git: 3e4127f8f293 - stable/13 - netmap: fix issues in nm_os_extmem_create()

[Vincenzo Maffione]

The branch stable/13 has been updated by vmaffione:

URL: https://cgit.FreeBSD.org/src/commit/?id=3e4127f8f2933029034ac618a0013f434cb4a420

commit 3e4127f8f2933029034ac618a0013f434cb4a420
Author:     Vincenzo Maffione <vmaffione at FreeBSD.org>
AuthorDate: 2021-03-20 17:15:50 +0000
Commit:     Vincenzo Maffione <vmaffione at FreeBSD.org>
CommitDate: 2021-03-23 21:17:23 +0000

    netmap: fix issues in nm_os_extmem_create()
    
    - Call vm_object_reference() before vm_map_lookup_done().
    - Use vm_mmap_to_errno() to convert vm_map_* return values to errno.
    - Fix memory leak of e->obj.
    
    Reported by:    markj
    Reviewed by:    markj
    MFC after:      1 week
    
    (cherry picked from commit ee7ffaa2e6e08b63efb4673610875d40964d5058)
---
 sys/dev/netmap/netmap_freebsd.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/sys/dev/netmap/netmap_freebsd.c b/sys/dev/netmap/netmap_freebsd.c
index e37815dc88d5..2cedea4440fe 100644
--- a/sys/dev/netmap/netmap_freebsd.c
+++ b/sys/dev/netmap/netmap_freebsd.c
@@ -664,6 +664,7 @@ nm_os_vi_detach(struct ifnet *ifp)
 
 #ifdef WITH_EXTMEM
 #include <vm/vm_map.h>
+#include <vm/vm_extern.h>
 #include <vm/vm_kern.h>
 struct nm_os_extmem {
 	vm_object_t obj;
@@ -726,17 +727,18 @@ nm_os_extmem_create(unsigned long p, struct nmreq_pools_info *pi, int *perror)
 			&obj, &index, &prot, &wired);
 	if (rv != KERN_SUCCESS) {
 		nm_prerr("address %lx not found", p);
+		error = vm_mmap_to_errno(rv);
 		goto out_free;
 	}
+	vm_object_reference(obj);
+
 	/* check that we are given the whole vm_object ? */
 	vm_map_lookup_done(map, entry);
 
-	// XXX can we really use obj after releasing the map lock?
 	e->obj = obj;
-	vm_object_reference(obj);
-	/* wire the memory and add the vm_object to the kernel map,
-	 * to make sure that it is not fred even if the processes that
-	 * are mmap()ing it all exit
+	/* Wire the memory and add the vm_object to the kernel map,
+	 * to make sure that it is not freed even if all the processes
+	 * that are mmap()ing should munmap() it.
 	 */
 	e->kva = vm_map_min(kernel_map);
 	e->size = obj->size << PAGE_SHIFT;
@@ -745,12 +747,14 @@ nm_os_extmem_create(unsigned long p, struct nmreq_pools_info *pi, int *perror)
 			VM_PROT_READ | VM_PROT_WRITE, 0);
 	if (rv != KERN_SUCCESS) {
 		nm_prerr("vm_map_find(%zx) failed", (size_t)e->size);
+		error = vm_mmap_to_errno(rv);
 		goto out_rel;
 	}
 	rv = vm_map_wire(kernel_map, e->kva, e->kva + e->size,
 			VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
 	if (rv != KERN_SUCCESS) {
 		nm_prerr("vm_map_wire failed");
+		error = vm_mmap_to_errno(rv);
 		goto out_rem;
 	}
 
@@ -760,9 +764,9 @@ nm_os_extmem_create(unsigned long p, struct nmreq_pools_info *pi, int *perror)
 
 out_rem:
 	vm_map_remove(kernel_map, e->kva, e->kva + e->size);
-	e->obj = NULL;
 out_rel:
 	vm_object_deallocate(e->obj);
+	e->obj = NULL;
 out_free:
 	nm_os_free(e);
 out: