mm/vmalloc: fix wrong behavior in vread

commit f608788cd2d6 ("mm/vmalloc: use rb_tree instead of list for vread()
lookups") use rb_tree instread of list to speed up lookup, but function
__find_vmap_area is try to find a vmap_area that include target address,
if target address is smaller than the leftmost node in vmap_area_root, it
will return NULL, then vread will read nothing.  This behavior is
different from the primitive semantics.

The correct way is find the first vmap_are that bigger than target addr,
that is what function find_vmap_area_exceed_addr does.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: f608788cd2d6 ("mm/vmalloc: use rb_tree instead of list for vread() lookups")
Signed-off-by: Chen Wandun <[email protected]>
Reported-by: Hulk Robot <[email protected]>
Cc: Serapheim Dimitropoulos <[email protected]>
Cc: Uladzislau Rezki (Sony) <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Wei Yongjun <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions