		\
 	FN(kallsyms_lookup_name),	\
+	FN(find_vma),			\
 	/* */
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper