Andrew, since you had picked the similar one which also depends on ASSERT_EXCLUSIVE_*, can you pick up this patch as well? On Thu, 2020-02-13 at 13:20 -0800, John Hubbard wrote: > On 2/13/20 10:38 AM, Qian Cai wrote: > > BUG: KCSAN: data-race in page_cpupid_xchg_last / put_page > > > > write (marked) to 0xfffffc0d48ec1a00 of 8 bytes by task 91442 on cpu 3: > > page_cpupid_xchg_last+0x51/0x80 > > page_cpupid_xchg_last at mm/mmzone.c:109 (discriminator 11) > > wp_page_reuse+0x3e/0xc0 > > wp_page_reuse at mm/memory.c:2453 > > do_wp_page+0x472/0x7b0 > > do_wp_page at mm/memory.c:2798 > > __handle_mm_fault+0xcb0/0xd00 > > handle_pte_fault at mm/memory.c:4049 > > (inlined by) __handle_mm_fault at mm/memory.c:4163 > > handle_mm_fault+0xfc/0x2f0 > > handle_mm_fault at mm/memory.c:4200 > > do_page_fault+0x263/0x6f9 > > do_user_addr_fault at arch/x86/mm/fault.c:1465 > > (inlined by) do_page_fault at arch/x86/mm/fault.c:1539 > > page_fault+0x34/0x40 > > > > read to 0xfffffc0d48ec1a00 of 8 bytes by task 94817 on cpu 69: > > put_page+0x15a/0x1f0 > > page_zonenum at include/linux/mm.h:923 > > (inlined by) is_zone_device_page at include/linux/mm.h:929 > > (inlined by) page_is_devmap_managed at include/linux/mm.h:948 > > (inlined by) put_page at include/linux/mm.h:1023 > > wp_page_copy+0x571/0x930 > > wp_page_copy at mm/memory.c:2615 > > do_wp_page+0x107/0x7b0 > > __handle_mm_fault+0xcb0/0xd00 > > handle_mm_fault+0xfc/0x2f0 > > do_page_fault+0x263/0x6f9 > > page_fault+0x34/0x40 > > > > Reported by Kernel Concurrency Sanitizer on: > > CPU: 69 PID: 94817 Comm: systemd-udevd Tainted: G W O L 5.5.0-next-20200204+ #6 > > Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 > > > > A page never changes its zone number. The zone number happens to be > > stored in the same word as other bits which are modified, but the zone > > number bits will never be modified by any other write, so it can accept > > a reload of the zone bits after an intervening write and it don't need > > to use READ_ONCE(). Thus, annotate this data race using > > ASSERT_EXCLUSIVE_BITS() to also assert that there are no concurrent > > writes to it. > > > > Suggested-by: Marco Elver <elver@xxxxxxxxxx> > > Signed-off-by: Qian Cai <cai@xxxxxx> > > --- > > > > v2: use ASSERT_EXCLUSIVE_BITS(). > > > Much cleaner, thanks to this new macro. You can add: > > > Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx> > > > thanks,
