On Sun, Jan 16, 2022 at 09:22:50AM -0300, Martin Pieuchot wrote: > IMHO this approach of let's try if it works now and revert if it isn't > doesn't help us make progress. I'd be more confident seeing diffs that > assert for the right lock in the functions called by uvm_mapanon() and > documentation about which lock is protecting which field of the data > structures.
I picked `vm_map's `size' as first underdocumented member. All accesses to it are protected by vm_map_lock(), either through the function itself or implicitly by already requiring the calling function to lock the map. So annotate functions using `size' wrt. the required lock. Index: uvm_map.c =================================================================== RCS file: /cvs/src/sys/uvm/uvm_map.c,v retrieving revision 1.282 diff -u -p -r1.282 uvm_map.c --- uvm_map.c 21 Dec 2021 22:21:32 -0000 1.282 +++ uvm_map.c 21 Jan 2022 13:03:05 -0000 @@ -805,6 +805,8 @@ uvm_map_sel_limits(vaddr_t *min, vaddr_t * Fills in *start_ptr and *end_ptr to be the first and last entry describing * the space. * If called with prefilled *start_ptr and *end_ptr, they are to be correct. + * + * map must be at least read-locked. */ int uvm_map_isavail(struct vm_map *map, struct uvm_addr_state *uaddr, @@ -2206,6 +2208,8 @@ uvm_unmap_kill_entry(struct vm_map *map, * If remove_holes, then remove ET_HOLE entries as well. * If markfree, entry will be properly marked free, otherwise, no replacement * entry will be put in the tree (corrupting the tree). + * + * map must be locked. */ void uvm_unmap_remove(struct vm_map *map, vaddr_t start, vaddr_t end, @@ -2976,6 +2980,9 @@ uvm_tree_sanity(struct vm_map *map, char UVM_ASSERT(map, addr == vm_map_max(map), file, line); } +/* + * map must be at least read-locked. + */ void uvm_tree_size_chk(struct vm_map *map, char *file, int line) { Index: uvm_map.h =================================================================== RCS file: /cvs/src/sys/uvm/uvm_map.h,v retrieving revision 1.71 diff -u -p -r1.71 uvm_map.h --- uvm_map.h 15 Dec 2021 12:53:53 -0000 1.71 +++ uvm_map.h 21 Jan 2022 12:51:26 -0000 @@ -272,7 +272,7 @@ struct vm_map { struct uvm_map_addr addr; /* [v] Entry tree, by addr */ - vsize_t size; /* virtual size */ + vsize_t size; /* [v] virtual size */ int ref_count; /* [a] Reference count */ int flags; /* flags */ struct mutex flags_lock; /* flags lock */