Message ID | 20190716110550.19086-1-paul.durrant@citrix.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | mm.h: fix BUG_ON() condition in put_page_alloc_ref() | expand |
On 16.07.2019 13:05, Paul Durrant wrote: > The BUG_ON() was misplaced when this function was introduced in commit > ec83f825 "mm.h: add helper function to test-and-clear _PGC_allocated". > It will fire incorrectly if _PGC_allocated is already clear on entry. Thus > it should be moved after the if statement. > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> And indeed I should have noticed during review. Thanks. Reviewed-by: Jan Beulich <jbeulich@suse.com> and in it goes. Jan
diff --git a/xen/include/xen/mm.h b/xen/include/xen/mm.h index 5d0c19f011..cfea38f801 100644 --- a/xen/include/xen/mm.h +++ b/xen/include/xen/mm.h @@ -667,9 +667,11 @@ static inline void put_page_alloc_ref(struct page_info *page) * the caller holding an additional reference. I.e. the allocation * reference must never be the last reference held. */ - BUG_ON((page->count_info & PGC_count_mask) <= 1); if ( test_and_clear_bit(_PGC_allocated, &page->count_info) ) + { + BUG_ON((page->count_info & PGC_count_mask) <= 1); put_page(page); + } } #endif /* __XEN_MM_H__ */
The BUG_ON() was misplaced when this function was introduced in commit ec83f825 "mm.h: add helper function to test-and-clear _PGC_allocated". It will fire incorrectly if _PGC_allocated is already clear on entry. Thus it should be moved after the if statement. Signed-off-by: Paul Durrant <paul.durrant@citrix.com> --- Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: George Dunlap <George.Dunlap@eu.citrix.com> Cc: Ian Jackson <ian.jackson@eu.citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Julien Grall <julien.grall@arm.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Tim Deegan <tim@xen.org> Cc: Wei Liu <wl@xen.org> --- xen/include/xen/mm.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)